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ZOOLOGY (141 journals)                  1 2     

Acta Herpetologica     Open Access   (Followers: 3)
Acta Theriologica     Full-text available via subscription   (Followers: 6)
Acta Zoologica     Hybrid Journal   (Followers: 3)
Acta Zoologica Cracoviensia     Free   (Followers: 2)
Acta zoológica mexicana     Open Access  
Advances in Zoology     Open Access  
Advances in Zoology and Botany     Open Access  
African Invertebrates     Open Access  
African Journal of Herpetology     Full-text available via subscription   (Followers: 1)
African Journal of Wildlife Research     Full-text available via subscription  
African Zoology     Hybrid Journal   (Followers: 7)
American Journal of Zoological Research     Open Access  
animal     Hybrid Journal   (Followers: 3)
Animal Behaviour     Hybrid Journal   (Followers: 194)
Animal Biology     Hybrid Journal   (Followers: 8)
Animal Biology & Animal Husbandry     Open Access   (Followers: 4)
Animal Biotelemetry     Open Access   (Followers: 2)
Animal Genetics     Hybrid Journal   (Followers: 7)
Animal Migration     Open Access   (Followers: 1)
Animal Studies Journal     Open Access   (Followers: 6)
Annales Zoologici     Full-text available via subscription  
Annales Zoologici Fennici     Open Access  
Annals of Animal Science     Open Access   (Followers: 1)
Annals of the Ditsong National Museum of Natural History     Full-text available via subscription  
Annual Review of Animal Biosciences     Full-text available via subscription   (Followers: 5)
Anthrozoos : A Multidisciplinary Journal of The Interactions of People & Animals     Hybrid Journal   (Followers: 8)
Applied Animal Behaviour Science     Hybrid Journal   (Followers: 16)
Applied Entomology and Zoology     Partially Free   (Followers: 2)
Aquatic Mammals     Full-text available via subscription   (Followers: 4)
Aquatic Sciences     Hybrid Journal   (Followers: 12)
Arquivos de Ciências Veterinárias e Zoologia da UNIPAR     Open Access  
Arthropod Management Tests     Hybrid Journal   (Followers: 1)
Asian Journal of Animal and Veterinary Advances     Open Access   (Followers: 8)
Australian Journal of Zoology     Hybrid Journal   (Followers: 1)
Bioacoustics : The International Journal of Animal Sound and its Recording     Partially Free   (Followers: 3)
Bird Conservation International     Hybrid Journal   (Followers: 18)
Bird Study     Full-text available via subscription   (Followers: 15)
Brazilian Journal of Veterinary Research and Animal Science     Open Access   (Followers: 7)
British Birds     Full-text available via subscription   (Followers: 11)
Bulletin of the Museum of Comparative Zoology     Full-text available via subscription   (Followers: 4)
Canadian Journal of Animal Science     Full-text available via subscription   (Followers: 4)
Canadian Journal of Zoology     Full-text available via subscription   (Followers: 12)
Contributions to Zoology     Open Access   (Followers: 3)
Der Zoologische Garten     Full-text available via subscription   (Followers: 3)
Ecology of Freshwater Fish     Hybrid Journal   (Followers: 18)
Edentata     Open Access  
European Journal of Taxonomy     Open Access   (Followers: 3)
Euscorpius     Open Access  
EvoDevo     Open Access   (Followers: 1)
Fieldiana Zoology     Full-text available via subscription   (Followers: 2)
Fish and Fisheries     Hybrid Journal   (Followers: 25)
Frontiers in Zoology     Open Access   (Followers: 8)
Graellsia     Open Access  
Herpetology Notes     Open Access  
Hystrix, the Italian Journal of Mammalogy     Open Access  
i-Perception     Open Access   (Followers: 3)
Iheringia. Série Zoologia     Open Access  
In Vitro Cellular & Developmental Biology - Animal     Hybrid Journal   (Followers: 1)
Integrative Zoology     Hybrid Journal  
International Journal of Odonatology     Hybrid Journal   (Followers: 1)
International Journal of Zoological Research     Open Access   (Followers: 2)
International Journal of Zoology     Open Access   (Followers: 2)
International Studies on Sparrows     Open Access  
International Zoo Yearbook     Hybrid Journal   (Followers: 2)
Invertebrate Reproduction & Development     Hybrid Journal   (Followers: 3)
Italian Journal of Animal Science     Open Access   (Followers: 2)
Italian Journal of Zoology     Hybrid Journal   (Followers: 1)
Journal of Agrobiology     Open Access   (Followers: 3)
Journal of Animal Ecology     Hybrid Journal   (Followers: 35)
Journal of Animal Physiology and Animal Nutrition     Hybrid Journal   (Followers: 5)
Journal of Animals     Open Access  
Journal of Apicultural Science     Open Access   (Followers: 1)
Journal of Applied Animal Research     Hybrid Journal   (Followers: 1)
Journal of Basic & Applied Zoology : Physiology     Open Access  
Journal of Experimental Zoology Part A: Ecological Genetics and Physiology     Hybrid Journal   (Followers: 2)
Journal of Experimental Zoology Part B : Molecular and Developmental Evolution     Hybrid Journal  
Journal of Freshwater Ecology     Hybrid Journal   (Followers: 11)
Journal of Herpetology     Full-text available via subscription   (Followers: 5)
Journal of Insects     Open Access  
Journal of Venomous Animals and Toxins     Open Access   (Followers: 4)
Journal of Venomous Animals and Toxins including Tropical Diseases     Open Access  
Journal of Wildlife Management     Hybrid Journal   (Followers: 28)
Journal of Zoo and Aquarium Research     Open Access   (Followers: 1)
Journal of Zoological Systematics and Evolutionary Research     Hybrid Journal   (Followers: 4)
Journal of Zoology     Hybrid Journal   (Followers: 10)
Laboratory Animals     Hybrid Journal   (Followers: 11)
Mammalia     Hybrid Journal   (Followers: 8)
Marine Ecology Progress Series MEPS     Hybrid Journal   (Followers: 9)
Mastozoología Neotropical     Open Access  
Memorias de la Conferencia Interna en Medicina y Aprovechamiento de Fauna Silvestre, Exótica y no Convencional     Open Access  
Monographs of the Transvaal Museum     Full-text available via subscription  
Natural History Sciences     Hybrid Journal  
Neotropical Primates     Open Access   (Followers: 1)
New Zealand Journal of Zoology     Hybrid Journal   (Followers: 1)
Papéis Avulsos de Zoologia     Open Access   (Followers: 1)
Parasite     Open Access   (Followers: 6)
Physiological and Biochemical Zoology     Full-text available via subscription   (Followers: 5)
Polish Journal of Entomology     Open Access   (Followers: 2)
Protist Genomics     Open Access   (Followers: 1)
Redia : Journal of Zoology     Open Access  

        1 2     

Journal Cover   Journal of Animal Ecology
  [SJR: 3.074]   [H-I: 102]   [35 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0021-8790 - ISSN (Online) 1365-2656
   Published by John Wiley and Sons Homepage  [1597 journals]
  • Unravelling the role of allochthonous aquatic resources to food web
           structure in a tropical riparian forest
    • Abstract: 1.The role of matter and energy flow across ecosystem boundaries for subsidized consumer populations is well known. However, little is known on the effects of allochthonous subsidies on food web structure and trophic niche dimensions of consumers in the tropics. 2.We excluded allochthonous aquatic insects from tropical streams using greenhouse‐type exclosures to test the influence of aquatic allochthonous subsidies on the trophic structure and niche dimensions of terrestrial predators using stable isotope methods. 3.In exclosure treatments, abundance and biomass of terrestrial predators, and biomass of phytophages, decreased and increased, respectively. Vegetation‐living predators were more responsive to allochthonous inputs than those living on the ground. Overall, lower availability of allochthonous inputs did not affect community‐wide metrics and niche width of predators. However, the niche width of some spider families had very low overlap between treatments, and others had wider isotopic niches in the control than exclusion treatment. Most of the C and N in predators living in control stretches came from aquatic subsidies, and those predators living in exclusion treatments switched their diets to terrestrial sources, showing a preference of predators for allochthonous subsidies. 4.Our results suggest that allochthonous subsidies are also relevant to tropical fauna living upon vegetation. Moreover, allochthonous resources may amplify the niche dimension of certain predators, or considerably change the trophic niche of others. Our study highlights the importance of including modern isotopic tools in elucidating the role of allochthonous resources on the patterns of trophic structure and niche dimensions of consumers from donor ecosystems. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-21T02:28:51.498297-05:
      DOI: 10.1111/1365-2656.12475
  • Changing climate cues differentially alter zooplankton dormancy dynamics
           across latitudes
    • Authors: Natalie T. Jones; Benjamin Gilbert
      Abstract: 1.In seasonal climates, dormancy is a common strategy that structures biodiversity and is necessary for the persistence of many species. Climate change will likely alter dormancy dynamics in zooplankton, the basis of aquatic food webs, by altering two important hatching cues: mean temperatures during the ice‐free season, and mean day length when lakes become ice free. Theory suggests that these changes could alter diversity, hatchling abundances and phenology within lakes, and that these responses may diverge across latitudes due to differences in optimal hatching cues and strategies. 2.To examine the role of temperature and day length on hatching dynamics, we collected sediment from 25 lakes across a 1800 km latitudinal gradient and exposed sediment samples to a factorial combination of two photoperiods (12 and 16 hours) and two temperatures (8°C and 12 °C) representative of historical southern (short photoperiod, warm) and northern (long photoperiod, cool) lake conditions. We tested whether sensitivity to these hatching cues varies by latitudinal origin and differs among taxa. 3.Higher temperatures advanced phenology for all taxa, and these advances were greatest for cladocerans followed by copepods and rotifers. Although phenology differed among taxa, the effect of temperature did not vary with latitude. The latitudinal origin of the egg bank influenced egg abundance and hatchling abundance and diversity, with these latter effects varying with taxa, temperature and photoperiod. 4.Copepod hatchling abundances peaked at mid latitudes in the high temperature and long photoperiod treatments, whereas hatchling abundances of other zooplankton were greatest at low latitudes and high temperature. The overall diversity of crustacean zooplankton (copepods and cladocerans) also reflected distinct responses of each taxa to our treatments, with the greatest diversity occurring at mid latitudes (~56° N) in the shorter photoperiod treatment. 5.Our results demonstrate that hatching cues differ for broad taxonomic groups that vary in developmental and life‐history strategies. These differences are predicted to drive latitude‐specific shifts in zooplankton emergence with climate change, and could alter the base of aquatic food webs. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-21T02:27:18.491941-05:
      DOI: 10.1111/1365-2656.12474
  • Climate and habitat interact to shape the thermal reaction norms of
           breeding phenology across lizard populations
    • Abstract: 1.Substantial plastic variation in phenology in response to environmental heterogeneity through time in the same population has been uncovered in many species. However, our understanding of differences in reaction norms of phenology among populations from a given species remains limited. 2.Since the plasticity of phenological traits is often influenced by local thermal conditions, we expect local temperature to generate variation in the reaction norms between populations. 3.Here, we explored temporal variation in parturition date across 11 populations of the common lizard (Zootoca vivipara) from four mountain chains as a function of air temperatures during mid‐gestation. We characterized among‐population variation to assess how local weather conditions (mean and variance of ambient temperatures during mid‐gestation) and habitat openness (an index of anthropogenic disturbance) influence the thermal reaction norms of the parturition date. 4.Our results provide evidence of interactive effects of anthropogenic disturbance and thermal conditions, with earlier parturition dates in warmer years on average especially in closed habitats. 5.Variation in the reaction norms for parturition date was correlated with mean local thermal conditions at a broad geographical scale. However populations exposed to variable thermal conditions had flatter thermal reaction norms. 6.Assessing whether environmental heterogeneity drives differentiation among reaction norms is crucial to estimate the capacity of different populations to contend with projected climatic and anthropogenic challenges. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-21T02:23:56.037811-05:
      DOI: 10.1111/1365-2656.12473
  • Host infection history modifies co‐infection success of multiple
           parasite genotypes
    • Abstract: 1.Co‐infections by multiple parasite genotypes are common and have important implications for host‐parasite ecology and evolution through within‐host interactions. Typically, these infections take place sequentially and therefore, the outcome of co‐infection may be shaped by host immune responses triggered by previous infections. For example, in vertebrates specific immune responses play a central role in protection against disease over the course of life, but co‐infection research has mostly focused on previously uninfected individuals. 2.Here, we investigated whether sequential exposure and activation of host resistance in rainbow trout Oncorhynchus mykiss affects infection success and interactions between co‐infecting parasite genotypes of the trematode eye‐fluke Diplostomum pseudospathaceum. 3.In accordance with earlier results, we show that a simultaneous attack of two parasite genotypes facilitates parasite establishment in previously uninfected hosts. However, we find for the first time that this facilitation in co‐infection is lost in hosts with prior infection. 4.We conclude that vertebrate host infection history can affect the direction of within‐host parasite interactions. Our results may have significant implications for the evolution of co‐infections and parasite transmission strategies. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-21T02:23:08.774991-05:
      DOI: 10.1111/1365-2656.12472
  • A trait‐based metric sheds new light on the nature of the body
           size‐depth relationship in the deep sea
    • Authors: B. L. Mindel; T. J. Webb, F. C. Neat, J. L. Blanchard
      Abstract: 1.Variation within species is an often‐overlooked aspect of community ecology, despite the fact that the ontogenetic structure of populations influences processes right up to the ecosystem level. Accounting for traits at the individual level is an important advance in the implementation of trait‐based approaches in understanding community structure and function. 2.We incorporate individual‐ and species‐level traits into one succinct assemblage structure metric, fractional size, which is calculated as the length of an individual divided by its potential maximum length. We test the implementation of fractional size in demersal fish assemblages along a depth gradient in the deep sea. We use data from an extensive trawl survey at depths of 300‐2030m on the continental slope of the Rockall Trough, Northeast Atlantic, to compare changes in fractional size structure along an environmental gradient to those seen using traditional taxonomic and trait‐based approaches. 3.The relationship between fractional size and depth was particularly strong, with the overall pattern being an increase with depth, implying that individuals move deeper as they grow. Body size increased with depth at the intra‐specific and assemblage levels. Fractional size, size structure and species composition all varied among assemblages, and this variation could be explained by the depth that the assemblage occupied. 4.The inclusion of individual‐level traits and population fractional size structure adds to our understanding at the assemblage level. Fractional size, or where an individual is in its growth trajectory, appears to be an especially important driver of assemblage change with depth. This has implications for understanding fisheries impacts in the deep sea and how these impacts may propagate across depths. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-12T08:10:13.921271-05:
      DOI: 10.1111/1365-2656.12471
  • Tick exposure and extreme climate events impact survival and threaten the
           persistence of a long‐lived lizard
    • Authors: Alice R. Jones; C Michael Bull, Barry W. Brook, Konstans Wells, Kenneth H. Pollock, Damien A. Fordham
      Abstract: 1.Assessing the impacts of multiple, often synergistic, stressors on the population dynamics of long‐lived species is becoming increasingly important due to recent and future global change. 2.Tiliqua rugosa (sleepy lizard) is a long‐lived skink (>30 years) that is adapted to survive in semi‐arid environments with varying levels of parasite exposure and highly seasonal food availability. We used an exhaustive database of 30‐years of capture‐mark‐recapture records to quantify the impacts of both parasite exposure and environmental conditions on the lizard's survival rates and long‐term population dynamics. 3.Lizard abundance was relatively stable throughout the study period; however there were changing patterns in adult and juvenile apparent survival rates, driven by spatial and temporal variation in levels of tick exposure and temporal variation in environmental conditions. Extreme weather events during the winter and spring seasons were identified as important environmental drivers of survival. 4.Climate models predict a dramatic increase in the frequency of extreme hot and dry winter and spring seasons in our South Australian study region; from a contemporary probability of 0.17 up to 0.47 ‐ 0.83 in 2080 depending on the emissions scenario. Our stochastic population model projections showed that these future climatic conditions will induce a decline in the abundance of this long‐lived reptile of up to 67% within 30 years from 2080, under worst case scenario modelling. 5.The results have broad implications for future work investigating the drivers of population dynamics and persistence. We highlight the importance of long‐term datasets and accounting for synergistic impacts between multiple stressors. We show that predicted increases in the frequency of extreme climate events have the potential to considerably and negatively influence a long‐lived species, which might previously have been assumed to be resilient to environmental perturbations. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-12T08:08:34.31838-05:0
      DOI: 10.1111/1365-2656.12469
  • A benign juvenile environment reduces the strength of antagonistic
           pleiotropy and genetic variation in the rate of senescence
