GPS Telemetry Data Research Articles

The Use of GPS Telemetry Data to Study Parturition, Den Location and Occupancy in the Brown Hyaena

Inferences about space use, activity and reproduction require an understanding of the behavioural processes that influence animal movements. Large volumes of movement data derived from GPS telemetry devices offer the opportunity to analyse animal behaviour on a very fine scale. GPS and satellite collars were fitted to female brown hyaenas (Parahyaenabrunnea) as part of a long-term monitoring study in southwestern Namibia. The date of parturition was determined by comparing changes in movement data and successful GPS positioning attempts. Distances moved on the day of parturition dropped to zero and frequent, unsuccessful GPS positioning attempts on the same day indicated locations in underground dens. Daily distances moved pre-partum, during parturition and post-partum differed significantly and reflected behavioural changes that can be monitored and used to draw inferences about the reproductive state of female brown hyaenas. The main predictors for den occupancy were the age of cubs, distance to closest food source and individual den. Mean occupancy over the entire denning period was 23 days, indicating that brown hyaenas readily move between dens, but individual breeding females showed den site fidelity. Therefore, GPS telemetry is a useful tool to accurately determine parturition in brown hyaenas to draw inferences about den occupancy.

Fine- and coarse-scale movements and habitat use by Wood Turtles (Glyptemys insculpta) based on probabilistic modeling of radiotelemetry and GPS-telemetry data

Understanding animal movement and habitat use is critical for the delineation of habitat requiring protection for species at risk. Defining critical habitat requires studies with observations at a fine enough scale to reflect how animals use and move among habitats and include enough individuals to generalize findings to the population. We present results of a multiyear study on 48 adult Wood Turtles (Glyptemys insculpta (Le Conte, 1830)) from two different populations monitored with low-frequency radiotelemetry and high-frequency GPS telemetry. Results demonstrated the propensity for conventional radiotelemetry to underestimate cumulative distances moved and overestimate the amount of habitat used by Wood Turtles. Together the two data sets demonstrate the propensity for Wood Turtles to remain in close proximity to the river and that some differences in habitat use occur between the sexes; males tended to move parallel to the river, whereas females moved perpendicular to the river. The GPS-telemetry data provided a robust spatiotemporal data set that provided a better understanding of frequently used habitat types and features. Overall, study results suggest that currently delineated areas of protected habitat are likely to be effective in conserving these two populations and provides significantly improved, spatially explicit knowledge that can be used to inform further mitigation efforts if necessary.

Are all data types and connectivity models created equal? Validating common connectivity approaches with dispersal data

AbstractAimThere is enormous interest in applying connectivity modelling to resistance surfaces for identifying corridors for conservation action. However, the multiple analytical approaches used to estimate resistance surfaces and predict connectivity across resistance surfaces have not been rigorously compared, and it is unclear what methods provide the best inferences about population connectivity. Using a large empirical data set on puma (Puma concolor), we are the first to compare several of the most common approaches for estimating resistance and modelling connectivity and validate them with dispersal data.LocationSouthern California, USA.MethodsWe estimate resistance using presence‐only data, GPS telemetry data from puma home ranges and genetic data using a variety of analytical methods. We model connectivity with cost distance and circuit theory algorithms. We then measure the ability of each data type and connectivity algorithm to capture GPS telemetry points of dispersing pumas.ResultsWe found that resource selection functions based on GPS telemetry points and paths outperformed species distribution models when applied using cost distance connectivity algorithms. Point and path selection functions were not statistically different in their performance, but point selection functions were more sensitive to the transformation used to convert relative probability of use to resistance. Point and path selection functions and landscape genetics outperformed other methods when applied with cost distance; no methods outperformed one another with circuit theory.Main conclusionsWe conclude that path or point selection functions, or landscape genetic models, should be used to estimate landscape resistance for wildlife. In cases where resource limitations prohibit the collection of GPS collar or genetic data, our results suggest that species distribution models, while weaker, may still be sufficient for resistance estimation. We recommend the use of cost distance‐based approaches, such as least‐cost corridors and resistant kernels, for estimating connectivity and identifying functional corridors for terrestrial wildlife.

