Journal Cover Journal of Applied Ecology
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   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0021-8901 - ISSN (Online) 1365-2664
   Published by John Wiley and Sons Homepage  [1580 journals]
  • Enhanced ecosystem functioning following stream restoration: the roles of
           habitat heterogeneity and invertebrate species traits
    • Authors: André Frainer; Lina E. Polvi, Roland Jansson, Brendan G. McKie
      Abstract: 1.Habitat restoration is increasingly undertaken in degraded streams and rivers to help improve biodiversity and ecosystem functioning. Follow-up assessments focused on outcomes for biodiversity have often found scant evidence for recovery, thus raising concerns about the efficacy of habitat restoration for improving ecological integrity. However, responses of other ecological variables, such as ecosystem process rates and the functional trait composition of biological assemblages, have been little assessed.2.We assessed how the restoration of habitat heterogeneity affected multiple functional parameters in 20 boreal stream reaches encompassing both more and less extensively restored sites, as well as channelised and natural reference sites. We further assessed relationships between our functional parameters and a fluvial geomorphic measure of habitat heterogeneity.3.Leaf decomposition was positively related to habitat heterogeneity. This was associated with shifts in the functional composition of detritivore assemblages, with the most obligate litter consumers more prominent in reaches showing higher habitat heterogeneity. The deposition of fine particulate organic matter was consistently higher in restored than channelised sites, and was positively related to the heterogeneity gradient. Algal biomass accrual per unit area did not vary either with restoration or the heterogeneity gradient.4.Synthesis and applications. Our findings demonstrate that restoration of river habitat heterogeneity can enhance retention and decomposition of organic matter, key ecosystem processes underpinning ecosystem functioning and service delivery. Significantly, enhanced litter decomposition was linked with a change in the functional composition rather than diversity of detritivore assemblages. Future evaluation of the success of habitat restorations should incorporate quantification of ecosystem processes and the functional traits of biota, in addition to measures of fluvial geomorphology and the more traditional biotic metrics, to facilitate a more comprehensive and mechanistic assessment of ecological responses.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-28T11:48:59.740118-05:
      DOI: 10.1111/1365-2664.12932
  • Top soil removal reduces water pollution from phosphorus and dissolved
           organic matter and lowers methane emissions from rewetted peatlands
    • Authors: Dominik Zak; Tobias Goldhammer, Alavaro Cabezas, Jörg Gelbrecht, Robert Gurke, Carola Wagner, Hendrik Reuter, Jürgen Augustin, Agata Klimkowska, Robert McInnes
      Abstract: 1.A valid strategy to mitigate the eutrophication of water bodies due to non-point source phosphorus (P) pollution and to reduce the emissions of greenhouse gases is the rewetting of degraded peatlands. However, long-term drainage and intensive agricultural use make it unlikely that the original sink functions for nutrients and carbon (C) as well as low-nutrient conditions can be re-established within a human time perspective.2.We hypothesised that the removal of the upper degraded peat layer can be a suitable measure to avoid the negative implications of excess mobilisation of P and C after rewetting. To evaluate the effect of top soil removal (TSR) we performed lab and field experiments in six inundated peatlands in northern Germany without TSR compared to six inundated sites with TSR. In addition we included data from a rewetted peatland where the degraded peat had been removed from about half of the area and groundwater level was just beneath the soil surface.3.The results emphasized that following inundation newly formed detritus mud layers overlying the former peat surface are the dominating source for P and methane in particular in sites without TSR but also in sites with TSR, although at significantly lower rates. Although highly decomposed peat released more or less no methane, dissolved organic matter (DOM) mobilisation was highest in this substrate while less decomposed peat was characterized in general by lowest rates of mobilisation.4.Synthesis and applications. In conclusion, top soil removal (TSR) prior to rewetting can be a suitable method to avoid the negative consequences of the excess release of phosphorus (P) and carbon post-rewetting. We developed a simple decision–support schematic to assist the peatland restoration process and to understand better the implications of TSR. Despite the potential benefits TSR should not be declared as a universal method, as it requires detailed consideration prior to application. However, this and other research demonstrate that it is inevitable that without any further management interventions high mobilisation of P, dissolved organic matter and methane may persist for centuries following rewetting of peatlands.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-28T11:07:12.262876-05:
      DOI: 10.1111/1365-2664.12931
  • Artificial light at night alters grassland vegetation species composition
           and phenology
    • Authors: Jonathan Bennie; Thomas W Davies, David Cruse, Fraser Bell, Kevin J Gaston
      Abstract: 1.Human settlements and transport networks are growing rapidly worldwide. Since the early 20th Century their expansion has been accompanied by increasing illumination of the environment at night, a trend that is likely to continue over the decades to come. Consequently, a growing proportion of the world's ecosystems are exposed to artificial light at night, profoundly altering natural cycles of light and darkness. While in recent years there have been advances in our understanding of the effects of artificial light at night on the behaviour and physiology of animals in the wild, much less is known about the impacts on wild plants and natural or semi-natural vegetation composition. This is surprising, as effects of low-intensity light at night on flowering, phenology and growth form are well known in laboratory and greenhouse studies.2.In a long-term experimental field study we exposed a semi-natural grassland to artificial light at intensities and wavelengths typical of those experienced by roadside vegetation under street lighting.3.We found that lighting affected the trajectory of vegetation change, leading to significant differences in biomass and plant cover in the dominant species.4.Changes in flowering phenology were variable between years, with grass species flowering between 4 days earlier and 12 days later under artificial light.5.Policy implications. Our results demonstrate that artificial light, at levels equivalent to those in street-lit environments, can affect species composition in semi-natural vegetation. This highlights the importance of considering artificial light as a driver of vegetation change in urban, suburban and semi-natural ecosystems, and where possible of minimising or excluding artificial light from habitats of conservation importance.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-28T10:50:22.139219-05:
      DOI: 10.1111/1365-2664.12927
  • Integrating local knowledge and research to refine the management of an
           invasive non-native grass in critically endangered grassy woodlands
    • Authors: Jennifer Firn; Emma Ladouceur, Josh Dorrough
      Abstract: 1.Globally the prevalence and impact of invasive non-native plant species is increasing rapidly. Experimentally-based research aimed at supporting management is limited in its ability to keep up with this pace, partly because of the importance of understanding historical abiotic and biotic conditions. Contrastingly, landholders are in unique positions to witness species turnover in grasslands, adapt management practices in response, and learn from successes and failures.2.This local knowledge could be crucial for identifying feasible solutions to land degradation, and ecological restoration, but local knowledge is rarely explicitly embedded in ecological research.3.In this study, we use a sequential exploratory strategy where we first interview (semi-directive approach) 15 landholders within the Bega region of New South Wales, Australia concerning the changing ecological characteristics of both extensively and intensively managed grassy woodlands and perceived impacts following arrival of the invasive exotic introduced species, African lovegrass, Eragrostis curvula.4.Based on the results of these interviews, we then conducted a field study where we tested seven landholder-generated hypotheses at 57 sites.5.The field study validated many of the landholder management perceptions including: African lovegrass was negatively correlated with species richness, canopy cover and dominant grasses like Themeda trianda. Mechanical slashing increased exotic African lovegrass abundance. The prevalence of African lovegrass in the soil seed bank was positively correlated with its abundance aboveground. Study observations that contradicted landholder perceptions included: African lovegrass was not more palatable nor did its’ abundance decline in response to increasing soil fertility. Spot spraying with herbicides was effective at controlling abundance, despite its reputation as ineffective. Landholder observations also highlighted key hypotheses concerning modes of spread that require long-term studies including the roles of drought and overgrazing.6.Synthesis and applications. Overall, we found local knowledge coupled with scientific methods can act in tandem as a highly effective approach for developing management recommendations. This approach identifies local perceptions that are not substantiated by scientific data to halt potentially harmful practices, and observations that are insightful predictions about the dynamics and impacts of non-native species that need long-term experiments to corroborate scientifically.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-28T10:50:19.09511-05:0
      DOI: 10.1111/1365-2664.12928
  • Managing trap-nesting bees as crop pollinators: spatiotemporal effects of
           floral resources and antagonists
    • Authors: Matteo Dainese; Verena Riedinger, Andrea Holzschuh, David Kleijn, Jeroen Scheper, Ingolf Steffan-Dewenter
      Abstract: 1.The decline of managed honeybees and the rapid expansion of mass-flowering crops increase the risk of pollination limitation in crops and raise questions about novel management approaches for wild pollinators in agroecosystems. Adding artificial nesting sites, such as trap nests, can promote cavity-nesting bees in agroecosystems, but effectiveness could be limited by the availability of floral resources in the surrounding landscape and by natural antagonists.2.In two European regions, we exposed artificial trap nests in paired field boundaries adjacent to oilseed rape (OSR) fields or non-flowering crops for two years within 32 landscapes covering two independent gradients of OSR cover and semi-natural habitat (SNH) cover in the landscape. We analysed the effects of local and landscape-wide floral resource availability, land-use intensity, landscape complexity and natural antagonists on community composition and population dynamics of trap-nesting bees.3.Number of brood cells showed a strong, three-fold increase in response to the additional nesting sites. Species richness and abundance of cavity-nesting bees that were active during OSR flowering increased significantly with increasing amount of early-season landscape-wide floral resource availability, such as the cultivation of OSR. Later foraging species benefited instead from the availability of late-season alternative flower resources or SNH cover once the mass-flowering had ceased. Density-dependent parasitism increased following mass-flowering, while no density-dependent effect was found during mass-flowering.4.Structural equation modelling revealed that the influence of floral resource availability on community growth rate was mediated by community size. Community size showed a strong negative effect on community growth rate. Despite positive density-dependent parasitism, antagonists had only weak regulating effects on community growth rate.5.Synthesis and applications. Trap-nesting bee populations grow markedly with the increasing availability of food resources in the landscape and effectiveness of trap nests is only marginally limited by natural antagonists. Thus, trap nests could be a simple pollinator-supporting strategy to accompany the current expansion of mass-flowering crops, and to ensure pollination services for insect-pollinated crops. Trap nests benefit not only early season active generalist bees during oilseed rape flowering but also species with later phenology if accompanied by other pollinator-supporting practices.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-28T10:30:36.924492-05:
      DOI: 10.1111/1365-2664.12930
  • Seals and shipping: quantifying population risk and individual exposure to
           vessel noise
    • Authors: Esther L. Jones; Gordon D. Hastie, Sophie Smout, Joseph Onoufriou, Nathan D. Merchant, Kate L. Brookes, David Thompson
      Abstract: Vessels can have acute and chronic impacts on marine species. The rate of increase in commercial shipping is accelerating, and there is a need to quantify and potentially manage the risk of these impacts.Usage maps characterising densities of grey and harbour seals and ships around the British Isles were used to produce risk maps of seal co-occurrence with shipping traffic. Acoustic exposure to individual harbour seals was modelled in a study area using contemporaneous movement data from 28 animals fitted with UHF global positioning satellite telemetry tags and automatic identification system data from all ships during 2014 and 2015. Data from four acoustic recorders were used to validate sound exposure predictions.Across the British Isles, rates of co-occurrence were highest within 50 km of the coast, close to seal haul-outs. Areas identified with high risk of exposure included 11 Special Areas of Conservation (SAC; from a possible 25). Risk to harbour seal populations was highest, affecting half of all SACs associated with the species.Predicted cumulative sound exposure level, cSELs(Mpw), over all seals was 176·8 dB re 1 μPa2 s (95% CI 163·3–190·4), ranging from 170·2 dB re 1μPa2 s (95% CI 168·4–171·9) to 189·3 dB re 1 μPa2 s (95% CI 172·6–206·0) for individuals. This represented an increase in 28·3 dB re 1 μPa2 s over measured ambient noise. For 20 of 28 animals in the study, 95% CI for cSELs(Mpw) had upper bounds above levels known to induce temporary threshold shift. Predictions of broadband received sound pressure levels were underestimated on average by 0·7 dB re 1 μPa (±3·3).Synthesis and applications. We present a framework to allow shipping noise, an important marine anthropogenic stressor, to be explicitly incorporated into spatial planning. Potentially sensitive areas are identified through quantifying risk to marine species of exposure to shipping traffic, and individual noise exposure is predicted with associated uncertainty in an area with varying rates of co-occurrence. The detailed approach taken here facilitates spatial planning with regard to underwater noise within areas protected through the Habitats Directive, and could be used to provide evidence for further designations. This framework may have utility in assessing whether underwater noise levels are at Good Environmental Status under the Marine Strategy Framework Directive.
      PubDate: 2017-04-28T01:15:41.056214-05:
      DOI: 10.1111/1365-2664.12911
  • Effects of shoreline armouring and overwater structures on coastal and
           estuarine fish: opportunities for habitat improvement
    • Authors: Stuart H. Munsch; Jeffery R. Cordell, Jason D. Toft
      Abstract: Nearshore ecosystems are increasingly recognized as critical habitats for fish of cultural, ecological and economic significance. These ecosystems are often densely inhabited by juvenile fish, highly productive and refuges from predation, leading ecologists to characterize them as nurseries. However, nearshore ecosystems are being transformed globally to support demands of growing coastal populations. Many shorelines are modified by armouring (e.g. seawalls, riprap) that minimizes erosion, and overwater structures (e.g. piers, docks) that facilitate waterfront use. These modifications affect the ecology of nearshore systems by restructuring, eliminating and shading shallow waters.Here, we review literature examining effects of armouring and overwater structures on coastal and estuarine fishes, and discuss how research and management can coordinate to minimize negative effects.Along armoured shorelines, fish assemblages differed from unarmoured sites, fish consumed less epibenthic and terrestrial prey, beach spawning was less successful and fish were larger. Under large overwater structures, visually oriented fish were less abundant and they fed less. Shade from overwater structures also interrupted localized movements of migratory fish. Thus, shoreline modifications impaired habitats by limiting feeding, reproduction, ontogenetic habitat shifts from shallow to deeper waters and connectivity.Research suggests that restoring shallow waters and substrate complexity, and minimizing shading underneath overwater structures, can rehabilitate habitats compromised by shoreline modifications.Synthesis and applications. Shoreline armouring and overwater structures often compromise fish habitats. These threats to nearshore fish habitats will become more severe as growing coastal populations and rising sea levels increase demands for shoreline infrastructure. Our ability to assess and rehabilitate nearshore fish habitats along modified shorelines will be enhanced by: focusing research attention on metrics that directly indicate fish habitat quality; implementing and evaluating shoreline features that repair compromised habitat functions within human-use constraints; collating natural history knowledge of nearshore ecosystems; and embracing the socio-ecological nature of habitat improvements by educating the public about conservation efforts and fostering appreciation of local nearshore ecosystems. Actions to reduce impacts of shoreline modifications on fish are particularly feasible when they align with societal goals, such as improving flood protection and providing spaces that facilitate recreation, education, and connections between people and nature.
      PubDate: 2017-04-24T01:05:56.881314-05:
      DOI: 10.1111/1365-2664.12906
  • Single-visit dynamic occupancy models: An approach to account for
           imperfect detection with Atlas data
    • Authors: Michelle A. Peach; Jonathan B. Cohen, Jacqueline L. Frair
      Abstract: 1.Atlas data provide biodiversity information at a relatively fine spatial grain over a broad spatial extent and, increasingly, at multiple points in time, which make them invaluable for understanding processes that affect species distributions over time. The effect of survey effort on species detection has long been appreciated and Atlases typically include survey standards and records of effort, but challenges remain in analysing Atlas data that has not been collected using a repeated sampling protocol designed to correct for imperfect detection.2.We developed a single-visit dynamic occupancy model to quantify the effects of climatic and land-use drivers on local species extinction and colonization while accounting for imperfect detection using repeat Atlas data. We evaluated model stability using data simulated under alternative scenarios and, ultimately, applied the model to empirical data for Canada warbler Cardellina canadensis, a wide-spread species exhibiting a long-term population decline.3.At sample sizes that are realistic for many Atlases (n=1000–10 000 independent survey blocks), our models produced unbiased estimates of detection, occupancy, colonization and extinction parameters. Slope estimates for explanatory covariates were somewhat less stable than overall occupancy, colonization and extinction rates, with covariate effects being sensitive to the total number of, and relationships among, explanatory variables.4.In comparison to other analyses of Canada warbler distributions that indicated minor changes over time, our approach identified a widespread decline in occupancy probability across New York, consistent with the broader population trend, particularly in the areas where it was initially more likely to occur.5.Synthesis and applications. A single-visit dynamic occupancy model is a novel method for analysing common, ecologically valuable datasets, such as Atlases, that lack repeated sampling necessary to correct for imperfect detection using alternative multi-season occupancy modelling approaches. As a result, using this method can improve understanding of species distributions and factors that shape them over time, thereby providing more accurate information to guide conservation and management.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-22T03:15:28.063335-05:
      DOI: 10.1111/1365-2664.12925
  • Forest restoration as a double-edged sword: the conflict between
           biodiversity conservation and pest control
    • Authors: Simon Kärvemo; Christer Björkman, Therese Johansson, Jan Weslien, Joakim Hjältén
      Abstract: Forestry has markedly changed a large proportion of the world's boreal forests, often with negative effects on biodiversity. As a result, forest restoration is increasingly implemented to counteract the negative effects. However, restoration measures aimed at mimicking natural disturbance regimes could simultaneously increase the risk of unwanted negative effects, such as damage by forest pest species. This study compares the effect of two restoration methods (prescribed burning and gap-cutting), on both biodiversity conservation and pest control, to provide a basis for solutions to this potential conflict.Bark beetles are ideal for studying this conflict, as this group is both species-rich and contains notorious pest species. We conducted a unique, large-scale field experiment in which we compared the effect of two different restoration methods on the abundance, species richness and assemblage composition of bark beetles. In addition, we estimated uncontrolled tree mortality by the number of trees that died post-restoration.Beetles were divided in two groups, primary and secondary, the former with an ability to kill growing trees. Bark beetle diversity did not differ between treatment groups prior to restoration. However, after restoration, assemblage composition and primary bark beetle abundance differed between the treatments. Furthermore, species richness was higher in burned and gap-cut stands compared to reference stands.The number of trees that died post-restoration was highest on burned sites, whereas no difference was found between gap-cut and reference stands. The number of dead trees was correlated with the number of primary beetles.Synthesis and applications. We demonstrate the potential for a conflict between forest restoration for biodiversity conservation and the potential risk for tree mortality caused by forest pests. This is likely to become a problem in many boreal forests; however, our results suggest that this conflict can be moderated by the choice of restoration method. The restoration method gap-cutting had a similar positive impact on bark beetle species richness as compared to the burning method, but did not as burning, increase tree mortality. Thus, in areas where there is an apparent risk for pest outbreaks, our data suggest that gap-cutting should be the chosen method to avoid an unwanted increase in tree mortality at the stand level.
