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- Leveraging local habitat suitability models to enhance restoration
benefits for species of conservation concern
Abstract: Abstract Efforts to restore habitats and conserve wildlife species face many challenges that are exacerbated by limited funding and resources. Habitat restoration actions are often conducted across a range of habitat conditions, with limited information available to predict potential outcomes among local sites and identify those that may lead to the greatest returns on investment. Using the Gunnison sage-grouse (Centrocercus minimus) as a case study, we leveraged existing resource selection function models to identify areas of high restoration potential across landscapes with variable habitat conditions and habitat-use responses. We also tested how this information could be used to improve restoration planning. We simulated change in model covariates across crucial habitats for a suite of restoration actions to generate heatmaps of relative habitat suitability improvement potential, then assessed the degree to which use of these heatmaps to guide placement of restoration actions could improve suitability outcomes. We also simulated new or worsening plant invasions and projected the resulting loss or degradation of habitats across space. We found substantial spatial variation in projected changes to habitat suitability and new habitat created, both across and among crucial habitats. Use of our heatmaps to target placement of restoration actions improved habitat suitability nearly fourfold and increased new habitat created more than 15-fold, compared to placements unguided by heatmaps. Our decision-support products identified areas of high restoration potential across landscapes with variable habitat conditions and habitat-use responses. We demonstrate their utility for strategic targeting of habitat restoration actions, facilitating optimal allocation of limited management resources to benefit species of conservation concern.
PubDate: 2024-08-24
- Off the conservation radar: the hidden story of Europe's tiny pea clams
(Bivalvia: Sphaeriidae)
Abstract: Abstract This study highlights the conservation problems faced by the tiny freshwater bivalves of the family Sphaeriidae, also known as pea, pill, or fingernail clams (or mussels) in Europe. Despite their global distribution, assumed ecological importance, and potential uses, basic knowledge about their taxonomy, biology, and ecology is very limited and much lower than for the larger freshwater bivalve taxa. Immediate scientific priorities are required to fill knowledge gaps regarding their taxonomy, genetic diversity, distribution, reproductive cycle, ecosystem functions, and population trends. Such fundamental knowledge is necessary to identify specific threats and develop appropriate conservation actions. Deploying environmental DNA analysis at a large scale could be a valuable way to fill gaps in distribution and strengthen monitoring in areas where local taxonomic knowledge is lacking. Until taxon-specific management plans can be developed, we recommend that efforts concentrate on the general protection and restoration of wetland habitats, implementing pollution control measures, and managing invasive species. These actions should be complemented by community engagement through citizen science initiatives. Additionally, prioritising data collection to fill existing knowledge gaps and updating conservation statuses (Red Lists) based on comprehensive assessments will be crucial. Implementing these actions will provide a starting point for the broader protection of freshwater ecosystems, thus benefiting pea clams and other interconnected species within these habitats.
PubDate: 2024-08-20
- Cross-taxon analysis in the highly threatened Mediterranean dunes reveals
consistent diversity patterns in butterfly and plant communities
Abstract: Abstract Butterflies and plant species are widely used as model systems in biodiversity and conservation research. However, little is known about spatial patterns of butterfly diversity linked to plant communities across coastal dune ecotones. We explored the relation between butterfly and vegetation diversity in a Mediterranean protected dune system in Central Italy. We sampled butterfly and plant communities on shifting and fixed dunes and investigated their distribution patterns by diversity indexes and Species Abundance Diversity models (SADs). We also computed species beta-diversity and analyzed the relation between butterfly communities and vegetation by correlation analyses. Cross-taxon congruence in species richness, composition and abundance was assessed using Mantel correlation tests. Both butterfly and plant diversity were higher on the fixed dunes than on the shifting dunes. In both communities, SADs were adequately described by the geometric series model, which is typical of harsh environments with simple communities dominated by few species. Among both butterflies and plants, we identified species found only on either the shifting or the fixed dunes. Correlation between plant and butterfly diversity was higher for entomophilous plant species than for the more abundant anemophilous ones. Our results indicate that both plant and butterfly communities respond to the sea-inland environmental gradient, forming distinct communities with specialized taxa. Our findings also provide evidence of the importance of butterfly-plant relations for preserving biological diversity and ecosystem functioning in Mediterranean coastal areas.