Improving estimation of flight altitude in wildlife telemetry studies

Abstract Altitude measurements from wildlife tracking devices, combined with elevation data, are commonly used to estimate the flight altitude of volant animals. However, these data often include measurement error. Understanding this error may improve estimation of flight altitude and benefit applied ecology. There are a number of different approaches that have been used to address this measurement error. These include filtering based on GPS data, filtering based on behaviour of the study species, and use of state‐space models to correct measurement error. The effectiveness of these approaches is highly variable. Recent studies have based inference of flight altitude on misunderstandings about avian natural history and technical or analytical tools. In this Commentary, we discuss these misunderstandings and suggest alternative strategies both to resolve some of these issues and to improve estimation of flight altitude. These strategies also can be applied to other measures derived from telemetry data. Synthesis and applications. Our Commentary is intended to clarify and improve upon some of the assumptions made when estimating flight altitude and, more broadly, when using GPS telemetry data. We also suggest best practices for identifying flight behaviour, addressing GPS error, and using flight altitudes to estimate collision risk with anthropogenic structures. Addressing the issues we describe would help improve estimates of flight altitude and advance understanding of the treatment of error in wildlife telemetry studies.

Do large carnivores use riparian zones? Ecological implications for forest management

As part of forest management guidelines, most North American jurisdictions require the preservation of forested areas adjacent to streams and rivers (i.e. riparian zones). Forested buffer strips with restrictions on timber harvest and road-building (i.e. riparian buffer zones) were originally implemented to protect aquatic functions and resources. Riparian buffer zones now also target terrestrial habitats and wildlife. Even so, forestry managers who implement guidelines seldom consider the value of riparian zones (RZs) for large carnivores, partly due to a lack of data available. In the present study, our objective was to understand the role of riparian zones and riparian buffer zones for large carnivores in managed boreal forests. We used nine years of GPS telemetry data (2007–2015) from radio collared grizzly bears (Ursus arctos) in the Kakwa region of west-central Alberta, Canada to quantify both the use (i.e. the amount of time grizzly bears spend in RZs) and selection (i.e. use in relation to the available riparian habitat) of RZs. We examined the effects of season, sex, distance class (0–30 or 30–60m from streams and rivers), and the surrounding forest (harvested versus non-harvested) on use and selection of RZs. We found grizzly bears spent 19.1% of their time within 60meters from streams and rivers. Selection of RZs declined relative to the distance from streams and rivers (10.8% within 0–30m and 8.4% within 30–60m). During summer, grizzly bears selected RZs in harvested areas and avoided them in non-harvested areas. There was no difference in selection of RZs in harvested areas between males and females; however, in non-harvested areas, females avoided RZs and selected RZs less compared to males. These results, particularly the selection of RZs in harvested areas where RZs consist mostly of riparian buffer zones, suggest that riparian buffers provide valuable grizzly bear habitat in multiple-use landscapes. Forest management practices can support grizzly bear habitat conservation efforts by implementing riparian buffer zones in identified grizzly bear habitat and considering grizzly bear habitat use of RZs and riparian buffers as one component of riparian zone management.

Counterintuitive roles of experience and weather on migratory performance

ABSTRACT Migration allows animals to live in resource-rich but seasonally variable environments. Because of the costs of migration, there is selective pressure to capitalize on variation in weather to optimize migratory performance. To test the degree to which migratory performance (defined as speed of migration) of Golden Eagles (Aquila chrysaetos) was determined by age- and season-specific responses to variation in weather, we analyzed 1,863 daily tracks (n = 83 migrant eagles) and 8,047 hourly tracks (n = 83) based on 15 min GPS telemetry data from Golden Eagles and 277 hourly tracks based on 30 s data (n = 37). Spring migrant eagles traveled 139.75 ± 82.19 km day−1 (mean ± SE; n = 57) and 25.59 ± 11.75 km hr−1 (n = 55). Autumn migrant eagles traveled 99.14 ± 59.98 km day−1 (n = 26) and 22.18 ± 9.18 km hr−1 (n = 28). Weather during migration varied by season and by age class. During spring, best-supported daily and hourly models of 15 min data suggested that migratory performance was influenced most st...