      PubDate: 2017-04-21T01:08:00.551688-05:
      DOI: 10.1111/1365-2664.12905
  • Remnant vegetation, plantings, and fences are beneficial for reptiles in
           agricultural landscapes
    • Authors: Stephanie A. Pulsford; Don A. Driscoll, Philip S. Barton, David B. Lindenmayer
      Abstract: Managing agricultural landscapes for biodiversity conservation is increasingly difficult as land use is modified or intensified for production. Finding ways to mitigate the negative effects of agriculture on biodiversity is therefore critical. We asked the question: How do remnant patches, paddock types and grazing regimes influence reptile assemblages in a grazing landscape?At 12 sites, we surveyed reptiles and environmental covariates in remnant woodland patches and in four paddock types: a) grazed pasture, b) linear plantings, c) coarse woody debris added to grazed pasture and d) fences between grazed pasture. Each site was either continuously or rotationally grazed.Remnant vegetation and other vegetation attributes such as tree cover and leaf litter greatly influenced reptiles. We recorded higher reptile abundance and species richness in areas with more tree cover and leaf litter. For rare species (captured in ≤4 sites
      PubDate: 2017-04-20T12:20:00.218777-05:
      DOI: 10.1111/1365-2664.12923
  • Dispersal and establishment limitation slows plant community recovery in
           post-agricultural longleaf pine savannas
    • Authors: Nash E. Turley; John L. Orrock, Joseph A. Ledvina, Lars A. Brudvig
      Abstract: Abandoned agricultural lands often have distinct plant communities from areas with no history of agriculture because plant species fail to recolonize. This may be due to dispersal limitation from a lack of seeds, or establishment limitation because of unsuitable environmental conditions. However, few experiments have directly tested how restoration activities may overcome these limitations.We studied longleaf pine savannas in South Carolina abandoned from agriculture >60 years ago that were immediately adjacent to remnant habitats (areas with no history of agriculture). Using 27 sites, we conducted a factorial experiment that sowed seeds of 12 species indicative of remnant communities and conducted restoration thinning of overstorey trees in half of 126, 1-ha patches to mimic canopy density of natural savannas. We also established vegetation transects to examine if restoration promotes spread of remnant species into post-agricultural areas.We found strong evidence for dispersal limitation in post-agricultural areas as over 99% of the occurrences of our focal species were in seed addition plots. Seed additions increased total species richness by 27%.Restoration thinning increased establishment in seed addition plots (measured as richness of sown species) by 126% and increased total richness by 88%. Restoration thinning also increased seed production in remnant habitats by an average of 6506% across our focal species. However, after 4 years, restoration thinning did not facilitate the natural spread of remnant species into adjacent post-agricultural sites.Synthesis and applications. We show that both dispersal and establishment limitation are key factors causing some plant species to be absent from post-agricultural sites. Dense canopy conditions limit seed production in remnant habitats and reduce establishment in post agricultural areas. Restoration thinning helps overcome these limitations and should facilitate the natural spread of species from remnant habitats but natural recovery may still be slow. Our results suggest that accelerating the recovery of post-agricultural habitats will require active restoration that reduces dispersal limitation (seed additions) and reinstates appropriate ecological conditions.
      PubDate: 2017-04-13T02:35:22.697306-05:
      DOI: 10.1111/1365-2664.12903
  • Effects of deer on woodland structure revealed through terrestrial laser
    • Authors: Markus P. Eichhorn; Joseph Ryding, Martin J. Smith, Robin M. A. Gill, Gavin M. Siriwardena, Robert J. Fuller
      Abstract: Terrestrial laser scanning (TLS) captures the three-dimensional structure of habitats. Compared to traditional methods of forest mensuration, it allows quantification of structure at increased resolution, and the derivation of novel metrics with which to inform ecological studies and habitat management.Lowland woodlands in the UK have altered in structure over the last century due to increased abundance of deer and a decline in management. We compared whole-canopy profiles between woodlands with high (>10 deer km−2) and low deer density (c. 1 deer km−2), and in stands with and without records of management interventions in the last 20 years, providing a test case for the application of TLS in habitat assessment for conservation and management.Forty closed-canopy lowland woodlands (height range 16·5–29·4 m) were surveyed using TLS in two regions of the UK, divided into areas of high- and low-deer abundance, and between plots which had been recently managed or were unmanaged. Three-dimensional reconstructions of the woodlands were created to document the density of foliage and stem material across the entire vertical span of the canopy.There was a 68% lower density of understorey foliage (0·5–2 m above-ground) in high-deer woodlands, consistent in both regions. Despite this, total amounts of foliage detected across the full canopy did not differ between deer density levels. High-deer sites were 5 m taller overall and differed in the distribution of foliage across their vertical profile. Managed woodlands, in contrast, exhibited relatively minor differences from controls, including a lower quantity of stem material at heights from 2 to 5 m, but no difference in foliage density. All main effects were replicated equally in both regions despite notable differences in stand structures between them.Synthesis and applications. Terrestrial laser scanning allows ecologists to move beyond two-dimensional measures of vegetation structure and quantify patterns across complex, heterogeneous, three-dimensional habitats. Our findings suggest that reduction of deer populations is likely to have a strong impact on woodland structures and aid in restoring the complex understorey habitats required by many birds, whereas management interventions as currently practiced have limited and inconsistent effects.
      PubDate: 2017-04-11T01:01:02.945168-05:
      DOI: 10.1111/1365-2664.12902
  • Plant traits of propagule banks and standing vegetation reveal flooding
           alleviates impacts of agriculture on wetland restoration
    • Authors: S.K. Dawson; D.I. Warton, R.T. Kingsford, P. Berney, D.A. Keith, J.A. Catford
      Abstract: 1.Restoration of degraded plant communities requires understanding of community assembly processes. Human land use can influence plant community assembly by altering environmental conditions and species’ dispersal patterns. Flooding, including from environmental flows, may counteract land use effects on wetland vegetation. We examined the influence of land use history and flood frequency on the functional composition of wetland plant communities along a regulated river.2.We applied fourth corner modelling to determine species’ trait-based responses to flooding and land use by combining data on i) the occupancy and abundance of species in propagule banks and standing vegetation, ii) species traits, and iii) environmental conditions of 22 standing vegetation and 108 soil propagule bank study sites. We used analysis of deviance to test how well each dataset characterised trait–environment interactions, and generalised linear models to identify traits related to species’ responses.3.The occupancy and abundance of native species in the propagule bank and standing vegetation increased with flood frequency and decreased with duration of agricultural land use. Species in standing vegetation with water-borne propagule dispersal (hydrochory) showed similar trends. In contrast, species with higher specific leaf area were associated with longer land use duration.4.Identifying trait–based differences in the propagule bank and standing vegetation can help disentangle effects of dispersal and environmental filters. The occupancy and abundance of hydrochorous species in standing vegetation were negatively related to land use duration, but hydrochorous species were positively related to land use duration based on their abundance in the propagule bank. This suggests that land use does not limit plant dispersal, but acts as an in situ abiotic filter limiting species presence in standing vegetation.5.Synthesis and applications. Land use duration and flood frequency have opposite effects on plant community traits in floodplain wetlands of the Macquarie Marshes, Australia. Legacies of agriculture can impede restoration of plant communities. Environmental flows that increase flooding may alleviate these impacts, especially in areas that have been used for agriculture for over 20 years, by providing dispersal and environmental filters that favour native wetland species. More flooding will likely be required to restore floodplains with longer histories of agricultural land use compared to floodplains less impacted by agriculture.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-10T09:20:52.603992-05:
      DOI: 10.1111/1365-2664.12922
  • Safari Science: Assessing the reliability of citizen science data for
           wildlife surveys
    • Authors: Cara Steger; Bilal Butt, Mevin B. Hooten
      Abstract: 1.Protected areas are the cornerstone of global conservation, yet financial support for basic monitoring infrastructure is lacking in 60% of them. Citizen science holds potential to address these shortcomings in wildlife monitoring, particularly for resource-limited conservation initiatives in developing countries – if we can account for the reliability of data produced by volunteer citizen scientists (VCS).2.This study tests the reliability of VCS data vs. data produced by trained ecologists, presenting a hierarchical framework for integrating diverse datasets to assess extra variability from VCS data.3.Our results show that, while VCS data are likely to be overdispersed for our system, the overdispersion varies widely by species. We contend that citizen science methods, within the context of East African drylands, may be more appropriate for species with large body sizes, which are relatively rare, or those that form small herds. VCS perceptions of the charisma of a species may also influence their enthusiasm for recording it.4.Tailored program design (such as incentives for VCS) may mitigate the biases in citizen science data and improve overall participation. However, the cost of designing and implementing high quality citizen science programs may be prohibitive for the small protected areas that would most benefit from these approaches.5.Synthesis and applications. As citizen science methods continue to gain momentum, it is critical that managers remain cautious in their implementation of these programs while working to ensure methods match data purpose. Context-specific tests of citizen science data quality can improve program implementation, and separate data models should be used when volunteer citizen scientists’ variability differs from trained ecologists’ data. Partnerships across protected areas and between protected areas and other conservation institutions could help to cover the costs of citizen science program design and implementation.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-10T09:20:50.77086-05:0
      DOI: 10.1111/1365-2664.12921
  • Corrigendum
    • PubDate: 2017-04-09T00:05:36.256096-05:
      DOI: 10.1111/1365-2664.12913
  • Building partnerships with communities for biodiversity conservation:
           lessons from Asian mountains
    • Authors: Charudutt Mishra; Juliette Claire Young, Matthias Fiechter, Brad Rutherford, Stephen Mark Redpath
      Abstract: Applied ecology lies at the intersection of human societies and natural systems. Consequently, applied ecologists are constantly challenged as to how best to use ecological knowledge to influence the management of ecosystems (Habel et al. 2013). As Hulme (2011) has pointed out, to do so effectively we must leave our ivory towers and engage with stakeholders. This engagement is especially important and challenging in areas of the world where poverty, weak institutions and poor governance structures conspire to limit the ability of local communities to contribute to biodiversity conservation.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-07T06:45:46.859536-05:
      DOI: 10.1111/1365-2664.12918
  • Optimizing the spatial planning of prescribed burns to achieve multiple
           objectives in a fire-dependent ecosystem
    • Authors: Brooke A. Williams; Luke P. Shoo, Kerrie A. Wilson, Hawthorne L. Beyer
      Abstract: 1.There is potential for negative consequences for the ecological integrity of fire-dependent ecosystems as a result of inappropriate fire regimes. This can occur when asset (property) protection is prioritised over conservation objectives in burn programs.2.Optimisation of fire management for multiple objectives is rarely undertaken. Here, we use integer linear programming to identify burn scheduling solutions that will cost-effectively achieve asset protection and conservation objectives.3.An approach to burn scheduling that favours a risk-averse asset protection strategy results in poor conservation outcomes. Conversely, a conservation-focused approach achieves only modest asset protection benefits. However, when formulated as a multi-objective problem, good conservation outcomes can be realised with only a small reduction in potential benefits for asset protection.4.A conservation-focused approach resulted in substantially more heterogeneity in burns at multiple spatial scales and a marked reduction in mean time since fire among all forest patches relative to an asset protection scenario. This increase in heterogeneity improves ecological integrity, while the resulting reduction in fuel load is beneficial for asset protection.5.Synthesis and applications. Mathematical optimisation is a powerful framework for informing fire management that improves the prioritisation and scheduling of controlled burns to efficiently achieve management objectives. By quantifying the trade-offs that exist between the two competing objectives of conservation and asset protection we demonstrate that compromise solutions can be identified that achieve good outcomes for both objectives. In a transparent and equitable manner, we show that conservation value may be improved within a fire-dependent ecosystem with only modest concession to asset protection performance. Explicitly evaluating trade-offs among competing objectives enables managers to identify potentially undesirable outcomes, and facilitate development of preferred solutions. Heterogeneous burning under the auspices of conservation also has the potential to reduce overall fuel loads within the ecosystem and thus its value for asset protection is likely underappreciated.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-07T06:27:38.609316-05:
      DOI: 10.1111/1365-2664.12920
  • Negative effects of pesticides under global warming can be counteracted by
           a higher degradation rate and thermal adaptation
    • Authors: Lin Op de Beeck; Julie Verheyen, Kent Olsen, Robby Stoks
      Abstract: 1.An alarming finding for biodiversity is that global warming and pesticides often interact synergistically. Yet, this synergism may not capture the full picture because two counteracting processes may reduce the higher impact of pesticides under warming: higher pesticide degradation in the environment and thermal adaptation of populations.2.We tested for the effects of warming and multiple pulses of the insecticide chlorpyrifos on life history and fitness-related physiological traits in the damselfly Ischnura elegans. To assess whether thermal adaptation is able to mitigate the impact of the pesticide under future warming, we exposed replicated populations from a colder, high latitude and from a warmer, low latitude in a common garden rearing experiment at 20 and 24°C (the respective mean summer water temperatures at both latitudes).3.At the higher temperature pesticide degradation was higher, leading to less accumulation after multiple pulses compared to the lower temperature. Accordingly, the pesticide caused less mortality and less oxidative damage at the higher temperature. This contradicts the general belief (based on studies that kept pesticide concentrations constant) of a higher impact of pesticides under warming. Furthermore, the reduction of the impact of the pesticide at the higher temperature was more pronounced in the warm-adapted low-latitude populations, indicating a counteracting role of thermal adaptation.4.Policy implications. Our findings provide proof-of-principle for two key insights that will allow improving ecological risk assessment of pesticides under global warming: (i) higher pesticide degradation in the environment under warming may temper the impact of multiple pesticide pulses; (ii) gradual thermal evolution may further reduce the impact of pesticides at high latitudes under global warming. This knowledge can be very important for policy makers to arrive at a more realistic forecasting of the impacts of chemical pollution and climate change interactions on organisms.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-07T06:17:40.772128-05:
      DOI: 10.1111/1365-2664.12919
  • Constrained by markets: processing costs limit potential for managing
           predator–prey interactions in a commercial fishery
    • Authors: Timothy E. Walsworth; Daniel E. Schindler, Timothy E. Essington
      Abstract: Selective fisheries may impact non-target species as well as limit the productivity of target species if their predators are not harvested. The outcomes of multi-species harvest strategies that include targeting predators depend on ecological and economic constraints, although the development of ecosystem-based management plans has typically focused on ecological constraints.In Chignik, Alaska, sockeye salmon support a valuable commercial fishery and, as juveniles, are preyed upon by coho salmon, a species not subject to a targeted harvest. Whether exploitation of coho salmon would enhance overall fishery value by releasing sockeye salmon from predation constraints is not understood. We employ simulation models to examine the ecological and economic conditions necessary for directly targeting coho salmon to benefit fishers and seafood processors, two distinct but inter-dependent stakeholders in this ecosystem.Model results indicate fishers are likely to experience increased value regardless of economic constraints, as long as coho salmon predation negatively affects sockeye salmon productivity. However, seafood processors are much more limited in the conditions which produce increased economic value, constrained by greater operation costs required to process harvested coho salmon.Synthesis and applications. The unique economic constraints and opportunities of different stakeholders can present contrasting outlooks on the potential benefits of alternative harvest strategies, even if the alternative strategies are predicted to increase yield. The findings herein demonstrate the importance of considering multiple stakeholders when considering alternative management strategies. Depending on the level of risk stakeholders are willing to accept, an active adaptive management strategy reducing coho salmon escapement to low levels could provide valuable information about ecosystem structure as well as potentially providing the greatest economic benefit to the fishery.