PubDate: 2024-08-16
- Short-term effects of clearing restoration on the relationship of plant
and moth communities
Abstract: Abstract Insects and plants share a close relationship; plants provide feeding opportunities, ecological niches, and shelters for insects, while insects, in turn, facilitate pollination for plants. Management actions might positively or negatively affect insect species richness and/or abundance, in particular, forest practices can significantly influence insect communities. In this study, we investigated the effects on plant and moth communities following the realization of an ecological corridor (composed of 10 clearings) in forest in NW of Italy. Specifically, through plant surveys and moth light traps, we investigated plant and moth communities and their relationship in newly shaped clearings and their surrounding forest. We found that plants responded quickly to clearing formation, presenting differentiated plant communities between xero-thermophile clearings, mesophile clearings and forest. These differences reflected on moth communities as well, allowing to find indicator species for each ecosystem. Structural variables (i.e. openness) and topography (i.e. elevation) were key factors affecting the differentiation of moth communities. On the other hand, plants explained most of the variance in moth communities, so, through plants, we differentiated moth communities into those typical of xero-thermophile clearings, mesophile clearings and forest. In conclusion, forest management significantly affects plant and moth communities. Newly shaped clearings support higher species richness (including specialist species) and abundance than closed canopy forest. To increase species richness and abundance for both plants and moths, we suggest conservation measures that include creating open habitats within forests at medium elevation (650–950 m a.s.l.).
PubDate: 2024-08-16
- Achieving structural heterogeneity and high multi-taxon biodiversity in
managed forest ecosystems: a European review
Abstract: Abstract The European Biodiversity Strategy has set the key goal to maintain and promote biodiversity. Managed forests here play a key role, as they are among the most diverse ecosystems. To create biodiversity rich managed forest landscapes, we need a deep understanding on how management affects forest structure and subsequently habitat quality on the local and landscape level. However, to date a confusingly large amount of different terms for various management systems exist and it remains unclear how forest structure and composition affected by specific management systems affect biodiversity. Here, we first aim to clarify forest management systems terminology. Second, we link existing management systems with forest structure and review at European level how these structures affect local α-, as well as landscape-scale β- and γ-biodiversity. We found that research and derived management guidelines have a strong focus on local forest stand heterogeneity and related α-diversity, while ignoring the importance of landscape-scale heterogeneity and therefore β- and γ-diversity. Instead of promoting one management system as an all-in-one-solution, a diversity of different forest management systems seems the most promising way to create biodiversity rich forest landscapes. We finally discuss how a combination of different management systems might help to create structurally rich forest habitats and landscapes, simulating different successional stages and promoting species rich communities.
PubDate: 2024-08-14
- Plant species richness in intensively managed temperate wet grasslands:
current state and the importance of edge habitats
Abstract: Abstract This study investigates within-site variation in the diversity and composition of aboveground vegetation and seed bank in intensively managed wet grasslands of north-western Germany, comparing field edges, field margins and field interiors. We tested the hypothesis that unfertilized buffer strips at field edges function as refugia of characteristic species even in grasslands that are managed intensively for silage production. In 55 grassland sites on each marsh and moor soils, respectively, we conducted vegetation surveys, seed bank analyses and soil chemical measurements in field edge, margin and interior plots, and searched for the factors causing within-site variation in vegetation composition. The total species pool was small at the 110 sites, i.e. 148 species in the aboveground vegetation and 107 species in the seed bank, demonstrating severe impoverishment. The α-diversity decreased from 23 species (median) per 200 m2 at the edge to 15 species in the interior, with 38 species occurring only at field edges. The number of species with conservation value was very low in aboveground vegetation and seed bank and was only slightly higher at the edge than in the interior. Soil P availability was ca. 30% lower at the unfertilized edges than in the interior. We conclude that unfertilized buffer strips at grassland edges may help reducing nutrient leaching from high-input grassland systems, but they have mostly lost their refugial function for phytodiversity after decades of intensive management. Restoration efforts with seed or green hay transfer from richer source habitats are needed to promote biodiversity in field-edge buffer strips.