Human recreation affects spatio-temporal habitat use patterns in red deer (Cervus elaphus).

The rapid spread and diversification of outdoor recreation can impact on wildlife in various ways, often leading to the avoidance of disturbed habitats. To mitigate human-wildlife conflicts, spatial zonation schemes can be implemented to separate human activities from key wildlife habitats, e.g., by designating undisturbed wildlife refuges or areas with some level of restriction to human recreation and land use. However, mitigation practice rarely considers temporal differences in human-wildlife interactions. We used GPS telemetry data from 15 red deer to study the seasonal (winter vs. summer) and diurnal (day vs. night) variation in recreation effects on habitat use in a study region in south-western Germany where a spatial zonation scheme has been established. Our study aimed to determine if recreation infrastructure and spatial zonation affected red deer habitat use and whether these effects varied daily or seasonally. Recreation infrastructure did not affect home range selection in the study area, but strongly determined habitat use within the home range. The spatial zonation scheme was reflected in both of these two levels of habitat selection, with refuges and core areas being more frequently used than the border zones. Habitat use differed significantly between day and night in both seasons. Both summer and winter recreation trails, and nearby foraging habitats, were avoided during day, whereas a positive association was found during night. We conclude that human recreation has an effect on red deer habitat use, and when designing mitigation measures daily and seasonal variation in human-wildlife interactions should be taken into account. We advocate using spatial zonation in conjunction with temporal restrictions (i.e., banning nocturnal recreation activities) and the creation of suitable foraging habitats away from recreation trails.

Winter sleep with room service: denning behaviour of brown bears with access to anthropogenic food

AbstractLarge quantities of food subsidies provided by humans to animal communities have the potential to change a variety of animal life traits, including denning behaviour of facultative hibernators like bears. Brown bears Ursus arctos regularly use anthropogenic food, but it has remained unclear if human food subsidies affect their hibernation and denning behaviour, despite the consequences this could have for bear interactions with humans and other species. We studied denning behaviour of European brown bears in Slovenia, where intensive supplemental feeding with corn is practiced throughout the year, including winter. We used GPS telemetry data to locate den sites and to monitor bear denning chronology. We conducted a meta‐analysis to compare our results with other bear populations across Europe, Asia and North America. A consistent relationship between latitude and time spent denning was observed for male and female brown bears across the species’ range (for each degree of latitude northwards, denning period increased for 3.1 days), and males on average denned 10.3 days longer than females throughout the latitudinal gradient. However, our study area deviated strongly from regions where supplemental feeding was not practiced. In Slovenia, denning period averaged 82 days for females and 57 days for males, which was 45 and 56% shorter compared to the time predicted for this latitude, respectively. We also observed regular den abandonments (61% of bears abandoned dens, on average 1.9 times per winter). During the winter period bears increased use of supplemental feeding sites for 61% compared to the non‐denning period. We conclude that the availability of anthropogenic food is an important driver of denning behaviour in brown bears. Reduction in the denning period increases the potential for bear interactions with other species, including humans, and we highlight possible management and ecological implications of this human‐caused perturbation to denning behaviour of wild ursids.