      PubDate: 2017-04-06T07:03:11.631722-05:
      DOI: 10.1111/1365-2664.12900
  • A three decade assessment of climate-associated changes in forest
           composition across the north-eastern USA
    • Authors: Arun K. Bose; Aaron Weiskittel, Robert G. Wagner
      Abstract: 1.Climate-associated changes in forest composition have been widely reported, particularly where changes in abiotic conditions have resulted in high mortality of sensitive species and have disproportionately favoured certain species better adapted to these newer conditions. In the north-eastern USA and south-eastern Canada, few studies have examined climate-related influences associated with forest composition, and none have considered broad-scale changes over a long temporal (>25 years) period.2.We used US Forest Service Forest Inventory and Analysis data from 1983–2014 across four north-eastern states (Maine, New Hampshire, New York, and Vermont) to assess temporal and spatial changes in the occurrence and abundance of American beech Fagus grandifolia Ehrh, sugar maple Acer sacharum L., red maple A. rubrum L., and birch Betula spp. saplings. We also tested the effects of biotic and abiotic factors on the distribution of the four studied deciduous species over the entire period examined.3.Occurrence and abundance of American beech have increased substantially over the past three decades, whereas the occurrence and abundance of three other deciduous species have decreased in all ecological provinces of the north-eastern USA, except the Midwest Broadleaf ecological province. Consequently, a clear shift in species composition is currently underway in the beech-maple-birch (BMB) forests of the north-eastern USA, with uncertain consequences for future ecosystem structure and function.4.In the studied region and over the entire period examined, the distribution of increased occurrence and abundance of beech relative to the three other deciduous species were associated with higher temperature and precipitation as well as higher conspecific basal area and dead tree basal area.5.Synthesis and applications. The change from beech-maple-birch forests to more beech-dominated forests with beech encroachment to new forest areas across the north-eastern USA may continue if higher intensity harvesting and disturbances (i.e. large-scale canopy openings) do not occur. This would be a significant management concern as beech is associated with a widespread bark disease, is commercially less desirable, and can limit natural regeneration from other species. Our results emphasize the need for management strategies such as higher intensity harvesting methods, vegetation control, and limiting browsing pressure to reduce beech dominance.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T07:15:38.332429-05:
      DOI: 10.1111/1365-2664.12917
  • Holistic management of live animals confiscated from illegal wildlife
    • Authors: Thomas N.E. Gray; Nick Marx, Vuthyravong Khem, Dean Lague, Vincent Nijman, Suwanna Gauntlett
      Abstract: The illegal wildlife trade is one of the most pressing environmental issues globally and a substantial contributor to the Anthropocene extinction crisis (Nijman 2010). In response combatting wildlife trade has attracted considerable global political support and, between 2010 and 2016, approximately U.S. $1.3 billion in donor and governmental funding (Wright et al. 2016). Much of this momentum has focused on iconic megafauna – rhinoceros Rhinocerotidae, elephant Elephantidae, and tiger Panthera tigris– and the transcontinental trade between Africa and Asia (Wright et al. 2016).This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-03T22:50:28.479833-05:
      DOI: 10.1111/1365-2664.12916
  • Restoration of endangered fen communities: the ambiguity of
           iron-phosphorus binding and phosphorus limitation
    • Authors: W.-J. Emsens; C.J.S. Aggenbach, A.J.P. Smolders, D. Zak, R. van Diggelen
      Abstract: 1.Low phosphorus (P) availability limits plant biomass production in fens, which is a prerequisite for the persistence of many endangered plant species. We hypothesized that P limitation is linked to soil iron (Fe) content and soil Fe:P ratios as iron compounds provide binding sites for dissolved P, presumably reducing P availability to plants.2.We sampled 30 fens in a trans-European field survey to determine how soil Fe pools relate to pools of P and Fe-bound P, and we measured vegetation P uptake and N:P ratio to assess where P limitation occurs. Next, we determined P uptake by Carex rostrata in experimental fen mesocosms to investigate interactive effects of soil Fe- and P pools (and -NDASH-fractions) and water levels (drained or rewetted).3.The field survey revealed that soil P pools correlate positively with soil Fe pools, regardless of fen degradation level, location, or sampling depth. Moreover, soil Fe- and P pools correlated positively with P uptake by the vegetation and negatively with vegetation N:P ratios. Generally, N:P ratios dropped below 10 g g−1 whenever thresholds of 15 mmol Fe L−1 soil and 3.3 mmol P L−1 soil were exceeded. Endangered fen species mainly thrived in Fe- (and thus P-) poor fens.4.The mesocosm experiment further showed that interactions between water levels and P pools determined plant P uptake: although fen rewetting led to an overall increase in P uptake, plants that had grown on drained Fe-rich soils with large acid-extractable P pools (>1.6 mmol Pacid L−1) could still sequester large quantities of P. Soil Fe:P ratio had no effect on P uptake.5.Synthesis and applications. Our findings have important implications for the management and restoration of endangered fen communities. We demonstrated the existence of an iron-phosphorus (Fe-P) binding ambiguity in fens: large Fe pools “trap” mobile P, thereby enhancing overall P availability to plants rather than diminishing it. For P limitation we suggest an empirical threshold of < 3.3 mmol P L−1 soil, which is mainly found in Fe-poor fens. Restoring fens by rewetting increases the relative availability of P and may not always result in favourable conditions for endangered fen communities. Rewetting of drained fens is most likely to be successful if soil P and Fe pools are well below 3.3 mmol L−1 and 15 mmol L−1 respectively.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-03T22:50:27.554472-05:
      DOI: 10.1111/1365-2664.12915
  • Yield reductions in agricultural grasslands in Norway after springtime
           grazing by pink-footed geese
    • Authors: Anne Kari Bergjord Olsen; Jarle W. Bjerke, Ingunn M. Tombre
      Abstract: 1.A large population increase of the Svalbard-breeding pink-footed goose Anser brachyrhynchus over recent decades has intensified the conflict with agriculture at the spring-staging sites in Norway. Knowledge of the yield loss caused by goose grazing in these northern areas is lacking, and the motivation behind the study was to quantify a relationship between grazing pressure and yield loss of agricultural grasslands and corresponding changes in vegetation composition.2.Field trials were established on agricultural grasslands at four sites in central Norway. Eight plots were established at each site; four with exclosures to exclude or reduce grazing from geese and four with access for the geese. The exact same plots were followed for 2–4 years. Dropping density, used as a measure of grazing pressure, and compressed sward height (CSH) were recorded throughout the goose staging periods, and dry matter yield was determined at first and second harvests. Plant samples from first harvests were analysed for vegetation composition.3.Grazing pressure varied between both years and sites. Exclosures reduced grazing pressure by 75–78% during high-pressure grazing periods and increased first harvest yields by up to 31%. At lower grazing pressure, exclosures prevented grazing completely. Grazing pressure was inversely correlated with dry matter yield at first harvest, but second harvest yields were unaffected.4.The fraction of sown species declined while the fraction of weeds increased during the study both in open plots and exclosures, but level of grazing pressure did not have any significant influence on the overall fraction of sown species, or in any specific year.5.Synthesis and applications. As the same plots were measured over several years, it was possible to quantify goose-grazing effects beyond one season. In the context of the wildlife-agriculture conflict, the results demonstrate that some farmers always suffer disproportionately with yearly variations. The relationship between grazing pressure and yield loss may provide knowledge to a regional goose grazing subsidy scheme in the study area, identifying the most affected areas and distributing the subsidies correspondingly. However, the seasonal variations in grazing pressure demonstrate the difficulty of targeting exact areas on a yearly basis. On the other hand, the observed variations may promote another management tool in the form of delayed ploughing of stubble fields before spring sowing, as stubble fields may attract more geese, reducing the grazing pressure on agricultural grasslands and hence the overall conflicts with agricultural interests.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-03T22:50:23.983637-05:
      DOI: 10.1111/1365-2664.12914
  • Tree growth is more sensitive than species distributions to recent changes
           in climate and acidic deposition in the northeastern United States
    • Authors: Jay W. Wason; Martin Dovciak, Colin M. Beier, John J. Battles
      Abstract: Tree-growth responses to environmental change could provide early detection of shifts in forest composition and help facilitate ecosystem management and conservation.We studied forest tree responses to recent trends in climate and acidic deposition using analyses of tree rings and long-term climate, deposition and forest plot data along an elevational climatic gradient in the northeastern United States. We analysed how (i) individual growth of dominant species (Picea rubens, Abies balsamea) and (ii) spatial distributions of all species, changed with elevation over time due to changing environment.We observed a mean 220 m upslope shift of temperature envelopes since the 1960s, consistent with regional climate warming, but found no evidence of synchronous upslope shifts in species abundance. Species' ranges were stable although some leaned upslope or downslope, suggesting species-specific migration lags or controls on species' ranges.Compared to species distributions, the growth of dominant species was more responsive to environmental change. Although the basal area of P. rubens declined within its range since the 1960s, its growth has increased recently with increasing precipitation pH and to a lesser extent with warming climate. Abies balsamea has gradually increased in both basal area and density since the 1960s, with its growth responding to precipitation pH but not climate. Historically, P. rubens grew better at lower and A. balsamea at higher elevations, but these elevation effects appeared to be mediated primarily by moisture, and have disappeared over time.Synthesis and applications. Mean tree-growth responses to changing climate (temperature, moisture) and precipitation chemistry were more consistent and more clearly detectable than shifts in tree species' ranges, suggesting that monitoring tree growth across climatically controlled species' ranges (e.g. along elevational or latitudinal gradients) may provide a powerful tool for early detection of potential future changes in forest composition in a changing environment.
      PubDate: 2017-04-01T00:16:11.632052-05:
      DOI: 10.1111/1365-2664.12899
  • Using beta diversity to inform agricultural policies and conservation
           actions on Mediterranean farmland
    • Authors: Joana Santana; Miguel Porto, Luís Reino, Francisco Moreira, Paulo Flores Ribeiro, José Lima Santos, John T. Rotenberry, Pedro Beja
      Abstract: Spatial variation in species composition (β-diversity) is an important component of farmland biodiversity, which together with local richness (α-diversity) drives the number of species in a region (γ-diversity). However, β-diversity is seldom used to inform conservation, due to limited understanding of its responses to agricultural management, and lack of clear links between β-diversity changes and conservation outcomes.We explored the value of β-diversity to guide conservation on farmland, by quantifying the contribution of bird α- and β-diversity to γ-diversity variation in low- and high-intensity Mediterranean farmland, before (1995–1997) and after (2010–2012) the Common Agricultural Policy reform of 2003. We further related β-diversity to landscape heterogeneity, and assessed the conservation significance of β-diversity changes.In 1995–1997, bird diversity was highest in low-intensity farmland, where it further increased in 2010–2012 due to a strong positive contribution of α-diversity to γ-diversity. In high-intensity farmland, diversity converged over time to much the same values of low-intensity farmland, with strong positive contributions of both α- and β-diversity. These patterns were largely consistent for total, farmland and species of European conservation concern assemblages, and less so for steppe birds.Beta diversity increased with landscape heterogeneity, particularly related to spatial gradients from agricultural to natural habitats in low-intensity farmland, and from annual to permanent crops (olive groves) in high-intensity farmland. The first gradient was associated with the replacement of steppe birds of high conservation concern by more generalist species, while the second was associated with the replacement between species with lower or higher affinity for woodland and shrubland habitats.Synthesis and applications. In low-intensity farmland, spatial variation in species composition (β-diversity) was largely stable over time, reflecting a positive conservation outcome related to persistence of landscape heterogeneity patterns required by endangered steppe bird species. In contrast, β-diversity in high-intensity farmland was favoured by increases in landscape heterogeneity driven by olive grove expansion, contributing to enhancement of total bird diversity. Overall, our results stress the value of β-diversity to understand impacts of agricultural policies and conservation actions, but also highlight the need to evaluate β-diversity changes against specific conservation goals.
      PubDate: 2017-03-30T02:30:33.345064-05:
      DOI: 10.1111/1365-2664.12898
  • Differential responses by stream and riparian biodiversity to in-stream
           restoration of forestry-impacted streams
    • Authors: Jarno Turunen; Jukka Aroviita, Hannu Marttila, Pauliina Louhi, Tiina Laamanen, Mikko Tolkkinen, Pirkko-Liisa Luhta, Bjørn Kløve, Timo Muotka
      Abstract: Forestry can have detrimental impacts on stream ecosystems, particularly via excessive sedimentation. A key challenge to stream management is therefore to identify the best restoration practices to mitigate the harmful impacts of fine sediments on stream biodiversity and ecosystem functioning.We studied the effects of restoration of sediment-impacted headwater streams on the habitat structure, hydrologic retention, biodiversity (microbes, bryophytes, benthic macroinvertebrates, riparian plants) and ecosystem functions (periphyton accrual rate and leaf breakdown) by comparing four treatments: wood-restored, boulder-restored, impacted (by fine sediments) and near-natural streams. The restored streams were sampled 3–7 years post-restoration. Restoration by wooden or boulder structures aimed to reduce deposited sediments and increase channel heterogeneity and hydraulic retention.Wooden structures were ineffective in removing fine bed sediments and did not induce positive responses in aquatic biota. Boulder additions reduced substrate limitation and thereby proved beneficial for aquatic bryophytes. Benthic macroinvertebrates were clearly impaired by sedimentation but responded weakly to restoration. Leaf-decomposing microbes and ecosystem functions were unresponsive to restoration but neither did they differ between near-natural and impacted streams, suggesting that they were little harmed by sedimentation.Wood addition enhanced hydraulic retention, and riparian plant assemblages along wood-restored streams resembled those in near-natural streams, suggesting that increased retention re-established a more natural flood regime. By contrast, riparian plant assemblages in boulder-restored streams did not differ from those in impacted streams.Synthesis and applications. Restoration improved several aspects of stream and/or riparian biodiversity, but had limited effects on ecosystem functions. Different restoration measures resulted in differing biodiversity outcomes: boulder addition was more effective at restoring in-stream heterogeneity and aquatic biodiversity, whereas wooden structures helped restore channel hydrology and retentiveness, and, consequently, riparian vegetation. Therefore applying both measures in the restoration of forested headwater streams with naturally stony substrates enhances stream habitat variability at the watershed scale, providing the most promising scenario for biodiversity benefits in broad-scale restoration designs. In-stream restoration that increases hydraulic retention has impacts that extend beyond ecosystem boundaries, reinforcing the need to restore, manage and protect streams and their riparian forests in an integrated effort.