    • Abstract: 1.The environment can play an important role in the evolution of senescence because the optimal allocation between somatic maintenance and reproduction depends on external factors influencing life expectancy. 2.The aims of this study were to experimentally test whether environmental conditions during early life can shape senescence schedules, and if so, to examine whether variation among individuals or genotypes with respect to the degree of ageing differs across environments. 3.We tested life‐history plasticity and quantified genetic effects on the pattern of senescence across different environments within a reaction norm framework by using an experiment on the three‐spined stickleback (Gasterosteus aculeatus, Linnaeus) in which F1 families originating from a wild annual population experienced different temperature regimes. 4.Male sticklebacks that had experienced a more benign environment earlier in life subsequently reduced their investment in carotenoid‐based sexual signals early in the breeding season, and consequently senesced at a slower rate later in the season, compared to those that had developed under harsher conditions. This plasticity of ageing was genetically determined. Both antagonistic pleiotropy and genetic variation in the rate of senescence were evident only in the individuals raised in the harsher environment. 5.The experimental demonstration of genotype‐by‐environment interactions influencing the rate of reproductive senescence provides interesting insights into the role of the environment in the evolution of life‐histories. The results suggest that benign conditions weaken the scope for senescence to evolve, and that the dependence on the environment may maintain genetic variation under selection. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-12T08:07:02.056005-05:
      DOI: 10.1111/1365-2656.12468
  • Energetic constraint of non‐monotonic mass change during offspring
           growth: a general hypothesis and application of a new tool
    • Authors: Jennifer M. Arnold; Ian C. T. Nisbet, Stephen A. Oswald
      Abstract: 1. Postnatal growth is an important life‐history trait and can be a sensitive indicator of ecological stress. For over 50 years, monotonic (never‐decreasing) growth has been viewed as the predominant trajectory of postnatal mass change in most animal species, notably among birds. However, prevailing analytical approaches and energetic constraints may limit detection of non‐monotonic (or multi‐phasic), determinate growth patterns, such as mass recession in birds (weight‐loss prior to fledging, preceded by overshooting adult mass), which is currently believed to be restricted to few taxa. 2. Energetic surplus and shortfall are widespread conditions that can directly influence the degree of mass overshooting and recession. Thus, we hypothesize that in many species prevailing energetic constraints force mass change away from a fundamental non‐monotonic trajectory to instead follow a monotonic curve. 3. We observed highly non‐monotonic, mass change trajectories (overshooting adult mass by up to almost 20%) among common tern Sterna hirundo chicks, a well‐studied species long‐established as growing monotonically. We quantified the prevalence and magnitude of non‐monotonic mass change prior to fledging for 313 common tern chicks that successfully fledged from two discrete populations in multiple years. We used a new approach for analysing non‐monotonic curves to examine differences in mass change trajectories between populations under contrasting abiotic (freshwater versus saltwater) and biotic stresses (low rates of food provisioning). 4. Some degree of mass recession occurred in 73% of all study chicks. Overshooting adult mass followed by extensive mass recession was most prevalent at our freshwater colony, being detected among 34 ‐ 38% of chicks annually. Non‐monotonic trajectories were less marked in populations experiencing ecological stress and among lower quality individuals. Chicks that were provisioned at higher rates were more likely to both overshoot adult mass and experience subsequent mass recession. 5. Our results provide strong support in common terns for the hypothesis that non‐monotonic trajectories are the fundamental pattern of mass change but are constrained to be monotonic under energetic shortfall. This justifies future tests of the generality of this hypothesis across a broad range of taxa. We also demonstrate a recent analytical tool that prevents routine fitting of monotonic curves without prior investigation of non‐monotonic trends. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-06T02:56:40.774168-05:
      DOI: 10.1111/1365-2656.12467
  • Phase‐dependent climate‐predator interactions explain three
           decades of variation in neonatal caribou survival
    • Abstract: 1.Climate can have direct and indirect effects on population dynamics via changes in resource competition or predation risk, but this influence can be modulated by density‐ or phase‐dependent processes. We hypothesized that for ungulates, climatic conditions close to parturition have a greater influence on the predation risk of neonates during population declines, when females are already under nutritional stress triggered by food limitation. 2.We examined the presence of phase‐dependent climate‐predator interactions on neonatal ungulate survival by comparing spatial and temporal fluctuations in climatic conditions, cause specific mortality, and per capita resource limitation. We determined cause‐specific fates of 1384 caribou (Rangifer tarandus) from 10 herds in Newfoundland, spanning more than 30 years during periods of numerical increase and decline, while exposed to predation from black bears (Ursus americanus) and coyotes (Canis latrans). 3.We conducted Cox proportional hazards analysis for competing risks, fit as a function of weather metrics, to assess pre‐ and post‐partum climatic influences on survival on herds in population increase and decline phases. We used cumulative incidence functions to compare temporal changes in risk from predators. 4.Our results support our main hypothesis; when caribou populations increased, weather conditions preceding calving were the main determinants of cause‐specific mortality, but when populations declined, weather conditions during calving also influenced predator‐driven mortality. Cause‐specific analysis showed that weather conditions can differentially affect predation risk between black bears and coyotes with specific variables increasing the risk from one species and decreasing the risk from the other. 5.For caribou, nutritional stress appears to increase predation risk on neonates, an interaction which is exacerbated by susceptibility to climatic events. These findings support the phase‐dependent climate‐predator (PDCP) interactions framework, where maternal body condition influences susceptibility to climate‐related events and, subsequently, risk from predation. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-03T09:51:52.094761-05:
      DOI: 10.1111/1365-2656.12466
  • Resource specialists lead local insect community turnover associated with
           temperature – analysis of an 18‐year full‐seasonal
           record of moths and beetles
    • Abstract: Insect responses to recent climate change are well documented, but the role of resource specialization in determining species vulnerability remains poorly understood. Uncovering local ecological effects of temperature change with high‐quality, standardized data provides an important first opportunity for predictions about responses of resource specialists, and long‐term time series are essential in revealing these responses. Here, we investigate temperature‐related changes in local insect communities, using a sampling site with more than a quarter‐million records from two decades (1992–2009) of full‐season, quantitative light trapping of 1543 species of moths and beetles. We investigated annual as well as long‐term changes in fauna composition, abundance and phenology in a climate‐related context using species temperature affinities and local temperature data. Finally, we explored these local changes in the context of dietary specialization. Across both moths and beetles, temperature affinity of specialists increased through net gain of hot‐dwelling species and net loss of cold‐dwelling species. The climate‐related composition of generalists remained constant over time. We observed an increase in species richness of both groups. Furthermore, we observed divergent phenological responses between cold‐ and hot‐dwelling species, advancing and delaying their relative abundance, respectively. Phenological advances were particularly pronounced in cold‐adapted specialists. Our results suggest an important role of resource specialization in explaining the compositional and phenological responses of insect communities to local temperature increases. We propose that resource specialists in particular are affected by local temperature increase, leading to the distinct temperature‐mediated turnover seen for this group. We suggest that the observed increase in species number could have been facilitated by dissimilar utilization of an expanded growing season by cold‐ and hot‐adapted species, as indicated by their oppositely directed phenological responses. An especially pronounced advancement of cold‐adapted specialists suggests that such phenological advances might help minimize further temperature‐induced loss of resource specialists. Although limited to a single study site, our results suggest several local changes in the insect fauna in concordance with expected change of larger‐scale temperature increases. Long‐term insect light trapping shows that temperature affinity of diet specialists increased through net gain of hot‐dwelling species and net loss of cold‐dwelling species. Persistence of cold‐dwelling species may have been facilitated by dissimilar phenological response of hot and cold‐dwelling species to an expanded growing season. Horse‐chestnut leaf miner (Cameraria ohridella) and acorn weevil (Curculio glandium) are examples of gained hot‐dwelling specialists. Photo credit: Jens Kirkeby (above) and Klaus Bek Nielsen.
      PubDate: 2015-11-02T00:57:32.65307-05:0
      DOI: 10.1111/1365-2656.12452
  • Onset of autumn shapes the timing of birth in Pyrenean chamois more than
           onset of spring
    • Authors: Charlotte Kourkgy; Mathieu Garel, Joel Appolinaire, Anne Loison, Carole Toigo
      Abstract: 1.In seasonal environments, birth dates are a central component for a species’ life history, with potential long‐term fitness consequences. Yet our understanding of selective pressures of environmental changes on birth dates is limited in wild mammals due to the difficulty of data collection. In a context of rapid climate change, the question of a possible mismatch between plant phenology and birth phenology also remains unanswered for most species. 2.We assessed whether and how the timing of birth in a mountain mammal (isard, Rupicapra pyrenaica) tracked changes in plant growing season, accounting for maternal traits, individual heterogeneity, and population density. We not only focused on spring conditions but also assessed to what extent onset of autumn can be a driver of phenological biological events and compared the magnitude of the response to the magnitude of the environmental changes. We relied on a 22‐year study based on intensively monitored marked individuals of known age. 3.Births were highly synchronized (80% of kids born within 25 days) and highly repeatable (84%; among‐females variation of 9.6 days, withinfemale variation of 4.2 days). Individual phenotypic plasticity allows females to respond rapidly to inter‐annual changes in plant phenology but did not prevent the existence of a mismatch: a 10‐day advance in the autumn or spring plant phenology led to 3.9 and 1.3 days advance in birth dates, respectively. 4.Our findings suggest that plant phenology may act as a cue to induce important stages of the reproductive cycle (e.g., conception and gestation length), subsequently affecting parturition dates, and stressed the importance of focusing on long‐term changes during spring for which females may show much lower adaptive potential than during autumn. These results also question the extent to which individual plasticity along with high heterogeneity among individuals will allow species to cope with demographic consequences of climate changes. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-27T02:05:55.9768-05:00
      DOI: 10.1111/1365-2656.12463
  • Top predators and habitat complexity alter an intraguild predation module
           in pond communities
    • Authors: Thomas L. Anderson; Raymond D. Semlitsch
      Abstract: Predator diversity and habitat complexity frequently influence species interactions at lower trophic levels, yet their joint investigation has been performed infrequently despite the demonstrated importance of each individual factor. We investigated how different top predators and varying habitat complexity influence the function of an intraguild predation module consisting of two larval salamanders, intraguild predator Ambystoma annulatum and intraguild prey A. maculatum. We manipulated predator food webs and habitat complexity in outdoor mesocosms. Top predators significantly influenced body condition and survival of A. annulatum, but habitat complexity had minimal effects on either response. A three‐way interaction among the covariates top predator identity, habitat complexity and A. annulatum survival influenced body condition and survival of A. maculatum via a density mediated indirect effect. Different top predator combinations had variable effects in different habitat complexity treatments on intraguild predator (A. annulatum) survival that subsequently influenced intraguild prey (A. maculatum) body condition and survival. Future work should consider how different top predators influence other food web components, which should vary due to predator attributes and the physical environments in which they co‐occur. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-17T09:16:33.031373-05:
      DOI: 10.1111/1365-2656.12462
  • Community structure influences species’ abundance along
           environmental gradients
    • Authors: A.P. Eloranta; I.P. Helland, O.T. Sandlund, T Hesthagen, O Ugedal, A.G. Finstad
      Abstract: Species response to abiotic environmental variation can be influenced by local community structure and interspecific interactions, particularly in restricted habitats such as islands and lakes. In temperate lakes, future increase in water temperature and runoff of terrestrial (allochthonous) dissolved organic carbon (DOC) are predicted to alter community composition and the overall ecosystem productivity. However, little is known about how the present community structure and abiotic environmental variation interact to affect the abundance of native fish populations. We used a space‐for‐time approach to study how local community structure interact with lake morphometric and climatic characteristics (i.e., temperature and catchment productivity) to affect brown trout (Salmo trutta L.) yield in 283 Norwegian lakes located in different biogeographical regions. Brown trout yield (based on data from standardized survey gill net fishing; g 100 m−2 gill net night−1) was generally lower in lakes where other fish species were present than in lakes with brown trout only. It showed an overall negative relationship with increasing temperature and a positive relationship with lake shoreline complexity. Brown trout yield was also negatively correlated with DOC load (measured using Normalized Difference Vegetation Index as a proxy) and lake size and depth (measured using terrain slope as a proxy), but only in lakes where other fish species were present. The observed negative response of brown trout yield to increasing DOC load and proportion of the pelagic open‐water area is likely due to restricted (littoral) niche availability and competitive dominance of more pelagic fishes such as Arctic charr (Salvelinus alpinus (L.)). Our study highlights that, through competitive interactions, the local community structure can influence the response of a species’ abundance to variation in abiotic conditions. Changes in biomass and niche use of top predators (such as the brown trout), associated with predicted changes in direct and indirect climatic factors, may have further influences on the structure and function of temperate lake ecosystems. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-17T09:15:49.110956-05:
      DOI: 10.1111/1365-2656.12461
  • Resource type influences the effects of reserves and connectivity on
           ecological functions
    • Authors: Nicholas A. Yabsley; Andrew D. Olds, Rod M. Connolly, Tyson S. H. Martin, Ben L. Gilby, Paul S. Maxwell, Chantal M. Huijbers, David S Schoeman, Thomas A. Schlacher
      Abstract: 1.Connectivity is a pivotal feature of landscapes that affects the structure of populations and the functioning of ecosystems. It is also a key consideration in conservation planning. But the potential functional effects of landscape connectivity are rarely evaluated in a conservation context. 2.The removal of algae by herbivorous fish is a key ecological function on coral reefs that promotes coral growth and recruitment. Many reef herbivores are harvested and some use other habitats (like mangroves) as nurseries or feeding areas. Thus, the effects of habitat connectivity and marine reserves can jointly promote herbivore populations on coral reefs thereby influencing reef health. 3.We used a coral reef seascape in eastern Australia to test whether seascape connectivity and reserves influence herbivory. We measured herbivore abundance and rates of herbivory (on turf algae and macroalgae) on reefs that differed in both their level of connectivity to adjacent mangrove habitats, and their level of protection from fishing. 4.Reserves enhanced the biomass of herbivorous fish on coral reefs in all seascape settings and promoted consumption of turf algae. Consumption of turf algae was correlated with the biomass of surgeonfish that are exploited outside reserves. By contrast, both reserve status and connectivity influenced herbivory on macroalgae. Consumption of macroalgae was greatest on fished reefs that were far from mangroves, and was not strongly correlated with any fish species. 5.Our findings demonstrate that landscape connectivity and reserve status can jointly affect the functioning of ecosystems. Moreover, we show that reserve and connectivity effects can differ markedly depending on resource type (in this case turf algae vs macroalgae). The effectiveness of conservation initiatives will therefore depend on our ability to understand how these multiple interactive effects structure the distribution of ecological functions. These findings have wider implications for the spatial conservation of heterogeneous environments and strengthen the case that the impact of conservation on ecosystem functioning is contingent on how reserves are positioned in landscapes. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-17T09:15:26.907173-05:
      DOI: 10.1111/1365-2656.12460
  • Influences of sampling effort on detected patterns and structuring
           processes of a Neotropical plant‐hummingbird network