Habitat associations in a recolonizing, low‐density black bear population

AbstractAmerican black bears are closely associated with forest habitat. They were nearly extirpated from the Central Interior Highlands, United States, in the early twentieth century, but have recolonized this part of the range since the 1960s. Due to lower population densities (as a result of recent recolonization), we hypothesized that bears in this region would show strong associations with forest habitat at both the home range and landscape scale. To test this, we analyzed hair snare and GPS telemetry data from five sampling grids with a combined spatial capture–recapture and resource selection function model to investigate individual space use within home ranges and landscape scale variation in density of black bears in the southern Missouri part of the Interior Highlands. We performed a linear discriminant analysis to identify habitat correlates of black bear density. We found that at the home range level, bears selected for more forested habitat and steeper slopes. Black bear density varied among sampling grids from 0.842 to 10.248 individuals/100 km2 which is at the low end of the spectrum of reported black bear densities. There were no clear habitat correlates for among‐grid variation in density, but in the three higher‐density grids, density declined with increasing forest cover and increasing distance from human settlements. This suggests that the bear populations benefited from more heterogeneous habitat and that rural settlements may represent food resources. Exploiting these anthropogenic resources could be facilitated by the fact that bears in our study were not hunted and were viewed as a novelty rather than a nuisance, which may lead to low perceived risk from anthropogenic sources. Our results highlight the need to interpret habitat associations of American black bears not only at local scales but also in the landscape context.

Diel movement patterns influence daily variation in wolf kill rates on moose

Abstract Variation in predation can have important consequences for predators and prey, but little is known about associated mechanisms. Diel interactions between predators and prey are commonly assumed to be influenced by movement speeds of both predators and prey individuals, sensu the ideal gas model, but the influencing factors of diel predation dynamics have yet to be empirically examined. In this study, we apply principles of the ideal gas model to predict diel variation in kill frequency of moose (Alces alces) by wolves (Canis lupus) in northern Ontario, Canada based on GPS radio‐telemetry data combined with field verification of kills. We used GPS telemetry data from wolves and moose combined with a unique data set on the diel pattern of wolf kills to test whether predator movement rate, prey movement rate, and ambient light condition influence diel variation in kill rates of wolves on moose. Our results indicate that the kill rate between wolves and moose was principally related to the effective movement rate of predators and prey, as predicted by the ideal gas model. We found little evidence that light conditions had any effect on kill rates, but rather the majority of kill rate variation corresponded to wolf movement rate, which was over an order of magnitude higher than that of moose.

Changes in habitat use and distribution of mouflon in the Kahuku Unit of Hawai‘i Volcanoes National Park

European mouflon sheep (Ovis gmelini musimon) were introduced to Kahuku Ranch on Hawai‘i Island in 1968 and 1974 for trophy hunting and have been detrimental to the native ecosystem by trampling, bark stripping, and browsing vegetation. In 2003, Hawai‘i Volcanoes National Park acquired Kahuku Ranch and managers began removing mouflon. The objective of this project was to determine whether hunting has changed the distribution of mouflon in Kahuku, to better understand mouflon behaviour and to expedite eradication efforts. Locations from hunting and GPS telemetry data during 2007–14 were used to determine the effect of hunting on mouflon distribution by examining distance to roads and habitat use. Mouflon seemed to avoid roads after hunting pressure increased and their distribution within vegetation types changed over time. Mouflon without hunting pressure were detected in native shrub habitat in 68% of all observations. Hunted mouflon were encountered less in native shrub habitat and more in other habitats including open forest, closed forest, and areas with no vegetation. These changes suggest that hunting has influenced the distribution of mouflon over time away from native shrub and into other vegetation types where they may be more difficult to control.

Assessing Movements of Brushtail Possums (Trichosurus vulpecula) in Relation to Depopulated Buffer Zones for the Management of Wildlife Tuberculosis in New Zealand.

In New Zealand, managing the threat of bovine tuberculosis (TB) to livestock includes population reduction of potentially infectious wildlife, primarily the brushtail possum (Trichosurus vulpecula). Population control is often targeted on forested buffer zones adjacent to farmland, in order to limit movements of possums across the buffer and reduce the risk of disease transmission to livestock. To assess the effectiveness of buffers in protecting livestock we analysed GPS telemetry data from possums located in untreated forest adjacent to buffers, and used these data to characterise patterns of movement that could lead to possums reaching farmland during the season when most dispersal occurs. Analyses of movement data showed that the direction of dispersal by sub-adult and adult possums and the extent of long exploratory movements were not biased toward forest buffers, even though these provided vacant habitat as suitable for possums as untreated forest. Instead, dispersal and exploratory movements were uncommon even for sub-adult possums and such events typically lasted <10 days. Dispersing possums settled predominantly in river valleys. A simulation model was developed for the 3-6-month dispersal season; it demonstrated a probability of <0.001 that an infected possum, originating from a low-density population with low disease prevalence in untreated forest, would move across 3 km of recently controlled forest buffer to reach farmland. Our results indicate short-term reduction in the risk of TB transmission from possums to livestock in New Zealand by the use of depopulated buffer zones, while acknowledging that the threat of disease spread from untreated forest is likely to increase over time as possum population density and, potentially, TB prevalence among those possums, increase in the buffer zone.