      PubDate: 2017-03-28T03:35:24.907609-05:
      DOI: 10.1111/1365-2664.12897
  • A national-scale model of linear features improves predictions of farmland
    • Authors: Martin J.P. Sullivan; James W. Pearce-Higgins, Stuart E. Newson, Paul Scholefield, Tom Brereton, Tom H. Oliver
      Abstract: 1.Modelling species distribution and abundance is important for many conservation applications, but it is typically performed using relatively coarse-scale environmental variables such as the area of broad land-cover types. Fine-scale environmental data capturing the most biologically-relevant variables have the potential to improve these models. For example, field studies have demonstrated the importance of linear features, such as hedgerows, for multiple taxa, but the absence of large-scale datasets of their extent prevents their inclusion in large-scale modelling studies.2.We assessed whether a novel spatial dataset mapping linear and woody linear features across the UK improves the performance of abundance models of 18 bird and 24 butterfly species across 3723 and 1547 UK monitoring sites respectively.3.Although improvements in explanatory power were small, the inclusion of linear features data significantly improved model predictive performance for many species. For some species, the importance of linear features depended on landscape context, with greater importance in agricultural areas.4.Synthesis and applications. This study demonstrates that a national-scale model of the extent and distribution of linear features improves predictions of farmland biodiversity. The ability to model spatial variability in the role of linear features such as hedgerows will be important in targeting agri-environment schemes to maximally deliver biodiversity benefits. Although this study focuses on farmland, data on the extent of different linear features are likely to improve species distribution and abundance models in a wide range of systems, and also can potentially be used to assess habitat connectivity.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-27T09:30:41.426985-05:
      DOI: 10.1111/1365-2664.12912
  • Landscape-scale interactions of spatial and temporal cropland
           heterogeneity drive biological control of cereal aphids
    • Authors: Aliette Bosem Baillod; Teja Tscharntke, Yann Clough, Péter Batáry
      Abstract: 1.Agricultural landscapes are characterised by dynamic crop mosaics changing in composition and configuration over space and time. While semi-natural habitat has been often shown to contribute to pest biological control, the effects of increasing landscape heterogeneity with cropland has been disregarded. Here, we examine how cereal aphids, their enemies and biological control are affected by the composition and configuration of the crop mosaic and its inter-annual change due to crop rotation.2.We studied the abundance of cereal aphids, natural enemies and aphid parasitism over two years on 51 winter wheat fields. Arthropods were monitored at three distances (0, 10, 30m) from field borders. Fields were embedded in landscapes of 1-km diameter selected along orthogonal gradients of compositional crop heterogeneity (crop diversity), configurational heterogeneity (field border and grassy field boundary length) and inter-annual change in cover of aphid host habitats (cereal, maize and grassland). We aimed to disentangle spatial and temporal heterogeneity effects through these independent landscape gradients.3.Aphid densities were lower in landscapes with smaller field size (more field borders) coupled with high amounts of grassy field boundaries. Aphid densities decreased also in landscapes with higher crop diversity when the cover of aphid host habitat had decreased from the year before. Aphid natural enemy densities decreased with smaller field size and high amounts of grassy field boundaries. Aphid parasitism decreased with the inter-annual expansion in aphid host habitat, but only in landscapes with small field sizes.4.Synthesis and applications. Our study shows for the first time that cereal aphid numbers can be reduced by optimizing the composition, configuration and temporal heterogeneity of the crop mosaic. We highlight the value of maintaining small field sizes in agricultural landscapes and high densities of grassy boundaries for reducing aphid abundance. Landscape-wide crop diversification can reduce aphid densities as well.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-27T09:21:18.151966-05:
      DOI: 10.1111/1365-2664.12910
  • The energy landscape predicts flight height and wind turbine collision
           hazard in three species of large soaring raptor
    • Authors: Guillaume Péron; Chris H. Fleming, Olivier Duriez, Julie Fluhr, Christian Itty, Sergio Lambertucci, Kamran Safi, Emily L.C. Shepard, Justin M. Calabrese
      Abstract: 1.Collisions of large soaring raptors with wind turbines and other infrastructures represent a growing conservation concern. We describe a way to leverage knowledge about raptor soaring behaviour to forecast the probability that raptors fly in the rotor-swept zone. Soaring raptors are theoretically expected to select energy sources (uplift) optimally, making their flight height dependent on uplift conditions. This approach can be used to forecast collision hazard when planning or operating wind farms. Empirical investigations of the factors influencing flight height have however so far been hindered by observation error.2.We propose a two-pronged approach. First, we fitted state-space models to z-axis GPS tracking data to filter heavy-tailed observation error and estimate the relationship between vertical movement parameters and weather variables describing the energy landscape (thermal and orographic uplift potential). Second, we fitted a mechanistic model of flight height above-ground based on aerodynamics and resource selection theories. The approach was replicated for five GPS-tracked Andean condors Vultur gryphus, eight griffon vultures Gyps fulvus, and six golden eagles Aquila chrysaetos.3.In all individuals, movement parameters correlated with thermal uplift potential in the expected direction. In all species, collision hazard was lowest for high thermal uplift potential values. Species-specificities in the presence of a peak in collision hazard for medium values of thermal uplift potential could be explained by differences in wing loading and aspect ratio.4.Synthesis and applications. Our fitted models convert weather data (thermal uplift potential) into a prediction of collision hazard (probability to fly in the rotor-swept zone), making it possible to prioritize different wind development projects with respect to the relative hazard they would pose to raptors. However, our model should be combined with post-construction monitoring to document, and eventually account for turbine avoidance behaviours in collision rate predictions.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-27T09:15:57.703861-05:
      DOI: 10.1111/1365-2664.12909
  • Livestock grazing alters multiple ecosystem properties and services in
           salt marshes: a meta-analysis
    • Authors: Kate E. Davidson; Mike S. Fowler, Martin W. Skov, Stefan H. Doerr, Nicola Beaumont, John N. Griffin
      Abstract: The far-reaching impacts of livestock grazing in terrestrial grasslands are widely appreciated, but how livestock affect the structure and functions of sensitive coastal ecosystems has hitherto lacked synthesis. Grazing-induced changes in salt marshes have the potential to alter the provision of valuable ecosystem services, such as coastal protection, blue carbon and biodiversity conservation.To investigate how livestock alter soil, vegetation and faunal properties in salt marshes, we conducted a global meta-analysis of ungulate grazer impacts on commonly measured ecosystem properties (498 individual responses from 89 studies). We also tested stocking density, grazing duration, grazer identity, continent and vegetation type as potential modifiers of the grazing effect. The majority of studies were conducted in Europe (75) or the Americas (12), and investigated cattle (43) or sheep (22) grazing.All measures of above-ground plant material (height, cover, above-ground biomass, litter) were decreased by grazing, potentially impairing coastal protection through diminished wave attenuation.Soil carbon was reduced by grazing in American, but not European marshes, indicating a trade-off with climate regulation that varies geographically. Additionally, grazing increased soil bulk density, salinity and daytime temperature, and reduced redox potential.Biodiversity responses depended on focal group, with positive effects of grazing on vegetation species richness, but negative effects on invertebrate richness. Grazing reduced the abundance of herbivorous invertebrates, which may affect fish and crustaceans that feed in the marsh. Overall vertebrate abundance was not affected, but there was provisional evidence for increases over a longer duration of grazing, potentially increasing birdwatching and wildfowling opportunities.Synthesis and applications. Our results reveal that the use of salt marshes for livestock production affects multiple ecosystem properties, creating trade-offs and synergies with other ecosystem services. Grazing leads to reductions in blue carbon in the Americas but not in Europe. Grazing may compromise coastal protection and the provision of a nursery habitat for fish while creating provisioning and cultural benefits through increased wildfowl abundance. These findings can inform salt marsh grazing management, based on local context and desired ecosystem services.
      PubDate: 2017-03-23T03:15:34.185105-05:
      DOI: 10.1111/1365-2664.12892
  • Landscape properties affect biodiversity response to retention approaches
           in forestry
    • Authors: Akira S. Mori; Shinichi Tatsumi, Lena Gustafsson
      Abstract: Retention forestry, in which trees and tree patches are set aside at harvest to promote biodiversity, has been proven to have positive effects on biodiversity at the stand-level across different taxa. However, the effectiveness of retention approaches with regard to landscape composition remains unexplored.We linked the effect sizes from two meta-analyses (31 case studies and 1050 comparisons from boreal and temperate regions), which quantified the effectiveness of biodiversity conservation as a result of retention practices, with the stand property of retention level (the percentage of trees retained after logging) and with Landsat-retrieved landscape data on forest cover and spatial configurations at three spatial scales (1, 3, and 5 km radii).We found that, in addition to the fundamental importance of tree retention as a local-scale implementation for conservation, landscape properties were important in models to predict biodiversity responses. The effect sizes for species richness decreased with increasing patch contiguity within the landscapes at all spatial scales. Similar results were observed for abundance responses at the largest spatial scale. These results suggest that biodiversity responses to tree retention may be weaker in less fragmented landscapes, which is in agreement with theoretical and empirical findings from agricultural landscapes (‘the intermediate landscape-complexity hypothesis’).The benefits of retention levels within a stand (percentage of trees retained) varied amongst species with different habitat requirements (forest-dependent, open habitat, and generalist species). Whilst this stand-level property was often an important determinant of biodiversity responses, models that included landscape properties as explanatory variables always performed better than those that were only based on the retention levels for all species groups. Thus, within-stand habitat conditions and landscape configurations likely have synergetic influences on biodiversity responses.Synthesis and applications. In addition to the importance of stand-level properties, such as the action of retention harvesting itself and the number of trees retained, conditions in the surrounding landscape can simultaneously affect biodiversity in stands that are managed under retention forestry. Our study suggests that retention patches are particularly important in moderately fragmented landscapes. Retention practices could be less important in previously unlogged and less fragmented landscapes, where setting aside large reserves is a conservation priority. For highly fragmented landscapes, different actions of forest restoration, which are not limited to set-aside actions during logging, would be important. Our study emphasizes that carefully planned conservation schemes with a large-scale perspective, as well as local-scale actions, such as retention forestry, are critical for effective forest management and conservation planning.
      PubDate: 2017-03-21T04:16:29.958715-05:
      DOI: 10.1111/1365-2664.12888
  • Ecosystem-scale impacts of non-timber forest product harvesting: effects
           on soil nutrients
    • Authors: Sheunesu Ruwanza; Charlie M. Shackleton
      Abstract: The harvesting of non-timber forest products (NTFPs) is a global phenomenon, the sustainability of which has been studied for many species at the individual and population level. However, the broader scale impacts of NTFP harvesting have been acknowledged but rarely examined.We assessed plant size and the soil attributes undercanopy and in the open, in replicate, paired harvested and non-harvested sites for three NTFPs differing in the extent of biomass removed, i.e. timber for firewood from a tree (Acacia karroo), fruits from a cactus (Opunita ficus-indica) and flowering culms from a grass (Cymbopogon marginatus). Soil variables tested included pH, resistivity, P, total N, nitrate nitrogen, ammonium nitrogen, K, Na, Ca and Mg.The extent of loss of soil nutrients decreased across the three NTFPs relative to the proportion of biomass removed. Thus, significant differences in more soil variables were evident for the firewood species, least for the fruit species and intermediate for the grass species. Lower soil pH, P, C and K were evident in soils collected underneath A. karroo, while losses in cations of Na, Ca and Mg were reported in soils underneath C. marginatus, and only NO3N losses were recorded underneath O. ficus-indica.Synthesis and applications. Our study reveals that while non-timber forest product (NTFP) harvesting may affect soil nutrients, this is not uniform between species and is likely to be a function of the extent of biomass removed and harvesting frequency. This indicates the need for caution in generalisations about the ecosystem-level impacts of NTFP harvesting as well as a concerted effort to better understand impacts at a greater range of scales than has been the case to date.
      PubDate: 2017-03-21T04:16:19.320602-05:
      DOI: 10.1111/1365-2664.12891
  • Soil drainage facilitates earthworm invasion and subsequent carbon loss
           from peatland soil
    • Authors: Xinwei Wu; Rui Cao, Xue Wei, Xinqiang Xi, Peili Shi, Nico Eisenhauer, Shucun Sun
      Abstract: Human activities have been a significant driver of environmental changes with tremendous consequences for carbon (C) dynamics. Peatlands are critical ecosystems because they store ~30% of the global soil organic C pool and are particularly vulnerable to anthropogenic changes. The Zoige peatland on the eastern Tibet Plateau, as the largest alpine peatland in the world, accounts for 1‰ of global peat soil organic C storage. However, this peatland has experienced dramatic climate change including increased temperature and reduced precipitation in the past decades, which likely is responsible for a decline of the water-table and facilitated earthworm invasion, two major factors reducing soil organic carbon (SOC) storage of peatlands.Because earthworms often are more active in low- than in high-moisture peatlands, we hypothesized that the simultaneous occurrence of water-table decline and earthworm invasion would synergistically accelerate the release of SOC from peatland soil. We conducted a field experiment with a paired split-plot design, i.e. presence vs. absence of the invasive earthworms (Pheretima aspergillum) nested in drained vs. undrained plots, respectively, for 3 years within the homogenous Zoige peatland.Water-table decline significantly decreased soil water content and bulk density, resulting in a marked reduction of SOC storage. Moreover, consistent with our hypothesis, earthworm presence dramatically reduced SOC in the drained but not in the undrained peatland through the formation of deep burrows and decreasing bulk density of the lower soil layer over 3 years. The variation in SOC likely was due to changes in above-ground plant biomass, root growth and earthworm behaviour induced by the experimental treatments.Synthesis and applications. We suggest that incentive measures should be taken to prevent further water-table decline and earthworm invasion for maintaining the soil carbon pool in Zoige peatland. Artificial filling of drainage canals should be implemented to increase the water-table level, facilitating the recovery of drained peatlands. Moreover, the dispersal of earthworms and their cocoons attached to the roots of crop plants and tree saplings from low-lying areas to the Zoige region should be prevented.
      PubDate: 2017-03-20T05:26:09.640739-05:
      DOI: 10.1111/1365-2664.12894
  • Depletion of heterogeneous source species pools predicts future invasion
    • Authors: Andrew M. Liebhold; Eckehard G. Brockerhoff, Mark Kimberley
      Abstract: Predicting how increasing rates of global trade will result in new establishments of potentially damaging invasive species is a question of critical importance to the development of national and international policies aimed at minimizing future invasions. Centuries of historical movement and establishment of invading species may have depleted the supply of species available for future invasions, and it has been suggested that the problem of invasions will diminish as a result of this. However, the extent to which source pool depletion affects future invasions remains unclear.Here we describe a mechanistic model that captures the simultaneous effects of depletion of source species pools along with increases in pathway rates (e.g. imports) to predict future numbers of new invasions. We assume that the distribution of species abundance within invasion pathways is positively skewed, which is modelled using a log-normal distribution. Given their high propagule pressure, the most abundant species are likely to invade first, while the many rare species are likely to invade only under high pathway volumes. We apply this model to the case study of bark beetle, Scolytinae, invasions in the USA.Source species pools in Europe and Asia (225 and 655 species of Scolytinae, respectively) are much larger than numbers that have historically established (16 and 32). Parameterization of the model indicates a highly skewed species abundance distribution in the pathway and this is confirmed by species frequencies in port inspection records, thus explaining why only a small fraction of species has historically invaded.Forecasts from the model indicate that with increasing rates of imports, more species from these regions are likely to invade in the future despite the depletion of the most abundant species from source species pools. Previous statistical models tend to underestimate future establishments in the presence of increasing import rates due to their failure to account for key underlying mechanisms.Policy implications. The mechanistic model developed here is widely applicable for predicting future invasions of all taxa and provides insights into how increases in rates of imports counteract the species pool depletion effect, resulting in the continued establishment of new species.
