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Understanding the evolution of local adaptations is a central aim of evolutionary biology and key for the identification of unique populations and lineages of conservation relevance. By combining RAD sequencing and whole-genome sequencing, we identify genetic signatures of local adaptation in mountain hares (Lepus timidus) from isolated and distinctive habitats of its wide distribution: Ireland, the Alps and Fennoscandia. Demographic modelling suggested that the split of these mountain hares occurred around 20 thousand years ago, providing the opportunity to study adaptive evolution over a short timescale. Using genome-wide scans, we identified signatures of extreme differentiation among hares from distinct geographic areas that overlap with area-specific selective sweeps, suggesting targets for local adaptation. Several identified candidate genes are associated with traits related to the uniqueness of the different environments inhabited by the three groups of mountain hares, including coat colour, ability to live at high altitudes and variation in body size. In Irish mountain hares, a variant of ASIP, a gene previously implicated in introgression-driven winter coat colour variation in mountain and snowshoe hares (L. americanus), may underlie brown winter coats, reinforcing the repeated nature of evolution at ASIP moulding adaptive seasonal colouration. Comparative genomic analyses across several hare species suggested that mountain hares' adaptive variants appear predominantly species-specific. However, using coalescent simulations, we also show instances where the candidate adaptive variants have been introduced via introgressive hybridization. Our study shows that standing adaptive variation, including that introgressed from other species, was a crucial component of the post-glacial dynamics of species.
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Lebres , Aclimatação , Adaptação Fisiológica/genética , Animais , Lebres/genética , Estações do Ano , Especificidade da EspécieRESUMO
Changing from summer-brown to winter-white pelage or plumage is a crucial adaptation to seasonal snow in more than 20 mammal and bird species. Many of these species maintain nonwhite winter morphs, locally adapted to less snowy conditions, which may have evolved independently. Mountain hares (Lepus timidus) from Fennoscandia were introduced into the Faroe Islands in 1855. While they were initially winter-white, within â¼65 y all Faroese hares became winter-gray, a morph that occurs in the source population at low frequency. The documented population history makes this a valuable model for understanding the genetic basis and evolution of the seasonal trait polymorphism. Through whole-genome scans of differentiation and single-nucleotide polymorphism (SNP) genotyping, we associated winter coat color polymorphism to the genomic region of the pigmentation gene Agouti, previously linked to introgression-driven winter coat color variation in the snowshoe hare (Lepus americanus). Lower Agouti expression in the skin of winter-gray individuals during the autumn molt suggests that regulatory changes may underlie the color polymorphism. Variation in the associated genomic region shows signatures of a selective sweep in the Faroese population, suggesting that positive selection drove the fixation of the variant after the introduction. Whole-genome analyses of several hare species revealed that the winter-gray variant originated through introgression from a noncolor changing species, in keeping with the history of ancient hybridization between the species. Our findings show the recurrent role of introgression in generating winter coat color variation by repeatedly recruiting the regulatory region of Agouti to modulate seasonal coat color change.
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Proteína Agouti Sinalizadora/genética , Introgressão Genética , Lebres/fisiologia , Pigmentação/genética , Polimorfismo de Nucleotídeo Único , Animais , Dinamarca , Evolução Molecular , Genética Populacional , Lebres/genética , Filogenia , Pigmentação/fisiologia , Estações do Ano , Seleção GenéticaRESUMO
Climate change is known to affect key life-history traits, such as body mass, reproduction, and survival in many species. Animal populations inhabiting mountain habitats are adapted to extreme seasonal environmental conditions but are also expected to be especially vulnerable to climate change. Studies on mountain ungulates typically focus on populations or sections of populations living above the tree line, whereas populations inhabiting forested habitats are largely understudied. Here, we investigate whether forested areas can mitigate the impact of climatic change on life-history traits by evaluating the interactive effects of temperature and habitat characteristics on body mass variation in the Alpine chamois Rupicapra rupicapra rupicapra. We examined data of 20,573 yearling chamois collected from 1993 to 2019 in 28 mountain ranges in the Austrian Eastern Alps, characterized by different proportion of forest cover. Our results show that the temporal decline of chamois body mass is less pronounced in areas with greater proportion of forest cover. For chamois living in forest habitats only, no significant temporal change in body mass was detected. Variation in body mass was affected by the interaction between density and snow cover, as well as by the interaction between spring temperatures and forest cover, supporting the role of forests as thermal buffer against the effects of increasing temperatures on life-history traits in a mountain ungulate. In turn, this study suggests a buffering effect of forests against climate change impacts. Assessments of the consequences of climate change on the life-history traits and population dynamics of mountain-dwelling species should thus consider the plasticity of the species with respect to the use and availability of different habitat types.
