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As temperatures warm in response to anthropogenic changes (climate change and urbanization), animals must respond adaptively to these changes or be displaced. Here, we use community science data (iNaturalist and BugGuide) to show that melanization in larval monarch butterflies (Danaus plexippus (Linnaeus, 1758), an endangered species in Canada) is correlated with latitude and temperature across a latitudinal gradient, indicating likely use in thermoregulation. We also predicted that melanization would decrease in cities where temperatures are consistently higher than rural areas; however, we found that while melanization was lower in urban areas, it was not statistically significant. Our results demonstrate the importance of considering life stage when assessing capacity for adaptation to anthropogenic change in vulnerable animal populations, like monarch butterflies. We also show the value of using community science to sample species (particular those of most concern) distributions across the landscape. [ABSTRACT FROM AUTHOR]

Variation in age of primiparity is important for population dynamics and wildlife management because it can affect population growth. Using a novel technique based on the trade-off between annual horn growth and reproduction, we estimated the age of primiparity for 2274 female mountain goats (Oreamnos americanus (Blainville, 1816)) harvested across British Columbia, Canada, from 1976 to 2019. We then investigated spatio-temporal variation in the probability that harvested females were primiparous when aged 3, 4, or 5 years and older using Bayesian ordinal regressions. We found that the probability of primiparity at 3 years decreased over time in nearly all mountain ranges. In the Coastal Mountain range, however, the probability of primiparity at age 3 significantly increased. These results suggest that the large coastal populations of mountain goats could be more resilient to harvest than other populations in British Columbia, which may be experiencing environmental effects promoting later primiparity. Models predicting age of primiparity from annual growth measures are a valuable tool for wildlife management and could help conservation of many species. [ABSTRACT FROM AUTHOR]

Evaluating nutritional condition provides insights of nutritional influences on wildlife populations. We sampled three measures of condition — body fat, body mass, and loin thickness — of adult female caribou (Rangifer tarandus (Linnaeus, 1758)) in boreal settings in the Northwest Territories (NT), Canada, in December and March, 2016–2018, and in mountain and boreal settings in British Columbia (BC), Canada, in December and February, 2014–2015. We evaluated the effect of calf-rearing on condition in December, compared influences of summer–autumn versus winter on condition over winter, and developed an annual profile of nutritional condition with estimates from caribou dying in summer. Mean December body fat was 8.4% in females with calves and 11.4% in females without calves, demonstrating the influence of lactation on condition. Over winter, nutritional condition did not decline in northeastern BC and it declined slightly in NT: body fat by 0.55 percentage points, mass by 2.8 kg, and loin thickness did not change. Body fat peaked in December, changed little over winter, but declined to a minimum by early summer, temporally coinciding with elevated rates of adult female mortality. Consistent with those of other ungulate studies worldwide, our findings suggest a need to focus on nutritional limitations operating in late spring through early autumn. [ABSTRACT FROM AUTHOR]

Assessing the challenges faced by wildlife populations is key to providing effective management but is problematic when dealing with populations in remote locations. Analyses of the stable carbon and nitrogen isotope composition (expressed as δ13C and δ15N values) of sequentially grown tissues, such as hairs, can be used to track changes in the eco-physiology of organisms. We generated δ13C and δ15N values from sequentially sampled (n = 465) hairs taken from wood bison (Bison bison athabascae Rhoads, 1898) (n = 27). Samples were taken from individuals prior to and after their release from captivity into the lower Innoko–Yukon river area of Alaska in 2015. Twenty months after release, individuals had a distinct seasonal pattern in δ13C values. Hairs from individuals that experienced food scarcity or long-distance movement were sampled as case studies. Nutritional stress in these cases lead to a rise in δ15N values and a decrease in δ13C values. Applications of δ13C and δ15N analyses of bison tail hairs could provide wildlife managers a valuable and minimally invasive tool to better understand bison seasonal metabolic status and determine the historical health and behavior of living and dead individuals. [ABSTRACT FROM AUTHOR]

The island rule postulates that the special ecological conditions on islands, such as limited resource availability, can cause populations of large-bodied animals to evolve smaller sizes and small-bodied populations to evolve larger sizes. Although support for the island rule is well documented (with notable exceptions and debate) in mammals and birds, similar trends are poorly explored in ectothermic vertebrates. As part of a larger study investigating the ecology of Eastern Hog-nosed Snakes (Heterodon platirhinos Latreille, 1801), we compared the mean and maximum sizes of a population from a barrier island (∼4 000 ha) to snakes on an adjacent larger island (∼363 000 ha) and two mainland sites (450 total snakes across all study sites). We did not observe a difference between the small and the large islands, but we did find differences between the smallest island and the mainland. Female snakes on the barrier island were 8% smaller than those on the mainland, and the female from the largest barrier island was 35% smaller than the largest documented H. platirhinos. In addition, we found that males did not exhibit dwarfism. We hypothesize that the observed dwarfism is a result of limited availability of large prey items and recommend that future studies distinguish between sexes in their analyses. [ABSTRACT FROM AUTHOR]

Animal populations are often limited by food availability, particularly during the breeding season. In birds, food limitation can impact several components of the reproductive cycle, including the timing of reproduction and reproductive output. Barn Swallows (Hirundo rustica Linnaeus, 1758) have experienced a population decline over the past 40 years in North America that is thought to be related to changes in prey availability. We monitored Barn Swallow reproductive behaviour and prey availability throughout two breeding seasons at 10 sites in Ontario, Canada, to test the hypothesis that limited prey availability during the breeding season affected reproductive behaviour. We found no relationship between food availability and number of eggs laid or number of young fledged. Neither did we observe higher rates of second brooding or more pairs nesting at breeding sites with higher food availability. Barn Swallows did not time their reproductive effort to maximize prey availability during the nesting period, but any mismatch in phenology of prey and bird reproduction at a breeding site was not associated with lower reproductive success. The results of this study did not support our hypothesis and suggest that Barn Swallow reproductive behaviour was not negatively affected by limited prey availability on the breeding grounds. [ABSTRACT FROM AUTHOR]

Anthropogenic disturbance can negatively impact animal populations and alter the behaviour of individuals. Disturbance associated with the energy sector has been increasing in the boreal forest of northern Alberta. Disturbances associated with the oil and gas industry vary in the infrastructure present and sensory stimuli generated. Two common types are compressor stations and roads. It is important to assess population consequences of disturbance on small mammals because they serve as prey, predators, and seed–spore dispersers in the terrestrial ecosystems that they inhabit. To test the effects of disturbance from the energy sector on the abundance and activity of small mammals, we used mark–recapture methods and live-trapped in forested areas with one side adjacent to a clearing with industrial infrastructure present (road or compressor station) or absent (control sites). We found no difference in abundance or activity of deer mice (Peromyscus maniculatus (Wagner, 1845)) and southern red-backed voles (Myodes gapperi (Vigors, 1830)) between sites and did not detect an edge effect on abundance within sites, regardless of the presence of industrial infrastructure. Our results suggest minimal effects of industrial disturbance on the abundance and activity of these species, and the infrastructure and sensory stimuli generated are unlikely to be key drivers of their population dynamics or behaviour. [ABSTRACT FROM AUTHOR]

Animal populations often decline due to habitat disturbance, but the initial response of organisms to human-induced environmental change is usually behavioral. Intra- and inter-specific interactions can restrict or facilitate access to resources, resulting in changes to individual fitness, and resource depletion may affect the frequency and strength of interactions. In birds, it is often assumed that feeding in groups increases foraging efficiency. We assessed how the reduction of seed resources provoked by cattle grazing affected different properties of seed-eating bird flocks in woodlands having the same structural characteristics but differing in seed abundance. Under lower availability of grass seeds (i.e., under grazing), flocks were smaller and less rich and birds showed a lower flocking propensity. This pattern could be explained by three non-exclusive hypotheses. Food reduction caused by grazing (i) decreases the number of seed-eating birds and concomitantly generates smaller flocks; (ii) reduces the density of nuclear species, decreasing the group cohesion in large flocks; (iii) makes large flocks less attractive by increasing individual competence for food. Our results provide evidence that cattle grazing affect the interactions of seed-eating birds and suggest the importance of understanding flocking behavior to bring about management actions. [ABSTRACT FROM AUTHOR]