    • Abstract: Virtually all empirical ecological interaction networks to some extent suffer from undersampling. However, how limitations imposed by sampling incompleteness affect our understanding of ecological networks is still poorly explored, which may hinder further advances in the field. Here, we use a plant‐hummingbird network with unprecedented sampling effort (2,716 hours of focal observations) from the Atlantic Rainforest in Brazil, to investigate how sampling effort affects the description of network structure (i.e. widely used network metrics) and the relative importance of distinct processes (i.e. species abundances vs traits) in determining the frequency of pairwise interactions. By dividing the network into time slices representing a gradient of sampling effort, we show that quantitative metrics, such as interaction evenness, specialization (H2’), weighted nestedness (wNODF) and modularity (Q; QuanBiMo algorithm), were less biased by sampling incompleteness than binary metrics. Furthermore, the significance of some network metrics changed along the sampling effort gradient. Nevertheless, the higher importance of traits in structuring the network was apparent even with small sampling effort. Our results (i) warn against using very poorly sampled networks as this may bias our understanding of networks, both their patterns and structuring processes, (ii) encourage the use of quantitative metrics little influenced by sampling when performing spatio‐temporal comparisons, and (iii) indicate that in networks strongly constrained by species traits, such as plant‐hummingbird networks, even small sampling is sufficient to detect their relative importance for the structure of interactions. Finally, we argue that similar effects of sampling are expected for other highly specialized subnetworks. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-17T09:14:59.336288-05:
      DOI: 10.1111/1365-2656.12459
  • Temperature‐associated habitat selection in a cold‐water
           marine fish
    • Authors: Carla Freitas; Esben Moland Olsen, Halvor Knutsen, Jon Albretsen, Even Moland
      Abstract: Habitat selection is a complex process, which involves behavioural decisions guided by the multiple needs and constraints faced by individuals. Climate‐induced changes in environmental conditions may alter those trade‐offs and resulting habitat use patterns. In this study we investigated the effect of sea temperature on habitat selection and habitat use of acoustically tagged Atlantic cod (Gadus morhua) at the Norwegian Skagerrak coast. Significant relationships between ocean temperature and habitat selection and use were found. Under favourable sea temperature thresholds (< 16°C), cod selected vegetated habitats, such as eelgrass and macroalgae beds, available in shallow areas. Selection for those habitats was especially high at night, when cod tended to ascend to shallower areas, presumably to feed. Selection and use of those habitats decreased significantly as temperature rose. Under increased sea surface temperature conditions, cod were absent from vegetated shallow habitats, both during the day and night, and selected instead non‐vegetated rocky bottoms and sand habitats, available in deeper, colder areas. This study shows the dynamic nature of habitat selection and strongly suggests that cod in this region have to trade off food availability against favourable temperature conditions. Future increases in ocean temperature are expected to further influence the spatial behaviour of marine fish, potentially affecting individual fitness and population dynamics. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-17T09:14:24.047631-05:
      DOI: 10.1111/1365-2656.12458
  • Ecological diversification associated with the pharyngeal jaw diversity of
           Neotropical cichlid fishes
    • Authors: Edward D. Burress
      Abstract: 1.Innovations can facilitate bursts of diversification by increasing access to novel resources and the attainment of novel functional designs. Pharyngognathy, exhibited by highly diverse groups such as wrasses and cichlid fishes, is hypothesized to increase foraging capacity and efficiency. 2.Here, I test the hypothesis that pharyngeal jaw shape and tooth morphology is adaptive in an ecologically diverse radiation of Neotropical cichlid fishes that spans North, Central, and South America. 3.I partitioned species into generalized trophic guilds using published stomach content analyses and quantified shape variation of the lower pharyngeal jaw using geometric morphometrics. Additionally, I tested for convergence in LPJ shape and trophic guild by mapping the phylogeny onto the principal components and testing for shifts towards similar evolutionary regimes. 4.Major LPJ shape variation included the length and orientation (i.e., narrow or wide) of the lateral processes and length of the medial process, which varied based on the proportion of fishes and plants consumed. Pharyngeal tooth number, diversity, and the frequency of tooth types were not evenly distributed among trophic guilds. There were seven distinct evolutionary regimes that converged upon four optima. 5.Pharyngeal jaw diversification is associated with the exploitation of novel resources among Neotropical cichlids such that pharyngeal specialization has increased access to otherwise poorly accessible resources, such as resources that are difficult to crush (e.g., hard shelled organisms) and assimilate (e.g., algae). This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-17T09:02:51.321324-05:
      DOI: 10.1111/1365-2656.12457
  • How to capture fish in a school' Effect of successive predator attacks
           on seabird feeding success
    • Abstract: 1.Prey aggregations, such as fish schools, attract numerous predators. This typically leads to the formation of multi‐specific groups of predators. These aggregations can be seen both as a place of increased competition and as a place of possible facilitation between predators. Consequently, the functional role of such predator‐prey aggregation is uncertain, and its effect on individual feeding success is virtually unknown. 2.Using underwater film footages of different predators feeding on fish schools during the sardine run in South Africa, we directly measured the in‐situ feeding success of individual Cape gannets Morus capensis in different foraging situations. 3.We determined the types of Cape gannet attacks (direct plunge dive or plunge dive followed by underwater pursuit) and we measured the occurrences and timing of attacks from the different species (mostly Cape gannets and long‐beaked common dolphins Delphinus capensis). We also estimated the size of the targeted fish schools. These observations were complemented with a simulation model to evaluate the cumulative effect of successive predator attacks on the prey aggregation structure. 4.The probability to capture a fish in one feeding attempt by Cape gannets averaged 0.28. It was lower when gannets engaged in underwater prey pursuit after the plunge compared to direct plunge (0.13 vs. 0.36). We found no effect of the number of prey on gannets’ feeding success. However, the timing and frequency of attacks influenced strongly and positively the feeding success of individuals. The probability to capture a fish was the lowest (0.16) when no attack occurred in the few seconds (1‐15 s) prior to a dive, and the highest (~0.4, i.e. more than twice) when one or two attacks occurred during this time window. The simulation model showed that a prey aggregation disorganized just after an attack, and that the maximum of disturbance was obtained a few seconds after the initiation of the successive attacks. 5.Our study suggests that, in multi‐species predator assemblages, the cumulative effect (through disorganisation of school cohesiveness) of the multiple species attacking a prey aggregation may increase the feeding success of each individual. Therefore, facilitation between predators is likely to overcome competition in these multi‐specific assemblages. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-13T03:52:16.24444-05:0
      DOI: 10.1111/1365-2656.12455
  • Assessing the structure and temporal dynamics of seabird communities: the
           challenge of capturing marine ecosystem complexity
    • Abstract: Understanding interspecific interactions, and the influences of anthropogenic disturbance and environmental change on communities, are key challenges in ecology. Despite the pressing need to understand these fundamental drivers of community structure and dynamics, only 17% of ecological studies conducted over the past three decades have been at the community level. Here, we assess the trophic structure of the procellariiform community breeding at South Georgia, to identify the factors that determine foraging niches and possible temporal changes. We collected conventional diet data from 13 sympatric species between 1974 and 2002, and quantified intra‐ and inter‐guild, and annual variation in diet between and within foraging habits. In addition, we tested the reliability of stable isotope analysis (SIA) of seabird feathers collected over a 13‐year period, in relation to those of their potential prey, as a tool to assess community structure when diets are diverse and there is high spatial heterogeneity in environmental baselines. Our results using conventional diet data identified a four‐guild community structure, distinguishing species that mainly feed on crustaceans; large fish and squid; a mixture of crustaceans, small fish and squid; or carrion. In total, Antarctic krill Euphausia superba represented 32%, and 14 other species a further 46% of the combined diet of all 13 predators, underlining the reliance of this community on relatively few types of prey. Annual variation in trophic segregation depended on relative prey availability; however, our data did not provide evidence of changes in guild structure associated with a suggested decline in Antarctic krill abundance over the past 40 years. Reflecting the differences in δ15N of potential prey (crustaceans vs. squid vs. fish and carrion), analysis of δ15N in chick feathers identified a three‐guild community structure that was constant over a 13‐year period, but lacked the trophic cluster representing giant petrels which was identified using conventional diet data. Our study is the first in recent decades to examine dietary changes in seabird communities over time. Conventional dietary analysis provided better resolution of community structure than SIA. However, δ15N in chick feathers, which reflected trophic (level) specialization, was nevertheless an effective and less time‐consuming means of monitoring temporal changes. In the past four decades, barely 20 published studies have attempted to describe seabird communities, only seven of which considered more than 10 species and none monitored temporal changes. This study is the first in recent decades to examine dietary changes in seabird communities over time.
      PubDate: 2015-10-06T09:14:29.916172-05:
      DOI: 10.1111/1365-2656.12434
  • Tackling extremes: Challenges for ecological and evolutionary research on
           extreme climatic events
    • Authors: Liam D. Bailey; Martijn de Pol
      Abstract: 1.Extreme climatic events (ECEs) are predicted to become more frequent as the climate changes. A rapidly increasing number of studies ‐ though few on animals ‐ suggest that the biological consequences of ECEs can be severe. 2.However, ecological research on the impacts of extreme climatic events (ECEs) has been limited by a lack of cohesiveness and structure. ECEs are often poorly defined and have often been confusingly equated with climatic variability, making comparison between studies difficult. Additionally, a focus on short‐term studies has provided us with little information on the long‐term implications of ECEs, and the descriptive and anecdotal nature of many studies has meant it is still unclear what the key research questions are. 3.Synthesizing the current state of work is essential to identify ways to make progress. We conduct a synthesis of the literature and discuss conceptual and practical challenges faced by research on ECEs. 4.We consider three steps to advance research. First, we discuss the importance of choosing an ECE definition and identify the pros and cons of ‘climatological’ and ‘biological’ definitions of ECEs. Second, we advocate research beyond short‐term descriptive studies to address questions concerning the long‐term implications of ECEs, focussing on selective pressures and phenotypically plastic responses and how they might differ from responses to a changing climatic mean. Finally, we encourage a greater focus on multi‐event studies that help us understand the implications of changing patterns of ECEs, through the combined use of modelling, experimental and observational field studies. 5.This paper aims to open a discussion on the definitions, questions and methods currently used to study ECEs, which will lead to a more cohesive approach to future ECE research. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-03T07:42:32.260903-05:
      DOI: 10.1111/1365-2656.12451
  • Within‐ and trans‐generational effects of herbivores and
           detritivores on plant performance and reproduction
    • Abstract: 1.Mutualistic and antagonistic aboveground and belowground species have the potential to be involved in strong interactions that can either weaken or strengthen their individual impacts on plants. Their impacts can also have delayed effects on a plant's progeny by altering offspring traits and survival. Few studies have explored the effect of herbivore and detritivore interactions with parent plants on offspring vital life‐cycle processes, such as seedling emergence rate, seedling establishment, and offspring survival. 2.In the field, I experimentally studied the combined effects of floral herbivores, root herbivores, and detritivores on plant growth and reproduction of Moricandia moricandioides (Brassicaceae). In particular, I analysed the trans‐generational effects of herbivores and detritivores on seed and juvenile production as well as on vital life‐cycle processes (i.e. seedling emergence rates, survival). 3.Floral herbivores strongly reduced the number of flowers, fruits, seeds, and juveniles. Detritivores had an impact on plant success by increasing seed quality (% N and N:C ratio), although the effect was altered by the presence of floral and root herbivores. 4.I found maternal effects (trans‐generational effects) of floral herbivores, root herbivores, and detritivores. Floral herbivores reduced seedling emergence and establishment. Floral and root herbivores in combination reduced seedling emergence timing, but the effect was counteracted by detritivores. Detritivores also reduced the negative effect of floral herbivores on offspring mortality rate. 5.This study shows that the impact of aboveground and belowground organisms on M. moricandioides plants go beyond seed production and were evident in the probability of establishment and survival of the following generation. Trans‐generational effects were induced by all three groups of interacting organisms and the net consequences for plant offspring depended on the organisms interacting with the plant. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-03T07:41:34.549976-05:
      DOI: 10.1111/1365-2656.12453
  • Experimental manipulation of floral scent bouquets restructures
           flower–visitor interactions in the field
    • Abstract: A common structural feature of natural communities is the non‐random distribution of pairwise interactions between organisms of different trophic levels. For plant–animal interactions, it is predicted that both stochastic processes and functional plant traits that facilitate or prevent interactions are responsible for these patterns. However, unbiased manipulative field experiments that rigorously test the effects of individual traits on community structure are lacking. We address this gap by manipulating floral scent bouquets in the field. Manipulation of floral scent bouquets led to quantitative as well as qualitative restructuring of flower–visitor networks, making them more generalized. Olfactometer trials confirmed both positive and negative responses to scent bouquets. Our results clearly show that the distribution of insect visitors to the two abundant study plant species reflects the insects' species‐specific preferences for floral scents, rather than for visual or morphological floral traits. Thus, floral scents may be of major importance in partitioning flower–visitor interactions. Integrating experimental manipulations of plant traits with field observations of interaction patterns thus represents a promising approach for revealing the processes that structure species assemblages in natural communities. Recently, network research moved from descriptive to mechanistic studies asking questions about the functional foundation of species interactions and community composition. This study is the first that directly characterizes the effect of an individual trait (floral scent bouquets) on the quantitative and qualitative distribution of plant‐animal interactions allowing conclusions about their co‐evolution and the maintenance of biodiversity.
      PubDate: 2015-10-02T01:08:53.543452-05:
      DOI: 10.1111/1365-2656.12441
  • Causes and consequences of repeatability, flexibility and individual
           fine‐tuning of migratory timing in pike
    • Authors: Petter Tibblin; Anders Forsman, Tobias Borger, Per Larsson
      Abstract: Many organisms undertake migrations between foraging and breeding habitats and while it is assumed that reproductive timing affects fitness, little is known about the degree of individual consistency, and about the causes and consequences of individual variation in migratory timing in organisms other than birds. Here, we report on a 6‐year mark–recapture study, including 2048 individuals, of breeding migration in anadromous pike (Esox lucius), an iteroparous top‐predatory fish that displays homing behaviour. By repeated sampling across years at a breeding site, we first quantify individual variation both within and between breeding events and then investigate phenotypic correlates and fitness consequences of arrival timing to the breeding site. Our data demonstrate that males arrive before females, that large males arrive later than small males, that the timing of breeding migration varies among years and that individuals are consistent in their timing across years relative to other individuals in the population. Furthermore, data on return rates indicate that arrival time is under stabilizing viability selection, and that individuals who are more flexible in their timing of arrival during the first reproductive years survive longer compared with less flexible individuals. Finally, longitudinal data demonstrate that individuals consistently fine‐tune their arrival timing across years, showing that the timing of arrival to breeding sites is influenced by experience. These findings represent rare evidence of how between‐ and within‐individual variations in migratory timing across breeding events are correlated with phenotypic and fitness traits in an ecologically important keystone species. Our results emphasize the importance of considering variation in migratory timing both between and within individuals in studies investigating the fitness consequences of migratory behaviour and have implications for future management. This study provides rare evidence of phenotypic correlates and fitness consequences of individual variation of migratory timing in an aquatic top‐predatory fish.