PubDate: 2024-08-05
- Which birds have the most to lose' an analysis of bird species’ feeding
habitat in changing Australian landscapes
Abstract: Abstract Australia has lost vast areas of its natural vegetation through agriculture and urbanization, resulting in the area of suitable habitat for many Australian bird species being greatly diminished. Given the geographical and ecological biases in anthropogenic land use, the impact of habitat loss now and into the future may be disproportionately high for some species, threatening their long-term persistence. Such changes are occurring rapidly, and habitat loss needs to be monitored dynamically to prevent extinction. To monitor changes in available unmodified species habitat, we use species’ area of feeding habitat (AFH), which represents the area of habitat within a species’ range with vegetation matching their feeding requirements. We analysed the past, current and future threats of habitat modification for 467 Australian bird species by calculating AFH across three time periods: pre-colonization, current (2020), and a projected future scenario (2100). These values were used to identify species subject to substantial habitat loss due to urbanization and agriculture and delineate predictors of such losses. Most species had experienced habitat loss since colonization (n = 442, 95%), and species that had already experienced considerable habitat loss were more likely to lose habitat into the future. Species with particular habitat associations (e.g., Mallee), were also more prone to greater proportions of habitat lost. The results highlight the utility of AFH and emphasize the importance of protecting what habitat remains for the species with highly depleted geographic ranges, noting that those that have experienced the most loss of unmodified habitat are the most likely to lose more unmodified habitat under future conditions.
PubDate: 2024-08-01
- Palms predict the distributions of birds in southwestern Amazonia and are
potential surrogates for land-use planning by citizen scientists
Abstract: Abstract In the absence of high-quality biodiversity data, land-use planners and conservationists often rely on biodiversity surrogates. Many studies have proposed surrogates based on assumptions about the environmental niches of species. However, the use of such assumptions is not always useful because biological processes and ecological interactions can operate at different scales due to the non-uniform geographical distribution of environmental conditions. In such cases, compositional heterogeneity across the same region can be expected but is often hidden by broad-scale environmental data. Furthermore, these assumptions may obscure important relationships between species and their environment. To elucidate this issue, we asked whether biotic interactions between two taxonomic groups are more important than other factors in reflecting the distribution of unsampled species. To do this, we compared the relationship between the distribution of bird species and the distribution of the five most-abundant palm species which are often considered indicators of bird communities. These species include Lepidocaryum tenue, Oenocarpus bataua, Oenocarpus bacaba, Mauritiella aculeata, and Attalea speciosa. Additionally, we considered environmental factors (precipitation, water-table levels, sand and clay contents) and the ecoregions along the Purus-Madeira interfluve as drivers of bird species composition. Our results show that bird-assemblage composition was strongly correlated with changes in palm-species abundance. The presence-absence data for bird-species showed that palm-species alone explained 25% and 19% of composition of all birds and only canopy birds, respectively. These palm species are abundant and can be easily identified and monitored by non-specialists, such as citizen scientists. Citizens are often involved in data acquisition but may not have the experience to sample large assemblages consisting of hundreds of species; thus, these five most-abundant palms species could serve as a cost-effective and efficient biodiversity surrogate for birds.