Partial migration, the phenomenon in which animal populations are composed of both migratory and nonmigratory individuals, is widespread among migrating animals. The proportion of migrants in these populations has direct influences on population genetics and dynamics, ecosystem dynamics, mating systems, evolution, and responses to environmental change, yet there are very few studies that measure the proportion of migrants. This is because existing methods to estimate the proportion of migrants are time-consuming and expensive. In this paper, we demonstrate a new method for estimating the proportion of migrants in a population based on sex ratio measurements. Many partially migratory taxa exhibit sex-biased migration or residency, and in these cases, the sex ratios of migrants and nonmigrants are fundamentally related to the proportion of migrants in the population. We define this relationship quantitatively and show how it can be used to infer the proportion of migrants in a population through a process we term "sex-ratio balancing". We obtain Bayesian estimates of proportion of migrants and quantify the uncertainty in these estimates with highest posterior density intervals. Lastly, we validate the sex-ratio balancing approach with a Chinook salmon (Oncorhynchus tshawytscha Walbaum in Artedi, 1792) data set. Sex-ratio balancing holds promise as a tool for quantifying partial migration and filling a key data gap about partially migratory taxa. [ABSTRACT FROM AUTHOR]

Understanding how habitat type and deterioration may affect parasitism is important in assessing the effects of human-induced environmental change on host–parasite dynamics. In this study, we examined inter-population differences in parasite load in the Mediterranean lizard Psammodromus algirus (Linnaeus, 1758). We analyzed prevalence and intensity of infection by blood parasites and ectoparasites in two populations separated by a 400 m elevational gradient and with different habitat types that also differed in the degree of human alteration. We also compared data obtained from the same populations 10 years later to assess whether there have been temporary changes in parasite loads. Results showed that prevalence and intensity of blood parasites were higher in the deteriorated lowland holm oak forest population than in the well-preserved upland oak forest. In contrast, the prevalence and intensity of infection by Ixodes Latreille, 1795 ticks was higher in the upland oak forest population. Individuals from the lowland population were in poorer condition. Intensities of infection by blood parasites and ectoparasites have decreased significantly from 2005–2006 to 2016 in both populations. Our results suggest that inter-population differences in parasite load may be explained by differences in habitat characteristics. This study contributes to the identification of ecosystems and habitats that are most sensitive to prevalence and intensity of infection by parasites. [ABSTRACT FROM AUTHOR]

The Atlantic blue mussel ( Mytilus edulis Linnaeus, 1758) exhibits doubly uniparental inheritance of mitochondrial (mt) DNA. Females are usually homoplasmic for a female-transmitted mt genome (the F type) and males are heteroplasmic for an F type and a male-transmitted mt genome (the M type). F types can undergo 'role-reversal' events, resulting in new male-transmitted mtDNA genomes known as recently masculinized (RM) types that co-occur in populations with evolutionarily older standard-male (SM) types. Phylogenetic analyses have shown that RM types periodically replace SM types. It has also been shown that sperm with RM mtDNA have greater swimming velocity and more efficient components of the electron transport chain compared to sperm with SM mtDNA, thus leading to the hypothesis that RM sperm may have a selective advantage over SM sperm. The present study examines the distribution of RM and SM mitotypes in male M. edulis ( n = 225) from 13 localities in southwestern Nova Scotia (Canada). The SM type was more common in all populations, with the proportion of RM types ranging from 0% to 24.1%. The highest proportion of RM types was observed in an aquaculture operation. Analyses of additional populations are required to evaluate the selective pressures affecting the geographic distribution of RM and SM mitotypes in M. edulis. [ABSTRACT FROM AUTHOR]

Habitat loss and fragmentation pose a continued and immediate threat to wildlife and create a persistent need for ecological information at the landscape scale to guide conservation efforts. Landscape features influence population connectivity for many species and genetic analyses can be employed to determine which of these features are most important. Because population connectivity through dispersal is important to the persistence of swamp rabbits ( Sylvilagus aquaticus (Bachman, 1837)) at the northern edge of their range, we used a landscape genetic approach to relate gene flow to landscape features that may impact dispersal success. We tested resistance values for attributes of land cover, watercourse corridors, canopy cover, and roads and used causal modeling and redundancy analysis to relate these representations of landscapes to genetic distance for swamp rabbits in southern Illinois, USA. Models that included canopy cover had the strongest correlations with genetic distance and were supported by our methods whereas other models were not. We concluded that high tree canopy cover enhances gene flow and landscape connectivity for swamp rabbits in southern Illinois. Our study provides important empirical evidence that landscape variables may impact the habitat connectivity of swamp rabbits. Preserving dispersal routes for swamp rabbits should focus on improving canopy cover, in both bottomland and upland, to connect suitable habitat. [ABSTRACT FROM AUTHOR]

Introduced non-native mammals can have negative impacts on native biota and it is important that their ecologies are quantified so that potential impacts can be understood. Red-necked wallabies ( Notamacropus rufogriseus (Desmarest, 1817)) became established on the Isle of Man (IOM), an island with UNESCO Biosphere status, following their escape from zoological collections in the mid-1900s. We estimated wallaby circadial activity and population densities using camera trap surveys and random encounter models. Their range in the IOM was derived from public sightings sourced via social media. Wallaby diet and niche breadth were quantified via microscopic examination of faecal material and compared with those of the European hare ( Lepus europaeus Pallas, 1778). The mean (±SE) population density was 26.4 ± 6.9 wallabies/km2, the mean (±SE) population size was 1742 ± 455 individuals, and the species' range was 282 km2, comprising 49% of the island. Wallaby diets were dominated by grasses, sedges, and rushes; niche breadth of wallabies and hares (0.55 and 0.59, respectively) and overlap (0.60) suggest some potential for interspecific competition and (or) synergistic impacts on rare or vulnerable plant species. The IOM wallaby population is understudied and additional research is required to further describe population parameters, potential impacts on species of conservation interest, and direct and indirect economic costs and benefits. [ABSTRACT FROM AUTHOR]

The spatial scales at which animals make behavioral trade-offs is assumed to relate to the scales at which factors most limiting resources and increasing mortality risk occur. We used global positioning system collar locations of 29 reproductive-age female black bears ( Ursus americanus Pallas, 1780) in three states to assess resource selection relative to bear population-specific density, an index of vegetation productivity, riparian corridors, or two road classes of and within home ranges during spring-summer of 2009-2013. Female resource selection was best explained by functional responses to vegetation productivity across nearly all populations and spatial scales, which appeared to be influenced by variation in bear density (i.e., intraspecific competition). Behavioral trade-offs were greatest at the landscape scale, but except for vegetation productivity, were consistent for populations across spatial scales. Females across populations selected locations nearer to tertiary roads, but females in Michigan and Mississippi selected main roads and avoided riparian corridors, whereas females in Missouri did the opposite, suggesting population-level trade-offs between resource (e.g., food) acquisition and mortality risks (e.g., vehicle collisions). Our study emphasizes that female bear population-level resource selection can be influenced by multiple spatially dependent factors, and that scale-dependent functional behavior should be identified for management of bears across their range. [ABSTRACT FROM AUTHOR]

Understanding population structure and resource selection is essential for wildlife management and conservation. We assessed the population structure of elk ( Cervus elaphus L.,1758) in central Ontario. We used fuzzy and hierarchical cluster analyses to elucidate elk population structure based on spatial data collected from 41 radio-collared elk. We assessed space use between core and satellite subpopulations with the minimum convex polygon (MCP) and fixed kernel methods. Both fuzzy and hard clustering indicated that elk in this part of central Ontario occur in a metapopulation that includes five subpopulations. The largest cluster consisted of a core group containing 22 radio-collared elk located in Burwash, with several satellite subpopulations spread along a 50 km long north-south axis and a small subpopulation to the west located in Worthington. Survival rates among subpopulations were similar, ranging from 0.71 to 0.83, and anthropogenic causes of mortality were predominant only in the Burwash subpopulation. Space use and density of elk differed between core and satellite subpopulations. Understanding population structure is important to develop appropriate management plans. Our results support the conclusion that metapopulation structure can be reliably assessed using spatial data. [ABSTRACT FROM AUTHOR]

The abundance-occupancy relationship is one of the most well-examined relationships in ecology. At the species level, a positive association has been widely documented. However, until recently, research on the nature of this relationship at broad taxonomic and spatial scales has been limited. Here, we perform a comparative analysis of 12 taxonomic groups across a large spatial scale (Canada), using data on Canadian species at risk: amphibians, arthropods, birds, freshwater fishes, lichens, marine fishes, marine mammals, molluscs, mosses, reptiles, terrestrial mammals, and vascular plants. We find a significantly positive relationship in all taxonomic groups with the exception of freshwater fishes (negative association) and lichens (no association). In general, our work underscores the strength and breadth of this apparently fundamental relationship and provides insight into novel applications for large-scale population dynamics. Further development of species-independent abundance-occupancy relationships, or those of a similar nature, might well prove instrumental in serving as starting points for developing species-independent reference points and recovery strategies. [ABSTRACT FROM AUTHOR]