      PubDate: 2015-09-28T00:59:32.197867-05:
      DOI: 10.1111/1365-2656.12439
  • How many routes lead to migration' Comparison of methods to assess and
           characterise migratory movements
    • Abstract: 1.Decreasing rate of migration in several species as a consequence of climate change and anthropic pressure, together with increasing evidence of space‐use strategies intermediate between residency and complete migration, are very strong motivations to evaluate migration occurrence and features in animal populations. 2.The main goal of this paper was to perform a relative comparison between methods for identifying and characterising migration at the individual and population level on the basis of animal location data. 3.We classified 104 yearly individual trajectories from five populations of three deer species as migratory or non‐migratory, by means of three methods: seasonal home range overlap, spatio‐temporal separation of seasonal clusters, and the Net Squared Displacement (NSD) method. For migratory cases, we also measured timing and distance of migration and residence time on the summer range. Finally, we compared the classification in migration cases across methods and populations. 4.All methods consistently identified migration at the population level, i.e., they coherently distinguished between complete or almost complete migratory populations and partially migratory populations. However, in the latter case, methods coherently classified only about 50% of the single cases, i.e. they classified differently at the individual‐animal level. We therefore infer that the comparison of methods may help point to ‘less‐stereotyped’ cases in the residency‐to‐migration continuum. For cases consistently classified by all methods, no significant differences were found in migration distance, or residence time on summer ranges. Timing of migration estimated by NSD was earlier than by the other two methods, both for spring and autumn migrations. 5.We suggest 3 steps to identify improper inferences from migration data, and to enhance understanding of intermediate space‐use strategies. We recommend: a) classifying migration behaviours using more than one method, b) performing sensitivity analysis on method parameters to identify the extent of the differences, and c) investigating inconsistently classified cases as these may often be ecologically interesting (i.e., less‐stereotyped migratory behaviours). This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-28T00:50:29.313141-05:
      DOI: 10.1111/1365-2656.12449
  • Patterns and predictors of β‐diversity in the fragmented
           Brazilian Atlantic forest: A multiscale analysis of forest specialist and
           generalist birds
    • Abstract: 1.Biodiversity maintenance in human‐altered landscapes (HALs) depends on the species turnover among localities, but the patterns and determinants of β‐diversity in HALs are poorly known. In fact, declines, increases, and neutral shifts in β‐diversity have all been documented, depending on the landscape, ecological group and spatial scale of analysis. 2.We shed some light on this controversy by assessing the patterns and predictors of bird β‐diversity across multiple spatial scales considering forest specialist and habitat generalist bird assemblages. 3.We surveyed birds from 144 point counts in 36 different forest sites across two landscapes with different amount of forest cover in the Brazilian Atlantic forest. We analysed β‐diversity among points, among sites, and between landscapes with multiplicative diversity partitioning of Hill numbers. We tested whether β‐diversity among points was related to within‐site variations in vegetation structure, and if β‐diversity among sites was related to site location and/or to differences among sites in vegetation structure and landscape composition (i.e. percent forest and pasture cover surrounding each site). 4.β‐diversity between landscapes was lower than among sites and among points in both bird assemblages. In forest specialist birds, the landscape with less forest cover showed the highest β‐diversity among sites (bird differentiation among sites), but generalist birds showed the opposite pattern. At the local scale, however, the less forested landscape showed the lowest β‐diversity among points (bird homogenisation within sites), independently of the bird assemblage. β‐diversity among points was weakly related to vegetation structure, but higher β‐diversity values were recorded among sites that were more isolated from each other, and among sites with higher differences in landscape composition, particularly in the less forested landscape. 5.Our findings indicate that patterns of bird β‐diversity vary across scales and are strongly related to landscape composition. Bird assemblages are shaped by both environmental filtering and dispersal limitation, particularly in less forested landscapes. Conservation and management strategies should therefore prevent deforestation in this biodiversity hotspot. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-24T02:19:18.114894-05:
      DOI: 10.1111/1365-2656.12448
  • Home is where the shell is: predicting turtle home range sizes
    • Authors: Alex Slavenko; Yuval Itescu, Flora Ihlow, Shai Meiri
      Abstract: 1.Home range is the area traversed by an animal in its normal activities. The size of home ranges is thought to be tightly linked to body size, through size effect on metabolic requirements. Due to the structure of Eltonian food pyramids, home range sizes of carnivores are expected to exceed those of herbivorous species. The habitat may also affect home range size, with reduced costs of locomotion or lower food abundance in e.g., aquatic habitats selecting for larger home ranges. Furthermore, home range of males in polygamous species may be large due to sexual selection for increased reproductive output. 2.Comparative studies on home range sizes have rarely been conducted on ectotherms. Because ectotherm metabolic rates are much lower than those of endotherms, energetic considerations of metabolic requirements may be less important in determining the home range sizes of the former, and other factors such as differing habitats and sexual selection may have an increased effect. 3.We collected literature data on turtle home range sizes. We used phylogenetic generalised least squares analyses to determine whether body mass, sex, diet, habitat and social structure, affect home range size. 4.Turtle home range size increases with body mass. However, body mass explains relatively little of the variation in home range size. Aquatic turtles have larger home ranges than semiaquatic species. Omnivorous turtles have larger home ranges than herbivores and carnivores, but diet is not a strong predictor. Sex and social structure are unrelated to home range size. 5.We conclude that energetic constraints are not the primary factor that determines home range size in turtles, and energetic costs of locomotion in different habitats probably play a major role. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-23T02:27:03.510908-05:
      DOI: 10.1111/1365-2656.12446
  • Spatial overlap in a solitary carnivore: support for the
           land‐tenure, kinship, or resource dispersion hypotheses'
    • Authors: L. Mark Elbroch; Patrick E. Lendrum, Howard Quigley, Anthony Caragiulo
      Abstract: 1.There are several alternative hypotheses about the effects of territoriality, kinship, and prey availability on individual carnivore distributions within populations. The first is the land‐tenure hypothesis, which predicts that carnivores regulate their density through territoriality and temporal avoidance. The second is the kinship hypothesis, which predicts related individuals will be clumped within populations, and the third is the resource dispersion hypothesis, which suggests that resource richness may explain variable sociality, spatial overlap, or temporary aggregations of conspecifics. 2.Research on the socio‐spatial organization of animals is essential in understanding territoriality, intra‐ and inter‐specific competition, and contact rates that influence diverse ecology, including disease transmission between conspecifics and courtship behaviors. 3.We explored these hypotheses with data collected on a solitary carnivore, the cougar (Puma concolor), from 2005 to 2012 in the Southern Yellowstone Ecosystem, Wyoming, USA. We employed 27 annual home ranges for 13 cougars to test whether home range overlap was better explained by land‐tenure, kinship, resource dispersion, or some combination of the three. 4.We found support for both the land‐tenure and resource dispersion hypotheses, but not for kinship. Cougar sex was the primary driver explaining variation in home range overlap. Males overlapped significantly with females, whereas the remaining dyads (F‐F, M‐M) overlapped significantly less. In support for the resource dispersion hypothesis, hunting opportunity (the probability of a cougar killing prey in a given location) was often higher in overlapping than in non‐overlapping portions of cougar home ranges. In particular, winter hunt opportunity rather than summer hunt opportunity was higher in overlapping portions of female‐female and male‐female home ranges. 5.Our results may indicate that solitary carnivores are more tolerant of sharing key resources with unrelated conspecifics than previously believed, or at least during periods of high resource availability. Further, our results suggest that the resource dispersion hypothesis, which is typically applied to social species, is applicable in describing the spatial organization of solitary carnivores. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-23T02:25:42.445382-05:
      DOI: 10.1111/1365-2656.12447
  • Edge effects and Geometric Constraints: a Landscape‐level Empirical
    • Abstract: Edge effects are pervasive in landscapes yet their causal mechanisms are still poorly understood. Traditionally, edge effects have been attributed to differences in habitat quality along the edge‐interior gradient of habitat patches, under the assumption that no edge effects would occur if habitat quality was uniform. This assumption was questioned recently after the recognition that geometric constraints tend to reduce population abundances near the edges of habitat patches, the so‐called “geometric edge effect” (GEE). Here we present the first empirical, landscape‐level evaluation of the importance of the GEE in shaping abundance patterns in fragmented landscapes. Using a dataset on the distribution of small mammals across 18 forest fragments, we assessed whether the incorporation of the GEE into the analysis changes the interpretation of edge effects and the degree to which predictions based on the GEE match observed responses. Quantitative predictions were generated for each fragment using simulations that took into account home range, density and matrix use for each species. The incorporation of the GEE into the analysis changed substantially the interpretation of overall observed edge responses at the landscape scale. Observed abundances alone would lead to the conclusion that the small mammals as a group have no consistent preference for forest edges or interiors, and that the black‐eared opossum Didelphis aurita (a numerically dominant species in the community) has on average a preference for forest interiors. In contrast, incorporation of the GEE suggested that the small mammal community as a whole has a preference for forest edges, whereas D. aurita has no preference for forest edges or interiors. Unexplained variance in edge responses was reduced by the incorporation of GEE, but remained large, varying greatly on a fragment‐by‐fragment basis. This study demonstrates how to model and incorporate the GEE in analyses of edge effects, and that this incorporation is necessary to properly interpret edge effects in landscapes. It also suggests that geometric constraints alone are unlikely to explain the variability in edge responses of a same species among different areas, highlighting the need to incorporate other ecological factors into explanatory models of edge effects. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-18T03:38:27.718009-05:
      DOI: 10.1111/1365-2656.12430
  • Spatial scale and movement behaviour traits control the impacts of habitat
           fragmentation on individual fitness
    • Authors: Lorenzo Cattarino; Clive A. McAlpine, Jonathan R. Rhodes
      Abstract: Habitat fragmentation, i.e., the breaking apart of habitat, can occur at multiple spatial scales at the same time, as a result of different land uses. Individuals of most species spend different amounts of times moving in different modes, during which they cover different distances and experience different fitness impacts. The scale at which fragmentation occurs interacts with the distance that individuals move in a particular mode to affect an individual's ability to find habitat. However, there is little knowledge of the fitness consequences of different scales of fragmentation for individuals with different traits of movement behaviour. This is critical to understand the mechanisms of persistence of different species in fragmented landscapes. The aim of this study is to quantify the impacts of habitat fragmentation at different scales on the fitness components (reproduction and survival) of individuals with different traits of movement behaviour. We developed a demographic model of individuals that adopt short and tortuous movements within foraging areas (foraging mode) and long and straight movements between foraging areas (searching mode). We considered individuals that adopt different movement modes with varying frequencies, inherently move different searching distances and experience different risks of mortality during searching. We then applied the model within a spatially‐explicit simulation framework where we varied simultaneously the degree of fragmentation within (fine scale) and between foraging areas (coarse scale). Fine‐scale fragmentation had a greater impact on reproduction and survival than coarse‐scale fragmentation, for those individuals with a low searching propensity. The impact of fine‐scale fragmentation on reproduction and survival interacted with the impact of coarse‐scale fragmentation on reproduction and survival, to affect the fitness of individuals with a high searching propensity, large inherent searching distances and high searching mortality rates. Habitat selection strongly mitigated the impact of the scale at which fragmentation occurred on individual fitness. Our findings suggest that the land use to target with conservation actions to reduce fragmentation, such as financial schemes that promote re‐vegetation or retention of standing vegetation, depends on the scale at which fragmentation occurs and the movement behaviour traits of the species of conservation concern. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-14T06:09:25.589053-05:
      DOI: 10.1111/1365-2656.12427
  • Immunosenescence and the ability to survive bacterial infection in the red
           flour beetle tribolium castaneum
    • Authors: Imroze Khan; Arun Prakash, Deepa Agashe
      Abstract: 1.In most animals, ageing is associated with a decline in immune function (immune senescence). However, different components of the immune system seem to age differentially, and many studies do not measure the ultimate fitness consequences of immune function after infection. Previous work shows that immune function may be traded off with other fitness components such as reproduction. It is possible that age alters the nature of these trade‐offs, particularly in conjunction with factors such as gender and mating that can also affect investment in immune function. 2.We tested the impact of age, sex and mating on post‐infection survivorship in Tribolium castaneum flour beetles, as well as the components of baseline constitutive innate immunity and external (secreted) immune function in uninfected individuals. We also tested whether the reproductive ability of uninfected females is traded off with immune function (baseline innate and external immunity) and post‐infection survivorship across age groups. 3.We found that age, sex and mating significantly affected immune components and infection outcome, although the magnitude and nature of the impact varied in each case. We found that older beetles were more susceptible to infection by the pathogen Bacillus thuringiensis even though major components of the constitutive innate immune defence (antibacterial and phenoloxidase activity) remained unchanged or improved with age. Thus, these aspects of innate immunity cannot explain the observed decline in post‐infection survival of older beetles. We did not find trade‐offs between the reproductive ability of uninfected females and their immune function. In contrast to innate immunity, external immunity showed an overall decline with age but was also affected by sex and mating. Finally, we show that bacterial infection alters external immunity via complex interactions between age, sex and mating status. 4.Our work uncovers novel interactions between age, sex and mating that can determine the evolution and outcome of immunosenescence by affecting the time course of relative investment in different immune and fitness components. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-14T06:08:24.600543-05:
      DOI: 10.1111/1365-2656.12433
  • Taxonomic and functional composition of arthropod assemblages across
           contrasting Amazonian forests
    • Abstract: Arthropods represent most of global biodiversity, with the highest diversity found in tropical rainforests. Nevertheless, we have a very incomplete understanding of how tropical arthropod communities are assembled. We conducted a comprehensive mass‐sampling of arthropod communities within three major habitat types of lowland Amazonian rainforest, including terra firme clay, white‐sand, and seasonally‐flooded forests in Peru and French Guiana. We examined how taxonomic and functional composition (at the family level) differed across these habitat types in the two regions. The overall arthropod community composition exhibited strong turnover among habitats and between regions. In particular, seasonally‐flooded forest habitats of both regions comprised unique assemblages. Overall, 17.7% (26 of 147) of arthropod families showed significant preferences for a particular habitat type. We present a first reproducible arthropod functional classification among the 147 taxa based on similarity among 21 functional traits describing feeding source, major mouthparts and microhabitats inhabited by each taxon. We identified seven distinct functional groups whose relative abundance contrasted strongly across the three habitats, with sap and leaf feeders showing higher abundances in terra firme clay forest. Our novel arthropod functional classification provides an important complement to link these contrasting patterns of composition to differences in forest functioning across geographic and environmental gradients. This study underlines that both environment and biogeographical processes are responsible for driving arthropod taxonomic composition while environmental filtering is the main driver of the variance in functional composition. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-08T04:47:49.109916-05:
      DOI: 10.1111/1365-2656.12445
  • Seasonal time constraints reduce genetic variation in life history traits
           along a latitudinal gradient
    • Abstract: 1.Time constraints cause strong selection on life history traits, because populations need to complete their life cycles within a shorter time. We therefore expect lower genetic variation in these traits in high‐ than in low‐latitude populations, since the former are more time constrained. 2.The aim was to estimate life history traits and their genetic variation in an obligately univoltine damselfly along a latitudinal gradient of 2,730 km. 3.Populations were grown in the laboratory at temperatures and photoperiods simulating those at their place of origin. In a complementary experiment individuals from the same families were grown in constant temperature and photoperiod that mimicked average conditions across the latitude. 4.Development time and size was faster and smaller, respectively, and growth rate was higher at northern latitudes. Additive genetic variance was very low for life history traits and estimates for egg development time and larval growth rate showed significant decreases towards northern latitudes. The expression of genetic effects in life history traits differed considerably when individuals were grown in constant rather than simulated and naturally variable conditions. 5.Our results support strong selection by time constraints. They also highlight the importance of growing organisms in their native environment for correct estimates of genetic variance at their place of origin. Our results also suggest that the evolutionary potential of life history traits is very low at northern compared to southern latitudes, but that changes in climate could alter this pattern. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-03T04:52:02.482165-05:
      DOI: 10.1111/1365-2656.12442
  • Effects of management on aquatic tree‐hole communities in temperate
           forests are mediated by detritus amount and water chemistry
    • Abstract: 1.Arthropod communities in water‐filled tree‐holes may be sensitive to impacts of forest management, for example via changes in environmental conditions such as resource input. 2.We hypothesized that increasing forest management intensity negatively affects arthropod abundance and richness and shifts community composition and trophic structure of tree‐hole communities. We predicted that this shift is caused by reduced habitat and resource availability at the forest stand scale as well as reduced tree‐hole size, detritus amount and changed water chemistry at the tree‐hole scale. 3.We mapped 910 water‐filled tree‐holes in two regions in Germany and studied 199 tree‐hole inhabiting arthropod communities. 4.We found that increasing forest management intensity indeed significantly reduced arthropod abundance and richness in water‐filled tree‐holes. The most important indirect effects of management intensity on tree‐hole community structure were the reduced amounts of detritus for the tree‐hole inhabiting organisms and changed water chemistry at the tree‐hole scale, both of which seem to act as a habitat filter. Although habitat availability at the forest stand scale decreased with increasing management intensity, this unexpectedly increased local arthropod abundance in individual tree‐holes. However, regional species richness in tree‐holes significantly decreased with increasing management intensity, most likely due to decreased habitat diversity. We did not find that the management‐driven increase in plant diversity at the forest stand scale affected communities of individual tree‐holes, for example via resource availability for adults. 5.Our results suggest that management of temperate forests has to target a number of factors at different scales to conserve diverse arthropod communities in water‐filled tree holes. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-02T02:31:52.11505-05:0
      DOI: 10.1111/1365-2656.12437
  • Cold‐seeking behaviour mitigates reproductive losses from fungal
           infection in Drosophila
    • Authors: Vicky L Hunt; Weihao Zhong, Colin D McClure, David T Mlynski, Elizabeth ML Duxbury, A Keith Charnley, Nicholas K Priest
      Abstract: 1.Animals must tailor their life history strategies to suit the prevailing conditions and respond to hazards in the environment. Animals with lethal infections are faced with a difficult choice: to allocate more resources to reproduction and suffer higher mortality or to reduce reproduction with the expectation of enhanced immunity and late‐age reproduction. But, how they do this is largely unknown. 2.Here, we have investigated the temperature preference of the fruit fly, Drosophila melanogaster, during infection with the fungal pathogen, Metarhizium robertsii, and the consequences of temperature preference on life history traits. We have used multiple measurements to assess the fitness consequences of temperature including age‐specific changes in mortality rate and reproduction, providing more sensitive measures of accounting for variation in fitness with age. 3.We report that D. melanogaster optimizes its life history by exploiting thermal variation. Fungus‐infected fruit flies seek out cooler temperatures, which immediately reduces their fecundity but, ultimately, increases their lifetime reproductive success. Colder temperatures reduced fungal growth rates both in vivo and in vitro, indicating that cooler temperatures increased resistance to the infection. 4.By comparing life history responses in infected and control animals, we found that cold seeking in infected animals facilitates a trade off between early‐ and late‐age reproduction, but does not otherwise provide life history benefits that are specific to infected animals. These results indicate that cold‐seeking is a mechanism for reducing the reproductive costs of infection. In contrast, uninfected control flies prefer warmer temperatures that optimise reproductive success via a rapid propagation strategy. 5.These findings help explain how life history trade‐offs are mediated and how animals cope with infection, which will be increasingly important given the recent emergence of fungal pathogens and global climate change. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-01T10:57:29.954457-05:
      DOI: 10.1111/1365-2656.12438
  • Reefscapes of fear: predation risk and reef heterogeneity interact to
           shape herbivore foraging behavior
    • Authors: Laura B. Catano; Maria C. Rojas, Ryan J. Malossi, Joseph R. Peters, Michael R. Heithaus, James W. Fourqurean, Deron E. Burkepile
      Abstract: Predators can exert strong direct and indirect effects on ecological communities by intimidating their prey. The nature of predation risk effects is often context dependent, but in some ecosystems these contingencies are often overlooked. Risk effects are often not uniform across landscapes or among species. Indeed, they can vary widely across gradients of habitat complexity and with different prey escape tactics. These context‐dependencies may be especially important for ecosystems such as coral reefs that vary widely in habitat complexity and have species‐rich predator and prey communities. With field experiments using predator decoys of the black grouper (Mycteroperca bonaci), we investigated how reef complexity interacts with predation risk to affect the foraging behavior and herbivory rates of large herbivorous fishes (e.g., parrotfishes and surgeonfishes) across four coral reefs in the Florida Keys (USA). In both high and low complexity areas of the reef we measured how herbivory changed with increasing distance from the predator decoy to examine how herbivorous fishes reconcile the conflicting demands of avoiding predation vs. foraging within a reefscape context. We show that with increasing risk, herbivorous fishes consumed dramatically less food (ca. 90 %) but fed at a faster rate when they did feed (ca. 26 %). Furthermore, we show that fishes foraging closest to the predator decoy were 40 % smaller than those that foraged at further distances. Thus, smaller individuals showed muted response to predation risk compared to their larger counterparts, potentially due to their decreased risk to predation or lower reproductive value (i.e., the asset protection principle). Habitat heterogeneity mediated risk effects differently for different species of herbivores, with predation risk more strongly suppressing herbivore feeding in more complex areas and for individuals at higher risk of predation. Predators appear to create a reefscape of fear that changes the size structure of herbivores towards smaller individuals, increases individual feeding rates, but suppresses overall amounts of primary producers consumed, potentially altering patterns of herbivory, an ecosystem process critical for healthy coral reefs. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-01T10:46:03.348313-05:
      DOI: 10.1111/1365-2656.12440
  • Multiple mating reveals complex patterns of assortative mating by
           personality and body size
    • Abstract: 1.Understanding patterns of non‐random mating is central to predicting the consequences of sexual selection. Most studies quantifying assortative mating focus on testing for correlations among partners’ phenotypes in mated pairs. Few studies have distinguished between assortative mating arising from preferences for similar partners (expressed by all or a subset of the population), versus from phenotypic segregation in the environment. Also, few studies have assessed the robustness of assortative mating against temporal changes in social conditions. 2.We tracked multiple matings by stream water striders (Aquarius remigis) across variable social conditions to investigate mating patterns by both body size and behavioural type (personality). We documented temporal changes in partner availability and used a mixed model approach to analyse individual behaviours and changes in mating status recorded on an hourly basis. We assessed whether all or only a subset of individuals in the population expressed a tendency to mate with similar phenotypes. Our analyses took into account variation in the level of competition and in the phenotypes of available partners. 3.Males and females exhibited significant assortative mating by body size: the largest males and females, and the smallest males and females mated together more often than random. However, individuals of intermediate size were equally likely to mate with small, intermediate or large partners. Individuals also displayed two contrasting patterns of assortative mating by personality (activity level). Individuals generally mated preferentially with partners of similar activity level. However, beyond that general trend, individuals with more extreme personalities tended to exhibit disassortative mating: the most active males mated disproportionately with less active females, and the least active males tended to mate with more active females. 4.Our analyses thus revealed multiple, distinct patterns of non‐random mating. These mating patterns did not arise from differences in partner availability among individuals and were robust to temporal changes in social conditions. Hence mating patterns likely reflect mate preferences or arise from male – male competition coupled with sexual conflict. Our study also stresses the importance of accounting for variation in partner availability and demonstrates the influence of behavioural variation on mating patterns. This article is protected by copyright. All rights reserved.
