Gustaf Samelius

Endoparasites in the feces of arctic foxes in a terrestrial ecosystem in Canada

Graphical abstract

Patterns of variation in reproductive parameters in Eurasian lynx (Lynx lynx).

Detailed knowledge of the variation in demographic rates is central for our ability to understand the evolution of life history strategies and population dynamics, and to plan for the conservation of endangered species. We studied variation in reproductive output of 61 radio-collared Eurasian lynx females in four Scandinavian study sites spanning a total of 223 lynx-years. Specifically, we examined how the breeding proportion and litter size varied among study areas and age classes (2-year-old vs. >2-year-old females). In general, the breeding proportion varied between age classes and study sites, whereas we did not detect such variation in litter size. The lack of differences in litter sizes among age classes is at odds with most findings in large mammals, and we argue that this is because the level of prenatal investment is relatively low in felids compared to their substantial levels of postnatal care.

Habitat Selection and Risk of Predation: Re-colonization by Lynx had Limited Impact on Habitat Selection by Roe Deer

Risk of predation is an evolutionary force that affects behaviors of virtually all animals. In this study, we examined how habitat selection by roe deer was affected by risk of predation by Eurasian lynx – the main predator of roe deer in Scandinavia. Specifically, we compared how habitat selection by roe deer varied (1) before and after lynx re-established in the study area and (2) in relation to habitat-specific risk of predation by lynx. All analyses were conducted at the spatial and temporal scales of home ranges and seasons. We did not find any evidence that roe deer avoided habitats in which the risk of predation by lynx was greatest and information-theoretic model selection showed that re-colonization by lynx had limited impact on habitat selection by roe deer despite lynx predation causing 65% of known mortalities after lynx re-colonized the area. Instead we found that habitat selection decreased when habitat availability increased for 2 of 5 habitat types (a pattern referred to as functional response in habitat selection). Limited impact of re-colonization by lynx on habitat selection by roe deer in this study differs from elk in North America altering both daily and seasonal patterns in habitat selection at the spatial scales of habitat patches and home ranges when wolves were reintroduced to Yellowstone National Park. Our study thus provides further evidence of the complexity by which animals respond to risk of predation and suggest that it may vary between ecosystems and predator-prey constellations.

Harmonizing circumpolar monitoring of Arctic fox: benefits, opportunities, challenges and recommendations

ABSTRACT The biodiversity working group of the Arctic Council has developed pan-Arctic biodiversity monitoring plans to improve our ability to detect, understand and report on long-term change in Arctic biodiversity. The Arctic fox (Vulpes lagopus) was identified as a target of future monitoring because of its circumpolar distribution, ecological importance and reliance on Arctic ecosystems. We provide the first exhaustive survey of contemporary Arctic fox monitoring programmes, describing 34 projects located in eight countries. Monitored populations covered equally the four climate zones of the species’ distribution, and there were large differences between populations in long-term trends, multi-annual fluctuations, diet composition, degree of competition with red fox and human interferences. Den density, number of active dens, number of breeding dens and litter size were assessed in almost all populations, while projects varied greatly with respect to monitoring of other variables indicative of population status, ecosystem state or ecosystem function. We review the benefits, opportunities and challenges to increased integration of monitoring projects. We argue that better harmonizing protocols of data collection and data management would allow new questions to be addressed while adding tremendous value to individual projects. However, despite many opportunities, challenges remain. We offer six recommendations that represent decisive progress toward a better integration of Arctic fox monitoring projects. Further, our work serves as a template that can be used to integrate monitoring efforts of other species, thereby providing a key step for future assessments of global biodiversity.

Components of population growth for Arctic foxes at a large Arctic goose colony: the relative contributions of adult survival and recruitment

ABSTRACT The abundance and distribution of animals often vary dramatically among years in Arctic environments. Such variation, in turn, is closely related to changes in food abundance and its effect on vital rates such as survival and recruitment. However, the relative importance of survival and recruitment to changes in population growth and how this varies with fluctuations in food abundance and climatic variation is poorly understood for most animals. The objective of this study was to examine how the relative importance of adult survival and recruitment to population change by Arctic foxes varies in relation to fluctuations in food abundance and climatic variation. Specifically, we used capture–recapture models to estimate how apparent adult survival and recruitment of Arctic foxes at a large Arctic goose colony varied in response to small mammal abundance, the numbers of two species of nesting geese and climate variation indexed by the Arctic Oscillation. Analyses of live capture data collected at Karrak Lake, Nunavut, Canada, from 2000 to 2015 showed that the population dynamics of Arctic foxes was driven largely by the pulsed dynamics in recruitment of foxes, whereas apparent survival of adult foxes was constant during the study. Recruitment fluctuated considerably among years and was correlated with fluctuations in small mammal abundance. Greater importance of recruitment to the population dynamics of Arctic foxes at our study site is characteristic of small and short-lived mammals.

Livestock depredation by large carnivores in the South Gobi, Mongolia

Abstract Context. Livestock depredation is a major conservation challenge around the world, causing considerable economical losses to pastoral communities and often result in retaliatory killing. In Mongolia, livestock depredation rates are thought to be increasing due to changes in pastoral practices and the transformation of wild habitats into pasture lands. Few studies have examined the interactions between humans and carnivores and even fewer have considered how recent changes in pastoral practices may affect depredation rates. Aim. This study aimed to assess the influence of herding practices on self-reported livestock losses to snow leopards and wolves in two communities in South Gobi, Mongolia. Methods. In total, 144 herder households were interviewed and an information-theoretic approach was used to analyse the factors influencing self-reported livestock losses to snow leopards and wolves. Key results. The majority of self-reported losses to both snow leopards and wolves occurred when herds were left unattended in the pastures. The economic loss associated with livestock losses to snow leopards and wolves amounted to an average loss of US

Spatial and temporal variation in natal dispersal by Eurasian lynx in Scandinavia

825 per herder and year. The number of livestock owned by a household and the frequency of shifting campsite had the strongest influence on livestock losses to snow leopards and wolves. Other determinants of livestock losses included frequency of visiting the soum (county) centre. Implications. On the basis of the findings, we make recommendations for mitigating the conflict with large carnivores, with focus on guiding future herding practices.