From high voltage (300 kV) to higher voltage (420 kV) power lines: reindeer avoid construction activities

Demands for increased energy production have initiated several new high-voltage power line projects, of which hundreds of km will traverse reindeer (Rangifer tarandus tarandus) habitat in central and northern parts of Scandinavia. We investigated area use of semidomesticated reindeer in the Essand reindeer district’s summer range (Norway) in connection with a new 420 kV power line built in 2008/2009 to replace an existing 300 kV line. We used 6 years (2008–2013) of GPS telemetry data from 5 to 22 female reindeer per season. During the construction period compared to the period before and after construction, predicted probability of use decreased on average 10 % within areas 6 km from the central infrastructure for the calving period, about 12 % within 3.5 km in summer and close to 13 % within 3.5 km in autumn. In the calving period prior to construction, as well as the calving period, summer and autumn for the years after construction, use of areas close to the infrastructure did not deviate from random. Resource selection functions showed significant effects of construction work, habitat quality, elevation and aspect on the area use of reindeer. We found no support for the hypothesis that power lines have negative effects on reindeer area use, independent of associated human activity during construction. Mitigation measures should focus on both the construction period of power lines, minimizing construction work when adjacent areas are utilized by reindeer, as well as keeping human activity to a minimum during operative years.

Structural habitat predicts functional dispersal habitat of a large carnivore: how leopards change spots.

Natal dispersal promotes inter-population linkage, and is key to spatial distribution of populations. Degradation of suitable landscape structures beyond the specific threshold of an individual's ability to disperse can therefore lead to disruption of functional landscape connectivity and impact metapopulation function. Because it ignores behavioral responses of individuals, structural connectivity is easier to assess than functional connectivity and is often used as a surrogate for landscape connectivity modeling. However using structural resource selection models as surrogate for modeling functional connectivity through dispersal could be erroneous. We tested how well a second-order resource selection function (RSF) models (structural connectivity), based on GPS telemetry data from resident adult leopard (Panthera pardus L.), could predict subadult habitat use during dispersal (functional connectivity). We created eight non-exclusive subsets of the subadult data based on differing definitions of dispersal to assess the predictive ability of our adult-based RSF model extrapolated over a broader landscape. Dispersing leopards used habitats in accordance with adult selection patterns, regardless of the definition of dispersal considered. We demonstrate that, for a wide-ranging apex carnivore, functional connectivity through natal dispersal corresponds to structural connectivity as modeled by a second-order RSF. Mapping of the adult-based habitat classes provides direct visualization of the potential linkages between populations, without the need to model paths between a priori starting and destination points. The use of such landscape scale RSFs may provide insight into predicting suitable dispersal habitat peninsulas in human-dominated landscapes where mitigation of human-wildlife conflict should be focused. We recommend the use of second-order RSFs for landscape conservation planning and propose a similar approach to the conservation of other wide-ranging large carnivore species where landscape-scale resource selection data already exist.

Social structure and space use of Amur tigers (Panthera tigris altaica) in Southern Russian Far East based on GPS telemetry data.

