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Rabies occurs throughout the Arctic, representing an ongoing public health concern for residents of northern communities. The Arctic fox (Vulpes lagopus) is the main reservoir of the Arctic rabies virus variant, yet little is known about the epidemiology of Arctic rabies, such as the ecological mechanisms driving where and when epizootics in fox populations occur. In this study, we provide the first portrait of the spatio‐temporal spread of rabies across northern Canada. We also explore the impact of seasonal and multiannual dynamics in Arctic fox populations and climatic factors on rabies transmission dynamics. We analysed data on rabies cases collected through passive surveillance systems in the Yukon, Northwest Territories, Nunavut, Nunavik and Labrador from 1953 to 2014. In addition, we analysed a large and unique database of trapped foxes tested for rabies in the Northwest Territories and Nunavut from 1974 to 1984 as part of active surveillance studies. Rabies cases occurred in all Arctic regions of Canada and were relatively synchronous among foxes and dogs (Canis familiaris). This study highlights the spread of Arctic rabies virus variant across northern Canada, with contrasting rabies dynamics between different yet connected areas. Population fluctuations of Arctic fox populations could drive rabies transmission dynamics in a complex way across northern Canada. Furthermore, this study suggests different impacts of climate and sea ice cover on the onset of rabies epizootics in northern Canada. These results lay the groundwork for the development of epidemiological models to better predict the spatio‐temporal dynamics of rabies occurrence in both wild and domestic carnivores, leading to better estimates of human exposure and transmission risk. [ABSTRACT FROM AUTHOR]

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Lemmings are a key component of tundra food webs and changes in their dynamics can affect the whole ecosystem. We present a comprehensive overview of lemming monitoring and research activities, and assess recent trends in lemming abundance across the circumpolar Arctic. Since 2000, lemmings have been monitored at 49 sites of which 38 are still active. The sites were not evenly distributed with notably Russia and high Arctic Canada underrepresented. Abundance was monitored at all sites, but methods and levels of precision varied greatly. Other important attributes such as health, genetic diversity and potential drivers of population change, were often not monitored. There was no evidence that lemming populations were decreasing in general, although a negative trend was detected for low arctic populations sympatric with voles. To keep the pace of arctic change, we recommend maintaining long-term programmes while harmonizing methods, improving spatial coverage and integrating an ecosystem perspective.

The poleward range shift of the red fox (Vulpes vulpes) > 1,700 km into the Arctic is one of the most remarkable distribution changes of the early twentieth century. While this expansion threatens a smaller arctic ecological equivalent, the arctic fox (Vulpes lagopus), the case became a textbook example of climate-driven range shifts. We tested this classical climate change hypothesis linked to an important range shift which has attracted little research thus far. We analysed Canadian fur harvest data from the Hudson's Bay Company Archives (14 trading posts; 1926-1950), testing hypotheses based on changes in summer and winter climates. Summer warming might have triggered a bottom-up increase in ecosystem productivity, while winter warming might have lowered thermal stress, both favouring red fox expansion. Additionally, we evaluated the hypothesis that red fox expansion was driven by the appearance of human sedentary sites (n = 110) likely bringing food subsidies into the unproductive tundra. Analysis of red fox expansion chronologies showed that expansion speed was higher during warmer winters. However, the expansions occurred under both cooling and warming trends, being faster during cooler summers in the Baffin Island region. The increasing proportion of red fox in fox fur harvests was best explained by human activity, while generalized linear mixed models also revealed a marginal effect of warmer winters. Generalized additive models confirmed human presence as the most important factor explaining rates of change in the proportion of red fox in fox fur harvests. Using historical ecology, we disentangled the relative influences of climate change and anthropogenic habitat change, two global drivers that transformed arctic biodiversity during the last century and will likely continue to do so during this century. Anthropogenic food subsidies, which constitute stable food sources, facilitated the invasion of the tundra biome by a new mammalian predator and competitor, with long-term consequences that still remain to be understood., (© 2019 The Authors. Journal of Animal Ecology © 2019 British Ecological Society.)

1. Flows of nutrients and energy across ecosystem boundaries have the potential to subsidize consumer populations and modify the dynamics of food webs, but how spatio-temporal variations in autochthonous and allochthonous resources affect consumers' subsidization remains largely unexplored. 2. We studied spatio-temporal patterns in the allochthonous subsidization of a predator living in a relatively simple ecosystem. We worked on Bylot Island (Nunavut, Canada), where arctic foxes (Vulpes lagopus L.) feed preferentially on lemmings (Lemmus trimucronatus and Dicrostonyx groenlandicus Traill), and alternatively on colonial greater snow geese (Anser caerulescens atlanticus L.). Geese migrate annually from their wintering grounds (where they feed on farmlands and marshes) to the Canadian Arctic, thus generating a strong flow of nutrients and energy across ecosystem boundaries. 3. We examined the influence of spatial variations in availability of geese on the diet of fox cubs (2003-2005) and on fox reproductive output (1996-2005) during different phases of the lemming cycle. 4. Using stable isotope analysis and a simple statistical routine developed to analyse the outputs of a multisource mixing model (SIAR), we showed that the contribution of geese to the diet of arctic fox cubs decreased with distance from the goose colony. 5. The probability that a den was used for reproduction by foxes decreased with distance from the subsidized goose colony and increased with lemming abundance. When lemmings were highly abundant, the effect of distance from the colony disappeared. The goose colony thus generated a spatial patterning of reproduction probability of foxes, while the lemming cycle generated a strong temporal variation of reproduction probability of foxes. 6. This study shows how the input of energy owing to the large-scale migration of prey affects the functional and reproductive responses of an opportunistic consumer, and how this input is spatially and temporally modulated through the foraging behaviour of the consumer. Thus, perspectives of both landscape and foraging ecology are needed to fully resolve the effects of subsidies on animal demographic processes and population dynamics., (© 2012 The Authors. Journal of Animal Ecology © 2012 British Ecological Society.)