      PubDate: 2017-03-20T05:25:44.509544-05:
      DOI: 10.1111/1365-2664.12895
  • Enhancing plant diversity in agricultural landscapes promotes both rare
           bees and dominant crop-pollinating bees through complementary increase in
           key floral resources
    • Authors: Louis Sutter; Philippe Jeanneret, Agustín M. Bartual, Gionata Bocci, Matthias Albrecht
      Abstract: 1.Enhancing key floral resources is essential to effectively mitigate the loss of pollinator diversity and associated provisioning of pollination functions in agro-ecosystems. However, effective floral provisioning measures may diverge among different pollinator conservation targets, such as the conservation of rare species or the promotion of economically important crop pollinators. We examined to what extent such diverging conservation goals could be reconciled.2.We analysed plant–bee visitation networks of 64 herbaceous semi-natural habitats representing a gradient of plant species richness to identify key resource plants of the three distinct conservation target groups: rare bees (of conservation concern), dominant wild crop-pollinating bees, and managed crop-pollinating bees (i.e. honey bees).3.Considering overall flower visitation, rare bees tended to visit nested subsets of plant species that were also visited by crop pollinators (46% and 77% nestedness in the dissimilarity between rare bees and wild crop pollinators or managed honey bees, respectively). However, the set of preferred plant species, henceforth ‘key plant species’ (i.e. those species disproportionately more visited than expected according to their floral abundance) was considerably more distinct and less nested among bee target groups.4.Flower visits of all bee target groups increased with plant species richness at a similar rate. Importantly, our analyses revealed that an exponential increase in the flower abundance of the identified key plant species and complementarity in the bee visitation pattern across plant species ─ rather than total flower abundance ─ were the major drivers of these relationships.5.Synthesis and applications. We conclude that the multiple goals of preserving high bee diversity, conserving rare species and sustaining crop pollinators can be reconciled if key plant species of different target groups are simultaneously available. This availability is facilitated by a high floral resource complementarity in the plant community. The list of identified key resource plant species we provide here can help practitioners such as land managers and conservationists to better design and evaluate pollinator conservation and restoration measures according to their goals. Our findings highlight the importance of identifying and promoting such plant species for pollinator conservation in agricultural landscapes.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-20T01:45:33.764701-05:
      DOI: 10.1111/1365-2664.12907
  • Urban development, land sharing and land sparing: the importance of
           considering restoration
    • Authors: Lydia Collas; Rhys E. Green, Alexander Ross, Josie H. Wastell, Andrew Balmford
      Abstract: 1.At present, there is limited knowledge of how best to reconcile urban development with biodiversity conservation, and in particular whether populations of wild species would be greater under low-density housing (with larger gardens), or high-density housing (allowing more area to be left as undeveloped green spaces). The land sharing/sparing framework – originally developed in the context of farming – can be applied to address this question.2.We sampled the abundance of trees in the city of Cambridge, UK, along a gradient of human density. We designed different scenarios of urban growth to accommodate the human population predicted in 2031. For each scenario, we projected the future city-wide tree population size and quantified its carbon sequestration potential. We also considered, for the first time in an urban sharing-sparing context, the implications of habitat restoration on degraded urban green space.3.We found that the density of most native and non-native tree species is presently highest in areas of low human density, compared to both higher-density areas and green space (which is largely maintained with few trees). However, restoring woodland in green spaces would lead to far greater densities of native trees than on any existing land use. Hence provided >2% of green space is restored, native tree population sizes would be larger if urban growth followed a land-sparing approach. Likewise, carbon sequestration would be maximised under land sparing coupled with restoration, but even so only a maximum of 2.5% of the city's annual greenhouse gas emissions could be offset.4.Whilst both tree populations and carbon storage thus appear to benefit from land-sparing development, the risk that this might widen the existing disconnect between people and nature must also be addressed – perhaps through a combination of adding housing in low density areas while ensuring these are in close proximity to high-quality green space.5.Synthesis and applications. In regions which have already been cleared of intact habitat, a combination of land-sparing urban development with the restoration of green space could accommodate urban population growth whilst dramatically improving the existing status of local tree populations. Where cities are expanding into intact habitat, the merits of urban development by land sparing may be even more pronounced. Studies in such regions are urgently needed.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-20T01:45:24.397082-05:
      DOI: 10.1111/1365-2664.12908
  • Corrigendum
    • PubDate: 2017-03-16T23:15:35.932588-05:
      DOI: 10.1111/1365-2664.12896
  • Harvesting biofuel grasslands has mixed effects on natural enemy
           communities and no effects on biocontrol services
    • Authors: Tania N. Kim; Aaron F. Fox, Bill D. Wills, Timothy D. Meehan, Douglas A. Landis, Claudio Gratton
      Abstract: 1.Perennial bioenergy systems, such as switchgrass and restored prairies, are alternatives to commonly used annual monocultures such as maize. Perennial systems require lower chemical input, provide greater ecosystem services such as carbon storage, greenhouse gas mitigation, and support greater biodiversity of beneficial insects. However, biomass harvest will be necessary in managing these perennial systems for bioenergy production, and it is unclear how repeated harvesting might affect ecosystem services.2.In this study, we examined how repeated production-scale harvesting of diverse perennial grasslands influences vegetation structure, natural enemy communities (arthropod predators and parasitoids), and natural biocontrol services in two states (Wisconsin and Michigan, USA) over multiple years.3.We found that repeated biomass harvest reduced litter biomass and increased bare ground cover. Some natural enemy groups, such as ground-dwelling arthropods, decreased in abundance with harvest whereas others, such as foliar-dwelling arthropods increased in abundance. The disparity in responses is likely due to how different taxonomic groups utilize vegetation and differences in dispersal abilities.4.At the community level, biomass harvest altered community composition, increased total arthropod abundance, and decreased evenness but did not influence species richness, diversity, or biocontrol services. Harvest effects varied with time, diminishing in strength both within the season (for total abundance and evenness), across seasons (for evenness), or were consistent throughout the duration of the study (for community composition). Greater functional redundancy and compensatory responses of the different taxonomic groups may have buffered against the potentially negative effects of harvest on biocontrol services.5.Synthesis and applications. Our results show that in the short-term, repeated harvesting of perennial grasslands (when insect activity is low) consistently altered vegetation structure but had mixed effects on natural enemy communities and no discernable effects on biocontrol services. However, the long-term effects of repeated harvesting on vegetation structure, natural enemies, and other arthropod-derived ecosystem services such as pollination and decomposition remain largely unknown.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-15T09:55:26.381519-05:
      DOI: 10.1111/1365-2664.12901
  • Harvesting as a potential selective pressure on behavioural traits
    • Authors: Martin Leclerc; Andreas Zedrosser, Fanie Pelletier
      Abstract: Human activities are a major evolutionary force affecting wild populations. Selective pressure from harvest has mainly been documented for life-history and morphological traits. The probability for an individual to be harvested, however, may also depend on its behaviour.We report empirical studies that examined whether harvesting can exert selective pressures on behavioural traits.We show that harvest-induced selection on behavioural traits is not specific to a particular harvest method and can occur throughout the animal kingdom.Synthesis and applications. Managers need to recognize that artificial selection caused by harvesting is possible. More empirical studies integrating physiological, behavioural, and life-history traits should be carried out to test specific predictions of the potential for harvest-induced selection on heritable traits using models developed in fisheries. To limit selective pressure on behaviour imposed by harvesting, managers could reduce harvest quotas or vary harvest regulations over time and/or space to reduce the strength of selection on a particular phenotype.
      PubDate: 2017-03-13T03:30:43.555208-05:
      DOI: 10.1111/1365-2664.12893
  • Examining the occupancy–density relationship for a low-density
    • Authors: Daniel W. Linden; Angela K. Fuller, J. Andrew Royle, Matthew P. Hare
      Abstract: The challenges associated with monitoring low-density carnivores across large landscapes have limited the ability to implement and evaluate conservation and management strategies for such species. Non-invasive sampling techniques and advanced statistical approaches have alleviated some of these challenges and can even allow for spatially explicit estimates of density, one of the most valuable wildlife monitoring tools.For some species, individual identification comes at no cost when unique attributes (e.g. pelage patterns) can be discerned with remote cameras, while other species require viable genetic material and expensive laboratory processing for individual assignment. Prohibitive costs may still force monitoring efforts to use species distribution or occupancy as a surrogate for density, which may not be appropriate under many conditions.Here, we used a large-scale monitoring study of fisher Pekania pennanti to evaluate the effectiveness of occupancy as an approximation to density, particularly for informing harvest management decisions. We combined remote cameras with baited hair snares during 2013–2015 to sample across a 70 096-km2 region of western New York, USA. We fit occupancy and Royle–Nichols models to species detection–non-detection data collected by cameras, and spatial capture–recapture (SCR) models to individual encounter data obtained by genotyped hair samples. Variation in the state variables within 15-km2 grid cells was modelled as a function of landscape attributes known to influence fisher distribution.We found a close relationship between grid cell estimates of fisher state variables from the models using detection–non-detection data and those from the SCR model, likely due to informative spatial covariates across a large landscape extent and a grid cell resolution that worked well with the movement ecology of the species. Fisher occupancy and density were both positively associated with the proportion of coniferous-mixed forest and negatively associated with road density. As a result, spatially explicit management recommendations for fisher were similar across models, though relative variation was dampened for the detection–non-detection data.Synthesis and applications. Our work provides empirical evidence that models using detection–non-detection data can make similar inferences regarding relative spatial variation of the focal population to models using more expensive individual encounters when the selected spatial grain approximates or is marginally smaller than home range size. When occupancy alone is chosen as a cost-effective state variable for monitoring, simulation and sensitivity analyses should be used to understand how inferences from detection–non-detection data will be affected by aspects of study design and species ecology.
      PubDate: 2017-03-11T03:36:18.384778-05:
      DOI: 10.1111/1365-2664.12883
  • Restored tallgrass prairies have reduced phylogenetic diversity compared
           with remnants
    • Authors: Rebecca S. Barak; Evelyn W. Williams, Andrew L. Hipp, Marlin L. Bowles, Gabriela M. Carr, Robert Sherman, Daniel J. Larkin
      Abstract: Ecological restoration is critical for mitigating habitat loss and providing ecosystem services. However, restorations often have lower diversity than remnant, reference sites. Phylogenetic diversity is an important component of biodiversity and ecosystem function that has only recently been used to evaluate restoration outcomes. To move towards prediction in the restoration of biodiversity, it is necessary to understand how phylogenetic diversity of restorations compares with that of reference sites, and where deficits are found, to evaluate factors constraining phylogenetic diversity.We quantified plant taxonomic and phylogenetic diversity in eastern tallgrass prairie, one of the most endangered ecosystems on earth. We measured diversity at large (site) and small (plot) scales in 19 restored prairies and compared patterns with those from 41 remnant prairies. To evaluate how environmental conditions and management actions influence outcomes, we tested the effects of soil properties and seed mix composition on diversity of restorations.Restored prairies were less phylogenetically diverse than remnants at both spatial scales. On the other hand, the total species richness of remnant and restored prairies did not significantly differ, but remnants had higher native richness. Restored communities were taxonomically and phylogenetically distinct from remnants.Soil properties (moisture and pH) influenced phylogenetic diversity and composition. There were positive relationships between the taxonomic and phylogenetic diversity of seed mixes and resulting diversity of planted assemblages (excluding volunteer species). Species in seed mixes were more closely related than expected by chance, and several clades found in remnant prairies were missing from seed mixes.Synthesis and applications. Restored tallgrass prairies had lower phylogenetic diversity than remnant prairies, which may contribute to the widely observed phenomenon of restorations not being functionally equivalent to reference sites. It is encouraging for restoration efforts that seed mix phylogenetic diversity predicted phylogenetic diversity of planted assemblages. This indicates that designing phylogenetically diverse seed mixes for restoration is beneficial. In addition, clades found in reference sites that are missing from restoration seed mixes could be added to new or existing restorations to reduce gaps in phylogenetic diversity. Further work on the effects of management on phylogenetic diversity is needed to advance restoration of biodiversity.
      PubDate: 2017-03-10T23:45:34.371769-05:
      DOI: 10.1111/1365-2664.12881
  • Embracing uncertainty in applied ecology
    • Authors: E. J. Milner-Gulland; Katriona Shea
      Abstract: Applied ecologists often face uncertainty that hinders effective decision-making.Common traps that may catch the unwary are: ignoring uncertainty, acknowledging uncertainty but ploughing on, focussing on trivial uncertainties, believing your models, and unclear objectives.We integrate research insights and examples from a wide range of applied ecological fields to illustrate advances that are generally underused, but could facilitate ecologists’ ability to plan and execute research to support management.Recommended approaches to avoid uncertainty traps are: embracing models, using decision theory, using models more effectively, thinking experimentally, and being realistic about uncertainty.Synthesis and applications. Applied ecologists can become more effective at informing management by using approaches that explicitly take account of uncertainty.
      PubDate: 2017-03-09T05:40:26.980164-05:
      DOI: 10.1111/1365-2664.12887
  • Harvesting wildlife affected by climate change: a modelling and management
           approach for polar bears
    • Authors: Eric V. Regehr; Ryan R. Wilson, Karyn D. Rode, Michael C. Runge, Harry L. Stern
      Abstract: The conservation of many wildlife species requires understanding the demographic effects of climate change, including interactions between climate change and harvest, which can provide cultural, nutritional or economic value to humans.We present a demographic model that is based on the polar bear Ursus maritimus life cycle and includes density-dependent relationships linking vital rates to environmental carrying capacity (K). Using this model, we develop a state-dependent management framework to calculate a harvest level that (i) maintains a population above its maximum net productivity level (MNPL; the population size that produces the greatest net increment in abundance) relative to a changing K, and (ii) has a limited negative effect on population persistence.Our density-dependent relationships suggest that MNPL for polar bears occurs at approximately 0·69 (95% CI = 0·63–0·74) of K. Population growth rate at MNPL was approximately 0·82 (95% CI = 0·79–0·84) of the maximum intrinsic growth rate, suggesting relatively strong compensation for human-caused mortality.Our findings indicate that it is possible to minimize the demographic risks of harvest under climate change, including the risk that harvest will accelerate population declines driven by loss of the polar bear's sea-ice habitat. This requires that (i) the harvest rate – which could be 0 in some situations – accounts for a population's intrinsic growth rate, (ii) the harvest rate accounts for the quality of population data (e.g. lower harvest when uncertainty is large), and (iii) the harvest level is obtained by multiplying the harvest rate by an updated estimate of population size. Environmental variability, the sex and age of removed animals and risk tolerance can also affect the harvest rate.Synthesis and applications. We present a coupled modelling and management approach for wildlife that accounts for climate change and can be used to balance trade-offs among multiple conservation goals. In our example application to polar bears experiencing sea-ice loss, the goals are to maintain population viability while providing continued opportunities for subsistence harvest. Our approach may be relevant to other species for which near-term management is focused on human factors that directly influence population dynamics within the broader context of climate-induced habitat degradation.
      PubDate: 2017-03-08T01:01:02.91271-05:0
      DOI: 10.1111/1365-2664.12864
  • Plant functional traits and environmental conditions shape community
           assembly and ecosystem functioning during restoration
    • Authors: Chad R. Zirbel; Tyler Bassett, Emily Grman, Lars A. Brudvig
      Abstract: Recovering biological diversity and ecosystem functioning are primary objectives of ecological restoration, yet these outcomes are often unpredictable. Assessments based on functional traits may help with interpreting variability in both community composition and ecosystem functioning because of their mechanistic and generalizable nature. This promise remains poorly realized, however, because tests linking environmental conditions, functional traits, and ecosystem functioning in restoration are rare.Here, we provide such a test through what is to our knowledge the first empirical application of the ‘response–effect trait framework’ to restoration. This framework provides a trait-based bridge between community assembly and ecosystem functioning by describing how species respond to environmental conditions based on traits and how the traits of species affect ecosystem functioning.Our study took place across 29 prairies restored from former agricultural fields in southwestern Michigan. We considered how environmental conditions affect ecosystem functioning through and independently of measured functional traits. To do so, we paired field-collected trait data with data on plant community composition and measures of ecosystem functioning and used structural equation modelling to determine relationships between environmental conditions, community-weighted means of functional traits and ecosystem functioning.Environmental conditions were predictive of trait composition. Sites restored directly from tillage (as opposed to those allowed to fallow) supported taller species with larger seeds and higher specific leaf area (SLA). Site age and fire frequency were both negatively related to SLA. We also found a positive relationship between soil moisture and SLA.Both trait composition and environmental conditions predicted ecosystem functioning, but these relationships varied among the measured functions. Pollination mode (animal pollination) increased and fire frequency decreased floral resource availability, seed mass had a negative effect on below-ground biomass production, and vegetative height increased decomposition rate. Soil moisture and fire frequency both increased while site age decreased above-ground biomass production, and site age and soil moisture both increased decomposition rate.Synthesis and applications. Our results suggest that both trait composition and environmental conditions play a role in shaping ecosystem function during restoration, and the importance of each is dependent on the function of interest. Because of this, environmental heterogeneity will be necessary to promote multiple ecosystem functions across restored landscapes. A trait-based approach to restoration can aid interpretation of variable outcomes through insights into community assembly and ecosystem functioning.
      PubDate: 2017-03-07T04:20:43.012248-05:
      DOI: 10.1111/1365-2664.12885
  • Suppressing competitive dominants and community restoration with native
           parasitic plants using the hemiparasitic Rhinanthus alectorolophus and the
           dominant grass Calamagrostis epigejos
    • Authors: Jakub Těšitel; Jan Mládek, Jan Horník, Tamara Těšitelová, Vojtěch Adamec, Lubomír Tichý
      Abstract: Dominance of native or alien competitive plants causes competitive exclusion of subordinate species and represents a major mechanism reducing biodiversity following land-use changes. The successful competitive strategies may, however, be interfered with by parasitic plants, which withdraw resources from other plants' vasculature. Parasitism may strongly reduce the growth of the dominants, which may facilitate regeneration of other species and consequently trigger restoration of natural communities of high diversity.Here, we aim to provide robust empirical evidence demonstrating this restoration potential of parasitic plants. We present a case study testing suppressive effects of hemiparasitic Rhinanthus alectorolophus on competitive grass Calamagrostis epigejos. In recent decades, C. epigejos has invaded many high-nature-value semi-natural grasslands of Central Europe, which is one of the prominent factors causing their biodiversity decline.We conducted three manipulative field experiments testing the effect of sowing of R. alectorolophus in different vegetation types infested by C. epigejos. Rhinanthus sowing was compared to different mowing treatments recommended as the ‘best practice’ management at respective sites.Rhinanthus alectorolophus established itself in most C. epigejos-dominated plots where sown. Calamagrostis epigejos was virtually exterminated in 2 years in two of the experiments (dry meadow and industrial area). In the wet-meadow experiment, the suppressive effect was variable as a result of uneven establishment success of Rhinanthus. In this experiment increased mowing intensity had an additional suppressive effect on C. epigejos. Rhinanthus also increased regeneration potential of other species by a temporary reduction of vegetation density. Restoration of target vegetation composition was, however, dependent on community context.Synthesis and applications. We demonstrated that hemiparasitic Rhinanthus alectorolophus is an accessible and efficient tool for targeted biological control of Calamagrostis epigejos, with a great potential to restore infested grassland vegetation. The strong effect of Rhinanthus is caused by interference with the underground storage and clonal growth strategy of Calamagrostis epigejos, which are both traits that underlie its competitive ability. The potential of native parasitic plants should be considered in restoration management of sites infested by competitive dominants, either alien or native.
      PubDate: 2017-03-06T00:20:43.332994-05:
      DOI: 10.1111/1365-2664.12889
  • Corrigendum
    • Abstract: This article corrects “Compensatory life-history responses of a mesopredator may undermine carnivore management efforts” by Minnie, Gaylard & Kerley (
      DOI : 10.1111/1365-2664.12581) and follows the publication of an Expression of Concern (
      DOI : 10.1111/1365-2664.12795).