To better understand the spatial structure of Amur tigers (Panthera tigris altaica) at the southern edge of their range we fitted 14 tigers (6♀♀ and 8♂♂) with 15 GPS-Argos collars between 2008 and 2011 in 2 study sites: the Ussuriskii Reserve of southern Sikhote-Alin and the Land of the Leopard National Park in southwest Primorye, Russian Far East. Fixed kernel estimates of male home ranges were larger than those of female home ranges (P < 0.05 [mean 95% fixed kernel(♀) = 401 ± 205 km(2) ; mean 95% fixed kernel(♂) = 778 ± 267 km(2)]). The home range size of females varied greatly, but on average was similar to estimates derived from earlier work further north. Low overlap of adjacent home ranges suggested that females retained exclusive territories. Real core areas of females overlapped only slightly, and remained stable over multiple years. The home ranges of adult males were smaller than those of males to the north, and in contrast to previous studies, high overlap among males indicated the absence of territoriality. Nonetheless, real core areas of males did not overlap, suggesting some spatial separation. In comparison to other tiger populations and other areas of the Russian Far East, the sex ratio in our 2 study areas was highly skewed towards males. We believe this skewed sex ratio resulted in the dissolution of territoriality of males due to an inability to defend individual females, with males resorting to scramble competition for mates. Continued monitoring of these sites to determine whether shifts in the sex ratio might result in a return to male territoriality would provide confirmation of our tentative hypothesis.

Revealing unexpected uses of space by wintering Aquila pomarina: how does satellite telemetry identify behaviour at different scales?

Little is understood about the dispersion and movements of Palaearctic migrant raptors while wintering in southern Africa. The high temporal and spatial resolution of GPS telemetry data provided the opportunity to describe how space is used by one such migratory raptor in its wintering range, the lesser spotted eagle Aquila pomarina. Kernel density estimation was used to map the distribution of three individuals at various spatial scales. In addition to their extremely large overall wintering range (up to 112 000 km2), three finer levels of spatial concentration were identified: favoured activity zones where the birds spent much of the winter, smaller core areas to which the birds returned each year, and tiny intensive foraging clusters. Philopatry was demonstrated by one bird which revisited core areas over eight wintering seasons. The same core areas, particularly the Waterberg, Grootfontein (Namibia) and the eastern and western sides of the Okavango Delta (Botswana), were visited by two other eagles in 2012/2013, although not simultaneously. Such results potentially provide important information on areas where conservation activities might be focused to mitigate human degradation of habitat.

Mapping migratory flyways in Asia using dynamic Brownian bridge movement models.

BackgroundIdentifying movement routes and stopover sites is necessary for developing effective management and conservation strategies for migratory animals. In the case of migratory birds, a collection of migration routes, known as a flyway, is often hundreds to thousands of kilometers long and can extend across political boundaries. Flyways encompass the entire geographic range between the breeding and non-breeding areas of a population, species, or a group of species, and they provide spatial frameworks for management and conservation across international borders. Existing flyway maps are largely qualitative accounts based on band returns and survey data rather than observed movement routes. In this study, we use satellite and GPS telemetry data and dynamic Brownian bridge movement models to build upon existing maps and describe waterfowl space use probabilistically in the Central Asian and East Asian-Australasian Flyways.ResultsOur approach provided new information on migratory routes that was not easily attainable with existing methods to describe flyways. Utilization distributions from dynamic Brownian bridge movement models identified key staging and stopover sites, migration corridors and general flyway outlines in the Central Asian and East Asian-Australasian Flyways. A map of space use from ruddy shelducks depicted two separate movement corridors within the Central Asian Flyway, likely representing two distinct populations that show relatively strong connectivity between breeding and wintering areas. Bar-headed geese marked at seven locations in the Central Asian Flyway showed heaviest use at several stopover sites in the same general region of high-elevation lakes along the eastern Qinghai-Tibetan Plateau. Our analysis of data from multiple Anatidae species marked at sites throughout Asia highlighted major movement corridors across species and confirmed that the Central Asian and East Asian-Australasian Flyways were spatially distinct.ConclusionsThe dynamic Brownian bridge movement model improves our understanding of flyways by estimating relative use of regions in the flyway while providing detailed, quantitative information on migration timing and population connectivity including uncertainty between locations. This model effectively quantifies the relative importance of different migration corridors and stopover sites and may help prioritize specific areas in flyways for conservation of waterbird populations.Electronic supplementary materialThe online version of this article (doi:10.1186/s40462-015-0029-6) contains supplementary material, which is available to authorized users.