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Herbivoria , Rupicapra , Animais , Áustria , Mudança Climática , FlorestasRESUMO
Global climate change has led to range shifts in plants and animals, thus threatening biodiversity. Latitudinal shifts have been shown to be more pronounced than elevational shifts, implying that northern range edge margins may be more capable to keeping pace with warming than upper elevational limits. Additionally, global climate change is expected to disadvantage habitat specialists. In the Alps, climatic variation along the elevation gradient allows the coexistence of habitat specialists and generalists. Alpine species are anticipated to adapt their elevational ranges to the change of various climate variables caused by global climate change. Regional differences might buffer elevational shifts. Furthermore, distinct climate variables might differently affect the shifts of habitat specialists and generalists. To study the effect of climate change on Alpine species, we analysed hunting bag, climate and biogeographical data of two grouse species (Tetrao tetrix and Lagopus muta) and two hare species (Lepus timidus varronis and L. europaeus) in Grisons, Switzerland, over a period of 30 years. Our results based on 84,630 harvested specimens were as follows: (1) only three out of seven climate variables changed significantly within the study period. (2) The grouse species significantly shifted towards higher elevations, whereas the hare species only shifted in their minimum/maximum elevations. (3) Hunting elevation of habitat generalists increased more than in habitat specialists. (4) The elevational shifts were mostly related to the number of frost days. (5) Hunting elevation increased especially in the southern biogeographical region. To conclude, all four taxa respond to climate change but habitat generalists more rapidly than habitat specialists. The range shift to higher elevations due to global climate change will lead to a reduction in habitat availability for snow-adapted species. Climate change is thus a serious threat to alpine biodiversity. Regions rich in alpine habitats will have an increased responsibility to conserve these species.
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Galliformes , Lebres , Altitude , Animais , Mudança Climática , Ecossistema , TemperaturaRESUMO
Alpine and Arctic species are considered to be particularly vulnerable to climate change, which is expected to cause habitat loss, fragmentation and-ultimately-extinction of cold-adapted species. However, the impact of climate change on glacial relict populations is not well understood, and specific recommendations for adaptive conservation management are lacking. We focused on the mountain hare (Lepus timidus) as a model species and modelled species distribution in combination with patch and landscape-based connectivity metrics. They were derived from graph-theory models to quantify changes in species distribution and to estimate the current and future importance of habitat patches for overall population connectivity. Models were calibrated based on 1,046 locations of species presence distributed across three biogeographic regions in the Swiss Alps and extrapolated according to two IPCC scenarios of climate change (RCP 4.5 & 8.5), each represented by three downscaled global climate models. The models predicted an average habitat loss of 35% (22%-55%) by 2100, mainly due to an increase in temperature during the reproductive season. An increase in habitat fragmentation was reflected in a 43% decrease in patch size, a 17% increase in the number of habitat patches and a 34% increase in inter-patch distance. However, the predicted changes in habitat availability and connectivity varied considerably between biogeographic regions: Whereas the greatest habitat losses with an increase in inter-patch distance were predicted at the southern and northern edges of the species' Alpine distribution, the greatest increase in patch number and decrease in patch size is expected in the central Swiss Alps. Finally, both the number of isolated habitat patches and the number of patches crucial for maintaining the habitat network increased under the different variants of climate change. Focusing conservation action on the central Swiss Alps may help mitigate the predicted effects of climate change on population connectivity.
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Distribuição Animal , Mudança Climática , Conservação dos Recursos Naturais , Lebres/fisiologia , Tundra , Animais , Ecossistema , Modelos Biológicos , Reprodução , SuíçaRESUMO
In wildlife management, differing perspectives among stakeholders generate conflicts about how to achieve disparate sustainability goals that include ecological, economic, and sociocultural dimensions. To mitigate such conflicts, decisions regarding wildlife management must be taken thoughtfully. To our knowledge, there exists no integrative modeling framework to inform these decisions, considering all dimensions of sustainability. We constructed a decision-support tool based on stakeholder workshops and a Bayesian decision network to inform management of wild ruminants in the federal state of Lower Austria. We use collaborative decision analysis to compare resource allocations while accounting for trade-offs among dimensions of sustainability. The tool is designed for application by non-technical users across diverse decision-making contexts with particular sets of wildlife management actions, objectives, and uncertainties. Our tool represents an important step toward developing and evaluating a transparent and replicable approach for mitigating wildlife-based conflicts in Europe and beyond.