      PubDate: 2017-03-05T23:55:24.370585-05:
  • Trophic mechanisms underlying bentho-demersal community recovery in the
           north-east Atlantic
    • Authors: Nina-Larissa Arroyo; Izaskun Preciado, Lucía López-López, Isabel Muñoz, Antonio Punzón
      Abstract: Bottom trawling is considered one of the greatest and most widespread causes of anthropogenic change in shelf seas, with major and prolonged impacts in areas with a long history of exploitation by fisheries such as the North Atlantic. Here, signs of recovery following the enforcement of regulations are increasingly being reported.We examined the extent to which biological diversity and functionality are restored when fishing pressure is reduced by evaluating changes in species biomass and that of the main functional groups present in the continental platform, as obtained from systematic survey (IBTS) results. Moreover, we examined how this recovery is mirrored in the trophic organization of the affected communities by assessing variations in link density and strength of the main consumer species and investigating whether variations in species richness were paralleled by changes in network properties. Finally, we investigated whether reductions in fishing pressure (fishing mortality) were correlated with the abovementioned variations in community and trophic structure of the bentho-demersal assemblages.Our results corroborate the apparent recovery of North Atlantic fishing stocks and further substantiate the improved welfare of the bentho-demersal assemblages of the Southern Bay of Biscay. Specifically, we found an increase in species richness and in the abundance of most functional groups, especially those more closely related to the benthos, following the reduction in fishing mortality. Increases in overall species richness were paralleled by an increase in the number of links and a reduction in mean interaction strength connecting the main consumer species with their prey items. This is in accordance with ecological theory and could explain the mechanism by which bentho-demersal assemblages restructure their trophic network towards more stable organizations.Synthesis and applications. Detecting patterns of recovery or change to alternative stable states following stress release is essential to unravel the effects of perturbations and to design effective management strategies. Our study shows that trophic network properties provide a convincing tool to evaluate and perceive recovery patterns. The trends shown in our study appear to be related with the decline in fishing mortality resulting from the enforcement of fisheries regulations in the area. They substantiate the efficiency of these regulations as a guarantee for an ecosystem approach to fisheries management and advocate their enforcement at a wider level as a convincing measure to preserve the sustainability of marine resources and their welfare.
      PubDate: 2017-03-02T01:05:59.473767-05:
      DOI: 10.1111/1365-2664.12879
  • Finding the best management policy to eradicate invasive species from
           spatial ecological networks with simultaneous actions
    • Authors: Sam Nicol; Regis Sabbadin, Nathalie Peyrard, Iadine Chadès
      Abstract: Spatial management of invasive species is more likely to be successful when multiple locations are treated simultaneously. However, selecting the best locations to act is difficult due to the many options available at any time.We design a near-optimal policy for applying multiple actions simultaneously for faster invasive species control within a network. Our method uses a recent optimisation tool, the graph-based Markov decision process (GMDP). Since the policy can be difficult to interpret, we extracted a simpler policy using classification trees. We applied our approach to the eradication of invasive mosquitofish Gambusia holbrooki from the habitat of the red-finned blue-eye Scaturiginichthys vermeilipinnis, a critically endangered fish with a global population that is restricted to seven artesian springs in Queensland, Australia.The policy returned by the GMDP was to manage springs occupied by mosquitofish and their connected neighbours, unless the neighbours were occupied by red-finned blue-eyes.Simultaneous management resulted in rapid declines in simulated mosquitofish occupancy even if eradication effectiveness was low; however, the cost of simultaneous eradication was high and sustained eradication effort was necessary to maintain low mosquitofish occupancy.Synthesis and applications. Our paper finds a near-optimal, multi-action control policy to remove an invasive species from a multi-species spatial network. We introduce the graph-based Markov decision process and apply it to a real case study – eradication of invasive mosquitofish from the habitat of the red-finned blue-eye. We find that the graph-based Markov decision process can generate policies for networks with extremely large state spaces; however, it works best when nodes have fewer than five neighbours. We conclude that simultaneous eradications are effective for rapid control of invasive species; however, managers should consider the cost and time required for an effective eradication program.
      PubDate: 2017-03-01T04:30:34.355034-05:
      DOI: 10.1111/1365-2664.12884
  • Increased habitat connectivity homogenizes freshwater communities:
           historical and landscape perspectives
    • Authors: Angela L. Strecker; Jeffrey T. Brittain
      Abstract: Increases in habitat connectivity can have consequences for taxonomic, functional, and genetic diversity of communities. Previously isolated aquatic habitats were connected with canals and pipelines in the largest water development project in the US history, the Columbia Basin Project (CBP; eastern Washington, USA), which also altered environmental conditions; however, the ecological consequences are largely unknown.Using a historical dataset, we examined long-term patterns in zooplankton communities, water chemistry and clarity, testing the hypothesis that increased connectivity will result in taxonomic homogenization. Further, we tested contemporary drivers of communities using a comprehensive set of environmental and landscape variables.Waterbodies were sampled for zooplankton community composition as well as physical and chemical variables inside and outside the CBP using methods consistent with historical studies.We found significant declines in salinity inside the CBP, whereas changes in water clarity were prevalent across all waterbodies. Increased connectivity via canals homogenized zooplankton communities over time, as well as increasing regional richness. Other long-term changes in zooplankton communities may be related to climate change, invasive species, and land-use changes.Synthesis and applications. Though canals may offer species spatial refugia, homogenization may decrease resilience to environmental stressors. These new hybrid aquatic landscapes, or hydroscapes, should be considered carefully in future water development, including specific plans for monitoring of species and environmental conditions, as well as mitigation of undesirable conditions and/or non-native species.
      PubDate: 2017-02-28T23:20:36.405875-05:
      DOI: 10.1111/1365-2664.12882
  • How common road salts and organic additives alter freshwater food webs: in
           search of safer alternatives
    • Authors: Matthew S. Schuler; William D. Hintz, Devin K. Jones, Lovisa A. Lind, Brian M. Mattes, Aaron B. Stoler, Kelsey A. Sudol, Rick A. Relyea
      Abstract: The application of deicing road salts began in the 1940s and has increased drastically in regions where snow and ice removal is critical for transportation safety. The most commonly applied road salt is sodium chloride (NaCl). However, the increased costs of NaCl, its negative effects on human health, and the degradation of roadside habitats has driven transportation agencies to seek alternative road salts and organic additives to reduce the application rate of NaCl or increase its effectiveness. Few studies have examined the effects of NaCl in aquatic ecosystems, but none have explored the potential impacts of road salt alternatives or additives on aquatic food webs.We assessed the effects of three road salts (NaCl, MgCl2 and ClearLane™) and two road salts mixed with organic additives (GeoMelt™ and Magic Salt™) on food webs in experimental aquatic communities, with environmentally relevant concentrations, standardized by chloride concentration.We found that NaCl had few effects on aquatic communities. However, the microbial breakdown of organic additives initially reduced dissolved oxygen. Additionally, microbial activity likely transformed unusable phosphorus from the organic additives to usable phosphorus for algae, which increased algal growth. The increase in algal growth led to an increase in zooplankton abundance. Finally, MgCl2 – a common alternative to NaCl – reduced compositional differences of zooplankton, and at low concentrations increased the abundance of amphipods.Synthesis and applications. Our results indicate that alternative road salts (to NaCl), and road salt additives can alter the abundance and composition of organisms in freshwater food webs at multiple trophic levels, even at low concentrations. Consequently, road salt alternatives and additives might alter ecosystem function and ecosystem services. Therefore, transportation agencies should use caution in applying road salt alternatives and additives. A comprehensive investigation of road salt alternatives and road salt additives should be conducted before wide-scale use is implemented. Further research is also needed to determine the impacts of salt additives and alternatives on higher trophic levels, such as amphibians and fish.
      PubDate: 2017-02-28T01:05:49.383856-05:
      DOI: 10.1111/1365-2664.12877
  • Quantification of within- and between-farm dispersal of Culicoides biting
           midges using an immunomarking technique
    • Authors: Christopher J. Sanders; Lara E. Harrup, Laura A. Tugwell, Victor A. Brugman, Marion England, Simon Carpenter
      Abstract: Culicoides biting midges (Diptera, Ceratopogonidae) are vectors of arboviruses that cause significant economic and welfare impact. Local-scale spread of Culicoides-borne arboviruses is largely determined by the between-farm movement of infected Culicoides.Study of the dispersal behaviour of Culicoides by capture–mark–recapture (CMR) is problematic due to the likelihood of mortality and changes in behaviour upon capture caused by the small size and fragility of these insects, evidenced by low recapture rates. To counter the problem of using CMR with Culicoides, this study utilised an ovalbumin immunomarking technique to quantify the within- and between-farm dispersal of Culicoides in southern England.Both within- and between-farm dispersal of Culicoides was observed. Of the 9058 Culicoides collected over 22 nights of trapping, 600 ovalbumin-positive Culicoides, of 12 species including those implicated as arbovirus vectors, were collected with a maximum dispersal distance of 3125 m.This study provides the first species-level data on the between-farm dispersal of potential bluetongue, Schmallenberg and African horse sickness virus vectors in northern Europe. High-resolution meteorological data determined upwind and downwind flight by Culicoides had occurred. Cumulative collection and meteorological data suggest 15·6% of flights over 1 km were upwind of the treatment area and 84·4% downwind.Synthesis and applications. The use of immunomarking eliminates the potential adverse effects on survival and behaviour of insect collection prior to marking, substantially improving the resolution and accuracy of estimates of the dispersal potential of small and delicate vector species such as Culicoides. Using this technique, quantification of the range of Culicoides dispersal with regard to meteorological conditions including wind direction will enable improved, data-driven modelling of the spread of Culicoides-borne arboviruses and will inform policy response to incursions and outbreaks.
      PubDate: 2017-02-28T01:05:43.360104-05:
      DOI: 10.1111/1365-2664.12875
  • Changes in soil microbial communities due to biological invasions can
           reduce allelopathic effects
    • Authors: Yang-Ping Li; Yu-Long Feng, Zong-Li Kang, Yu-Long Zheng, Jiao-Lin Zhang, Ya-Jun Chen
      Abstract: Soil microbes are important in mediating allelopathic interactions between invasive and native plants in the field. However, it was not known how these interactions vary in the process of biological invasions and the effects of soil microbes; this knowledge may facilitate understanding the dynamics and mechanisms of biological invasions and managing invaded ecosystems.We conducted competition and seed germination experiments to determine the allelopathic effects of Ageratina adenophora in soils from 42 sites with varying abundances of the invasive plant. Then we isolated the microbes that could degrade the allelochemicals of the invasive plant and tested their functions.In both experiments, the allelopathic effects of the invasive plant were much stronger in soils from non-invaded sites than in soils from invaded sites. Activities of the allelochemical-degrading microbes were higher and degradation of the allelochemicals of the invasive plant was faster in soils from invaded sites than in soils from non-invaded sites. In living soils from 30 sites with increasing abundance of A. adenophora, the allelopathic effects of the invasive plant decreased and degradation of the allelochemicals and activity of the allelochemical-degrading microbes gradually increased.Two bacterial strains were isolated from the soils. Inoculation of Arthrobacter sp. ZS, which was isolated from soil invaded by A. adenophora, greatly increased the degradation of the allelochemicals, thereby decreasing its allelopathic effects.Synthesis and applications. Our results indicate that soils may accumulate microbes that can degrade allelochemicals in the process of biological invasions, gradually reducing the allelopathic effects of invasive species. The effects of soil microbes should be considered when studying dynamics and mechanisms of biological invasions. Application of allelochemical-degrading microbes may facilitate ecological restoration of invaded or newly disturbed ecosystems by alleviating allelopathic inhibition of invasive plants on native plants.
      PubDate: 2017-02-27T04:45:29.686769-05:
      DOI: 10.1111/1365-2664.12878
  • Interacting livestock and fire may both threaten and increase viability of
           a fire-adapted Mediterranean carnivorous plant
    • Authors: Maria Paniw; Pedro F. Quintana-Ascencio, Fernando Ojeda, Roberto Salguero-Gómez
      Abstract: Quantifying interactive effects of environmental drivers on population dynamics can be critical for a robust analysis of population viability. Fire regimes, among the most widespread disturbances driving population dynamics, are increasingly modified by and interact with human activities. However, viability of fire-adapted species is typically assessed overlooking disturbance interactions, potentially resulting in suboptimal management actions.We investigated whether increasing human disturbances in fire-prone ecosystems may pose a threat or an opportunity to improve population viability, using demographic data of the carnivorous, post-fire recruiting plant Drosophyllum lusitanicum, endemic to heathlands in the southwestern Mediterranean Basin. We built integral projection models and simulated population dynamics under different combinations of two key disturbance types affecting populations: fire and livestock browsing and trampling. We used perturbation analyses to determine potential long-term consequences of maintaining fundamentally different disturbance types.Despite most populations inhabiting browsed habitats, simulations showed a greater extinction risk in populations under high livestock pressure compared with ones under low or moderate pressures. Extinction risk decreased when fire return intervals shortened in populations under low or moderate livestock pressure; however, the opposite pattern emerged in heavily browsed populations, where short intervals between fires increased extinction.Elasticity analyses showed that decreases in viability under frequent disturbance interactions (heavy browsing and frequent fire) may be explained by selection against seed dormancy in populations with frequent browsing and trampling. This may potentially cause populations to collapse when fires kill above-ground plants without populations being able to recover from a seed bank.Synthesis and applications. Incorporating disturbance interactions can result in a different assessment of viability of a fire-adapted species than considering fire regimes alone. In Mediterranean ecosystems, fire management may be more effective when integrating moderate human activities. However, replacing fires by human disturbances, a currently widespread strategy in many fire-prone ecosystems, is not recommended since it may fundamentally alter population dynamics and selection pressures and decrease viability of fire-adapted species.
      PubDate: 2017-02-23T04:30:54.633792-05:
      DOI: 10.1111/1365-2664.12872
  • Increasing biodiversity in urban green spaces through simple vegetation
    • Authors: Caragh G. Threlfall; Luis Mata, Jessica A. Mackie, Amy K. Hahs, Nigel E. Stork, Nicholas S. G. Williams, Stephen J. Livesley
      Abstract: Cities are rapidly expanding world-wide and there is an increasing urgency to protect urban biodiversity, principally through the provision of suitable habitat, most of which is in urban green spaces. Despite this, clear guidelines of how to reverse biodiversity loss or increase it within a given urban green space is lacking.We examined the taxa- and species-specific responses of five taxonomically and functionally diverse animal groups to three key attributes of urban green space vegetation that drive habitat quality and can be manipulated over time: the density of large native trees, volume of understorey vegetation and percentage of native vegetation.Using multi-species occupancy-detection models, we found marked differences in the effect of these vegetation attributes on bats, birds, bees, beetles and bugs. At the taxa-level, increasing the volume of understorey vegetation and percentage of native vegetation had uniformly positive effects. We found 30–120% higher occupancy for bats, native birds, beetles and bugs with an increase in understorey volume from 10% to 30%, and 10–140% higher occupancy across all native taxa with an increase in the proportion of native vegetation from 10% to 30%. However, increasing the density of large native trees had a mostly neutral effect. At the species-specific level, the majority of native species responded strongly and positively to increasing understorey volume and native vegetation, whereas exotic bird species had a neutral response.Synthesis and applications. We found the probability of occupancy of most species examined was substantially reduced in urban green spaces with sparse understorey vegetation and few native plants. Our findings provide evidence that increasing understorey cover and native plantings in urban green spaces can improve biodiversity outcomes. Redressing the dominance of simplified and exotic vegetation present in urban landscapes with an increase in understorey vegetation volume and percentage of native vegetation will benefit a broad array of biodiversity.
      PubDate: 2017-02-23T04:30:47.705089-05:
      DOI: 10.1111/1365-2664.12876
  • Seasonal variation in the biocontrol efficiency of bacterial wilt is
           driven by temperature-mediated changes in bacterial competitive
    • Authors: Zhong Wei; Jianfeng Huang, Tianjie Yang, Alexandre Jousset, Yangchun Xu, Qirong Shen, Ville-Petri Friman
      Abstract: Microbe-based biocontrol applications hold the potential to become an efficient way to control plant pathogen disease outbreaks in the future. However, their efficiency is still very variable, which could be due to their sensitivity to the abiotic environmental conditions.Here, we assessed how environmental temperature variation correlates with ability of Ralstonia pickettii, an endophytic bacterial biocontrol agent, to suppress the Ralstonia solanacearum pathogen during different tomato crop seasons in China.We found that suppression of the pathogen was highest when the seasonal mean temperatures were around 20 °C and rapidly decreased with increasing mean crop season temperatures. Interestingly, low levels of disease incidence did not correlate with low pathogen or high biocontrol agent absolute densities. Instead, the biocontrol to pathogen density ratio was a more important predictor of disease incidence levels between different crop seasons. To understand this mechanistically, we measured the growth and strength of competition between the biocontrol agent and the pathogen over a naturally occurring temperature gradient in vitro. We found that the biocontrol strain grew relatively faster at low temperature ranges, and the pathogen at high temperature ranges, and that similar to field experiments, pathogen suppression peaked at 20 °C.Together, our results suggest that temperature-mediated changes in the strength of bacterial competition could potentially explain the variable R. solanacearum biocontrol outcomes between different crop seasons in China.Synthesis and applications. Our results suggest that abiotic environmental conditions, such as temperature, can affect the efficacy of biocontrol applications. Thus, in order to develop more consistent biocontrol applications in the future, we might need to find and isolate bacterial strains that can retain their functionality regardless of the changing environmental conditions.