LiDAR Remote Sensing of Forest Structure and GPS Telemetry Data Provide Insights on Winter Habitat Selection of European Roe Deer

The combination of GPS-Telemetry and resource selection functions is widely used to analyze animal habitat selection. Rapid large-scale assessment of vegetation structure allows bridging the requirements of habitat selection studies on grain size and extent, particularly in forest habitats. For roe deer, the cold period in winter forces individuals to optimize their trade off in searching for food and shelter. We analyzed the winter habitat selection of roe deer (Capreolus capreolus) in a montane forest landscape combining estimates of vegetation cover in three different height strata, derived from high resolution airborne Laser-scanning (LiDAR, Light detection and ranging), and activity data from GPS telemetry. Specifically, we tested the influence of temperature, snow height, and wind speed on site selection, differentiating between active and resting animals using mixed-effects conditional logistic regression models in a case-control design. Site selection was best explained by temperature deviations from hourly means, snow height, and activity status of the animals. Roe deer tended to use forests of high canopy cover more frequently with decreasing temperature, and when snow height exceeded 0.6 m. Active animals preferred lower canopy cover, but higher understory cover. Our approach demonstrates the potential of LiDAR measures for studying fine scale habitat selection in complex three-dimensional habitats, such as forests.

Thresholds in the capacity of boreal caribou to cope with cumulative disturbances: Evidence from space use patterns

Boreal caribou, an ecotype of woodland caribou (Rangifer tarandus caribou), are closely associated with the boreal forest, which has been significantly modified by anthropogenic activities over the last century. The species’ response to disturbances has been extensively researched – a reflection of the importance of habitat loss in the decline of boreal caribou. We investigated how female caribou cope with disturbances using GPS telemetry data collected on 48 females in a highly managed landscape in Québec, Canada, between 2004 and 2010, using home-range size as a proxy of caribou space use behaviour. Individuals were found to expand their home ranges as the amount of disturbances in their habitat increased, up to a point where further increase caused home range contraction. The density of major roads and the proportion of clearcuts had an important impact on space use throughout the whole year, but the impact of roads was particularly important during calving, summer and rut, while the impact of clearcuts prevailed in spring, early and late winter. Furthermore, we found that a more convoluted shape of cutblocks amplified the effect of clearcuts on caribou space use. These non-linear responses suggest that there is a limit to the adaptability of caribou in coping with anthropogenic disturbances. Although home range expansion could affect survival through the use of unknown habitats, individuals confined in smaller home ranges could be forced into an ecological trap and be more easily detected by predators, making current disturbance levels in the boreal forest and their cumulative amount in the landscape a major issue for the conservation of these boreal caribou populations.

Eurasian lynx hunting red deer: is there an influence of a winter enclosure system?

As in several Central European areas, in the Bohemian Forest Ecosystem (Germany and the Czech Republic), fenced feeding enclosures are used for the winter management of red deer (Cervus elaphus), which is an important component of the Eurasian lynx’s (Lynx lynx) winter diet. Using GPS telemetry data, we tested whether (1) lynx hunted red deer mainly selecting for high prey densities and environmental characteristics like a good level of habitat heterogeneity, independently of the enclosures’ presence; (2) enclosures attracted lynx and (3) positively influenced their predation on red deer, being predictable and abundant prey sources throughout the winter; or (4) extremely high deer densities inside the enclosures rather negatively influenced lynx predation on this species. We first compared lynx space usage and predation on red deer inside and outside the enclosures. Then, we investigated the effects of the environment, prey densities and the enclosure distance for the area outside of enclosures. Prey densities positively influenced lynx space usage, whilst the probability of predation on red deer was highest at medium to low red deer densities. Habitat heterogeneity and terrain ruggedness influenced both lynx space usage and probability of predation on red deer. Regarding the effect of enclosures, the ratio “area used during night vs. daytime” was larger by a factor of 2 inside compared to outside enclosures, and the probability of predation on red deer was three times higher inside rather than outside of enclosures; however, these differences were not statistically significant, suggesting that the influence of the enclosures is not very pronounced.