PubDate: 2024-08-01
- Everybody needs good neighbours: movement, habitat use, and conspecific
association in a reintroduced mesopredator
Abstract: Abstract As a reintroduction progresses through the establishment, growth, and regulation phases, density-dependent mechanisms increasingly drive population dynamics. This can complicate efforts to reinforce these populations if the translocated individuals (henceforth reinforcers) are excluded, or existing residents become displaced. This is especially pertinent for islands and fenced havens, where immigration is often only possible by translocation. Conspecific associations offer insights into how these density-dependent mechanisms manifest in space and time. We investigated how movement, habitat use, and conspecific associations differed between eastern quoll (Dasyurus viverrinus) residents and reinforcers at a conservation-fenced haven. We used GPS collars to quantify distances travelled per night, home and core ranges, nocturnal (activity) and diurnal (denning) habitat use and preference, and conspecific associations over three periods: baseline (residents only, days 3–21), release (both cohorts, days 22–32), and settlement (reinforcers only, days 33–52) for ≤ 42 days post-release (depending on GPS unit longevity). Eastern quolls travelled greater mean distances per night (< 2.15 km, x̄ 1.75 km) and had larger home ranges (< 251 ha, x̄ 178 ha) during the release period. Reinforcers had larger home ranges (249 ha) and greater overlap with other collared eastern quolls (115 ha) when compared to residents (range 90 ha, overlap 46 ha). We found a significant preference for grassland habitat across all animals and periods. During the settlement period, we found a preference for nocturnal activity in greater understory and south-west facing aspects, and lower movement correlation, sociality, and den sharing between collared eastern quolls. Finally, we found lower den sharing in reinforcers (29%) compared to residents (52%), and for fawn- animals compared to dark-morphs. Our results revealed short-term movements, habitat use, and conspecific associations at a greater spatiotemporal resolution than has ever been achieved for this species. Our findings offer important insights into the importance of appropriate habitat and conspecific cueing for reintroductions, and highlight the need to monitor density-dependent mechanisms to inform adaptive management to promote positive outcomes for both initial reintroductions and reinforcements.
PubDate: 2024-08-01
- Invasive black rats menacing endangered lizards
Abstract: Abstract Despite the pernicious impacts that invasive black rats Rattus rattus have on island ecosystems, little is known about their effect upon insular reptiles, which are a highly vulnerable but pivotal element of island biota. To bring to light these effects, we evaluated the threat posed by R. rattus on the critically endangered Canarian spotted lizard Gallotia intermedia by analyzing its frequency of occurrence on rat feces, estimating rat abundance and density, and correlating these parameters with previous lizard censuses. We genetically detected that 14.96% of all rat feces contained G. intermedia, with 27.27% of individual R. rattus consuming this lizard. Rat density varied from 0.740 ± 0.474 to 2.183 ± 1.137 rats/ha and was correlated with larger declines of G. intermedia between past censuses and those of 2019. These results confirm for the first time that R. rattus consumes and impacts this endemic and endangered lizard species. From a broader perspective, this is one of the first studies detecting rat impact on a large-sized reptile, which calls for further attention to the interaction between invasive rats and a highly vulnerable but essential component of island ecosystems.
PubDate: 2024-08-01
- Regional foraging areas of green turtles (Chelonia mydas) nesting at
Aldabra Atoll: insights from stable isotopes and satellite telemetry
Abstract: Abstract Sea turtles spend the majority of their lives at foraging grounds. These areas are important for population persistence but generally occur in coastal habitats, which are under increasing human pressure. Identifying key foraging areas is therefore an important step to understanding critical sea turtle habitats, and therefore their threats. Isotope ratios (δ15N, δ13C) from skin tissues of 90 green turtles (Chelonia mydas) nesting at the regionally important rookery of Aldabra Atoll, Seychelles, were analyzed with samples collected during two periods: 51 samples from March to September 2021, and 39 samples from January to April 2022. These analyses were complemented by nine satellite tracks to identify key foraging areas. Hierarchical clustering and discriminant function analysis identified two main foraging areas: the East African coast (Tanzania and Somalia) and northern Madagascar. Isotopic values indicated that the majority of green turtles nesting at Aldabra forage at one of these two areas, with slightly more green turtles visiting the East African coast. Geographical isotopic patterns were not found latitudinally, suggesting a potential limit to this approach for coastal areas in the Western Indian Ocean. However, we found longitudinal variation of δ13C and δ15N that few studies have reported. This is the first study in this region to combine satellite telemetry and stable isotope analysis to assign likely foraging areas of green turtles and advances understanding of the complex migration patterns and foraging ecology of this species. We demonstrate the potential and the limitations of stable isotope analysis for identifying/characterizing green turtle foraging areas in this region.