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Animais Selvagens , Teorema de Bayes , Conservação dos Recursos Naturais , Técnicas de Apoio para a Decisão , Ruminantes , Animais , Conservação dos Recursos Naturais/métodos , Áustria , Tomada de DecisõesRESUMO
Small forest dwelling mammals are considered to be major consumers and vectors of hypogeous ectomycorrhizal (ECM) fungi, which have lost the ability of active spore discharge. Fungal spore dispersal by mycophagy is deemed an important process involved in forest regeneration, resilience and vitality, primarily based on evidence from Australia and the Pacific Northwestern USA, but is poorly known for Central European mountainous forests thus far. Small mammal mycophagy was investigated by live trapping and microscopical analysis of faecal samples. All small mammal species recorded (Myodes glareolus, Microtus agrestis, Pitymys subterraneus, Apodemus spp., Glis glis, Sorex spp.) had ingested spores of ECM fungi, albeit in varying amounts. My. glareolus was found to be the most important vector of ECM fungal spores, both in quantity and diversity. Species of the genus Sorex seem to play a hitherto underestimated role as dispersers of fungal spores. Glis glis is likely to be an important vector owing to its large home range. Hypogeous ECM basidiomycetes accounted for most spores found in the faecal samples. The frequency of various genera of hypogeous ECM ascomycetes and ECM epigeous fungi was much lower. Comparison with null models indicated a non-random structure of the mycophagy network similar to other mutualistic bipartite networks. Mycophagy can be considered (1) to contribute to nutrition of small forest mammals, (2) to play a pivotal role for forest regeneration and functioning by providing mycorrhizal inoculum to tree seedlings and (3) to be vital for reproduction and diversity of the still poorly known hypogeous fungi.
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Mamíferos , Micorrizas/crescimento & desenvolvimento , Árvores/crescimento & desenvolvimento , Animais , Biodiversidade , Europa (Continente) , Fezes/microbiologia , Comportamento Alimentar , Cadeia Alimentar , Agricultura Florestal , Estado Nutricional , Dinâmica Populacional , Plântula/crescimento & desenvolvimentoRESUMO
Uptake and use of energy are of key importance for animals living in temperate environments that undergo strong seasonal changes in forage quality and quantity. In ungulates, energy intake strongly affects body mass gain, an important component of individual fitness. Energy allocation among life-history traits can be affected by internal and external factors. Here, we investigate large-scale variation in body growth patterns of Alpine chamois Rupicapra rupicapra rupicapra, in relation to sex, age, temperature, and habitat variations across 31 (sub)populations in the Central European Alps. Taking advantage of an exceptionally large dataset (n = 178,175) of chamois hunted over 27 consecutive years between 1993 and 2019 in mountain ranges with different proportions of forest cover, we found that (i) patterns of body mass growth differ between mountain ranges, with lower body mass but faster mass growth with increasing proportion of forest cover and that (ii) the effect of spring and summer temperatures on changes in body growth patterns are larger in mountain ranges with lower forest cover compared to mountain ranges with higher forest cover. Our results show that patterns of body mass growth within a species are more plastic than expected and depend on environmental and climatic conditions. The recent decline in body mass observed in Alpine chamois populations may have greater impacts on populations living above the treeline than in forests, which may buffer against the effects of increasing temperatures on life-history traits.
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In modern wildlife ecology, spatial population genetic methods are becoming increasingly applied. Especially for animal species in fragmented landscapes, preservation of gene flow becomes a high priority target in order to restore genetic diversity and prevent local extinction. Within Central Europe, the Alps represent the core distribution area of the black grouse, Lyrurus tetrix. At its easternmost Alpine range, events of subpopulation extinction have already been documented in the past decades. Molecular data combined with spatial analyses can help to assess landscape effects on genetic variation and therefore can be informative for conservation management. Here, we addressed whether the genetic pattern of the easternmost Alpine black grouse metapopulation system is driven by isolation by distance or isolation by resistance. Correlative ecological niche modeling was used to assess geographic distances and landscape resistances. We then applied regression-based approaches combined with population genetic analyses based on microsatellite data to disentangle effects of isolation by distance and isolation by resistance among individuals and subpopulations. Although population genetic analyses revealed overall low levels of genetic differentiation, the ecological niche modeling showed subpopulations to be clearly delimited by habitat structures. Spatial genetic variation could be attributed to effects of isolation by distance among individuals and isolation by resistance among subpopulations, yet unknown effects might factor in. The easternmost subpopulation was the most differentiated, and at the same time, immigration was not detected; hence, its long-term survival might be threatened. Our study provides valuable insights into the spatial genetic variation of this small-scale metapopulation system of Alpine black grouse.