      PubDate: 2017-02-23T04:30:34.888802-05:
      DOI: 10.1111/1365-2664.12873
  • A synthesis of tree functional traits related to drought-induced mortality
           in forests across climatic zones
    • Authors: Michael J. O'Brien; Bettina M. J. Engelbrecht, Julia Joswig, Gabriela Pereyra, Bernhard Schuldt, Steven Jansen, Jens Kattge, Simon M. Landhäusser, Shaun R. Levick, Yakir Preisler, Päivi Väänänen, Cate Macinnis-Ng
      Abstract: Forest dieback caused by drought-induced tree mortality has been observed world-wide. Forecasting which trees in which locations are vulnerable to drought-induced mortality is important to predict the consequences of drought on forest structure, biodiversity and ecosystem function.In this paper, our central aim was to compile a synthesis of tree traits and associated abiotic variables that can be used to predict drought-induced mortality.We reviewed the literature that specifically links drought mortality to functional traits and site conditions (i.e. edaphic variables and biotic conditions), targeting studies that show clear use of tree traits in drought analysis. We separated the review into five climatic zones to determine global vs. regionally restricted relationships between traits and mortality.Our synthesis identifies a number of traits that have clear relationships with drought-induced mortality (e.g. wood density at the species level and tree size and growth at the individual level). However, the lack of direct relationships between most traits and drought-induced mortality highlights areas where future research should focus to broaden our understanding.Synthesis and applications. Our synthesis highlights established relationships between traits and drought-induced mortality, presents knowledge gaps for future research focus and suggests monitoring and research avenues for improving our understanding of drought-induced mortality. It is intended to assist ecologists and natural resource managers choose appropriate and measurable parameters for predicting local and regional scale tree mortality risk in different climatic zones within constraints of time and funding availability.
      PubDate: 2017-02-18T01:30:34.050383-05:
      DOI: 10.1111/1365-2664.12874
  • Combining human acceptance and habitat suitability in a unified
           socio-ecological suitability model: a case study of the wolf in
    • Authors: Dominik M. Behr; Arpat Ozgul, Gabriele Cozzi
      Abstract: Habitat suitability models (HSMs) are commonly used in conservation practise to assess the potential of an area to be occupied and colonised. A major limitation of these models, however, is the omission of spatially explicit understanding of human acceptance towards the focal species. As wildlife is more and more subject to human-dominated landscapes, ignoring the sociological component will result in misrepresentation of the observed processes and inappropriate management.We distributed 10 000 questionnaires across Switzerland and identified key socio-demographical factors correlated with human acceptance of the wolf. We then created a spatially explicit acceptance model based on geo-referenced socio-demographical, social and geographical information. Finally, we combined our acceptance model with a HSM to obtain a unified socio-ecological suitability model, which included human and ecological components.We showed that the key factors associated with human acceptance were perception of how harmful the wolf is, interest in wolf-related issues, need for livestock protection, and fear of the wolf. Perceived harmfulness was in turn correlated with direct and indirect experience with the wolf, and level of education.Our acceptance map predicted decreasing acceptance with increasing altitude of residency and proximity to locations of confirmed wolf presence. This resulted in the overall opposition to the wolf for the Alpine region, albeit substantial regional differences.We found little spatial overlap (6% of Switzerland) between areas where the wolf was accepted and areas of suitable habitat. These areas of socio-ecological suitability were concentrated in the Jura Mountains and in the eastern and southern Alps, and were absent in the western and central Alps. Particularly in the Jura region, which is yet to be colonised, management of human acceptance will be a crucial conservation target.Synthesis and applications. We developed an integrative, socio-ecological approach that allowed us to accurately reproduce recent wolf recolonisation. We anticipate our framework to be a powerful tool to reliably evaluate overall suitable habitats and predict short to medium-term range expansion for species whose distribution is also dependent on human attitudes. Because our approach is sensitive to both the ecological and human component, it is ideally suited to identify key regions where proactive and targeted socio-ecological management plans are needed.
      PubDate: 2017-02-16T19:01:02.337995-05:
      DOI: 10.1111/1365-2664.12880
  • The importance of trees for woody pasture bird diversity and effects of
           the European Union's tree density policy
    • Authors: Simon Jakobsson; Regina Lindborg
      Abstract: Recent reforms in the Common Agricultural Policy aim for a greening of the subsidy system with potential improvements for biodiversity conservation. As part of that process, the tree density limit for pastures to qualify for European Union subsidies has been increased from 50 to 100 trees per hectare. However, recent studies show that the high biodiversity values of these habitats may be threatened by these limits, highlighting the need for policy improvements. Still, little is known about the direct effects of tree density limitations on bird communities in woody pastures.We investigated how bird diversity and species composition are affected by tree density in 49 Swedish woody pastures along a gradient of 4–214 trees per hectare. We recorded bird communities, tree density and stand structure estimates in the field and estimated forest cover in the surrounding landscape from aerial photos. Using generalised additive models and redundancy analysis, we analysed how bird territorial species richness, bird abundance and species composition are affected by tree density, taking into account other local and landscape scale explanatory variables.Tree density had a significant positive effect on bird species richness at low tree densities and species richness saturated at approximately 50 trees per hectare. Shrub density had a significant positive linear effect on both bird species richness and abundance. Tree and shrub density were also the major drivers of bird community composition, with secondary effects of tree species diversity and landscape forest cover.Policy implications. Our results show that tree density is not the limiting factor, but rather a driver of bird diversity and species composition in woody pastures and that tree density limits may fail to capture the whole range of biological values. To improve policy recommendations, we therefore stress the importance of considering additional social–ecological drivers associated to management quality, e.g. taking into account moral and cultural motivations among farmers, to preserve biodiversity in woody pastures.
      PubDate: 2017-02-14T03:50:33.493541-05:
      DOI: 10.1111/1365-2664.12871
  • Using dark diversity and plant characteristics to guide conservation and
    • Authors: Jesper Erenskjold Moeslund; Ane Kirstine Brunbjerg, Kevin Kuhlmann Clausen, Lars Dalby, Camilla Fløjgaard, Anders Juel, Jonathan Lenoir
      Abstract: Dark diversity is a promising concept for prioritising management efforts as it focuses on species that are present in the regional pool, but locally absent even though environmental requirements are met. Currently, we lack knowledge of what characterises species belonging to the dark diversity more often than others, although this is important knowledge for restoration and conservation actions.We applied the concept to a massive national (Danish) plant diversity data base, containing 236 923 records from 15 160 surveys involving 564 species. This enabled the first geographically comprehensive (43 000 km2) assessment of dark diversity, at a spatial resolution relevant for conservation and restoration planning (78 m2) across multiple terrestrial habitats, thereby maximising the practical applications of this concept. The probability for a given plant species to belong to the dark diversity was computed and logistically regressed against variables representing its ecological preferences (e.g. nutrient availability), strategies (competitor, stress tolerant, ruderal), mycorrhizal relationships, establishment capacities (seed mass) and dispersal abilities.Forty-six percent of the species had a high probability (>95%) of being part of dark diversity, whereas for 7% of the species this probability was less than 60%.Typical dark diversity plant species tended to depend on mycorrhiza, were mostly adapted to low light and low nutrient levels, had poor dispersal abilities and were ruderals and stress intolerant.Synthesis and applications. Characterising species that are more often absent from suitable sites than others (dark diversity species) has important implications for the planning and management of natural ecosystems. From our study, practitioners gain insight into the factors triggering the absence of individual plant species in a seemingly suitable habitat. We highlight the need to carefully consider mycorrhizal inoculations with a suitable assemblage of fungi to promote the establishment success of dark diversity plants. Additionally, time-lags in plant species dispersal and establishment as well as spatial connectivity in fragmented habitats are central to consider in nature management although assisted migration might also aid poor dispersers. Finally, nutrient-poor localities are probably important ‘islets’ allowing nitrophobic dark diversity plant species to thrive within agricultural landscapes that are generally nutrient-rich.
      PubDate: 2017-02-09T01:10:42.508159-05:
      DOI: 10.1111/1365-2664.12867
  • When road-kill hotspots do not indicate the best sites for road-kill
    • Authors: Fernanda Zimmermann Teixeira; Andreas Kindel, Sandra Maria Hartz, Scott Mitchell, Lenore Fahrig
      Abstract: The effectiveness of measures installed to mitigate wildlife road-kill depends on their placement along the road. Road-kill hotspots are frequently used to identify priority locations for mitigation measures. However, in situations where previous road mortality has reduced population size, road-kill hotspots may not indicate the best sites for mitigation.The purpose of this study was to identify circumstances in which road-kill hotspots are not appropriate indicators for the selection of the best road-kill mitigation sites. We predicted that: (i) road-kill hotspots can move in time from high-traffic road segments to low-traffic segments, due to population depression near the high-traffic segment caused by road mortality; (ii) this shift will occur earlier for more mobile species because they should interact more often with the road; (iii) this shift can occur even if the low-traffic segment runs through lower quality habitat than the high-traffic segment. To test these predictions, we simulated population size and road-kill over time for two populations, one exposed to a road segment with high traffic and the other to a road segment with low traffic.Our simulation results supported Predictions 1 and 3, while Prediction 2 was not supported.Synthesis and applications. Our results indicate that, for new roads, road-kill hotspots can be useful to indicate appropriate sites for mitigation. On older roads, road-kill hotspots may not indicate the best sites for road mitigation due to population depression caused by road mortality. Direct measures of the road impact on the population, such as per capita mortality, are better indicators of appropriate mitigation sites than road-kill hotspots.
      PubDate: 2017-02-04T01:40:38.011674-05:
      DOI: 10.1111/1365-2664.12870
  • Resource selection and landscape change reveal mechanisms suppressing
           population recovery for the world's most endangered antelope
    • Authors: Abdullahi H. Ali; Adam T. Ford, Jeffrey S. Evans, David P. Mallon, Matthew M. Hayes, Juliet King, Rajan Amin, Jacob R. Goheen
      Abstract: Understanding how bottom-up and top-down forces affect resource selection can inform restoration efforts. With a global population size of
      PubDate: 2017-02-03T04:15:32.415154-05:
      DOI: 10.1111/1365-2664.12856
  • Plant, soil and microbial controls on grassland diversity restoration: a
           long-term, multi-site mesocosm experiment
    • Authors: Ellen L. Fry; Emma S. Pilgrim, Jerry R.B. Tallowin, Roger S. Smith, Simon R. Mortimer, Deborah A. Beaumont, Janet Simkin, Stephanie J. Harris, Robert S. Shiel, Helen Quirk, Kate A. Harrison, Clare S. Lawson, Phil J. Hobbs, Richard D. Bardgett
      Abstract: The success of grassland biodiversity restoration schemes is determined by many factors; as such their outcomes can be unpredictable. There is a need for improved understanding of the relative importance of below-ground factors to restoration success, such as contrasting soil type and management intensities, as well as plant community composition and order of assembly.We carried out an 8-year mesocosm experiment across three locations in the UK to explore the relative and interactive roles of various above-ground and below-ground factors in the establishment of target species, to determine general constraints on grassland restoration. Each location had a series of mesocosms with contrasting soil types and management status, which were initially sown with six grasses typical of species-poor grasslands targeted for restoration.Over 5 years, sets of plant species were added, to test how different vegetation treatments, including early-coloniser species and the hemiparasite Rhinanthus minor, and soil type and management, influenced the establishment of target plant species and community diversity.The addition of early-coloniser species to model grasslands suppressed the establishment of target species, indicating a strong priority effect. Soil type was also an important factor, but effects varied considerably across locations. In the absence of early-coloniser species, low soil nutrient availability improved establishment of target species across locations, although R. minor had no beneficial effect.Synthesis and applications. Our long-term, multi-site study indicates that successful restoration of species-rich grassland is dependent primarily on priority effects, especially in the form of early-coloniser species that suppress establishment of slow-growing target species. We also show that priority effects vary with soil conditions, being stronger in clay than sandy soils, and on soils of high nutrient availability. As such, our work emphasises the importance of considering priority effects and local soil conditions in developing management strategies for restoring plant species diversity in grassland.
      PubDate: 2017-02-01T05:31:00.509926-05:
      DOI: 10.1111/1365-2664.12869
  • Microhabitat heterogeneity and a non-native avian frugivore drive the
           population dynamics of an island endemic shrub, Cyrtandra dentata
    • Authors: Lalasia Bialic-Murphy; Orou G. Gaoue, Kapua Kawelo
      Abstract: Understanding the role of environmental change in the decline of endangered species is critical for designing scale-appropriate restoration plans. For locally endemic rare plants on the brink of extinction, frugivory can drastically reduce local recruitment by dispersing seeds away from geographically isolated populations. Dispersal of seeds away from isolated populations can ultimately lead to population decline. For localized endemic plants, fine-scale changes in microhabitat can further limit population persistence. Evaluating the individual and combined impact of frugivores and microhabitat heterogeneity on the short-term (i.e. transient) and long-term (i.e. asymptotic) dynamics of plants will provide insight into the drivers of species rarity.In this study, we used 4 years of demographic data to develop matrix projection models for a long-lived shrub, Cyrtandra dentata (H. St. John & Storey) (Gesneriaceae), which is endemic to the island of O'ahu in Hawai'i. Furthermore, we evaluated the individual and combined influence of a non-native frugivorous bird, Leiothrix lutea, and microhabitat heterogeneity on the short-term and long-term C. dentata population dynamics.Frugivory by L. lutea decreased the short-term and long-term population growth rates. However, under the current level of frugivory at the field site the C. dentata population was projected to persist over time. Conversely, the removal of optimum microhabitat for seedling establishment (i.e. rocky gulch walls and boulders in the gulch bottom) reduced the short-term and long-term population growth rates from growing to declining.Survival of mature C. dentata plants had the greatest influence on long-term population dynamics, followed by the growth of seedlings and immature plants. The importance of mature plant survival was even greater when we simulated the combined effect of frugivory and the loss of optimal microhabitat, relative to population dynamics based on field conditions. In the short-term (10 years), however, earlier life stages had the greatest influence on population growth rate.Synthesis and applications. This study emphasizes how important it is to decouple rare plant management strategies in the short vs. long-term in order to prioritize restoration actions, particularly when faced with multiple stressors not all of which can be feasibly managed. From an applied conservation perspective, our findings also illustrate that the life stage that, if improved by management, would have the greatest influence on population dynamics is dependent on the timeframe of interest and initial conditions of the population.
      PubDate: 2017-01-31T22:45:47.610043-05:
      DOI: 10.1111/1365-2664.12868
  • Estimating non-indigenous species establishment and their impact on
           biodiversity, using the Relative Suitability Richness model
    • Authors: Brian Leung; Johanna Bradie
      Abstract: Key questions in invasion biology include where will a non-indigenous species (NIS) establish, and how will it affect biodiversity? Scientists have addressed the first question, largely through correlating species’ distributions with environmental factors (i.e. species distribution models, SDM). Conceptually, SDMs reflect a species’ abiotic constraints, but in reality, they measure the realized rather than fundamental niche. This is a limitation of SDMs, but analysed correctly, it may also be a strength since SDMs already incorporate the outcome of species interactions.We postulate that we can use the relative predicted probabilities of occurrences in each location from SDMs to predict the outcome of interactions between species. Based on this idea, we develop the Relative Suitability Richness (RSR) model, and generate two protocols to (i) assess theoretically whether we can predict the probability of establishment, and (ii) by conducting counterfactual analyses, the extent to which we can infer the impact of NIS on biodiversity.Species distribution models based solely on abiotic factors have the potential to predict species establishment well, even when biotic interactions are strong. However, predictions improved with inclusion of biotic data, even with only partial information. Even with weak environmental predictors and no community data, macro-scale predictions could still be strong and one can estimate loss of native populations, as long as the fitting environment was representative of the prediction environment. If environmental conditions change, predictions were still possible so long as either good environmental predictors and/or biotic information was available.Policy implications. Risk analyses are often recommended to guide management practices; they depend upon forecasting the likelihood and severity of an invasion. The Relative Suitability Richness protocols developed here predict non-indigenous species occurrences and impact, using even partial biotic data on native species occurrences, to provide key information needed to estimate invasion risk, prioritize management effort and advance invasive species policy.
      PubDate: 2017-01-31T22:45:40.740023-05:
      DOI: 10.1111/1365-2664.12862
  • Impact of cane toads on a community of Australian native frogs, determined
    • Authors: Andrew Taylor; Hamish I. McCallum, Graeme Watson, Gordon C. Grigg
      Abstract: Invasive species may have devastating impacts on native biota. Cane toads Rhinella marina continue to invade northern Australia and the consequences for the endemic frogs are unclear. Monitoring frogs in such remote areas is difficult because their activity depends heavily on unpredictable rainfall events.We developed an autonomous acoustic monitoring system which used machine learning techniques to identify up to 22 calling species in real time. Ten of these systems, capable of operating for at least a year without attention, were deployed over a 10-year period along the Roper River valley in the Northern Territory, logging more than 4 million records pre- and post-toad invasion.Within 5 years of their arrival, cane toads became one of the most prominent members of the anuran community. We detected an overall impact, with six frog species declining in calling activity and one apparently increasing. However, almost all species detected initially were detected at the end of the monitoring period, and again on a follow-up survey after a further 10 years.Synthesis and applications. The overall impact of cane toads on endemic frogs has been largely one of rarefaction rather than elimination. Rather than having a devastating impact on the endemic frogs, cane toads have become a component of the amphibian community. Autonomous recording and identification systems such as ours have great potential for long term monitoring of vocalising species in remote and variable environments.