Landscape barriers to gene flow, such as rivers, can affect animal populations by limiting the potential for rescue of these isolated populations. We tested the riverine barrier hypothesis, predicting that the St. Lawrence River in eastern Canada would cause genetic divergence of Canada lynx ( Lynx canadensis Kerr, 1792) populations by restricting dispersal and gene flow. We sampled 558 lynx from eastern Canada and genotyped these at 14 microsatellite loci. We found three genetic clusters, defined by the St. Lawrence River and the Strait of Belle Isle, a waterway separating Newfoundland from mainland Canada. However, these waterways were not absolute barriers, as we found 24 individuals that appeared to have crossed them. Peripheral populations of lynx are threatened in parts of Canada and the USA, and it is thought that these populations are maintained by immigration from the core. Our findings suggest that in eastern North America, rescue might be less likely because the St. Lawrence River restricts dispersal. We found that ice cover was often sufficient to allow lynx to walk across the ice in winter. If lynx used ice bridges in winter, then climate warming could cause a reduction in the extent and longevity of river and sea ice, further isolating these peripheral lynx populations. [ABSTRACT FROM AUTHOR]

While many approaches to modeling body condition exist, ranging from arbitrary morphometric indices to sophisticated cone modeling, few approaches have attempted to develop a standardized, simplified method for determining total body fat and protein in otariids. Our goal was to develop a method for predicting the body condition of juvenile Steller sea lions ( Eumetopias jubatus (Schreber, 1776)) using simple morphometrics such as measurements of girth, length, mass, and blubber depth. We compared a candidate set of models to determine which metrics best predicted total body water (TBW) measures obtained by deuterium isotope dilution. Furthermore, we used AICc (Akaike's information criterion corrected for small sample size) model selection methods and cross-validation to choose and validate the best suite of predictors. TBW was best predicted by a model that included mass, standard length, axial girth with the addition of blubber depths on the lateral side of the neck and dorsal surface of the hip. The results presented here show that blubber depth is an important addition to modeling body composition and may improve upon nonlethal, population-level estimates of nonisotopically derived values of TBW in juvenile Steller sea lions. Additionally, our models present a model development framework for other research efforts for use in determining body condition in otariids. [ABSTRACT FROM AUTHOR]

The immunological variation in wild populations and its relation to life-history traits has recently become a central topic in the field of evolutionary biology, considering the critical contribution of immunity to an individual's fitness. A common technique used by ecologists to estimate immunocompetence in wild populations is the phytohemagglutinin (PHA) - skin test. In this test, the degree of local swelling triggered by PHA is usually considered an estimate of T-lymphocyte activity, although there is an ongoing debate regarding this interpretation. Here, we coupled the PHA-skin test with a histological analysis to examine the temporal development of the cell-mediated response in the subterranean rodent Talas tuco-tuco ( Ctenomys talarum Thomas, 1898). The inflammation response involved lymphocytes, neutrophils, eosinophils, and macrophages at the site of injection, achieving an increase of total leukocytes from 12 to 48 h after injection. However, the abundance of any of the leukocytes observed did not correlate with the degree of swelling at any time studied, suggesting that caution should be taken when interpreting the results of the PHA-induced swelling response. Particularly, the magnitude of macroscopic swelling should not be considered a priori as indicative of T-lymphocyte activity in wild-caught rodents. Our results highlight the importance of avoiding oversimplified approaches to measuring immunocompetence. [ABSTRACT FROM AUTHOR]

North American elk ( Cervus elaphus L., 1758) are an important component of Canada's natural ecosystems. Overhunting and habitat decline in the 19th century led to the near eradication of Rocky Mountain elk ( Cervus elaphus nelsoni Bailey, 1935) and Manitoban elk ( Cervus elaphus manitobensis Millais, 1915) within Alberta. Though elk populations have been restored within provincial and national parks, it is unknown to what degree historic population declines affected overall genetic diversity and population structuring of the two subspecies. This study targeted 551 bp of mitochondrial D-loop DNA from 50 elk remains recovered from 16 archaeological sites (2260 BCE (before common era) to 1920 CE (common era)) to examine the former genetic diversity and population structure of Alberta's historic elk populations. Comparisons of ancient and modern haplotype and nucleotide diversity suggest that historic population declines reduced the mitochondrial diversity of Manitoban elk, while translocation of animals from Yellowstone National Park in the early 20th century served to maintain the diversity of Rocky Mountain populations. Gene flow between the two subspecies was significantly higher in the past than today, suggesting that the two subspecies previously formed a continuous population. These data on precontact genetic diversity and gene flow in Alberta elk provide essential baseline data integral for elk management and conservation in the province. [ABSTRACT FROM AUTHOR]

Many herbivore species expand their dietary niche breadths by switching from browse-rich diets in dry seasons to grass-rich diets in rainy seasons, in response to phenological changes in plant availability and quality. We analyzed stable isotope series along tail hairs of captive and free-ranging African elephant ( Loxodonta africana (Blumenbach, 1797)) to compare patterns of seasonal dietary variability across individuals. Results from elephants translocated from the wild into captivity, where their diets are semicontrolled, revealed tail hair growth rates of ∼0.34 mm/day, on average, and relatively rapid isotope turnover through the transition from wild into captivity. Sampling hairs at 10 mm increments thus archives dietary chronologies at a resolution suitable for tracking diet switches at seasonal, and even subseasonal, scales. Hairs of free-ranging elephants showed extensive carbon isotopic variability within individuals, consistent with seasonal switches between C3-browsing and C4-grazing. Similarly extensive, but asynchronous, shifts in nitrogen isotope ratios were also observed, suggesting an influence of factors other than seasonality. Across individuals, switching patterns differed across habitats, and across age classes, with older, larger animals including increasing amounts of C3 browse into their diets. These results demonstrate how stable isotope approaches characterize complex patterns of resource use in wildlife populations. [ABSTRACT FROM AUTHOR]

Refugia likely represent a critical resource necessary for the persistence of populations of Boreal Toads ( Anaxyrus boreas boreas (Baird and Girard, 1852)) in a given area. However, the features that define suitable refuge microsites and the extent to which the habitat surrounding refugia is exploited remains unclear. We sought to describe refuge characteristics in the context of their surroundings and to determine whether local-scale movement behaviour associated with refuge use might provide a novel perspective of landscape-level habitat selection. A pilot study suggested that refugia were selected primarily for physical structure in the form of coarse woody debris, but this was not the case. Instead, refugia provided favourable microclimates with elevated relative humidity compared with the surrounding habitat. Boreal Toads tended to forage at night within 15 m from refugia. This distance was used to calculate activity centres across toad summer home ranges. Activity centres prioritized the importance of treeless habitat overall and wetland habitat for females when compared with 50% core home ranges. This approach could be used to pinpoint critical habitat at the landscape scale, which may be of particular importance for conserving populations currently in decline. [ABSTRACT FROM AUTHOR]

We studied populations of three tundra-dwelling wolf spider (Lycosidae) species to determine reproductive trait relationships and developmental timing in the Arctic. We collected 451 Pardosa lapponica (Thorell, 1872), 176 Pardosa sodalis Holm, 1970, and 117 Pardosa moesta Banks, 1892 during summer 2008. We used log-likelihood ratio tests and multiple linear regressions to determine the best predictors of fecundity and relative reproductive effort. Female body size best explained the variation in fecundity and body condition was the best predictor for relative reproductive effort. We tested for a trade-off between the allocation of resources to individual eggs and the number of eggs produced (fecundity) within each species using linear regression. There was variation in detectable egg size and number trade-offs among sites and these may be related to local variation in resource allocation linked to density-related biotic or abiotic factors. These findings contribute to knowledge about the fitness of arctic wolf spiders in the region of study and are particularly relevant in light of the effects that climate changes are predicted to have on the arctic fauna. [ABSTRACT FROM AUTHOR]