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When wild-caught Eurasian lynx (Lynx lynx) from the Slovak Carpathian Mountains were reintroduced to Central Switzerland in the early 1970s and spread through the north-western Swiss Alps (NWA), they faced a largely unfamiliar landscape with strongly fragmented forests, high elevations, and intense human land use. For more than 30 years, radio-collared lynx have been monitored during three different project periods (in the 1980s, 1990s, and 2010s). Our study explored, how lynx over generations have learned to adjust to the alpine environment. We predicted that (1) lynx nowadays select more strongly for open habitats, higher elevations, and steep slopes compared to the early stages of recolonization and that (2) consequently, there were significant changes in the Eurasian lynx' prey spectrum. To test our predictions, we analyzed telemetry data (VHF, GPS) of 13 adult resident lynx in the NWA over 35 years, using Resource Selection Functions. Furthermore, we compared kills recorded from different individuals inhabiting the same region during three project periods. In general, lynx preferred forested areas, but over the years, they avoided open habitat less. Compared to the early stage of the recolonization, lynx in the most recent project period selected for higher elevations and the proportion of chamois in their prey spectrum surmounted that of roe deer. Potential driving factors for the observed changes could be increasing tolerance to human presence, intraspecific competition, or fitness benefits through exploitation of new resources. Long-term studies like ours provide important insight into how animals can respond to sudden environmental changes, e.g., in the course of translocations into new areas or anthropogenic alterations of their habitats.
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Wildlife-related accidents, especially deer-vehicle accidents, pose a serious problem for road safety and animal protection in many countries. Knowledge of spatial and temporal patterns of deer-vehicle accidents is inevitable for accident analysis and mitigation efforts with temporal deer-vehicle accident data being much more difficult to obtain in sufficient data quality. We described the temporal patterns of roe deer (Capreolus capreolus) roadkills occurring in the period 2002-2006 in southeastern Austria. Using a comprehensive dataset, consisting of 11.771 data points, we examined the influence of different time units (i.e. season, month, day of week, day of year), illumination categories (coarse and fine temporal resolution) and lunar phases on deer-vehicle accidents by performing linear and generalized additive models. Thereby, we identified peak accident periods within the analyzed time units. Highest frequencies of deer-vehicle accidents occurred in November, May and October, on Fridays, and during nights. Relationships between lunar phases and roe deer-vehicle accidents were analysed, providing evidence for high frequencies of deer-vehicle accidents during full moon phases. We suggest that deer-vehicle accidents are dependent both on human activity in traffic and wildlife activity, which is in turn affected by phenology, intra- and interspecific competition, climatic and astronomical events. Our results highlight, that short-term mitigation measures (e.g. traffic controls and speed limits) can be highly effective to reduce deer-vehicle accidents, but should be flexibly adapted to specific temporal periods.
Assuntos
Acidentes de Trânsito/estatística & dados numéricos , Cervos , Lua , Estações do Ano , Animais , Fatores de TempoRESUMO
In female mammals, reproduction, and in particular lactation, is the energetically most exigent life-history phase. Reproduction is strongly controlled by body reserves and food availability, so females with better body condition or food supply are believed to have higher reproductive output. Additionally, the growth and mortality of young mammals depends on their postnatal development. Therefore, the degree of precociality affects energetic demands for both mothers and young. To study the reproductive performance of the precocial European hare (Lepus europaeus), we analysed relationships between six predictor variables describing maternal and environmental effects and nine response variables relating to reproduction from 217 captive females. We compared the data with those of precocial and altricial mammal species from an extensive literature search. For hares, we found: (1) Heavier females had heavier litters at birth. (2) In summer and spring, total litter mass was larger than in winter. (3) At the end of lactation, the litters of multiparous females were heavier than those of primiparous females. (4) Both older females and females giving birth for the first time had relatively high leveret mortality during lactation. Comparing our results with the literature for other mammals revealed that the body condition (i.e., body mass) of females before birth is predictive of reproductive parameters in both precocial and altricial species. In the precocial hare, female body condition is no longer predictive of reproductive parameters at the end of lactation, whereas in altricial species, female body condition remains predictive of reproduction (litter mass at the end of lactation, offspring mortality) until the end of lactation. We conclude that these effects are caused by precocial offspring feeding on solid food soon after birth and, thus, being less dependent on the mother's body condition during lactation than altricial offspring. In line with this, precociality might have evolved as a way of buffering offspring against maternal effects.