      PubDate: 2015-08-31T10:16:42.440296-05:
      DOI: 10.1111/1365-2656.12436
  • Adaptive strategies in nocturnally migrating insects and songbirds:
           contrasting responses to wind
    • Abstract: 1. Animals that use flight as their mode of transportation must cope with the fact that their migration and orientation performance is strongly affected by the flow of the medium they are moving in, i.e. by the winds. Different strategies can be used to mitigate the negative effects and benefit from the positive effects of a moving flow. The strategies an animal can use will be constrained by the relationship between the speed of the flow and the speed of the animal's own propulsion in relation to the surrounding air. 2. Here we analyse entomological and ornithological radar data from north‐western Europe to investigate how two different nocturnal migrant taxa, the noctuid moth Autographa gamma and songbirds, deal with wind by analysing variation in resulting flight directions in relation to the wind‐dependent angle between the animal's heading and track direction. 3. Our results, from fixed locations along the migratory journey, reveal different global strategies used by moths and songbirds during their migratory journeys. As expected, nocturnally migrating moths experienced a greater degree of wind drift than nocturnally migrating songbirds, but both groups were more affected by wind in autumn than in spring. 4. The songbirds’ strategies involve elements of both drift and compensation, providing some benefits from wind in combination with destination and time control. In contrast, moths expose themselves to a significantly higher degree of drift in order to obtain strong wind assistance, surpassing the songbirds in mean ground speed, at the cost of a comparatively lower spatiotemporal migratory precision. 5. Moths and songbirds show contrasting but adaptive responses to migrating through a moving flow, which are fine‐tuned to the respective flight capabilities of each group in relation to the wind currents they travel within. This article is protected by copyright. All rights reserved.
      PubDate: 2015-07-04T08:31:09.134657-05:
      DOI: 10.1111/1365-2656.12420
  • Testing predator‐prey theory using broad‐scale manipulations
           and independent validation
    • Authors: Robert Serrouya; Bruce N. McLellan, Stan Boutin
      Abstract: 1.A robust test of ecological theory is to gauge the predictive accuracy of general relationships parameterized from multiple systems but applied to a new area. To address this goal, we used an ecosystem‐level experiment to test predator‐prey theory by manipulating prey abundance to determine whether predation was density dependent, density independent, compensatory, or depensatory (inversely density dependent) on prey populations. 2.Understanding the nature of predation is of primary importance in community ecology because it establishes whether predation has little effect on prey abundance (compensatory), whether it promotes coexistence (density dependent), reduces the equilibrium of prey (density independent), or whether it can be destabilizing (depensatory). 3.We used theoretical predictions consisting of functional and numerical equations parameterized independently from meta‐analyses on wolves (Canis lupus) and moose (Alces alces), but applied to our specific wolf‐moose system. Predictions were tested by experimentally reducing moose abundance across 6500 km2 as a novel way of evaluating the nature of predation. 4.Depensatory predation of wolves on moose was the best explanation of the population dynamic – a mechanism that has been hypothesized to occur but has rarely been evaluated. Adding locally obtained kill rates and numerical estimates to the independent data provided no benefit to model predictions, suggesting that the theory was robust to local variation. 5.These findings have critical implications for any organism that is preyed upon but that also has, or will be, subject to increased human exploitation or perturbations from environmental change. If depensatory predation is not accounted for in harvest models, predicted yields will be excessive and lead to further population decline. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-22T23:36:51.462408-05:
      DOI: 10.1111/1365-2656.12413
  • Who escapes detection? Quantifying the causes and consequences of
           sampling biases in a long‐term field study
    • Authors: Lindall R. Kidd; Ben C. Sheldon, Emily G. Simmonds, Ella F. Cole
      Abstract: Inferences drawn from long‐term field studies are vulnerable to biases in observability of different classes of individuals, which may lead to biases in the estimates of selection, or fitness. Population surveys that monitor breeding individuals can introduce such biases by not identifying individuals that fail early in their reproductive attempts. Here, we quantify how the standard protocol for detecting breeding females introduces bias in a long‐term population study of the great tit, Parus major. We do so by identifying females whose breeding attempts fail before they would normally be censused, and explore whether this early failure can be predicted by a number of intrinsic and extrinsic factors. We investigate the effect of these biases on estimates of reproductive performance and selection. We show that females that go undetected by standard censusing because they fail early in their breeding attempt were less likely to have been previously trapped within our study site and were more likely to breed in poor quality habitats. Furthermore we demonstrate that this bias sampling had lead previous studies on this population to overestimate the reproductive performance of unringed females, which are likely to be immigrants to the population. Finally, we show that these biases in detectability influence estimates of selection on a key life history trait. While these conclusions are specific to this study, we suggest that such effects are likely to be widespread, and that more attention should be given to whether or not methods for surveying natural populations introduce systematic bias that will influence conclusions about ecological and evolutionary processes. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-17T02:23:46.475224-05:
      DOI: 10.1111/1365-2656.12411
  • Body size affects individual winter foraging strategies of
           thick‐billed murres in the Bering Sea
    • Authors: Rachael A. Orben; Rosana Paredes, Daniel D. Roby, David B. Irons, Scott A. Shaffer
      Abstract: 1.Foraging and migration often require different energetic and movement strategies. Though not readily apparent, constraints during one phase might influence the foraging strategies observed in another. For marine birds that fly and dive, body size constraints likely present a trade‐off between foraging ability and migration as smaller bodies reduce flight costs whereas larger bodies are advantageous for diving deeper. 2.This study examines individual wintering strategies of deep diving thick‐billed murres (Uria lomvia) breeding at three colonies in the south‐eastern Bering Sea, St Paul, St George, and Bogoslof. These colonies, arranged north to south, are located such that breeding birds forage in a gradient from shelf to deep‐water habitats. 3.We used geolocation time‐depth recorders and stable isotopes from feathers to determine differences in foraging behaviour and diet of murres during three non‐breeding periods, 2008‐11. Body size was quantified by a principal component analysis (wing, culmen, head+bill, and tarsus length). A hierarchical cluster analysis identified winter foraging strategies based on individual movement, diving behaviour, and diet (inferred from stable isotopes). 4.Structural body size differed by breeding island. Larger birds from St Paul had higher wing‐loading than smaller birds from St George. Larger birds, mainly from St Paul, dove to deeper depths, spent more time in the Bering Sea, and likely consumed higher trophic‐level prey in late winter. Three winter foraging strategies were identified. The main strategy, employed by small birds from all three breeding colonies in the first two years, was characterized by high residency areas in the North Pacific south of the Aleutians and nocturnal diving. In contrast, 31% of birds from St Paul remained in the Bering Sea, and foraged mainly during the day, apparently feeding on higher trophic‐level prey. Throat feather stable isotopes indicated that individuals exhibited flexibility in the use of this colony‐specific foraging strategy. The third strategy only occurred in 2010/11, when birds dove more and deeper, suggesting limited prey resources. 5.Foraging strategies partitioned with respect to annual differences, presumably in response to shifts in distribution of prey, and were linked to body size. The presence of a colony specific wintering strategy suggests the potential for overwinter survival differences between these populations. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-11T03:10:40.65794-05:0
      DOI: 10.1111/1365-2656.12410
  • Predictive modelling of habitat selection by marine predators with respect
           to the abundance and depth distribution of pelagic prey
    • Abstract: Understanding the ecological processes that underpin species distribution patterns is a fundamental goal in spatial ecology. However, developing predictive models of habitat use is challenging for species that forage in marine environments, as both predators and prey are often highly mobile and difficult to monitor. Consequently, few studies have developed resource selection functions for marine predators based directly on the abundance and distribution of their prey. We analyse contemporaneous data on the diving locations of two seabird species, the shallow‐diving Peruvian Booby (Sula variegata) and deeper‐diving Guanay Cormorant (Phalacrocorax bougainvilliorum), and the abundance and depth distribution of their main prey, Peruvian anchoveta (Engraulis ringens). Based on this unique dataset, we develop resource selection functions to test the hypothesis that the probability of seabird diving behaviour at a given location is a function of the relative abundance of prey in the upper water column. For both species, we show that the probability of diving behaviour is mostly explained by the distribution of prey at shallow depths. While the probability of diving behaviour increases sharply with prey abundance at relatively low levels of abundance, support for including abundance in addition to the depth distribution of prey is weak, suggesting that prey abundance was not a major factor determining the location of diving behaviour during the study period. The study thus highlights the importance of the depth distribution of prey for two species of seabird with different diving capabilities. The results complement previous research that points towards the importance of oceanographic processes that enhance the accessibility of prey to seabirds. The implications are that locations where prey is predictably found at accessible depths may be more important for surface foragers, such as seabirds, than locations where prey is predictably abundant. Analysis of the relative importance of abundance and accessibility is essential for the design and evaluation of effective management responses to reduced prey availability for seabirds and other top predators in marine systems. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-09T09:47:12.049722-05:
      DOI: 10.1111/1365-2656.12409
  • Habitat‐mediated carry‐over effects lead to context dependent
           outcomes of species interactions
    • Authors: Benjamin G. Van Allen; Volker H.W. Rudolf
      Abstract: When individuals disperse, their performance in newly colonized habitats can be influenced by the conditions they experienced in the past, leading to environmental carry‐over effects. While carry‐over effects are ubiquitous in animal and plant systems, their impact on species interactions and coexistence are largely ignored in traditional coexistence theory. Here we used a combination of modeling and experiments with two competing species to examine when and how such environmental carry‐over effects influence community dynamics and competitive exclusions. We found that variation in the natal habitat quality of colonizing individuals created carry‐over effects which altered competitive coefficients, fecundity and mortality rates, and extinction probabilities of both species. As a consequence, the dynamics of competitive exclusion within and across habitat types was contingent on the natal habitat of colonizing individuals, indicating that spatial carry‐over effects can fundamentally alter the dynamics and outcome of interspecific competition. Interestingly, carry‐over effects persistently influenced dynamics in systems with interspecific competition for the entire duration of the experiment while carry‐over effects were transient and only influenced initial dynamics in single species populations. Thus carry‐over effects can be enhanced by species interactions, suggesting that their long‐term effects may often not be accurately predicted by single species studies. Given that carry‐over effects are ubiquitous in heterogeneous landscapes, our results provide a novel mechanism that could help explain variation in the structure of natural communities. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-09T09:42:27.646628-05:
      DOI: 10.1111/1365-2656.12408
  • Habitat features and long‐distance dispersal modify the use of
           social information by a long‐distance migratory bird
    • Authors: Clark S. Rushing; Michele R. Dudash, Peter P. Marra
      Abstract: 1.The processes by which individuals select breeding sites have important consequences for individual fitness as well as population‐ and community‐dynamics. Although there is increasing evidence that many animal species use information acquired from conspecifics to assess the suitability of potential breeding sites, little is known about how the use of this social information is modified by biotic and abiotic conditions. 2.We used an automated playback experiment to simulate two types of social information, post‐breeding public information and pre‐breeding location cues, to determine the relative importance of these cues for breeding site selection by a migratory songbird, the American redstart (Setophaga ruticilla). In addition, we used stable hydrogen isotopes to determine the dispersal status of individuals that responded to our experimental treatments and quantify whether long‐distance dispersers use different social cues to select breeding sites compared to philopatric individuals. 3.We found that points that received pre‐breeding location cue treatments were significantly more likely to be settled by redstarts than control points that received no playback. However, we found no evidence the redstarts used post‐breeding public information gathered during one season to select breeding sites the following year. Breeding site habitat structure was also a strong predictor of settlement probability, indicating that redstarts modified the use of social information based on habitat cues. Furthermore, stable hydrogen isotope signatures from individuals that responded to location cue treatments suggest that long‐distance dispersers may rely more heavily on these cues than local recruits. 4.Collectively, these results indicate that redstarts use multiple sources of information to select breeding sites, which could buffer individuals from selecting suboptimal sites when they breed in unfamiliar locations or when habitat quality becomes decoupled from social cues. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-08T05:09:23.236002-05:
      DOI: 10.1111/1365-2656.12395
  • Animal personality in a foundation species drives community divergence and
           collapse in the wild
    • Authors: Jonathan N. Pruitt; Andreas P. Modlmeier
      Abstract: 1.Despite thousands of papers on the topic, precious few of the studies on animal personality have considered the role of personality in shaping community‐level processes. Here we test the effect of individual variation on the long‐term trajectories of biological communities, from initiation to their demise. The spider Anelosimus studiosus builds webs that serve as habitat for >50 species of spider, which together construct a species‐rich silken reef. This species also exhibits a temporally consistent behavioral polymorphism where females exhibit either an aggressive or docile phenotype (personality). 2.In this study we established incipient colonies of either two docile or two aggressive females and then tracked community succession and persistence over seven years in the field. In particular we noted the community compositions associated with colony extinction/collapse events, which are common in this species. 3.The community composition of webs founded by different phenotypes diverged rapidly in their early successional stages. However, this period of divergence was ephemeral and all communities eventually converged on a similar composition; communities founded by aggressive females merely took longer to reach it. This secondary stage of community convergence was itself short‐lived and independent of founders’ personality; all communities collapsed within a year of achieving it. 4.Experimentally imposing this fatal climax composition on colonies caused 80% of communities to collapse within a year, suggesting that this climax composition actually causes the collapse of the community. Community collapse was characterized by a complete die‐off of the foundation species and the dispersal of all other spiders. Thus, the behavioral traits of the founding, foundational individuals of these communities dictate their path of succession and longevity in the wild. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-08T05:08:59.11412-05:0
      DOI: 10.1111/1365-2656.12406
  • Implications of scaled δ15N fractionation for community
           predator‐prey body mass ratio estimates in size‐structured
           food webs
    • Authors: J. C. P. Reum; S. Jennings, M. E. Hunsicker