PubDate: 2024-08-01
- Using joint species distribution modelling to predict distributions of
seafloor taxa and identify vulnerable marine ecosystems in New Zealand
waters
Abstract: Abstract Effective ecosystem-based management of bottom-contacting fisheries requires understanding of how disturbances from fishing affect seafloor fauna over a wide range of spatial and temporal scales. Spatial predictions of abundance for 67 taxa were developed, using an extensive dataset of faunal abundances collected using a towed camera system and spatially explicit predictor variables including bottom-trawl fishing effort, using a Joint Species Distribution Model (JSDM). The model fit metrics varied by taxon: the mean tenfold cross-validated AUC score was 0.70 ± 0.1 (standard deviation) for presence–absence and an R2 of 0.11 ± 0.1 (standard deviation) for abundance models. Spatial predictions of probability of occurrence and abundance (individuals per km2) varied by taxon, but there were key areas of overlap, with highest predicted taxon richness in areas of the continental shelf break and slope. The resulting joint predictions represent significant advances on previous predictions because they are of abundance, allow the exploration of co-occurrence patterns and provide credible estimates of taxon richness (including for rare species that are often not included in more commonly used single-species distribution modelling). Habitat-forming taxa considered to be Vulnerable Marine Ecosystem (VME) indicators (those taxa that are physically or functionally fragile to anthropogenic impacts) were identified in the dataset. Spatial estimates of likely VME distribution (as well as associated estimates of uncertainty) were predicted for the study area. Identifying areas most likely to represent a VME (rather than simply VME indicator taxa) provides much needed quantitative estimates of vulnerable habitats, and facilitates an evidence-based approach to managing potential impacts of bottom-trawling.
PubDate: 2024-07-30
- Factors driving human–elephant conflict: statistical assessment of
vulnerability and implications for wildlife conflict management in Sri
Lanka
Abstract: Abstract Human–elephant conflict (HEC) is a serious social–ecological problem in Sri Lanka’s elephant range regions, as between 200 and 400 elephants have been killed annually over the last years, and more than 1200 people have died from the consequences of elephant encounters within a decade. Crop foraging causes economic damage to farming households. The study aims to understand factors driving vulnerability to HEC among the population. Employing a cross-communal multi-item large-N field survey (N = 651), authors were able to describe living conditions and perceptions of Sri Lankan villagers affected by HEC. By running a multiple regression analysis with correlated variables, the study is able to correlate independent variables to vulnerability, namely socio-economic conditions, environmental change and land-use, and awareness. Furthermore, a vulnerability map has been created, identifying Puttalam, Anuradhapura, Kurunegala, Matale, and Polonnaruwa districts as conflict hotspots. Private electric fences as a widespread protection measure were found to have unintended negative side-effects to non-protected households. The findings suggest the urgent need to upscale public policies mitigating the consequences of HEC on affected populations by reducing overall vulnerability to environmental hazards, including human–wildlife conflict.
PubDate: 2024-07-27
- Correction: Human disturbance and habitat structure drive eurasian otter
habitat selection in heavily anthropized river basins
- Recovering connectivity through restoration corridors in a fragmented
landscape in the magdalena river’s valley in Colombia
Abstract: Abstract Forest fragmentation is one of the main drivers of global biodiversity loss leading to the isolation of wildlife populations. This study focuses on understanding the role of restoration corridors as a strategy promoting resilience and viability of mammal and bird populations in a fragmented landscape in Colombia. We installed 98 camera-trap stations − 8497 camera-trap days - in four different land cover categories: (1) forest fragments, (2) natural corridors, (3) stablished corridors and (4) pastures. We evaluated if restoration corridors do promote connectivity for large vertebrates and recover species richness and functional diversity lost in anthropogenically transformed pastures. We used indices of taxonomic and functional diversity and a non-metric multidimensional scaling to evaluate the influence of land cover over mammal and bird communities. Both, species richness and functional diversity have higher values in forests, followed by natural corridors and corridors and lower values in open pastures. Differences in species composition were greater between forests and pastures, and species composition of restoration corridors begins to resemble that of riparian forests and forest fragments. Our results provide initial evidence on the role of restoration corridors as an efficient strategy aimed to recover biodiversity and functional diversity in pervasively fragmented landscapes.