Assuntos
Herança Materna/fisiologia , Reprodução/fisiologia , Animais , Feminino , Lebres , Lactação/fisiologia , Tamanho da Ninhada de Vivíparos/fisiologiaRESUMO
The link between adaptive genetic variation, individual fitness and wildlife population dynamics is fundamental to the study of ecology and evolutionary biology. In this study, a Bayesian modelling approach was employed to examine whether individual variability at two major histocompatibility complex (MHC) class II loci (DQA and DRB) and eight neutral microsatellite loci explained variation in female reproductive success for wild populations of European brown hare (Lepus europaeus). We examined two aspects of reproduction: the ability to reproduce (sterility) and the number of offspring produced (fecundity). Samples were collected from eastern Austria, experiencing a sub-continental climatic regime, and from Belgium with a more Atlantic-influenced climate. As expected, reproductive success (both sterility and fecundity) was significantly influenced by age regardless of sampling locality. For Belgium, there was also a significant effect of DQA heterozygosity in determining whether females were able to reproduce (95% highest posterior density interval of the regression parameter [-3.64, -0.52]), but no corresponding effect was found for Austria. In neither region was reproduction significantly associated with heterozygosity at the DRB locus. DQA heterozygotes from both regions also showed a clear tendency, but not significantly so, to produce a larger number of offspring. Predictive simulations showed that, in Belgium, sub-populations of homozygotes will have higher rates of sterile individuals and lower average offspring numbers than heterozygotes. No similar effect is predicted for Austria. The mechanism for the spatial MHC effect is likely to be connected to mate choice for increased heterozygosity or to the linkage of certain MHC alleles with lethal recessives at other loci.
Assuntos
Lebres/genética , Antígenos de Histocompatibilidade Classe II/genética , Modelos Genéticos , Reprodução/genética , Alelos , Animais , Áustria , Teorema de Bayes , Bélgica , Feminino , Fertilidade/genética , Frequência do Gene , Loci Gênicos , Homozigoto , Infertilidade Feminina/genética , Repetições de Microssatélites , Modelos EstatísticosRESUMO
Color molts from summer brown to winter white coats have evolved in several species to maintain camouflage year-round in environments with seasonal snow. Despite the eco-evolutionary relevance of this key phenological adaptation, its molecular regulation has only recently begun to be addressed. Here, we analyze skin transcription changes during the autumn molt of the mountain hare (Lepus timidus) and integrate the results with an established model of gene regulation across the spring molt of the closely related snowshoe hare (L. americanus). We quantified differences in gene expression among three stages of molt progression-"brown" (early molt), "intermediate," and "white" (late molt). We found 632 differentially expressed genes, with a major pulse of expression early in the molt, followed by a milder one in late molt. The functional makeup of differentially expressed genes anchored the sampled molt stages to the developmental timeline of the hair growth cycle, associating anagen to early molt and the transition to catagen to late molt. The progression of color change was characterized by differential expression of genes involved in pigmentation, circadian, and behavioral regulation. We found significant overlap between differentially expressed genes across the seasonal molts of mountain and snowshoe hares, particularly at molt onset, suggesting conservatism of gene regulation across species and seasons. However, some discrepancies suggest seasonal differences in melanocyte differentiation and the integration of nutritional cues. Our established regulatory model of seasonal coat color molt provides an important mechanistic context to study the functional architecture and evolution of this crucial seasonal adaptation.