In Canada, three subspecies of American badgers ( Taxidea taxus (Schreber, 1777)) traditionally are identified; two of which are listed as endangered because of their restricted geographic range and low population sizes. To verify their subspecific designations and genetic insularity, we analyzed mitochondrial control region sequences within and among badger subspecies ( Taxidea taxus jacksoni Schantz, 1946, Taxidea taxus jeffersonii (Harlan, 1825), and Taxidea taxus taxus (Schreber, 1777)) from nine locations in Canada and bordering United States. Although subspecies designations were supported (a priori subspecific designations, n = 3, AMOVA: FST = 0.40, p < 0.001), insular populations also were found within subspecific ranges as shown by spatial analysis of molecular variation, which suggested that our sample set consisted of five genetic groups ( FST = 0.39, p < 0.001). These five distinct groupings included the subdivision of T. t. jeffersonii on either side of the Selkirk Mountains, and of T. t. jacksoni in the western part of its range grouping more closely with T. t. taxus of Manitoba. These results indicate that endangered populations of badgers may be more segregated than previously identified using morphological characteristics as proxies for subspecific designation. These results have important implications for the conservation of badgers in Canada, particularly of the two endangered subspecies. [ABSTRACT FROM AUTHOR]

Habitat selection is the disproportionate use of habitat compared with availability. Many studies have focused on specialists, but few have considered habitat selection in populations that are generalists, which can be composed of generalist individuals or individuals that specialize on different habitats. We tested habitat selection and individual specialization in a northern population of a supposed generalist, the Snapping Turtle ( Chelydra serpentina (L., 1758)), during the active season and winter using telemetry. Habitat selection was tested at two spatial scales by comparing random points to home ranges and turtle locations using Euclidean distances. Turtles selected home ranges from the habitats available in the population range. However, at the population level, all aquatic habitats were equally preferred, and the population behaved as a generalist owing to individuals specialized on different habitats. Over half of the individuals showed evidence of individual specialization on different habitat types. Turtles did not select habitat within home ranges during the active season, but overwintering turtles chose locations that were colder than haphazard stations in the same habitats, likely to reduce metabolic costs and the risk of acidosis. These findings have implications for the management of this species at risk and for understanding the evolution of resource generalization. [ABSTRACT FROM AUTHOR]

Availability of preferred forage is hypothesized to be positively related to demographic performance in selective ungulates. Comparing two regions with high density of moose (Alces alces (L., 1758)) having contrasting demographic performance and different composition of available plant species, we show that such a positive relationship may not always apply. The high-performance region (HP) had an estimated 41% higher total availability of browse per capita than the low-performance region (LP), but the availability of preferred species did not differ between the two regions. Although birch (genus Betula L.) was the most abundant browse in both regions (comprising 66% and 50% of the shoot amount available per m2 in HP and LP, respectively), it dominated the diet of moose only in HP (constituting, e.g., 69% of all trees browsed in summer compared with 22% in LP). Further research is needed to identify the cause of the seemingly suboptimal use of birch in LP. We also quantified factors that determine forage availability, of which recent logging clearly was the most important: it multiplied browse availability but also reduced coverage of bilberry (Vaccinum myrtillus L.), an important forage plant. Our study shows that for selective ungulates, indices of carrying capacity based on forage availability may not apply uniformly across ranges. On a émis l'hypothèse selon laquelle la disponibilité des fourrages préférés est en corrélation positive avec la performance démographique chez certains ongulés. En comparant deux régions à densité élevée d'élans (Alces alces (L., 1758)) qui diffèrent par la performance démographique des élans et par la composition des espèces de plantes, nous montrons qu'une telle relation positive n'existe pas nécessairement. La région de haute performance (HP) présente une disponibilité totale de brout plus élevée de 41 % par individu que la région de faible performance (LP), mais la disponibilité des espèces préférées est la même dans les deux régions. Bien que les bouleaux (le genre Betula L.) soient les espèces de brout les plus abondantes dans les deux régions (représentant respectivement 66 % et 50 % de la quantité des pousses disponibles par m2 dans HP et LP), ils prédominent dans le régime alimentaire des élans seulement dans HP (représentant, par ex., 69 % de tous les arbres broutés en été, par comparaison à 22 % dans LP). Il faudra des recherches supplémentaires pour identifier la cause de l'utilisation apparemment suboptimale des bouleaux dans LP. Nous avons aussi mesuré les facteurs qui déterminent la disponibilité des fourrages, dont la coupe forestière récente est nettement le plus important; la coupe augmente la disponibilité des fourrages, mais elle réduit la couverture de la myrtille commune (Vaccinium myrtillus L.), une plante fourragère importante. Notre étude démontre que, chez certains ongulés, les indices de stock limite basés sur la disponibilité des fourrages peuvent ne pas s'appliquer uniformément sur tout l'ensemble de l'aire de répartition. [ABSTRACT FROM AUTHOR]

In most previous studies of habitat selection, the use of a given habitat type is assumed to be directly proportional to its availability. However, the use and (or) the selection of a given habitat may be conditional on the availability of that habitat. We aim here to (i) identify the environmental variables involved in habitat selection, (ii) identify classes of individuals with similar patterns of habitat selection, and (iii) assess whether habitat use changes with changing availability of habitat types, within monthly home ranges of female western roe deer (Capreolus capreolus (L., 1758)). We found that some females adjust their habitat use according to the distribution of resources within habitats. Females with similar home ranges in terms of resource quantity and quality showed similar patterns of habitat selection. Differences in habitat use between 2 years with contrasting resource availability showed that temporal changes of environmental conditions influenced the pattern of habitat selection by female roe deer. Habitat selection also differed between periods of the life cycle likely because of contrasted energy requirements. This study shows that the relationship between habitat use by herbivores and habitat availability is nonproportional, and that the availability of resources influences use mostly at intermediate values. [ABSTRACT FROM AUTHOR]

Because of their wide-ranging habits, conserving large carnivores such as American black bears (Ursus americanus Pallas, 1780) often depends on understanding habitat needs beyond the boundary of protected areas. We studied habitat selection by black bears in the vicinity of Bruce Peninsula National Park, Ontario - a small, isolated population whose persistence appears dependent on habitat on lands outside the Park. We used an approach based on Euclidean distances to document seasonal habitat selection at two spatial scales and to identify candidate habitat types for protection. Adult females selected dense mixed forests to establish home ranges within the population range, whereas subadults and yearlings selected dense deciduous forests. Within home ranges, adults selected dense mixed forest in spring-summer and dense deciduous forest in late summer - fall. Subadults selected dense deciduous forest, marsh, dense mixed forest, and water during the spring-summer and avoided developed lands and roads. Yearlings selected dense mixed forest, dense deciduous forest, and sparse forests in spring-summer and dense deciduous forest and dense mixed forest in late summer - fall. The selection of dense deciduous and dense mixed forest stands, especially at the broader scale, suggests that strategies to ensure persistence of this isolated population should focus on protecting the integrity of these stands. [ABSTRACT FROM AUTHOR]

Human-caused landscape change negatively affects the sustainability of many wildlife populations. In Alberta, Canada, grizzly bears (Ursus arctos L., 1758) live in one of the most populated and heavily exploited landscapes in which the species survives. Long-term physiological stress in individual animals may be the predominant mechanism linking landscape change with impaired wildlife population health. Hair cortisol concentration has been validated as a biomarker of long-term stress in humans and domestic animals; however, limited work has examined factors that may affect its measurement or interpretation. We have measured cortisol in as few as five guard hairs of a grizzly bear and have identified factors influencing hair cortisol concentration in this species. Hair cortisol varies with hair type, body region, and capture method. It is not influenced by colour, age, sex, environmental exposure (18 days), or prolonged laboratory storage (>1 year) and does not vary along the length of the hair shaft. Recommendations for prudent use of hair cortisol analysis in grizzly bears are discussed with implications for the development of hair cortisol concentration as a tool to monitor long-term stress in other wildlife. Les modifications anthropiques du paysage affectent négativement la durabilité de plusieurs populations de la faune sauvage. En Alberta, Canada, les ours grizzlis (Ursus arctos L., 1758) habitent l'un des paysages les plus densément peuplés et fortement exploités dans lesquels l'espèce arrive à survivre. Le stress physiologique à long terme chez les animaux individuels est vraisemblablement le mécanisme qui relie les modifications du paysage à la détérioration de la santé de la population de faune sauvage. La concentration de cortisol dans le poil constitue un biomarqueur éprouvé du stress à long terme chez les humains et les animaux domestiques; cependant, peu de travaux ont examiné les facteurs qui peuvent en affecter la mesure ou l'interprétation. Nous avons dosé le cortisol dans aussi peu que cinq poils de garde de grizzlis et identifié les facteurs qui contrôlent la concentration de cortisol dans le poil chez cette espèce. Le cortisol dans le poil varie en fonction du type de poil, de la région du corps et de la méthode de capture. Il n'est pas influencé par la couleur, l'âge, le sexe, l'exposition au milieu (18 jours), ni l'entreposage en laboratoire (>1 an); il ne varie pas le long de la tige du poil. Nous commentons nos recommandations pour un usage prudent de l'analyse du cortisol des poils chez les grizzlis et discutons des conséquences sur l'utilisation plus étendue du cortisol des poils comme outil pour suivre le stress de longue durée chez d'autres animaux sauvages. [ABSTRACT FROM AUTHOR]