      Abstract: Nitrogen stable isotope ratios (δ15N) may be used to estimate community‐level relationships between trophic level (TL) and body size in size‐structured food webs and hence the mean predator to prey body mass ratio (PPMR). In turn, PPMR is used to estimate mean food chain length, trophic transfer efficiency, rates of change in abundance with body mass (usually reported as slopes of size‐spectra) and to calibrate and validate food web models. When estimating TL, researchers had assumed that fractionation of δ15N (Δδ15N) did not change with TL. However, a recent meta‐analysis indicated that this assumption was not as well supported by data as the assumption that Δδ15N scales negatively with the δ15N of prey. We collated existing fish community δ15N‐body size data for the Northeast Atlantic and tropical Western Arabian Sea, and combined this with new data from the Northeast Pacific. This was used to estimate TL‐body mass relationships and PPMR under constant and scaled Δδ15N assumptions, and to assess how the scaled Δδ15N assumption affects our understanding of the structure of these food webs. Adoption of the scaled Δδ15N approach markedly reduces the previously reported differences in TL at body mass among fish communities from different regions. With scaled Δδ15N, TL‐body mass relationships became more positive and PPMR fell. Results implied that realized prey size choices in these size‐structured fish communities are less variable than previously assumed and food chains potentially longer. The adoption of generic PPMR estimates for calibration and validation of size‐based fish community models is better supported than hitherto assumed, but predicted slopes of community size‐spectra are more sensitive to a given change or error in realized PPMR when PPMR is small. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-05T05:51:56.890855-05:
      DOI: 10.1111/1365-2656.12405
  • Movement is the glue connecting home ranges and habitat selection
    • Abstract: 1.Animal space use has been studied by focusing either on geographic (e.g., home ranges, species’ distribution) or environmental (e.g., habitat use and selection) space. However, all patterns of space use emerge from individual movements, which are the primary means by which animals change their environment. 2.Individuals increase their use of a given area by adjusting two key movement components: the duration of their visit, and/or the frequency of re‐visits. Thus, in spatially heterogeneous environments animals exploit known, high‐quality resource areas by increasing their Residence Time (RT) in and/or decreasing their Time to Return (TtoR) to these areas. We expected that spatial variation in these two movement properties should lead to observed patterns of space use in both geographic and environmental spaces. We derived a set of 9 predictions linking spatial distribution of movement properties to emerging space use patterns. We predicted that, at a given scale, high variation in RT and TtoR among habitats leads to strong habitat selection, and that long RT and short TtoR result in a small home range size. 3.We tested these predictions using moose (Alces alces) GPS tracking data. We first modelled the relationship between landscape characteristics and movement properties. Then, we investigated how the spatial distribution of predicted movement properties (i.e., spatial autocorrelation, mean, and variance of RT and TtoR) influences home range size and hierarchical habitat selection. 4.In landscapes with high spatial autocorrelation of RT and TtoR, a high variation in both RT and TtoR occurred in home ranges. As expected, home range location was highly selective in such landscapes (i.e., 2nd‐order habitat selection); RT was higher and TtoR lower within the selected home range than outside, and moose home ranges were small. Within home ranges, a higher variation in both RT and TtoR was associated to higher selectivity among habitat types (i.e., 3rd‐order habitat selection). 5.Our findings show how patterns of geographic and environmental space use correspond to the two sides of a coin, linked by movement responses of individuals to environmental heterogeneity. By demonstrating the potential to assess the consequences of altering RT or TtoR (e.g., through human disturbance or climatic changes) on home range size and habitat selection, our work sets the basis for new theoretical and methodological advances in movement ecology. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-16T00:15:47.35042-05:0
      DOI: 10.1111/1365-2656.12394
  • Predicting the continuum between corridors and barriers to animal
           movements using Step Selection Functions and Randomized Shortest Paths
    • Abstract: 1.The loss, fragmentation, and degradation of habitat everywhere on Earth prompt increasing attention to identifying landscape features that support animal movement (corridors) or impede it (barriers). Most algorithms used to predict corridors assume that animals move through preferred habitat either optimally (e.g. Least Cost Path), or as random‐walkers (e.g. Current Models), but neither extreme is realistic. 2.We propose that corridors and barriers are two sides of the same coin, and that animals experience landscapes as spatio‐temporally dynamic corridor‐barrier continua connecting (separating) functional areas where individuals fulfill specific ecological processes. Based on this conceptual framework, we propose a novel methodological approach that uses high‐resolution individual‐based movement data to predict corridor‐barrier continua with increased realism. 3.Our approach consists of two innovations. First, we use Step Selection Functions (SSF) to predict friction maps quantifying corridor‐barrier continua for tactical steps between consecutive locations. Second, we introduce to movement ecology the Randomized Shortest Path algorithm (RSP) which operates on friction maps to predict the corridor‐barrier continuum for strategic movements between functional areas. By modulating the parameter Ѳ, which controls the trade‐off between exploration and optimal exploitation of the environment, RSP bridges the gap between algorithms assuming optimal movements (when Ѳ approaches infinity, RSP is equivalent to LCP) or random‐walk (when Ѳ → 0, RSP → Current Models). 4.Using this approach, we identify migration corridors for GPS‐monitored wild reindeer (Rangifer t. tarandus) in Norway. We demonstrate that reindeer movement is best predicted by an intermediate value of Ѳ, indicative of a movement trade‐off between optimization and exploration. Model calibration allows identification of a corridor‐barrier continuum that closely fits empirical data, and demonstrates that RSP outperforms models that assume either optimality or random‐walk. 5.The proposed approach models the multi‐scale cognitive maps by which animals likely navigate real landscapes, and generalizes the most common algorithms for identifying corridors. Because sub‐optimal, but non‐random, movement strategies are likely widespread, our approach has the potential to predict more realistic corridor‐barrier continua for a wide range of species. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-07T03:56:33.585073-05:
      DOI: 10.1111/1365-2656.12386
  • What is the animal doing' Tools for exploring behavioral structure in
           animal movements
    • Authors: Eliezer Gurarie; Chloe Bracis, Maria Delgado, Trevor D. Meckley, Ilpo Kojola, C. Michael Wagner
      Abstract: 1.Movement data provide a window ‐ often our only window ‐ into the cognitive, social and biological processes that underlie the behavioral ecology of animals in the wild. Robust methods for identifying and interpreting distinct modes of movement behavior are of great importance, but complicated by the fact that movement data are complex, multivariate, and dependent. Many different approaches to exploratory analysis of movement have been developed to answer similar questions and practitioners are often at a loss for how to choose an appropriate tool for a specific question. 2.We apply and compare four methodological approaches: first passage time (FPT), Bayesian partitioning of Markov models (BPMM), behavioral change point analysis (BCPA), and a fitted multi‐state random walk (MRW) to three simulated tracks and two animal trajectories ‐ a sea lamprey (Petromyzon marinus) tracked for 12 hours and a wolf (Canis lupus) tracked for one year. 3.The simulations ‐ in which, respectively, velocity, tortuosity, and spatial bias change ‐ highlight the sensitivity of all methods to model misspecification. Methods that do not account for autocorrelation in the movement variables lead to spurious change points while methods that do not account for spatial bias completely miss changes in orientation. We make suggestions towards unifying directions for methodological advances. 4.When applied to the animal data, the methods broadly agree on the structure of the movement behaviors. Important discrepancies, however, reect differences in the assumptions and nature of the outputs. Important trade‐offs are between the strength of the a priori assumptions (low in BCPA, high in MRW), complexity of output (high in the BCPA, low in the BPMM and MRW), and explanatory potential (highest in the MRW). 5.The animal track analysis suggests some general principles for the exploratory analysis of movement data, including ways to exploit the strengths of the various methods. We argue for close and detailed exploratory analysis of movement before fitting complex movement models. This article is protected by copyright. All rights reserved.
      PubDate: 2015-04-23T09:48:38.045866-05:
      DOI: 10.1111/1365-2656.12379
  • Can habitat selection predict abundance'
    • Authors: Mark S. Boyce; Chris J. Johnson, Evelyn H. Merrill, Scott E. Nielsen, Erling J. Solberg, Bram Moorter
      Abstract: Habitats have substantial influence on the distribution and abundance of animals. Animals’ selective movement yields their habitat use. Animals generally are more abundant in habitats that are selected most strongly. Models of habitat selection can be used to distribute animals on the landscape or their distribution can be modeled based on data of habitat use, occupancy, intensity of use, or counts of animals. When the population is at carrying capacity or in an ideal free distribution, habitat selection and related metrics of habitat use can be used to estimate abundance. If the population is not at equilibrium, models have the flexibility to incorporate density into models of habitat selection; but abundance might be influenced by factors influencing fitness that are not directly related to habitat thereby compromising the use of habitat‐based models for predicting population size. Scale and domain of the sampling frame, both in time and space, are crucial considerations limiting application of these models. Ultimately, identifying reliable models for predicting abundance from habitat data requires an understanding of the mechanisms underlying population regulation and limitation. This article is protected by copyright. All rights reserved.
      PubDate: 2015-03-16T02:44:25.832642-05:
      DOI: 10.1111/1365-2656.12359
  • Animal personality meets community ecology: founder species aggression and
           the dynamics of spider communities
    • Authors: John L. Quinn
      First page: 1457
      Abstract: Silken web‐reef created by the spider Anelosimus studiosus (main picture) and close‐up (insert picture) of multi‐female, adult colony of the same species. (photographs: T. Jones, J. Pruitt and A. Wild) In Focus: Pruitt, J.N. & Modlmeier, A.P. (2015) Animal personality in a foundation species drives community divergence and collapse in the wild. Journal of Animal Ecology, 84 Interspecific interactions form the cornerstone of niche theory in community ecology. The 7‐year study In Focus here supports the view that variation within species could also be crucially important. Spider communities created experimentally in the wild, with either aggressive or docile individuals of the same founder species, were highly divergent in patterns of community succession for several years. Eventually, they converged on the same community composition only to collapse entirely shortly after, apparently because of the specific mix of aggression phenotypes within and between species just before collapse. These results suggest numerous avenues of research for behavioural ecology and evolutionary community ecology in metapopulations, and could help to resolve differences between competing theories. Spider communities seeded with either aggressive or docile individuals of the same founder species in the wild were highly divergent in patterns of succession but converged after seven years. These field data suggest numerous avenues of research and could help to resolve differences between competing theories in community ecology.
      PubDate: 2015-10-09T03:53:38.884364-05:
      DOI: 10.1111/1365-2656.12435
  • Diet complexity in early life affects survival in released pheasants by
           altering foraging efficiency, food choice, handling skills, and gut
    • Authors: Mark A. Whiteside; Rufus Sage, Joah R. Madden
      First page: 1480
      Abstract: Behavioural and physiological deficiencies are major reasons why reintroduction programs suffer from high mortality when captive animals are used. Mitigation of these deficiencies is essential for successful reintroduction programs. Our study manipulated early developmental diet to better replicate foraging behaviour in the wild. Over two years we hand‐reared 1800 pheasants (Phasianus colchicus), from one day old, for seven weeks under different dietary conditions. In year one, 900 pheasants were divided into three groups and reared with (i) commercial chick crumb, (ii) crumb plus 1% live mealworm or (iii) crumb plus 5% mixed seed and fruit. In year two, a further 900 pheasants were divided into two groups and reared with (i) commercial chick crumb or (ii) crumb plus a combination of 1% mealworm and 5% mixed seed and fruit. In both years the commercial chick crumb acted as a control treatment, whilst those with live prey and mixed seeds and fruits mimicking a more naturalistic diet. After seven weeks reared on these diets pheasants were released into the wild. Post release survival was improved with exposure to more naturalistic diets prior to release. We identified four mechanisms to explain this. Pheasants reared with more naturalistic diets: 1) foraged for less time and had a higher likelihood of performing vigilance behaviours; 2) were quicker at handling live prey items; 3) were less reliant on supplementary feed which could be withdrawn; 4) developed different gut morphology. These mechanisms allowed the pheasants to: 1) reduce the risk of predation by reducing exposure time whilst foraging, while allowing more time to be vigilant; 2) be better at handling and discriminating natural food items, and not be solely reliant on supplementary feed; 3) have a better gut system to cope with the natural forage after the cessation of supplementary feeding in the spring. Learning food discrimination, preference and handling skills by the provision of a more naturalistic diet is essential prior to the release of pheasants in a reintroduction program. Subsequent diet, foraging behaviour, gut morphology and digestive capabilities all work together as one nutritional complex. Simple manipulations during early development can influence these characteristics to better prepare an individual for survival upon release. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-21T02:20:38.113759-05:
      DOI: 10.1111/1365-2656.12401
  • Contrasting responses of male and female foraging effort to
           year‐round wind conditions
    • Authors: Sue Lewis; Richard A. Phillips, Sarah J. Burthe, Sarah Wanless, Francis Daunt
      First page: 1490
      Abstract: There is growing interest in the effects of wind on wild animals, given evidence that wind speeds are increasing and becoming more variable in some regions, particularly at temperate latitudes. Wind may alter movement patterns or foraging ability, with consequences for energy budgets and, ultimately, demographic rates. These effects are expected to vary among individuals due to intrinsic factors such as sex, age or feeding proficiency. Furthermore, this variation is predicted to become more marked as wind conditions deteriorate, which may have profound consequences for population dynamics as the climate changes. However, the interaction between wind and intrinsic effects has not been comprehensively tested. In many species, in particular those showing sexual size dimorphism, males and females vary in foraging performance. Here, we undertook year‐round deployments of data loggers to test for interactions between sex and wind speed and direction on foraging effort in adult European shags Phalacrocorax aristotelis, a pursuit‐diving seabird in which males are c. 18% heavier. We found that foraging time was lower at high wind speeds but higher during easterly (onshore) winds. Furthermore, there was an interaction between sex and wind conditions on foraging effort, such that females foraged for longer than males when winds were of greater strength (9% difference at high wind speeds vs. 1% at low wind speeds) and when winds were easterly compared with westerly (7% and 4% difference, respectively). The results supported our prediction that sex‐specific differences in foraging effort would become more marked as wind conditions worsen. Since foraging time is linked to demographic rates in this species, our findings are likely to have important consequences for population dynamics by amplifying sex‐specific differences in survival rates. There is a concern that increasing wind speeds are affecting the foraging ability of animals. The authors show that the foraging effort of female European shags was greater than males as wind conditions worsened. The findings have important consequences on the survival prospects of the two sexes as the climate changes. Photo credit: Richard Bardgett.