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We reviewed research on wildlife overpasses in the context of their genetic effectiveness to provide connectivity between population patches that have been isolated by road construction. The potential ecological consequences of such habitat fragmentation include reduction of gene flow between subpopulations and hence an increase in genetic differentiation and a decrease in genetic diversity. Among the solutions to provide connectivity between patches isolated by roads, wildlife overpasses are one of the most expensive alternatives. Despite the high costs associated with their construction, most of the studies assessing their use by wildlife remain observational, reporting evidence for passage use but few data on the number of individual crossings. Moreover, the use itself of wildlife overpasses does not appear sufficient to assess their effectiveness from a genetic viewpoint because a minimum number of individuals is required to assure gene flow between population patches and because the spatiotemporal dimension of individual movements and demographic parameters of subpopulations must be considered. So far, there is no evidence that wildlife overpasses do or do not efficiently address genetic issues. This lack of data is probably due to the fact that few mitigation efforts have implemented monitoring programs that incorporate sufficient experimental designs into pre- and postconstruction evaluation. To assess the genetic effectiveness of wildlife overpasses, long-term monitoring programs, including fieldwork and genetic analyses, are needed.
Assuntos
Acidentes de Trânsito/prevenção & controle , Animais Selvagens/genética , Conservação dos Recursos Naturais/métodos , Ecossistema , Planejamento Ambiental , Fluxo Gênico/genética , Genética Populacional , AnimaisRESUMO
The Austrian province of Tyrol belongs to the areas where the alveolar echinococcosis (AE) caused by the fox tapeworm Echinococcus multilocularis (E. multilocularis) is highly endemic. In Central Europe and since 2011 in Austria, a growing incidence of human cases of AE has been observed, presumably linked with increasing fox populations infected by the fox tapeworm E. multilocularis. Hunting and the related activities put hunters in a high-risk group, and they are considered particularly vulnerable for the contraction of an AE. In light of this risk and the increased number of AE cases made public in Austria, the objective of the study was to investigate the prevalence of AE in hunters and to provide a possible connection to the incidence increase. In 2015 and 2016, we examined 813 serums of active hunters from all nine districts of Tyrol and serologically tested them for E. multilocularis antibodies. Twenty-one (2.58%) positive results in ELISA were detected via Western blot (WB), and only one (0.12%) serum showed a low positive reaction. No lesion in the liver parenchyma could be detected by abdominal ultrasonography in this patient so far, but the risk of developing alveolar echinococcosis remains for this WB-positive hunter. Risk factor analysis of these 813 hunters revealed that 697 (85.7%) hunted red foxes regularly and 332 (40.8%) of those skinned them as well. Three hundred and eighteen (39.1%) out of the 813 hunters were owners of hunting dogs; 89 (10.9%) and 243 (29.9%) were owners of non-hunting dogs and cats, respectively. Our results indicate that hunters do not have a greater risk of infection with E. multilocularis compared to non-hunters in Austria. The cause of the unexpected increase in AE cases in Austria remains unclear.
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Information concerning factors regulating Alpine mountain hare (Lepus timidus varronis) populations such as host-parasite interactions is missing as only a few parasitological surveys exist of this subspecies. Parasites are not only dependent on their host but also on suitable environmental conditions for infestation. Abiotic environmental factors have an important regulating role on parasites in mammals. It is estimated that the elevation range of parasites is likely to shift in response to alternate host movement and changes in climate. Here we assess the parasitic infestation in the Alpine mountain hare by analysing the parasites in faeces and comparing the parasite infestation at different elevation ranges and at varied weather conditions for two years in the Austrian Alps. Almost half of the faecal samples were free of parasites (46.2%, nâ¯=â¯52). Most frequent was the infection by Coccidia (46.2%), whereas stomach intestine strongylids, Trichuris spp, and Cestoda were only found in 9.6% of all faeces. Hence, only Coccidia may be prevalent enough to regulate Alpine mountain hare populations in the Austrian Alps. Elevation had a significant positive effect on the infection of animals by Trichuris spp, whereas temperature had a significant negative effect on the infection by any parasite traceable in faeces and, when looking at the parasite groups individually, on Coccidia.