Sexual dimorphism and age-related differences are sources that contribute to morphologic and physiologic variation within animal populations. Measurement of animal performance may indicate whether this variation is functionally relevant. Our study aimed to experimentally test this statement in a captive population of House Sparrows (Passer domesticus (L., 1758)) by examining age- and sex-related differences in escape response and its relationship to several morphological (tarsus, wing, tail lengths, and body mass) and physiological traits (cell-mediated immunity, natural antibodies, complement activity, hematocrit, and stress response). Escape response from a predator is considered a good variable to measure animal performance, because natural selection clearly favours individuals that avoid predators successfully. Our experimental design also aimed to standardize possible confounding factors affecting escape behaviour under natural conditions. We exposed sparrows to short episodes of high predation risk by simulating the attack of a predator and assumed that the capture order of individuals was related to their escape capacity. The optimal strategy was the immediate escape response for all individuals. We found that first-year males were the best escapers. In support of the hypothesis, juvenile males gathered a better optimum of several morphological and physiological characters that related to capture order. Le dimorphisme sexuel et les différences reliées à l'âge sont des sources qui contribuent à la variation morphologique et physiologique au sein des populations animales. La mesure de la performance animale peut indiquer si cette variation est fonctionnellement pertinente. Notre étude vise à testé expérimentalement cet énoncé dans une population en captivité de moineaux domestiques (Passer domesticus (L., 1758)) en examinant les différences sexuelles et reliées à l'âge dans la réaction de fuite et ses relations à plusieurs traits morphologiques (longueurs du tarse, de l'aile et de la queue, masse corporelle) et physiologiques (immunité cellulaire, anticorps naturels, activité du système complémentaire, hématocrite, réponse au stress). La réaction de fuite en présence d'un prédateur est considérée comme un bonne variable pour mesurer la performance animale, parce que la sélection naturelle favorise nettement les individus qui réussissent à éviter leurs prédateurs. Notre plan d'expérience cherche aussi à standardiser les facteurs confondants qui affectent le comportement de fuite dans les conditions naturelles. Nous avons exposé des moineaux à de courts épisodes de risque élevé de prédation en simulant l'attaque d'un prédateur et avons présumé que l'ordre de capture des individus est relié à leur capacité de fuite. La stratégie optimale chez tous les individus était la réaction immédiate de fuite. Ce sont les mâles dans leur première année qui fuient avec le plus de succès. Les jeunes mâles possèdent aussi de façon optimale un meilleur ensemble de plusieurs caractéristiques morphologiques et physiologiques reliées à l'ordre de capture, ce qui appuie l'hypothèse. [ABSTRACT FROM AUTHOR]

In mammal populations, the spatial and genetic structure can be affected by dispersal, philopatry, and relatedness. Bobcats (Lynx rufus (Schreber, 1777)) are thought to exhibit typical mammalian dispersal behaviour where males disperse and females are philopatric, potentially leading to higher relatedness among females compared with males. We used 10 microsatellite loci to examine population structure and sex-biased dispersal in 146 bobcats sampled in southern Illinois during 1993-2001 using population genetic descriptive statistics, a Bayesian clustering algorithm, relatedness (rxy), and autocorrelation analyses. A randomization test demonstrated that female dyads had significantly higher rxy values with respect to randomly selected dyads (rxy = 0.093 ± 0.222, P = 0.012) and spatial autocorrelation analyses determined that females in close proximity (<5 km) had a high probability of being related (P = 0.001). Conversely, rxy values for males were not different from the null distribution (rxy = 0.019 ± 0.122, P = 0.3158) and no significant relationships were found with spatial autocorrelation analysis. Additionally, it was demonstrated that bobcats in southern Illinois approximated a panmictic population with no obvious barriers to gene flow. The pattern of relatedness observed in this study confirmed that females were philopatric and males dispersed, corroborating existing observational data for this species. Dans les populations de mammifères, les structures spatiales et génétiques peuvent être affectées par la dispersion, la philopatrie et la consanguinité. On pense que les lynx roux (Lynx rufus (Schreber, 1777)) possèdent un comportement de dispersion typique des mammifères dans lequel les mâles se dispersent et les femelles sont philopatriques, ce qui entraîne potentiellement une plus forte parenté entre les femelles qu’entre les mâles. Nous analysons 10 locus microsatellites afin d’étudier la structure de population et la dispersion variable en fonction du sexe chez 146 lynx roux échantillonnés dans le sud de l’Illinois en 1993-2001; nous utilisons des statistiques génétiques descriptives, un algorithme bayésien de groupement et des analyses de parenté (rxy) et d’autocorrélation. Un test de randomisation montre que les dyades femelles ont des valeurs significativement plus élevées de rxy par rapport aux dyades choisies au hasard (rxy = 0,093 ± 0,222, P = 0,012) et les analyses d’autocorrélation spatiale montrent que les femelles rapprochées (<5 km) ont une forte probabilité d’être parentes (P = 0,001). À l’inverse, les valeurs de rxy des mâles ne diffèrent pas de celles d’une distribution nulle (rxy = 0,019 ± 0,122, P = 0,3158) et l’analyse d’autocorrélation spatiale ne révèle aucune relation significative. De plus, nous démontrons que les lynx roux du sud de l’Illinois forment presque une population panmixique sans barrière évidente au flux génique. Le patron de parenté observé dans notre étude confirme que les femelles sont philopatriques et que les mâles se dispersent, ce qui corrobore les observations antérieures faites sur cette espèce. [ABSTRACT FROM AUTHOR]

Peripheral populations of widespread species are often considered unworthy of conservation efforts; however, they may be adapted to the conditions found at the range edge and are therefore important to the future evolutionary potential of the species. Blanchard’s Cricket Frog (Acris blanchardi Harper, 1947) is widespread and abundant throughout the central United States, but is declining at the northern edge of its range. To assess the distinctiveness and conservation value of the northern populations, we investigated the spatial genetic structure and phylogeography of this anuran using mitochondrial control region sequences. Analysis of 479 individuals identified 101 haplotypes, with relatively low nucleotide diversity. Two moderately divergent clades were found. One was restricted to the southwest, which was probably a refugium during the Pleistocene, whereas the other occurred primarily across the north and is likely the result of postglacial colonization. The genetic distinctiveness of northern populations indicates the potential for adaptive differences of individuals in this region relative to those in the south. We therefore conclude that conservation efforts are justified for the declining northern populations of Blanchard’s Cricket Frog, and we use the spatial genetic structure described here to develop specific recommendations for this anuran. On considère souvent que les populations périphériques d’espèces à large répartition ne valent pas les efforts de conservation; elles peuvent, cependant, être adaptées aux conditions qui prévalent à la périphérie de l’aire de répartition et ainsi être importantes pour le potentiel évolutif futur de l’espèce. La rainette grillon de Blanchard (Acris blanchardi Harper, 1947) est une espèce largement répandue et abondante dans tout le centre des États-Unis, mais elle est en déclin à la marge nord de son aire de répartition. Afin d’évaluer la particularité et la valeur de conservation des populations nordiques, nous avons étudié la structure génétique et la phylogéographie de cet anoure à l’examen des séquences de la région de contrôle mitochondriale. Une analyse de 479 individus a révélé l’existence de 101 haplotypes, avec une diversité relativement basse des nucléotides. Il existe deux clades à divergence moyenne. L’un est restreint à la région sud-ouest, qui a probablement servi de refuge au pléistocène, alors que l’autre est surtout répandu dans tout le nord et résulte vraisemblablement de la colonisation postglaciaire. La différenciation génétique des populations nordiques laisse croire à un potentiel de différences adaptives chez les animaux de cette région par rapport aux animaux du sud. Nous concluons qu’il est justifié de déployer des efforts de conservation pour les populations nordiques déclinantes de la rainette grillon de Blanchard; nous utilisons la structure génétique spatiale décrite ici pour mettre de l’avant des recommandations spécifiques au sujet de cet anoure. [ABSTRACT FROM AUTHOR]