      PubDate: 2015-08-18T04:05:54.998495-05:
      DOI: 10.1111/1365-2656.12419
  • Alternative reproductive tactics in female striped mice: heavier females
           are more likely to breed solitary than communally
    • Authors: Davina L. Hill; Neville Pillay, Carsten Schradin
      First page: 1497
      Abstract: 1.Alternative reproductive tactics (ARTs) are discrete reproductive phenotypes governed by decision‐rules called strategies. ARTs are fixed for life in species with alternative strategies, while tactic expression is plastic in species with a single strategy. ARTs have been investigated in males of many species, but few studies have tested whether the same theoretical framework applies in females. 2.Female striped mice (Rhabdomys pumilio) employ three ARTs: communal breeders give birth in a nest shared with female kin and a breeding male, and show allo‐parental care; returners give birth away from the shared nest and later return to it; and solitary breeders give birth away from the shared nest and do not return to the group. 3.Here, studying free‐living female striped mice over six breeding seasons, we tested whether ARTs arise from alternative strategies or a single strategy. 4.We also asked to what extent stochastic extrinsic factors explain whether individuals become solitary rather than group‐living. 5.Females switched tactics, consistent with a single strategy, so we tested whether this represented a mixed or conditional single strategy. Only the latter predicts differences between ARTs in traits indicating competitive ability, such as body mass or age, before individuals adopt a tactic. We weighed females at conception when they were still group‐living to eliminate potential confounding effects of gestation and subsequent social tactic (solitary‐ versus group‐living) on body mass. 6.Females that went on to use a solitary ART were heavier than those that became communal breeders and returners, in support of a conditional strategy. 7.Solitary breeders also arose through extrinsic factors (mortality of all adult female group members). They weighed less than females that became solitary while relatives were alive, but did not differ in body mass from communal breeders and returners. 8.We conclude that ART theory applies to both sexes, with female striped mice following a conditional single strategy. Future studies should consider the possibility that phenotypes that superficially resemble evolved tactics might also arise through non‐adaptive extrinsic causes. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-14T06:07:56.327864-05:
      DOI: 10.1111/1365-2656.12431
  • Conflict and cooperation over sex: the consequences of social and genetic
           polyandry for reproductive success in dunnocks
    • Authors: Eduardo S. A. Santos; Luana L. S. Santos, Malgorzata Lagisz, Shinichi Nakagawa
      First page: 1509
      Abstract: 1.Conflict and cooperation within and between the sexes are among the driving forces that lead to the evolution of mating systems. Among mating strategies, female genetic polyandry and male reproductive cooperation pose challenging evolutionary questions regarding the maintenance of systems where one sex suffers from reduced fitness. 2.Here, we investigate the consequences of social and genetic polyandry for reproductive success of females and males in a population of the dunnock, Prunella modularis. 3.We show that female multiple mating ameliorates the negative effects of inbreeding. We, however, found little evidence that females engage in extra‐group (pair) mating with less related or more heterozygous males. 4.Breeding in socially polyandrous groups reduced the amount of paternity lost to extra‐group males, such that, on average, cobreeding and monogamous males fledged a similar number of young. Importantly, ca. 30% of cobreeding male dyads were related, suggesting they could gain indirect fitness benefits. Taken together, cobreeding males achieve equivalent reproductive success to monogamous counterparts under most circumstances. 5.Our study has revealed unexpected complexities in the variable mating system of dunnocks in New Zealand. Our results differ from the well‐known Cambridge dunnock study and can help our understanding of the evolution and maintenance of various breeding systems in the animal kingdom. This article is protected by copyright. All rights reserved.
      PubDate: 2015-08-10T02:41:53.851029-05:
      DOI: 10.1111/1365-2656.12432
  • Differential contribution of demographic rate synchrony to population
           synchrony in barn swallows
    • First page: 1530
      Abstract: 1.Populations of many species show temporally synchronous dynamics over some range, mostly caused by spatial autocorrelation of the environment that affects demographic rates. Synchronous fluctuation of a demographic rate is a necessary, but not sufficient condition for population synchrony because population growth is differentially sensitive to variation in demographic rates. Little is known about the relative effects of demographic rates to population synchrony, because it is rare that all demographic rates from several populations are known. 2.We develop a hierarchical integrated population model with which all relevant demographic rates from all study populations can be estimated and apply it to demographic data of barn swallows Hirundo rustica from 9 sites that were between 19 and 224 km apart from each other. We decompose the variation of the population growth and of the demographic rates (apparent survival, components of productivity, immigration) into global and local temporal components using random effects which allowed the estimation of synchrony of these rates. 3.The barn swallow populations fluctuated synchronously, but less so than most demographic rates. The highest synchrony showed the probability of double brooding, while fledging success was highly asynchronous. Apparent survival, immigration and total productivity achieved intermediate levels of synchrony. The growth of all populations was most sensitive to changes in immigration and adult apparent survival, and both of them contributed to the observed temporal variation of population growth rates. 4.Using a simulation model we show that immigration and apparent survival of juveniles and adults were able to induce population synchrony, but not components of local productivity due to their low population growth rate sensitivity. Immigrants are mostly first time breeders and consequently their number depends on productivity of neighbouring populations. Since total productivity was synchronized we conclude that it contributed to population synchrony in an indirect way through dispersing individuals which appear as immigrants at the local scale. 5.The hierarchical integrated population model is promising for achieving an improved mechanistic understanding of population synchrony. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-14T06:10:21.61986-05:0
      DOI: 10.1111/1365-2656.12423
  • Live fast, die old: no evidence of reproductive senescence or costs of
           mating in a damselfly (Odonata: Zygoptera)
    • Authors: Christopher Hassall; Thomas N. Sherratt, Phillip C. Watts, David J. Thompson
      First page: 1542
      Abstract: Recent examples of actuarial senescence in wild insect populations have challenged the long‐held assumption that the brevity of wild insect life spans precludes senescence. We investigate age‐related patterns in mating behaviour in adults of a short‐lived damselfly, Coenagrion puella and the implications of this mating. Using capture histories for 1033 individuals over two field seasons, we conduct both pooled and stratified analyses of variations in breeding activity. Pooled analyses suggest that there is strong age‐related variation in the probability of being present at the mating rendezvous. However, no age‐related variation was observed in the probability of mating. Stratified approaches confirmed a general pattern of age‐related declines in survival probability, but provided only equivocal evidence of an effect of age on transition between temporary breeding states. Mating males and females showed greater survival than non‐mating individuals, possibly as a consequence of higher body condition. Older males that were not currently breeding were less likely to commence breeding on the next day, but showed no patterns in breeding cessation. Overall, transitions between both breeding states declined with age, suggesting that males that breed tend to continue breeding while those that do not breed continue to be unsuccessful. Female mating rates were consistently high across all ages with no age‐related decline apparent. While previous research has demonstrated actuarial senescence in this population, as does this study, we find little evidence of either age‐related declines in reproductive behaviour or breeding‐related declines in survival, which might indicate functional senescence or costs of mating, respectively. Indeed, the greater survival in mating individuals of both sexes suggests that variations in individual quality may mediate both reproductive success and longevity. Contrary to recent studies, we found no compelling evidence for reproductive senescence or a cost of mating in an important and well‐studied model odonate. The possible link between condition and ageing suggests that individual quality needs to be taken into account when studying senescence. We recommend the use of multistrata models for the future investigation of these phenomena. In a previous study the authors demonstrated that older damselflies show signs of ageing despite their short lifespans, but in this comprehensive study the authors show that there appears to be neither a decline in reproductive performance nor a ‘cost of sex’ in terms of increased risk of mortality in breeding individuals.
      PubDate: 2015-07-16T01:17:06.544669-05:
      DOI: 10.1111/1365-2656.12407
  • Colour polymorphism torn apart by opposing positive
           frequency‐dependent selection, yet maintained in space
    • Authors: Swanne P. Gordon; Hanna Kokko, Bibiana Rojas, Ossi Nokelainen, Johanna Mappes
      First page: 1555
      Abstract: Polymorphic warning signals in aposematic species are enigmatic because predator learning and discrimination should select for the most common coloration, resulting in positive frequency‐dependent survival selection. Here, we investigated whether differential mating success could create sufficiently strong negative frequency‐dependent selection for rare morphs to explain polymorphic (white and yellow) warning coloration in male wood tiger moths (Parasemia plantaginis). We conducted an experiment in semi‐natural conditions where we estimated mating success for both white and yellow male moths under three different morph frequencies. Contrary to expectations, mating success was positively frequency‐dependent: white morph males had high relative fitness when common, likewise yellow morph males had high relative fitness when instead they were common. We hence built a model parameterized with our data to examine whether polymorphism can be maintained despite two sources of positive frequency dependence. The model includes known spatial variation in the survival advantage enjoyed by the yellow morph, and assumes that relative mating success follows our experimentally derived values. It predicts that polymorphism is possible under migration for up to approximately 20% exchange of individuals between subpopulations in each generation. Our results suggest that differential mating success combined with spatial variation in predator communities may operate as a selection mosaic that prevents complete fixation of either morph. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-26T10:03:19.281835-05:
      DOI: 10.1111/1365-2656.12416
  • Spatial and spatiotemporal variation in metapopulation structure affects
           population dynamics in a passively dispersing arthropod
    • Authors: A De Roissart; S Wang, D Bonte
      First page: 1565
      Abstract: 1.The spatial and temporal variation in the availability of suitable habitat within metapopulations determines colonization‐extinction events, regulates local population sizes and eventually affects local population and metapopulation stability. Insights into the impact of such a spatiotemporal variation on the local population and metapopulation dynamics are principally derived from classical metapopulation theory and have not been experimentally validated. 2.By manipulating spatial structure in artificial metapopulations of the spider mite Tetranychus urticae, we test to which degree spatial (island‐mainland metapopulations) and spatiotemporal variation (classical metapopulations) in habitat availability affect the dynamics of the metapopulations relative to systems where habitat is constantly available in time and space (patchy metapopulations). 3.Our experiment demonstrates that (i) spatial variation in habitat availability decreases variance in metapopulation size, decreases density dependent dispersal at the metapopulation level, while (ii) spatiotemporal variation in habitat availability increases patch extinction rates, decreases local population and metapopulation sizes, and decreases density dependence in population growth rates. We found dispersal to be negatively density dependent and overall low in the spatial variable mainland‐island metapopulation. 4.This demographic variation subsequently impacts local and regional population dynamics and determines patterns of metapopulation stability. Both local and metapopulation‐level variability is minimised in mainland‐island metapopulations relative to classical and patchy ones. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-19T05:49:00.784855-05:
      DOI: 10.1111/1365-2656.12400
  • The sign of cascading predator effects varies with prey traits in a
           detrital system
    • Authors: Xinwei Wu; John N. Griffin, Xinqiang Xi, Shucun Sun
      First page: 1610
      Abstract: 1.Theory and experiments show that the nature of ‘green’ trophic cascades, between predators, herbivores and plants, varies with several key species traits: predator hunting mode and predator‐and‐prey habitat domains. Meanwhile, ‘brown’ cascades between predators, environment‐modifying detritivores and plants have been largely overlooked and the roles of species traits, particularly prey traits, in determining the nature of these cascades remains unclear. 2.We hypothesize that, in predator‐detritivore‐plant interaction chains, the burrowing ability of plant‐facilitating detritivores determines their response to predators and thus the sign of indirect effect transmitted. In the dung‐decomposer food web of an alpine meadow, we predicted that in the presence of aboveground predacious beetles: 1) non‐burrowing detritivores will suffer mortality due to predation and transmit negative indirect effects to plants, whereas 2) burrowing detritivores will escape predation by retreating deeper into the soil, transmitting positive indirect effects to plants. 3.In support of predictions, experiments showed that a single species of predacious beetle: 1) reduced the density of the non‐burrowing species and indirectly reduced dung loss rate, soil nutrient concentrations and plant biomass, but 2) drove the burrowing species deeper, indirectly improved soil conditions and increased plant biomass. 4.These results show that the burrowing ability of a detritivore can determine whether it transmits a negative indirect effect mediated by a reduction in its density, or a positive indirect effect mediated by its behavioral response to predation risk. 5.We call for further tests of our detritivore‐trait hypothesis in different regions and ecosystems to further develop a general trait‐based framework for trophic cascades in detrital food webs. We further advance the general hypothesis that the locomotion traits of prey species (e.g., burrowing/flying ability) may help explain their behavioral response to predation risk and the nature of indirect effect they transmit from predators to plants. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-23T09:27:03.93-05:00
      DOI: 10.1111/1365-2656.12403
  • Ecosystem‐level effects of a globally‐spreading invertebrate
           invader are not moderated by a functionally similar native
    • Authors: Marcin Penk; Kenneth Irvine, Ian Donohue
      First page: 1628
      Abstract: 1.Biological invasions are a key element of human‐induced global environmental change. However, lack of knowledge of the indirect consequences of invasions, combined with poor understanding of how their ecological effects depend upon competitive attributes of the receiving community, hinders our ability to manage and predict the effects of invasive species on ecosystems. 2.We established an experiment using a combination of both additive and substitutive experimental designs to explore effects of the globally‐spreading mysid shrimp Hemimysis anomala on the biological structure of outdoor pond mecososms in the absence and presence of a functionally similar native competitor, Mysis salemaai. 3.The naturally smaller H. anomala had considerably stronger effects on primary producers, multiple aspects of consumer assemblages and overall biological structure of the ponds in comparison to the functionally similar native. Moreover, the magnitude of these effects was generally independent of the presence of M. salemaai and even total mysid density. H. anomala reduced both the abundance and diversity of zooplankton assemblages significantly, triggering a strong trophic cascade on phytoplankton and a simultaneous increase of benthic invertebrate biomass. These findings indicate that invasion by H. anomala may exacerbate the effects of nutrient enrichment on lakes. 4.Our results demonstrate that introduced species can, irrespective of the presence of functionally similar natives, induce complex changes to ecosystems that reach beyond direct consumptive effects. Moreover, the cascading indirect effects of invasion can exacerbate the impacts of other stressors. Disregarding the complexity of indirect effects therefore risks underestimating significantly the global ecological footprint of biological invasions. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-23T09:21:39.75134-05:0
      DOI: 10.1111/1365-2656.12402
  • Synergistic effects of fire and elephants on arboreal animals in an
           African savannah
    • Authors: Robert M. Pringle; Duncan M. Kimuyu, Ryan L. Sensenig, Todd M. Palmer, Corinna Riginos, Kari E. Veblen, Truman P. Young
      First page: 1637
      Abstract: Disturbance is a crucial determinant of animal abundance, distribution, and community structure in many ecosystems, but ways in which multiple disturbance types interact remain poorly understood. The effects of multiple‐disturbance interactions can be additive, sub‐additive, or super‐additive (synergistic). Synergistic effects in particular can accelerate ecological change; thus, characterizing such synergies, the conditions under which they arise, and how long they persist has been identified as a major goal of ecology. We factorially manipulated two principal sources of disturbance in African savannahs, fire and elephants, and measured their independent and interactive effects on the numerically dominant vertebrate (the arboreal gekkonid lizard Lygodactylus keniensis) and invertebrate (a guild of symbiotic Acacia ants) animal species in a semi‐arid Kenyan savannah. Elephant exclusion alone (minus fire) had negligible effects on gecko density. Fire alone (minus elephants) had negligible effects on gecko density after 4 months, but increased gecko density two‐fold after 16 months, likely because the decay of fire‐damaged woody biomass created refuges and nest sites for geckos. In the presence of elephants, fire increased gecko density nearly three‐fold within 4 months of the experimental burn: fire increased the incidence of elephant damage to trees, which in turn improved microhabitat quality for geckos. However, this synergistic positive effect of fire and elephants attenuated over the ensuing year, such that only the main effect of fire was evident after 16 months. Fire also altered the structure of symbiotic plant‐ant assemblages occupying the dominant tree species (Acacia drepanolobium); this influenced gecko habitat selection but did not explain the synergistic effect of fire and elephants. However, fire‐driven shifts in plant‐ant occupancy may have indirectly mediated this effect by increasing trees’ susceptibility to elephant damage. Our findings confirm the importance of fire × elephant interactions in structuring arboreal wildlife populations. Where habitat modification by megaherbivores facilitates co‐occurring species, fire may amplify these effects in the short term by increasing the frequency or intensity of herbivory, leading to synergy. In the longer term, tree mortality due to both top‐kill by fire and toppling by large herbivores may reduce overall microhabitat availability, eliminating the synergy. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-01T10:28:37.535511-05:
      DOI: 10.1111/1365-2656.12404
  • Time‐scale dependency of host plant biomass‐ and
           trait‐mediated indirect effects of deer herbivory on a swallowtail
    • Authors: S. Takagi; T. Miyashita
      First page: 1657