PubDate: 2024-07-20
- Negative impacts of future forest succession on three threatened butterfly
species
Abstract: Abstract The dynamic interplay between anthropogenic activities and biodiversity conservation necessitates a nuanced understanding of habitat change, especially in contexts marked by transitions from grasslands to forested areas. This investigation utilised three threatened butterfly species—the Marsh Fritillary, Apollo, and Large Blue—as models to explore how grassland associated species respond to altered environmental conditions. The methodology encompassed extensive field surveys and statistical analyses with ecological niche modelling to determine their current and future distributions on the Island of Gotland. The species were surveyed under distinct years from 2017 to 2020 in a total of 3333 hectares in a 6000 hectare area—the Marsh Fritillary in 2017 (1232 hectares), Apollo in 2019 (2346 hectares), and Large Blue in 2020 (2256 hectares). Results revealed that the estimated current extents of suitable habitats were 49,104 hectares for the Marsh Fritillary (15.6% of the island), 45,646 hectares for Apollo (14.5%), and 33,089 hectares for Large Blue (10.5%). In general, increased forest and shrub cover and decreased heterogeneity negatively affected butterfly occupancy, but each species exhibited unique habitat preferences. The predictive modelling demonstrated that continued succession would reduce the amount of habitats predicted to be suitable and generated alarming forecasts—a twofold increase in forest and shrub cover suggests habitat declines of 41%, 47%, and 65% for the Marsh Fritillary, Apollo, and Large Blue, respectively. Given these findings, proactive measures are imperative for strategically managing these habitats to preserve landscape heterogeneity and accommodate diverse ecological needs. This study is important to conservation management providing, crucial insights amid anthropogenic and ecological changes.
PubDate: 2024-07-09
- Landrace in situ (on-farm) conservation: European Union achievements
Abstract: Abstract This paper offers an insight on present status of on-farm conservation of landrace diversity in the European Union. The review initially examines the types of materials that are the object of on-farm conservation, assesses the current status of maintenance and reproduction within farms and gardens, explores the motivations that drive ongoing conservation efforts as a foundation for future enhancement and identifies the key actors involved and their respective roles. Secondarily, it reviews European Union policies and their provisions supporting the conservation of crop diversity in the fields, with a particular focus on regulations pertaining to the commercialization of landrace seeds. Given that the availability of propagation material remains a primary constraint to the widespread dissemination of landraces, the review also includes current achievements and identifies constraints that could be mitigated. The discussion highlights how to continue and intensify the development and implementation of agro-environmental and seed policies as well as how further collection, documentation, study and promotion of the traditional farmers’ knowledge ̶ associated with the development, production and utilization of the traditional local products ̶ can improve the present situation. It is hoped that the model applied in the European Union could be also useful in other regions of the world.
PubDate: 2024-07-09
- Global species hotspots and COI barcoding cold spots of marine Gastropoda
Abstract: Abstract With the on-going efforts in digitising museum collections, increased participation of citizen scientists, and greater accessibility to research data, accurately determining global patterns of diversity has become more achievable. Here, we used occurrence records from the Global Biodiversity Information Facility, with annotation of authoritative taxonomy, to evaluate the taxonomic richness of marine gastropods and to identify global species hotspots for this group. We also reviewed the availability of genetic resources within hotspots to detect potentially important regions where reference sequences for identifying these organisms are wanting. We find 33,268 unique and valid species under 3291 genera belonging to 380 gastropod families that have been recorded from 1662 to 2023. Globally, only 12.1% of reported species are linked to a COI barcode, whilst 27.1% of the families are represented with complete mitogenomes. Georeferenced records show the wide albeit disparate distribution of observations and species counts. The compiled dataset, published by organisations that are restricted to 55 countries, reveal a seeming lack of local submissions, but nonetheless demonstrates the growing contribution of citizen science platforms. We present 28 marine provinces across the globe as putative gastropod species hotspots and call for further work and stronger involvement, particularly within COI barcoding cold spots, to address the observed genetic reference inequity. Lastly, we highlight the important and relevant role of open and inclusive science to biodiversity monitoring and research.