In Argentinean agroecosystems, house mice (Mus musculus L., 1758) show a discontinuous distribution, with high abundances in farms but scarce abundance in crop fields. In our study area, the abundance of M. musculus could be affected by their movements among farms. We hypothesize that (1) M. musculus do not move among farms versus (2) M. musculus do move among farms. Furthermore, based on our second hypothesis, M. musculus move actively (hypothesis 2.1) or passively by human transport (hypothesis 2.2). Based on hypothesis 1, we predict that genetic subdivision will exist among farms and that genetic divergence will be independent of geographic distance. Based on hypothesis 2.1, genetic differentiation will be correlated with geographic distance. Based on hypothesis 2.2, genetic subdivision will be absent, or genetic differentiation will be related to human movements. We examined genetic variation among farms (n = 15) using five microsatellite loci and tracked the movements of 36 individuals from five farms with fluorescent powders. Populations of M. musculus showed genetic differentiation at both farm and shed scales. Genetic and geographic distances were significantly correlated. There was no evidence of passive movements of M. musculus. The movements of 36 M. musculus within farms, tracked with fluorescent powder, were short. According to these results, hypothesis 2.1 is favoured. Dans les écosystèmes agricoles d’Argentine, la souris domestique (Mus musculus L., 1758) possède une répartition discontinue avec de fortes abondances dans les fermes et de faibles densités dans les champs cultivés. Dans notre région d’étude, les déplacements des M. musculus d’une ferme à l’autre pourraient affecter leur abondance. Notre hypothèse (1) veut qu’il n’y ait pas de déplacements de M. musculus entre les fermes et l’hypothèse contraire (2) que M. musculus se déplace d’une ferme à l’autre. D’après cette dernière hypothèse, M. musculus se déplace activement (hypothèse 2,1) ou ses déplacements sont passifs et s’expliquent par le transport par les humains (hypothèse 2,2). D’après l’hypothèse 1, on peut prédire qu’il y aura une subdivision génétique entre les fermes et que la divergence génétique sera indépendante de la distance géographique. D’après l’hypothèse 2,1, la différentiation génétique sera en corrélation avec la distance génétique. D’après l’hypothèse 2,2, on s’attend à une absence de subdivision génétique ou alors à une différentiation reliée aux déplacements des humains. Nous avons déterminé la variation génétique entre les fermes (n = 15) d’après cinq locus microsatellites et nous avons suivi les déplacements de 36 individus dans cinq fermes à l’aide de poudres fluorescentes. Les populations de M. musculus possèdent une différentiation génétique tant à l’échelle des fermes qu’à celle des hangars. Il y a une corrélation significative entre les distances génétiques et géographiques. Il n’y a aucune indication de déplacements passifs de M. musculus et les déplacements observés chez les 36 M. musculus à l’aide des poudres fluorescentes à l’intérieur des fermes sont de courte distance. Ces résultats appuient l’hypothèse 2,1. [ABSTRACT FROM AUTHOR]

Neonatal survival influences growth of unhunted populations of suburban white-tailed deer (Odocoileus virginianus (Zimmerman, 1780)). Understanding the interaction of habitat and survival may inform conservation efforts and studies of life history of cervids at high density. We chose two forest preserves representative of forests in suburban Chicago. We radio-marked 56 neonates (1999-2001) to investigate mortality and habitat use. Through 1 July, 21 of 29 (72%) neonates and 6 of 22 (27%) died mostly because of predation by coyotes (Canis latrans Say, 1823). Akaike’s information criterion suggested that optimal mark-recapture models of survival contained covariates reflecting differences by preserve and timing chosen to coincide with behavioral change from hiding to accompanying the doe. Survival was lower during early parturition (0.26-0.78) relative to the latter part (0.90-0.96). Early fawns (hiders) at one site had lower survival (0.26-0.29) than fawns at the other (0.78). Lower survival associated with larger home ranges, greater movement, and reduced understory cover, suggesting that hiding cover may mediate fawn survival in the presence of predators. Our study demonstrates spatial heterogeneity in population biology of suburban deer and suggests that site-specific differences may influence neonate survival in the face of coyote predation. La survie des nouveau-nés influence la croissance des populations suburbaines non chassées de cerfs de Virginie (Odocoileus virginianus (Zimmerman, 1780)). Une connaissance des interactions entre l’habitat et la survie pourrait consolider les efforts de conservation et les études du cycle biologique des cervidés aux fortes densités. Nous avons choisi deux réserves forestières représentatives des forêts de la région suburbaine de Chicago. Nous avons muni d’étiquettes radio 56 nouveau-nés (1999-2001) afin d’étudier la mortalité et l’utilisation de l’habitat. Durant la période qui va jusqu’au 1er juillet, 21 de 29 (72 %) nouveau-nés et 6 de 22 (27 %) sont morts principalement de prédation par les coyotes (Canis latrans Say, 1823). Le critère d’information d’Akaike indique que les modèles optimaux de marquage-recapture de la survie contiennent des covariables qui reflètent des différences reliées à la réserve et aussi le moment choisi pour le changement comportemental de la dissimulation à l’accompagnement de la biche. La survie est moindre durant la partie précoce de la mise bas (0,26-0,78) par rapport à la partie tardive (0,90-0,96). Les jeunes faons (les dissimulateurs) de l’un des sites ont une survie plus basse (0,26-0,29) que les faons de l’autre site (0,78). La survie réduite est associée aux domaines vitaux plus grands, aux déplacements plus importants et à une couverture réduite du sous-bois, ce qui laisse croire que la couverture disponible pour la dissimulation peut expliquer la survie des faons en présence de prédateurs. Notre étude démontre l’existence d’hétérogénéité spatiale dans la biologie des populations suburbaines de cerfs et indique que des différences spécifiques aux sites peuvent influencer la survie des nouveau-nés en présence de prédation par les coyotes. [ABSTRACT FROM AUTHOR]

Many populations of lake sturgeon (Acipenser fulvescens Rafinesque, 1817) are below historic population sizes, and migration barriers have likely contributed to some of these population declines. Dams and natural barriers can potentially isolate populations along a single river and can have a strong effect on the ability of lake sturgeon to move upstream. Along the Namakan River in Ontario, Canada, a series of natural rapids could impede movement of lake sturgeon and fragment the sturgeon into several small populations. Movement patterns of lake sturgeon were assessed using genetics and acoustic telemetry. Samples were collected from five locations along the river, each one separated by a rapid or falls, and were analyzed at 12 microsatellite loci. No significant genetic differences were observed between the five segments, indicating that the groups of lake sturgeon are not isolated. There were no significant differences in genetic diversity between the five segments. Therefore, migration is likely occurring both upstream and downstream. The acoustic telemetry study also confirmed bidirectional movement of adult fish. The natural rapids and falls along the Namakan River do not appear to be a significant barrier to movement of lake sturgeon, and the lake sturgeon within this river represent a single population. Plusieurs populations d’esturgeons jaunes (Acipenser fulvescens Rafinesque, 1817) se retrouvent à des densités inférieures à celles du passé et il est vraisemblable que des barrières à la migration aient contribué au déclin de certaines de ces populations. Les barrages et les barrières naturelles peuvent potentiellement isoler les populations le long du cours d’une même rivière et affecter fortement la capacité des esturgeons jaunes à se déplacer vers l’amont. Le long de la rivière Namakan en Ontario, Canada, une série de rapides naturels pourrait entraver le déplacement des esturgeons jaunes et les séparer en plusieurs petites populations. Nous avons évalué les patrons de déplacement des esturgeons jaunes à l’aide de la génétique et de la télémétrie acoustique. Nous avons prélevé des esturgeons à cinq sites sur le cours de la rivière, chacun séparé par un rapide ou une chute, et procédé à une analyse génétique de 12 locus microsatellites. Il n’y a aucune différence génétique significative entre les cinq segments, ce qui indique que les groupes d’esturgeons jaunes ne sont pas isolés. Il n’y a pas non plus de différence significative de diversité génétique entre les cinq segments. Il se produit donc vraisemblablement de la migration tant vers l’amont que vers l’aval. La télémétrie acoustique confirme aussi les déplacements des poissons adultes dans les deux directions. Les rapides naturels et les chutes le long de la Namakan ne semblent pas constituer des barrières significatives aux déplacements des esturgeons jaunes qui forment donc une seule population dans cette rivière. [ABSTRACT FROM AUTHOR]