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Glucocorticoids and glucocorticoid metabolites are increasingly used to index physiological stress in wildlife. Although feces is often abundant and can be collected noninvasively, exposure to biotic and abiotic elements may influence fecal glucocorticoid metabolite (FGM) concentrations, leading to inaccurate conclusions regarding wildlife physiological stress. Using captive snowshoe hares (Lepus americanus) and simulated environmental conditions, we evaluated how different realistic field conditions and temporal sampling constraints might influence FGM concentrations using an 11-oxoetiocholanolone-enzyme immunoassay. We quantified how fecal pellet age (i.e., 0-6 days), variable summer temperatures, and precipitation affected FGM concentrations. Fecal pellet age had a strong effect on FGM concentrations (ßAge = 0.395, s.d. = 0.085; ß2Age = -0.061, s.d. = 0.012), which were lowest at the beginning and end of our exposure period (e.g., meanday6 = 37.7 ng/mg) and typically highest in the middle (meanday3 = 51.8 ng/mg). The effect of fecal pellet age on FGM concentrations varied across treatments with warm-dry and cool-wet conditions resulting in more variable FGM concentrations relative to control samples. Given the confounding effects of exposure and environmental conditions, if fresh fecal pellet collection is not an option, we encourage researchers to develop a temporally consistent sampling protocol to ensure all samples are exposed to similar environmental conditions.
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Exposição Ambiental , Lebres/fisiologia , Estresse Fisiológico , Animais , Fatores de Confusão Epidemiológicos , Fezes/química , Feminino , Glucocorticoides/metabolismo , Masculino , Metaboloma , Modelos BiológicosRESUMO
Long recognized as a threat to wildlife, livestock grazing in protected areas has the potential to undermine conservation goals, via competition, habitat degradation, human-carnivore conflict and disruption of predator-prey relationships. In the Strictly Protected Area Zorkul in Tajikistan (Zorkul Reserve), grazing is commonplace despite official prohibition, with potentially detrimental effects on local fauna, in particular, snow leopard Panthera uncia, wolf Canis lupus, brown bear Ursus arctos, argali sheep Ovis ammon, Asiatic ibex Capra sibirica, and long-tailed marmot Marmota caudata. To understand the impacts of grazing and associated human pastoralism on the large mammal community in Zorkul Reserve we used data from camera traps to build models of ungulate and carnivore site use intensity, and we investigated carnivore summer diets using microscopic scat analysis. While sample sizes limited our inference for several species, we found that site use of the most common ungulate, argali, decreased with proximity to herder's camps, indicating possible displacement into sub-optimal habitats. However, no such pattern was present in carnivore site use. For wolf and snow leopard, the most frequently encountered prey items were argali and marmot, while bear depended almost exclusively on marmot. While current pastoralist practices in the reserve may not be incompatible with wildlife presence, our findings suggest that pastoralism may negatively impact ungulates by displacing them from otherwise suitable habitats, with unknown fitness consequences for ungulates or the predators that depend upon them. Managing Zorkul Reserve and other actively grazed protected areas to meet potentially competing demands of local pastoralist communities and conservation will require careful consideration of such interactions to minimize the risk of cascading negative impacts on wildlife.
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Carnivoridade , Conservação dos Recursos Naturais , Ecossistema , Felidae , Gado , Ovinos , Lobos , Animais , Animais Selvagens/fisiologia , Conservação dos Recursos Naturais/métodos , Espécies em Perigo de Extinção , Felidae/fisiologia , Cabras/fisiologia , Herbivoria , Humanos , Gado/fisiologia , Marmota/fisiologia , Comportamento Predatório , Ovinos/fisiologia , Tadjiquistão , Ursidae/fisiologia , Lobos/fisiologiaRESUMO
Animals that occupy temperate and polar regions have specialized traits that help them survive in harsh, highly seasonal environments. One particularly important adaptation is seasonal coat colour (SCC) moulting. Over 20 species of birds and mammals distributed across the northern hemisphere undergo complete, biannual colour change from brown in the summer to completely white in the winter. But as climate change decreases duration of snow cover, seasonally winter white species (including the snowshoe hare Lepus americanus, Arctic fox Vulpes lagopus and willow ptarmigan Lagopus lagopus) become highly contrasted against dark snowless backgrounds. The negative consequences of camouflage mismatch and adaptive potential is of high interest for conservation. Here we provide the first comprehensive review across birds and mammals of the adaptive value and mechanisms underpinning SCC moulting. We found that across species, the main function of SCC moults is seasonal camouflage against snow, and photoperiod is the main driver of the moult phenology. Next, although many underlying mechanisms remain unclear, mammalian species share similarities in some aspects of hair growth, neuroendocrine control, and the effects of intrinsic and extrinsic factors on moult phenology. The underlying basis of SCC moults in birds is less understood and differs from mammals in several aspects. Lastly, our synthesis suggests that due to limited plasticity in SCC moulting, evolutionary adaptation will be necessary to mediate future camouflage mismatch and a detailed understanding of the SCC moulting will be needed to manage populations effectively under climate change.