      Abstract: Despite recent attempts to quantify the relative strength of density‐ and trait‐mediated indirect effects, rarely has the issue been properly addressed at the population level. Most research is based on short‐term small‐scale experiments in which behavioral and/or physiological responses prevail. Here we estimated the time‐scales during which density‐ and trait‐mediated effects manifest, as well as the strength of these effects, using an interaction chain with three organisms (deer‐plant‐butterfly). A hierarchical Bayesian model was performed by using a long‐term dataset of deer density in the Boso Peninsula, central Japan (where local densities differ spatially and temporally) as well as densities of the swallowtail butterfly Byasa alcinous and its host plant Aristolochia kaempferi. The time‐scale effect of deer on plant quantity and quality was estimated according to the degree of carry‐over effects. The negative influence on leaf density showed a temporal saturation pattern over the long term, while the positive influence on leaf quality due to resprouting of leaves after deer browsing, showed no clear temporal trend. The net indirect effect changed from positive to negative with time, with the negative density‐mediated effect becoming prominent in the long‐term. Our novel approach is widely applicable in assessing the dynamic impacts of wildlife if the spatio‐temporal variability of expansion and/or invasion history is known. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-26T09:55:12.410035-05:
      DOI: 10.1111/1365-2656.12415
  • Lotic cyprinid communities can be structured as nest webs and predicted by
           the stress‐gradient hypothesis
    • Authors: Brandon K. Peoples; Lori A. Blanc, Emmanuel A. Frimpong
      First page: 1666
      Abstract: 1.Little is known about how positive biotic interactions structure animal communities. Nest association is a common reproductive facilitation in which associate species spawn in nests constructed by host species. Nest associative behavior is nearly obligate for some species, but facultative for others; this can complicate interaction network topology. 2.Nest web diagrams can be used to depict interactions in nesting‐structured communities and generate predictions about those interactions, but have thus far only been applied to cavity‐nesting vertebrate communities. Likewise, the stress‐gradient hypothesis (SGH) predicts that prevalent biotic interactions shift from competition to facilitation as abiotic and biotic stress increase; this model has been hardly applied to animal communities. Here, both of these models were applied to nest associative fish communities, and extended in novel ways to broaden their applicability. 3.A nest web was constructed using spawning observations over three years in several streams in southwestern Virginia, USA. Structural equation modeling (SEM) was then implemented through an information‐theoretic framework to identify the most plausible nest web topology in stream fish communities at 45 sites in the New River Basin of the central Appalachian Mountains, USA. To test the SGH, the per‐nest reproductive success of “strong” (nearly obligate) nest associates was used to represent interaction importance. Eigenvectors were extracted from a principal coordinate analysis (PCoA) of proportional species abundances to represent community structure. Both of these metrics were regressed on physical stress, a combination of catchment‐scale agricultural land use and stream size (representing spatiotemporal habitat variability). 4.Seventy‐one percent of SEM model evidence supported a parsimonious interaction topology in which strong associates rely on a single host (Nocomis), but not other species. PCoA identified a gradient of community structure dominated by Nocomis and associates, to communities dominated by other reproductive groups. Both metrics of interaction importance responded positively to physical stress. 5.This study demonstrates that nest webs can be useful in a variety of systems, and that SEM can be a quantitative extension of this framework. Likewise, the SGH can be used to understand positive interactions in animal communities, and can be extended to predict proportional representation of facilitating and beneficiary species in communities. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-14T06:07:28.928809-05:
      DOI: 10.1111/1365-2656.12428
  • Reef flattening effects on total richness and species responses in the
    • Authors: Steven P. Newman; Erik H. Meesters, Charlie S. Dryden, Stacey M. Williams, Cristina Sanchez, Peter J. Mumby, Nicholas V. C. Polunin
      First page: 1678
      Abstract: There has been ongoing flattening of Caribbean coral reefs with the loss of habitat having severe implications for these systems. Complexity and its structural components are important to fish species richness and community composition, but little is known about its role for other taxa or species‐specific responses. This study reveals the importance of reef habitat complexity and structural components to different taxa of macrofauna, total species richness, and individual coral and fish species in the Caribbean. Species presence and richness of different taxa were visually quantified in one hundred 25‐m2 plots in three marine reserves in the Caribbean. Sampling was evenly distributed across five levels of visually estimated reef complexity, with five structural components also recorded: the number of corals, number of large corals, slope angle, maximum sponge and maximum octocoral height. Taking advantage of natural heterogeneity in structural complexity within a particular coral reef habitat (Orbicella reefs) and discrete environmental envelope, thus minimizing other sources of variability, the relative importance of reef complexity and structural components was quantified for different taxa and individual fish and coral species on Caribbean coral reefs using boosted regression trees (BRTs). Boosted regression tree models performed very well when explaining variability in total (82·3%), coral (80·6%) and fish species richness (77·3%), for which the greatest declines in richness occurred below intermediate reef complexity levels. Complexity accounted for very little of the variability in octocorals, sponges, arthropods, annelids or anemones. BRTs revealed species‐specific variability and importance for reef complexity and structural components. Coral and fish species occupancy generally declined at low complexity levels, with the exception of two coral species (Pseudodiploria strigosa and Porites divaricata) and four fish species (Halichoeres bivittatus, H. maculipinna, Malacoctenus triangulatus and Stegastes partitus) more common at lower reef complexity levels. A significant interaction between country and reef complexity revealed a non‐additive decline in species richness in areas of low complexity and the reserve in Puerto Rico. Flattening of Caribbean coral reefs will result in substantial species losses, with few winners. Individual structural components have considerable value to different species, and their loss may have profound impacts on population responses of coral and fish due to identity effects of key species, which underpin population richness and resilience and may affect essential ecosystem processes and services. Relationships with complexity and structural components are identified for a range of taxa and individual species for the first time, revealing ongoing flattening of Caribbean coral reefs will result in substantial species losses with few winners, which may have profound impacts on population responses and ecosystem resilience.
      PubDate: 2015-09-06T23:54:08.96976-05:0
      DOI: 10.1111/1365-2656.12429
  • The developmental race between maturing host plants and their butterfly
           herbivore – the influence of phenological matching and temperature
    • First page: 1690
      Abstract: Interactions between herbivorous insects and their host plants that are limited in time are widespread. Therefore, many insect‐plant interactions result in a developmental race, where herbivores need to complete their development before plants become unsuitable while plants strive to minimize damage from herbivores by outgrowing them. When spring phenologies of interacting species change asymmetrically in response to climate warming there will be a change in the developmental state of host plants at the time of insect herbivore emergence. In combination with altered temperatures during the subsequent developmental period, this is likely to affect interaction strength as well as fitness of interacting species. Here, we experimentally explore if the combined effect of phenological matching and thermal conditions influence the outcome of an insect‐host interaction. We manipulated both developmental stages of the host plants at the start of the interaction and temperature during the subsequent developmental period in a model system of a herbivorous butterfly, Anthocharis cardamines, and five of its Brassicaceae host plant species. Larval performance characteristics were favoured by earlier stages of host plants at oviposition as well as by higher developmental temperatures on most of the host species. The probability of a larva needing a second host plant covered the full range from no influence of either phenological matching or temperature to strong effects of both factors, and complex interactions between them. The probability of a plant outgrowing a larva was dependent only on the species identity. This study demonstrates that climatic variation can influence the outcome of consumer‐resource interactions in multiple ways and that its effects differ among host plant species. Therefore, climate warming is likely to change the temporal match between larval and plant development in some plant species, but not in the others. This is likely to have important implications for host plant use and possibly influence competitive relationships. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-26T10:02:38.748873-05:
      DOI: 10.1111/1365-2656.12417
  • A bust but no boom: Responses of floodplain bird assemblages during and
           after prolonged drought
    • Authors: Katherine E. Selwood; Rohan H. Clarke, Shaun C. Cunningham, Hania Lada, Melodie A. McGeoch, Ralph Mac Nally
      First page: 1700
      Abstract: Climate change alters the frequency and severity of extreme events, such as drought. Such events will be increasingly important in shaping communities as climate change intensifies. The ability of species to withstand extreme events (resistance) and to recover once adverse conditions abate (resilience) will determine their persistence. We estimated the resistance and resilience of bird species during and after a 13‐yr drought (the ‘Big Dry’) in floodplain forests in southeastern Australia. We conducted bird surveys at the beginning and end of the Big Dry, and after the abrupt end to the drought (the ‘Big Wet’), to evaluate species‐specific changes in reporting rates among the three periods. We assessed changes in bird breeding activity before and after the Big Wet to estimate demographic resilience based on breeding. Between the start and the end of the Big Dry (1998 vs 2009), 37 of 67 species declined substantially. Of those, only two had increased reporting rates after the Big Wet (2009 vs 2013) that were equal to or larger than their declines, while three partially recovered. All other declining species showed low resilience: 25 showed no change in reporting rates and seven declined further. The number of breeding species and total breeding activity of all species declined after the Big Wet, and there was no change in the number of young produced. The Big Dry caused widespread declines in the floodplain avifauna. Despite the drought being broken by two years of well‐above‐average rainfall and subsequent near‐average rainfall, most species showed low resilience and there was little indication that overall breeding had increased. The effects of drought appeared to be pervasive for much of the floodplain avifauna, regardless of species traits (species body mass, fecundity, mobility or diet). Ecosystems such as these are likely to require active management and restoration, including reinstatement of natural flooding regimes, to improve ecological condition, to enhance resistance and resilience to extreme climate events. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-04T07:11:35.992196-05:
      DOI: 10.1111/1365-2656.12424
  • Genetic, ecological and geographic covariables explaininghost range and
           specificity of a microsporidian parasite
    • Authors: Benjamin Lange; Andrea Patricia Kaufmann, Dieter Ebert
      First page: 1711
      Abstract: Parasites often have a smaller geographic distribution than their hosts. Common garden infection trials can untangle the role that historical contingencies, ecological conditions and the genetic constitution of local host populations play in limiting parasite geographic range: however, infection trials usually overestimate the range of hosts in which a parasite could naturally persist. This study overcomes that problem by using multi‐generation, long‐term persistence experiments. We study the microsporidian parasite Hamiltosporidium tvaerminnensis in monoclonal populations of Daphnia magna from 43widely spread sites. The parasite persisted well in hosts collected from its natural geographic range, but demonstrated long‐term persistence in only a few host genotypes outside this range. Genetic distance between hosts from the parasite's origin site and newly tested host populations correlated negatively with parasite persistence. Furthermore, the parasite persisted only in host populations from habitats with a high likelihood of drying up in summer, although we excluded environmental variation in our experiments. Together, our results suggest that host genetic factors play the dominant role in explaining the limited geographic range of parasites, and that these genetic differences covary with geographic distance and the habitat type the host is adapted to. This article is protected by copyright. All rights reserved.
      PubDate: 2015-07-05T21:56:25.452638-05:
      DOI: 10.1111/1365-2656.12421
  • Raccoon contact networks predict seasonal susceptibility to rabies
           outbreaks and limitations of vaccination
    • Authors: Jennifer J. H. Reynolds; Ben T. Hirsch, Stanley D. Gehrt, Meggan E. Craft
      First page: 1720
      Abstract: Infectious disease transmission often depends on the contact structure of host populations. Although it is often challenging to capture the contact structure in wild animals, new technology has enabled biologists to obtain detailed temporal information on wildlife social contacts. In this study, we investigated the effects of raccoon contact patterns on rabies spread using network modeling. Raccoons (Procyon lotor) play an important role in the maintenance of rabies in the US. It is crucial to understand how contact patterns influence the spread of rabies in raccoon populations in order to design effective control measures and to prevent transmission to human populations and other animals. We constructed a dynamic system of contact networks based on empirical data from proximity logging collars on a wild suburban raccoon population, and then simulated rabies spread across these networks. Our contact networks incorporated the number and duration of raccoon interactions. We included differences in contacts according to sex and season, and both short‐term acquaintances and long‐term associations. Raccoons may display different behaviors when infectious, including aggression (furious behavior) and impaired mobility (dumb behavior); the network model was used to assess the impact of potential behavioral changes of rabid raccoons. We also tested the effectiveness of different vaccination coverage levels on rabies spread. Our results demonstrate that when rabies enters a suburban raccoon population, the likelihood of a disease outbreak affecting the majority of the population is high. Both the magnitude of rabies outbreaks and the speed of rabies spread depend strongly on the time of year that rabies is introduced into the population. When there is a combination of dumb and furious behaviors in the rabid raccoon population, there are similar outbreak sizes and speed of spread to when there are no behavioral changes due to rabies infection. By incorporating detailed data describing the variation in raccoon contact rates into a network modeling approach, we were able to show that suburban raccoon populations are highly susceptible to rabies outbreaks, that the risk of large outbreaks varies seasonally, and that current vaccination target levels may be inadequate to prevent the spread of rabies within these populations. Our findings thus provide new insights into rabies dynamics in raccoon populations and have important implications for disease control. This article is protected by copyright. All rights reserved.
      PubDate: 2015-08-21T01:08:50.304131-05:
      DOI: 10.1111/1365-2656.12422
  • Rapid human‐induced divergence of life‐history strategies in
           Bahamian livebearing fishes (family Poeciliidae)
    • First page: 1732
      Abstract: 1.Human‐induced rapid environmental change (HIREC) can have dramatic impacts on ecosystems, leading to rapid trait changes in some organisms and extinction in others. Such changes in traits signify that human actions can lead to cases of increased phenotypic diversity, and consequently can strongly impact population‐, community‐, and ecosystem‐level dynamics. 2.Here, we examine whether the ecological consequences of habitat fragmentation have led to changes in the life histories of three native species of mosquitofish (Gambusia spp.) inhabiting tidal creeks on six different Bahamian islands. We address two important questions: (1) how predictable and parallel are life‐history changes in response to HIREC across islands and species, and (2) what is the relative importance of shared (i.e., parallel) responses to fragmentation, differences between species or islands, and species‐ or island‐specific responses to fragmentation' 3.Phenotypic differences between fragmentation regimes were as great or greater than differences between species or islands. While some adult life histories (lean weight and fat content) showed strong, shared responses to fragmentation, offspring‐related life histories (embryo fat and fecundity) exhibited idiosyncratic, island‐specific, responses. While shared responses to fragmentation appeared largely driven by a reduction in piscivorous fish density, increased conspecific density, and changes in salinity, we found some evidence that among‐population variation in male reproductive investment and embryo fat content may have arisen via variation in conspecific density. 4.Our results suggest that phenotypic responses to HIREC can be complex, with the predictability of response varying across traits. We therefore emphasize the need for more theoretical and empirical work to better understand the predictability of phenotypic responses to human‐induced disturbances. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-14T06:07:01.341815-05:
      DOI: 10.1111/1365-2656.12425
  • Cool tadpoles from Arctic environments waste less nutrients – High
           gross growth efficiencies lead to low consumer‐mediated nutrient
           recycling in the North
    • Authors: Antonia Liess; Junwen Guo, Martin I. Lind, Owen Rowe
      First page: 1744
      Abstract: Endothermic organisms can adapt to short growing seasons, low temperatures, and nutrient limitation by developing high growth rates and high gross growth efficiencies (GGEs). Animals with high GGEs are better at assimilating limiting nutrients and thus should recycle (or loose) fewer nutrients. Longer guts in relation to body mass may facilitate higher GGE under resource limitation. Within the context of ecological stoichiometry theory, this study combines ecology with evolution by relating latitudinal life history adaptations in GGE, mediated by gut length, to its ecosystem consequences, such as consumer‐mediated nutrient recycling. In common garden experiments, we raised Rana temporaria tadpoles from two regions (Arctic/ Boreal) under two temperature regimes (18/ 23°C) crossed with two food quality treatments (high/ low nitrogen content). We measured tadpole GGEs, total nutrient loss (excretion + egestion) rates, and gut length during ontogeny. In order to maintain their elemental balance, tadpoles fed low‐nitrogen (N) food had lower N excretion rates and higher total phosphorous (P) loss rates than tadpoles fed high quality food. In accordance with expectations, Arctic tadpoles had higher GGEs and lower N‐loss rates than their low latitude conspecifics, especially when fed low‐N food, but only in ambient temperature treatments. Arctic tadpoles also had relatively longer guts than Boreal tadpoles during early development. That temperature and food quality interacted with tadpole region of origin in affecting tadpole GGEs, nutrient loss rates and relative gut length, suggests evolved adaptation to temperature and resource differences. With future climate change, mean annual temperatures will increase. Additionally, species and genotypes will migrate north. This will change the functioning of Boreal and Arctic ecosystems by affecting consumer‐mediated nutrient recycling and thus affect nutrient dynamics in general. Our study shows that evolved latitudinal adaption can change key ecosystem functions. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-14T06:04:07.699851-05:
      DOI: 10.1111/1365-2656.12426
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