The diet of the Barn Owl (Tyto alba (Scopoli, 1769)) was studied over an 8-year period in the Jura mountains of France, during two population surges of its main rodent prey (common voles, Microtus arvalis (Pallas, 1778), and European water voles, Arvicola terrestris (L.,1758)), allowing us to test whether T. alba is an opportunistic predator as is often cited in the literature or exhibits more complex patterns of prey selection as is reported in arid environments. Small mammals were sampled by trapping and index methods. We observed (i) significant correlations between the proportions of A. terrestris, M. arvalis, and woodland rodents in the diet and their respective densities in the field; (ii) interactions between populations of A. terrestris and M. arvalis, indicating that the proportion of each species in diet was affected by the density of the other; (iii) proportions of red-toothed shrews (genus Sorex (L., 1758)) in the diet did not correlate with their abundance in the field, indicating that those species were likely to be preyed upon when others were no longer available. This confirms that T. alba is generally opportunistic; however, prey selection of a focal species (e.g., Sorex spp., grassland species) can be affected by the density or availability of the other prey species. Nous avons étudié le régime alimentaire de l’effraie des clochers (Tyto alba (Scopoli, 1769)), sur une période de 8 années dans les montagnes du Jura en France, durant deux pics démographiques d’abondance des principaux rongeurs qui leur servent de proies (les campagnols des champs, Microtus arvalis (Pallas, 1778), et les campagnols terrestres, Arvicola terrestris (L., 1758)). Nous avons ainsi pu tester si T. alba est un prédateur opportuniste comme l’indique souvent la littérature ou si elle montre des patrons plus complexes de sélection des proies comme il a été observé dans les milieux arides. Les petits mammifères ont été échantillonnés par trappage et par méthodes indiciaires. Nous observons (i) des corrélations significatives entre les proportions d’A. terrestris, de M. arvalis et des rongeurs forestiers dans le régime alimentaire et leurs densités respectives en nature, (ii) des interactions entre les populations d’A. terrestris et de M. arvalis, ce qui indique que la proportion de chacune des espèces dans le régime est affectée par la densité de l’autre espèce et (iii) des proportions de musaraignes à dents rouges (genre Sorex (L., 1758)) dans le régime qui ne correspondent pas à leur abondance en nature, ce qui laisse croire que ces espèces sont utilisées lorsque les autres ne sont plus disponibles. Cela confirme que T. alba est généralement une opportuniste, mais que la sélection des proies d’une espèce ciblée particulière (par ex. les Sorex spp., des espèces de prairies) peut être affectée par la densité ou disponibilité des autres espèces de proies. [ABSTRACT FROM AUTHOR]

We studied the effect of a recolonizing wolf (Canis lupus L., 1758) population on a resident lynx (Lynx lynx (L., 1758)) population in south-central Sweden. Wolf and lynx share the same prey species, western roe deer (Capreolus capreolus (L., 1758)), and the size difference between the two species suggests a strong potential for interference competition. The spatial distributions of lynx family groups (n = 378) over four winters were not significantly affected by the increase in size and range of the wolf population. Survival of lynx kittens until 9 months of age did not differ significantly inside (54%; n = 37) and outside (62%; n = 42) wolf territories, and female lynx (n = 3) selected natal den sites (n = 19) in the same local area before and after wolf establishment. Furthermore, lynx home-range size (n = 42) did not increase as a result of presence of wolves and space use by female lynx (n = 3) was not affected by wolf establishment. We found no evidence of cleptoparasitism by wolves on roe deer killed by lynx. We conclude that the intensity of interference and exploitation competition between wolves and lynx was low. [ABSTRACT FROM AUTHOR]

We investigated the relation between temperature and diel activity patterns of Necromys lasiurus (Lund, 1841) in 10 sites of open vegetation (grassland fields) in the Cerrado (savanna-like vegetation) of central Brazil. We used live traps equipped with timing devices during two trapping sessions: in the end of the dry season (session 1, October 2001) and in the wet season (session 2, January-February 2002). Necromys lasiurus is basically a diurnal rodent with more pronounced crepuscular and nocturnal activity in the dry season than in the wet season. Only in the wet season did we detect significant between-gender differences, with males being less active than females in the first hours after sunrise but more active between 0900 and 1200. There was no significant activity-temperature relation in the dry season, but in the wet season, both genders showed a positive relation between ambient temperature and activity. Individuals might be avoiding hot midday hours in the end of the dry season to minimize time exposure to a physiologically stressful condition caused by the joint action of high temperatures and extremely low relative humidity (<15%). In the rainy season, the high relative humidity (80%-90%) might allow the animals to show a positive relation between activity and ambient temperature. [ABSTRACT FROM AUTHOR]

The hypothesis that patterns of habitat selection of greater horseshoe bats (Rhinolophus ferrumequinum (Schreber, 1774)) vary across seasons in a temperate deciduous forest was investigated. Variables associated with potentially important ecological factors for greater horseshoe bats (physical structure of shrub stratum, crown canopy, insect availability, lunar phase, and weather) were collected for different seasons, and 75 sampling sites were established in the Luotong Mountain Nature Reserve in northeast China. Insect abundance was highest in late summer and lowest in late autumn. Poisson generalized linear models showed that the activity of greater horseshoe bats was positively related to the height and density of shrub stratum in late summer, whereas the activity of greater horseshoe bats was associated with insect abundance in early and late autumn. During periods of intermediate prey abundance (early summer), the height and density of shrub stratum, as well as insect abundance, influenced the activity of greater horseshoe bats. Shrub stratum may provide shelter against predation for foraging greater horseshoe bats. These results support our prediction that there was a trade-off between importance of food and cover among seasons for foraging bats. These findings are useful for the conservation and management of greater horseshoe bats. [ABSTRACT FROM AUTHOR]

The taxonomic identity of the historical and current wolf (Canis lupus L., 1758 or Canis lycaon Schreber, 1775 or their hybrids) population in Minnesota (MN) and the Great Lakes region has been, and continues to be, controversial. So too does its legal status under the U.S. Endangered Species Act. This review summarizes the morphological and genetic information about that population and concludes that historically the MN population consisted of a gray wolf (C. lupus) in the west and an eastern type (Canis lupus lycaon or C. lycaon) in the east with intergrades or hybrids between the two in most of the state. After extirpation in much of its original MN range, the now-recovered population was infused with gray wolves from Ontario but still consists of hybrid lycaon × gray wolves, probably with higher content gray wolves in the west and higher content lycaon in the east but with most wolves morphologically appearing to be gray wolves. Because the current Wisconsin and Michigan wolf population was derived from MN wolves, they would be primarily hybrids as well. Future research should seek to relate genetic data with morphological measurements in MN wolves. In addition, attempts to breed coyotes (Canis latrans Say, 1823) with gray wolves in captivity would shed considerable light on the controversy over the origin and taxonomic identity of the newly proposed C. lycaon. [ABSTRACT FROM AUTHOR]

The introduction of alien species to islands by human activity can cause catastrophic consequences for small populations of island endemics. Hybridization between the endangered and endemic insular lizard Podarcis atrata (Boscá, 1916) from the Columbretes Islands (Mediterranean, Spain) and the common mainland lizard Podarcis hispanica (Steindachner, 1870) could potentially occur because mainland haplotypes have already been detected in the islands, the two species are closely genetically related, and the frequency of visitors to these islands is increasing. However, reproductive decisions of lizards are often mediated by species recognition mechanisms based on chemical cues. On the basis of this observation, even if some mainland P. hispanica lizards were introduced to the islands, interspecific recognition might make rare an eventual hybridization with the insular P. atrata. We examined interspecific chemical recognition between the insular P. atrata and the mainland P. hispanica. Our results showed that lizards of both sexes responded more strongly (i.e., directed a significantly higher number of tongue flicks) to scents of conspecific individuals than to scents of heterospecifics. Chemical recognition of conspecifics by endemic island P. atrata lizards may reduce the occurrence of hybridization with introduced mainland P. hispanica lizards and protect the insular gene pool. [ABSTRACT FROM AUTHOR]

The rodent Oligoryzomys longicaudatus (Bennett, 1832) (Rodentia, Cricetidae) inhabits southern forests of Argentina and Chile, a region severely affected by glaciations during the Pleistocene-Holocene periods. We evaluate here the diversity of the mitochondrial control region to characterize the genetic structure of this species from forests and bushy areas of seven populations from Argentina and four populations from Chile. Statistical analyses showed shallow haplotype trees and mismatch distributions compatible with recent range expansions. The presence of “private” haplotypes indicates that current levels of gene flow among populations of each country would be low to moderate. Significant differences in haplotype frequencies were detected between eastern and western populations, indicating that the Andes mountains would be an effective geographic barrier for gene flow despite the existing valleys that could act as corridors for dispersion. A single clade containing all the haplotypes was recovered in the phylogenetic trees, suggesting postglacial dispersion from a single refugium during the Last Glacial Maximum. The higher effective size and levels of polymorphism in populations from Chile suggest that the refugium was located in this country. The asymmetric gene flow from Chile to Argentina may reflect a recent colonization of the eastern populations. [ABSTRACT FROM AUTHOR]