      PubDate: 2017-01-30T04:16:34.100309-05:
      DOI: 10.1111/1365-2664.12859
  • Interpreting and predicting the spread of invasive wild pigs
    • Authors: Nathan P. Snow; Marta A. Jarzyna, Kurt C. VerCauteren
      Abstract: The eruption of invasive wild pigs (IWPs) Sus scrofa throughout the world exemplifies the need to understand the influences of exotic and nonnative species expansions. In particular, the continental USA is precariously threatened by a rapid expansion of IWPs, and a better understanding of the rate and process of spread can inform strategies that will limit the expansion.We developed a spatially and temporally dynamic model to examine three decades (1982–2012) of IWP expansion, and predict the spread of IWPs throughout the continental USA, relative to where IWPs previously inhabited. We used the model to predict where IWPs are likely to invade next.The average rate of northward expansion increased from 6·5 to 12·6 km per year, suggesting most counties in the continental USA could be inhabited within the next 3–5 decades. The spread of IWPs was primarily associated with expansion into areas with similar environmental characteristics as their previous range, with the exception of spreading into colder regions. We identified that climate change may assist spread into northern regions by generating milder winters with less snow. Otherwise, the spread of IWPs was not dependent on agriculture, precipitation or biodiversity at the county level. The model correctly predicted 86% of counties that were invaded during 2012, and those predictions indicate that large portions of the USA are in immediate danger of invasion.Synthesis and applications. Anti-invasion efforts should focus along the boundaries of current occupied range to stop natural expansion, and anti-invasion policies should focus on stopping anthropogenic transport and release of invasive wild pigs. Our results demonstrate the utility of a spatio-temporal examination to inform strategies for limiting the spread of invasive wild pigs.
      PubDate: 2017-01-30T04:16:29.627375-05:
      DOI: 10.1111/1365-2664.12866
  • Grape moth density in Bordeaux vineyards depends on local habitat
           management despite effects of landscape heterogeneity on their biological
    • Authors: Adrien Rusch; Lionel Delbac, Denis Thiéry
      Abstract: Biological control of crop pests is a major ecosystem service affected by several variables acting at multiple spatial scales. Among these variables, heterogeneity at the habitat and landscape scales are known key drivers of trophic interactions and pest density in agroecosystems. However, studies that try to disentangle their relative effects in perennial cropping systems are scarce and nothing is known about their impacts on insect pest density and pesticide applications.We examined the effect of heterogeneity at these two scales on grape moths, one of the most damaging insect pests in European vineyards, and their biological control in 20 vineyards during three consecutive years. We used local vegetation management and the proportion of semi-natural habitats in the surrounding landscape as proxies of heterogeneity at the habitat and landscape scales. Grape moth density was measured over time, as well as biological control services provided by different groups: birds, invertebrate predators, parasitoids and entomopathogenic fungi.Over the 3 years, grape moth density was mainly determined by local heterogeneity, with significantly fewer larvae of the first generation established in vineyards with full compared to partial grass cover.Despite these effects, biological control of grape moths was not primarily affected by local vegetation management but by landscape heterogeneity, and the direction of this effect varied over time. Notably, predation by birds increased with landscape heterogeneity in spring, depending on local vegetation management, while attacks by pathogenic fungi decreased with landscape heterogeneity during winter.Synthesis and applications. Our results suggest that bottom-up processes related to habitat heterogeneity drive grape moth occurrence much more than top-down processes. These results have important implications for the ecological intensification of vineyard landscapes. We found that maintaining full grass cover within vineyards reduced grape moth density to a level below common intervention thresholds. Landscape heterogeneity in the close vicinity of vineyards contributed to improved biological pest control by birds, but depended on local vegetation management. Moreover, opposing effects of landscape management on biological pest control services over time revealed that strategies based only on manipulating landscape heterogeneity might not be the optimal option to limit grape moth density in vineyards.
      PubDate: 2017-01-30T04:16:17.070665-05:
      DOI: 10.1111/1365-2664.12858
  • Sweat bees on hot chillies: provision of pollination services by native
           bees in traditional slash-and-burn agriculture in the Yucatán Peninsula
           of tropical Mexico
    • Authors: Patricia Landaverde-González; José Javier G. Quezada-Euán, Panagiotis Theodorou, Tomás E. Murray, Martin Husemann, Ricardo Ayala, Humberto Moo-Valle, Rémy Vandame, Robert J. Paxton
      Abstract: Traditional tropical agriculture often entails a form of slash-and-burn land management that may adversely affect ecosystem services such as pollination, which are required for successful crop yields. The Yucatán Peninsula of Mexico has a >4000 year history of traditional slash-and-burn agriculture, termed ‘milpa’. Hot ‘Habanero’ chilli is a major pollinator-dependent crop that nowadays is often grown in monoculture within the milpa system.We studied 37 local farmers’ chilli fields (sites) to evaluate the effects of landscape composition on bee communities. At 11 of these sites, we undertook experimental pollination treatments to quantify the pollination of chilli. We further explored the relationships between landscape composition, bee communities and pollination service provision to chilli.Bee species richness, particularly species of the family Apidae, was positively related to the amount of forest cover. Species diversity decreased with increasing proportion of crop land surrounding each sampling site. Sweat bees of the genus Lasioglossum were the most abundant bee taxon in chilli fields and, in contrast to other bee species, increased in abundance with the proportion of fallow land, gardens and pastures which are an integral part of the milpa system.There was an average pollination shortfall of 21% for chilli across all sites; yet the shortfall was unrelated to the proportion of land covered by crops. Rather, chilli pollination was positively related to the abundance of Lasioglossum bees, probably an important pollinator of chilli, as well indirectly to the proportion of fallow land, gardens and pastures that promote Lasioglossum abundance.Synthesis and applications. Current, low-intensity traditional slash-and-burn (milpa) agriculture provides Lasioglossum spp. pollinators for successful chilli production; fallow land, gardens and pasture therefore need to be valued as important habitats for these and related ground-nesting bee species. However, the negative impact of agriculture on total bee species diversity highlights how agricultural intensification is likely to reduce pollination services to crops, including chilli. Indeed, natural forest cover is vital in tropical Yucatán to maintain a rich assemblage of bee species and the provision of pollination services for diverse crops and wild flowers.
      PubDate: 2017-01-27T01:10:50.582826-05:
      DOI: 10.1111/1365-2664.12860
  • Meta-corridor solutions for climate-vulnerable plant species groups in
           South Korea
    • Authors: Hyeyeong Choe; James H. Thorne, Robert Hijmans, Jiyoen Kim, Hyuksoo Kwon, Changwan Seo
      Abstract: Vulnerability assessments can provide useful information for the establishment of climate change adaptation strategies. We performed spatial vulnerability assessments for multiple plant species that incorporate potential range shifts to areas of future suitable climate. We conducted the assessments at a national level for plant species organized into vulnerable species groups. We then identified a climate meta-corridor for each vulnerable group that could potentially be a pathway for multiple species.We estimated climate suitability for 2297 South Korean terrestrial plant species under current climate conditions and climate projections for 2050 using the Multivariate Adaptive Regression Splines multiresponse species distribution model. We classified the plants into five groups based on their current spatial distribution patterns: centrally located species, wide-range species, coastal mountain species, montane species, and lowland species. Three vulnerability assessment components — exposure, spatial disruption, and dispersal pressure — were used to calculate the spatial vulnerability of each species. Vulnerability values were averaged by group. We identified climate meta-corridors that would link current suitable areas to future climatically suitable areas, and tested the corridors for multi-species accessibility.The vulnerability assessment indicates that coastal mountain, montane, and lowland species groups, comprising 37% of all modelled species, are the most vulnerable to climate change. The climate meta-corridor for each group overlaps at least some portion of 83% or more of its species' current modelled ranges. The current and future climate-suitable areas for the lowland species group have very little spatial overlap, suggesting a high priority should be placed on the corridor identified for these species. We found that the destinations of the climate corridors converge, raising questions about large numbers of species moving to limited areas, and that transboundary corridor modelling is needed on the Korean Peninsula.Policy implications. Each of the three meta-corridors has unique policy implications: assisted migration for the highest elevation species for the montane; significant conservation and restoration work for the lowland; and perhaps no direct intervention but monitoring to evaluate effectiveness of the relatively intact habitats of the coastal mountain meta-corridor. Overall, implementation policies for climate connectivity will be context-dependent, requiring different approaches dependent on local and regional conditions and the species targeted.
      PubDate: 2017-01-25T05:02:04.918834-05:
      DOI: 10.1111/1365-2664.12865
  • A species effect on storm erosion: Invasive sedge stabilized dunes more
           than native grass during Hurricane Sandy
    • Authors: Bianca R. Charbonneau; Louise S. Wootton, John P. Wnek, J. Adam Langley, Michael A. Posner
      Abstract: Vegetation and biogeomorphology are highly coupled in beach dune systems, but plant species effects on abating storm erosion are largely unexplored.We quantified coastal dune erosion from Hurricane Sandy (October 2012) as a function of pre-storm system characteristics – dune height, beach width and dominant vegetation stabilizing dunes (native Ammophila breviligulata or invasive Carex kobomugi) at Island Beach State Park, New Jersey, USA. We assessed dune erosion using a combination of pre- and post-Sandy aerial image spatial analyses in ArcGIS and GPS field mapping. Our two erosion metrics are novel, macroscale 2D surface area changes and Dune Crest Transgression, the later of which is measured at the microscale (1 m−1) and analysed using a mixed model incorporating spatial autocorrelation.We document a species-specific effect on collision erosion. Although C. kobomugi reduces native diversity and abundance, it may be beneficial for coastal protection, as dunes fronted and stabilized by C. kobomugi suffered less erosion than those dominated by A. breviligulata under the same abiotic conditions.Dune height and beach width were equal for species prior to the storm and therefore do not account for or confound differences in erosion. Similarly, traditional calculations of erosion with volumetric loss confer these results.Synthesis and applications. This is the first study to show a species effect on coastal dune erosion. Native Ammophila breviligulata stabilized dune stretches suffered more erosion from Hurricane Sandy than complimentary invasive Carex kobomugi stretches, contradicting anecdotal reports that foredunes stabilized by a shorter statured species are more prone to erosion. This study highlights the importance of vegetation for dune stability and management using two novel metrics for erosion. Our erosion metrics are related to volumetric loss, can be monitored and calculated by managers with or without remote sensing, and can be applied to other systems. Discussions on coastal management of dunes as habitats and protective buffers must include vegetation and the results of this study suggest that not all species are equal with regard to their ability to combat storm erosion. Multidisciplinary studies with applied implications will grow increasingly important as storms continue to grow more frequent, severe and unpredictable with climate change.
      PubDate: 2017-01-25T01:00:49.779127-05:
      DOI: 10.1111/1365-2664.12846
  • Density-dependent vulnerability of forest ecosystems to drought
    • Authors: Alessandra Bottero; Anthony W. D'Amato, Brian J. Palik, John B. Bradford, Shawn Fraver, Mike A. Battaglia, Lance A. Asherin
      Abstract: Climate models predict increasing drought intensity and frequency for many regions, which may have negative consequences for tree recruitment, growth and mortality, as well as forest ecosystem services. Furthermore, practical strategies for minimizing vulnerability to drought are limited. Tree population density, a metric of tree abundance in a given area, is a primary driver of competitive intensity among trees, which influences tree growth and mortality. Manipulating tree population density may be a mechanism for moderating drought-induced stress and growth reductions, although the relationship between tree population density and tree drought vulnerability remains poorly quantified, especially across climatic gradients.In this study, we examined three long-term forest ecosystem experiments in two widely distributed North American pine species, ponderosa pine Pinus ponderosa (Lawson & C. Lawson) and red pine Pinus resinosa (Aiton), to better elucidate the relationship between tree population density, growth and drought. These experiments span a broad latitude and aridity range and include tree population density treatments that have been purposefully maintained for several decades. We investigated how tree population density influenced resistance (growth during drought) and resilience (growth after drought compared to pre-drought growth) of stand-level growth during and after documented drought events.Our results show that relative tree population density was negatively related to drought resistance and resilience, indicating that trees growing at lower densities were less vulnerable to drought. This result was apparent in all three forest ecosystems, and was consistent across species, stand age and drought intensity.Synthesis and applications. Our results highlighted that managing pine forest ecosystems at low tree population density represents a promising adaptive strategy for reducing the adverse impacts of drought on forest growth in coming decades. Nonetheless, the broader applicability of our findings to other types of forest ecosystems merits additional investigation.
      PubDate: 2017-01-24T07:51:18.198756-05:
      DOI: 10.1111/1365-2664.12847
  • Prioritizing landscapes for restoration based on spatial patterns of
           ecosystem controls and plant–plant interactions
    • Authors: Jomar M. Barbosa; Gregory P. Asner
      Abstract: The widespread degradation of natural ecosystems requires cost-efficient restoration techniques that minimize risk and consider context-specific restoration conditions. However, meeting these demands can be difficult because information on ecosystem-level factors controlling vegetation and continuous spatial data on species interactions are often lacking.Using airborne light detection and ranging (LiDAR) data from a Hawaiian dry forest, we delineated crowns and assessed the 3D structure of more than 700 000 shrubs and trees. We used Random Forest machine learning to assess the relative importance of resource availability, environmental conditions, and disturbance regimes on canopy density. We then modelled and scaled up plant–plant interactions (i.e. potential nursery effects) to landscape units using a LiDAR-derived Canopy Coalescence (CC) index. We used the relative importance of ecosystem factors, canopy cover, and CC index to prioritize landscapes for restoration.Here, we demonstrate a methodological framework that prioritizes landscapes in need of restoration (i.e. planting woody species) using two ecological perspectives: (i) ecosystem-level controls on remnant woody vegetation, and (ii) potential interactions between established canopies and seedlings (e.g. nursery effect, competition).Our results highlight the heterogeneous nature of ecosystem-level drivers affecting forest structure along elevation gradients. Consequently, the degree of potential nursery interactions between established canopies and seedlings at the landscape-scale was context-specific.Synthesis and applications. Our study provides a methodological approach that prioritizes landscapes for restoration by identifying the main controls on tree spatial distribution and by inferring the favourable conditions for seedlings. This approach can guide land managers to define cost-efficient restoration strategies for large ecological areas.
      PubDate: 2017-01-24T05:29:37.765641-05:
      DOI: 10.1111/1365-2664.12857
  • Long-term satellite tracking reveals region-specific movements of a large
           pelagic predator, the shortfin mako shark, in the western North Atlantic
    • Authors: Jeremy J. Vaudo; Michael E. Byrne, Bradley M. Wetherbee, Guy M. Harvey, Mahmood S. Shivji
      Abstract: As upper level predators, sharks serve an important role in marine ecosystems, but are often at risk from fisheries. Successful management of these species will require detailed information about their movements and distributions.Using satellite telemetry, we investigated the long-term horizontal movements and seasonal distributions of shortfin mako sharks Isurus oxyrinchus in the western North Atlantic Ocean.Twenty-six sharks (14 USA, 12 Mexico) were tracked for durations of 78–527 days. Ten sharks were tracked for >1 year. Sharks displayed region-specific movements, with little distributional overlap between the Gulf of Mexico and Caribbean Sea, and the western North Atlantic. Sharks tagged off the USA ranged over a larger area, including shelf and pelagic habitats. Their core distribution was largely over the continental shelf and fluctuated seasonally, ranging from South Carolina, USA, in the winter to Nova Scotia, Canada, in the autumn, and appeared to follow seasonal productivity peaks while favouring warmer waters. Sharks tagged off Mexico displayed more restricted movements, largely confined to shelf habitats, with core activity centred year-round on the eastern Campeche Bank, Mexico.Sharks moved across the jurisdictional management boundaries of 17 nations, and the proportion of tracked sharks harvested (22%) was twice that obtained from previous fisheries-dependent, conventional tagging studies.Sharks also displayed considerable variability in movements, with seven sharks tagged off the USA making long-distance, highly directional southern excursions into unproductive subtropical/tropical waters before returning north.Policy implications. The large-scale and region-specific movements of shortfin mako sharks underscore the need for close cooperation amongst western North Atlantic nations and implementation of regionally and seasonally specific management strategies. The movement patterns also provide baseline information, which could be used in spatially explicit stock assessment models. Identification of high-use areas by shortfin mako sharks provides focal areas for quantifying interactions with fisheries. The high harvest rate observed in our fisheries-independent tracking study raises questions about the true rate of fisheries mortality experienced by shortfin mako sharks, calling for a cautionary interpretation of past stock assessments used to determine management policy for this highly migratory species of conservation concern.
      PubDate: 2017-01-23T01:40:58.299816-05:
      DOI: 10.1111/1365-2664.12852
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