PubDate: 2024-07-06
- Priority conservation areas for protected saproxylic beetles in Romania
under current and future climate scenarios
Abstract: Abstract Climate change threatens species and ecosystems globally, including forest ecosystems that support rich invertebrate diversity. Saproxylic beetles, that depend on old-growth trees and deadwood, are facing increasing pressure. Consequently, conserving these beetles has become a priority for EU Member States. We developed ensemble species distribution models for five saproxylic beetles for current and three future time horizons under two Shared Socioeconomic Pathways and two Global Circulation Models. We used a systematic conservation planning approach to assess the effectiveness and resilience to climate change of the Romanian Natura 2000 network for saproxylic beetles while identifying areas for prospective protected area expansion to meet EU conservation targets. Our study revealed that under all scenarios and time horizons, the saproxylic beetles may lose over 80% of their suitable habitat and restrict their distribution to higher elevations. According to the conservation prioritization analysis, we found that, when considering 30% of the landscape as being protected, an average of 85% of species distribution is retained within priority areas overlapping the Carpathian Mountains, while for the current protected area coverage (18% of Romania’s terrestrial area), the existing Natura 2000 network does not perform satisfactorily, with only ~ 30% of the saproxylic species distributions falling within the network. Our results corroborate previous findings on saproxylic beetle range shifts and contractions due to climate change. Furthermore, our findings question the effectiveness of the current Natura 2000 network, as it is currently inadequate for protecting these species. To achieve the goals of the EU Biodiversity Strategy 2030 of protecting at least 30% of the EU’s territory, we advocate the expansion of the Natura 2000 sites to future suitable saproxylic beetle habitats.
PubDate: 2024-07-04
- Biotic and abiotic dispersal of a large-seeded keystone genus in
Madagascar
Abstract: Abstract In tropical forests, most plant species rely on frugivorous animals for seed dispersal services. Such mutualisms are imperiled by defaunation, which disproportionately affects large-bodied vertebrates and may impact the interactions of the large-seeded plants they disperse. However, frugivore-mediated seed dispersal (zoochory) may not be the only mechanism ensuring the dispersal of a given plant species. With a focus on large-seeded canopy trees in the genus Canarium in the rainforests of Madagascar, thought to be dispersed by large-bodied lemur species, we investigated the contribution of multiple dispersal mechanisms to the movement of large seeds. Specifically, we (1) examined the potential for dispersal by abiotic factors, such as winds and runoff associated with frequent cyclones, (2) documented the animal species that could effectively contribute to their primary and secondary seed dispersal, and (3) determined how non-lemur and abiotic dispersal compare to the imperiled function of extant, though threatened, lemur primary dispersers. Using field observations and experiments, we found that wind, water, and secondary dispersal can move seeds considerable distances away from the parent plants, though they were less effective at long-distance dispersal than primary dispersers (i.e., large-bodied lemurs). For secondary dispersal, we found that dispersal distance is positively correlated with predation, potentially reducing dispersal effectiveness. Future comparisons with predation of primary or abiotically dispersed seeds will be necessary. Our research highlights the role of understudied mechanisms in the dispersal of large-seeded plants in Madagascar. Understanding the existence and impact of non-lemur dispersers in these imperiled forests can help complete our understanding of the mechanisms that shaped their astounding biodiversity and may mediate their response to ongoing environmental change.
PubDate: 2024-07-02
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