The Fennoscandian arctic fox (Vulpes lagopus (L., 1758)) population is critically endangered, possibly because of increased interference competition from red foxes (Vulpes vulpes (L., 1758)) and fading cycles in microtine rodents, which cause food shortage. It is not known how these factors drive arctic fox population trends. To test their role in arctic fox decline, we developed a spatially explicit and individual-based model that allowed us to simulate fox interactions and food availability in a real landscape. A sensitivity analysis revealed that simulated arctic fox population size and den occupancy were strongly correlated with fecundity and mortality during the microtine crash phase, but also with red fox status. Model simulations suggested that arctic fox population trends depended on microtine cycles and that arctic fox distributions were restricted by red fox presence. We compared the model predictions with field data collected at Vindelfjällen, Sweden. The model recreated the observed arctic fox trend only with the inclusion of arctic fox avoidance of red fox home ranges. The results indicate that avoidance behaviours can affect population trends and hence that relatively small numbers of red foxes can have a strong negative impact on arctic fox population size and distribution. [ABSTRACT FROM AUTHOR]

Understanding haul-out behavior of ice-associated pinnipeds is essential for designing and interpreting population surveys and for assessing effects of potential changes in their ice environments. We used satellite-linked transmitters to obtain sequential information about location and haul-out state for Pacific walruses, Odobenus rosmarus divergens (Illiger, 1815), in the Bering Sea during April of 2004, 2005, and 2006. We used these data in a generalized mixed model of haul-out bout durations and a hierarchical Bayesian model of haul-out probabilities to assess factors related to walrus haul-out behavior, and provide the first predictive model of walrus haul-out behavior in sea ice habitat. Average haul-out bout duration was 9 h, but durations of haul-out bouts tended to increase with durations of preceding in-water bouts. On average, tagged walruses spent only about 17% of their time hauled out on sea ice. Probability of being hauled out decreased with wind speed, increased with temperature, and followed a diurnal cycle with the highest values in the evening. Our haul-out probability model can be used to estimate the proportion of the population that is unavailable for detection in spring surveys of Pacific walruses on sea ice. [ABSTRACT FROM AUTHOR]

Predators generate a “landscape of fear” within which prey can minimize the risk of predation by selecting low-risk areas. Depending on the spatial structure of this “landscape”, i.e., whether it is coarse- or fine-grained, prey may respond to increased risk by shifting their home ranges or by fine-scale redistributions within these ranges, respectively. We studied how wild boar (Sus scrofa L., 1758) responded to temporal changes in risk in hunted areas (risky habitat) surrounding a nature reserve (refuge habitat). Animals with home ranges “in contact” with the reserve during the low-risk season were the only ones to shift toward the refuge when the risk increased. These shifts occurred at two temporal scales in response to the increased risk during the daytime and during the hunting season. Whereas animals not influenced by the reserve found food and shelter in forest during the hunting season, shifts to the refuge area were detrimental to the rather scarce forest areas in the reserve. This confirms that spatiotemporal changes in risk are major drivers of animal distribution when predation strongly limits their fitness. Their response is, however, scale-dependent and reflects at the individual level the perceived structure of their “landscape of fear”. [ABSTRACT FROM AUTHOR]

For solitary carnivores a polygynous mating system should lead to predictable patterns in space-use dynamics. Females should be most influenced by resource distribution and abundance, whereas polygynous males should be strongly influenced by female spatial dynamics. We gathered mean annual home-range-size estimates for male and female bobcats (Lynx rufus (Schreber, 1777)) from previous studies to address variation in home-range size for this solitary, polygynous carnivore that ranges over much of North America. Mean annual home ranges for bobcats (171 males, 214 females) from 29 populations covering the entire north to south and east to west range demonstrated female home-range sizes varied more than an order of magnitude and that, on average, males maintained home ranges 1.65 times the size of females. Male home-range sizes scaled isometrically with female home-range sizes indicating that male bobcats increase their home-range size proportional to female home-range size. Using partial correlation analysis we also detected an inverse relationship between environmental productivity, estimated using the normalized difference vegetation index, and home-range size for females but not males. This study provides one of the few empirical assessments of how polygyny influences home-range dynamics for a wide-ranging carnivore. [ABSTRACT FROM AUTHOR]

Knowledge of movement patterns of white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) inhabiting landscapes intensively modified by agricultural systems is important to the present and future understanding of deer ecology. Little information exists regarding daily and seasonal movements of white-tailed deer in north-central South Dakota. Therefore, our goal was to determine movement patterns and home-range use of female white-tailed deer in north-central South Dakota. From January 2005 to January 2007, 29 adult (>18 months) and 13 yearling (8-18 months) white-tailed deer were monitored for movement using radiotelemetry. We collected 2822 locations, calculated 76 home ranges, and documented 50 seasonal movements. Mean migration distance between summer and winter home ranges was 19.4 km (SE = 2.0 km). Mean 95% home-range size was 10.2 km2 (SE = 1.2 km2, n = 27) during winter and 9.2 km2 (SE = 1.0 km2, n = 49) during summer. Ambient temperature appeared to be a primary cause of seasonal migration. Additionally, movements exhibited by white-tailed deer in north-central South Dakota were influenced by a highly fragmented landscape dominated by row crops and pasture or grassland. [ABSTRACT FROM AUTHOR]

Prey often exhibit reduced escape behavior on islands where predators are absent or scarce. Models of escape and refuge use predict that prey from populations having lower predation pressure have shortened flight initiation distance (FID; distance between a predator and a prey when escape begins), reduced distance fled and tendency to enter refuge, and shortened hiding time before emerging from refuge. By ourselves simulating approaching predators, we tested these predictions for two populations of the Balearic lizard, Podarcis lilfordi (Müller, 1927), on the islets of Rei (higher predation pressure) and Aire (lower) adjacent to Menorca. FID, distance fled, and hiding time were shorter and probability of entering refuge was lower on Aire than on Rei, confirming all predictions. All effect sizes were large, indicating major differences in antipredatory behavior between islets. These findings are consistent with data for other lizards on FID and limited data on distance fled and refuge entry. The effect of predation pressure on hiding time is a novel finding. Our results and those of previous studies suggest that relaxation of predation pressure leads to reduced natural selection for maintenance of antipredatory behavior at all stages of predator-prey interactions over a relatively short time span. [ABSTRACT FROM AUTHOR]

The guanaco (Lama guanicoe (Müller, 1776)) is a monomorphic polygynous mammal whose adult sex ratio is expected to be balanced or biased towards females. Remarkably male-biased sex ratios of adult guanacos are often estimated from road surveys. We analyzed the distribution of guanaco social groups recorded during road surveys in Patagonia, Argentina, to test the hypothesis that group assignation based upon behavioral traits is not unequivocal and can be biased by survey factors. Guanacos are organized into three social units (family groups, male groups, and solitary males) that are identified by their grouping behaviour. We recorded 992 guanaco groups, and estimated an adult sex ratio of 3.2 males/female. We used generalized additive models to test the null hypothesis that the probability of recording a group as a family group was constant. Alternatively, this probability could decrease when juvenile abundance and (or) detectability was low. The most parsimonious model showed that the probability of classifying a “family” group increased with date, and decreased with group size, distance to the observer, and time of day. Our results do not support the null hypothesis and suggest that road surveys are unsuitable to estimate reliably the social structure or sex ratio of guanaco populations. [ABSTRACT FROM AUTHOR]

For wildlife management and conservation biology, it is important to be able to estimate the status and distribution of animals and to monitor their population trends. In the Etosha National Park, Namibia, there is a lack of knowledge about numbers and distribution of spotted hyenas (Crocuta crocuta (Erxleben, 1777)) and factors regulating their population. To estimate hyena density and distribution, tape-recorded vocalizations (call-ups) were performed to attract hyenas in the central and eastern parts of Etosha. Eighty-five adult and subadult hyenas responded to the calls, with most of them responding in an area with high density of migratory ungulates, principally springbok (Antidorcas marsupialis (Zimmermann, 1780)), wildebeest (Connochaetes taurinus (Burchell, 1823)), and Burchell’s zebra (Equus burchelli (Gray, 1824)). These migratory species are the main prey of spotted hyenas in Etosha. There was a strong spatial relationship between hyena density and migratory prey biomass. Based on this mathematical correlation, I estimated 203 ± 79 hyenas, i.e., 2.7 ± 1.1 hyenas/100 km2, in the central and eastern parts of Etosha. Applying this correlation to the western part of the park, it was possible to estimate 339 ± 176 spotted hyenas, corresponding to an overall density of 2.1 ± 1.0 hyenas/100 km2, in the whole Etosha National Park. [ABSTRACT FROM AUTHOR]