Wildlife Monographs最新文献

The ongoing biodiversity crisis requires policy tools to establish baselines and assess biodiversity status. Reindeer and caribou (Rangifer tarandus) are iconic ungulates in the Arctic and subarctic, but populations are declining. Although the species is considered vulnerable globally in the International Union for Conservation of Nature [IUCN] Red List, more detailed policy tools at the population level would allow for targeted conservation efforts nationally. We developed an environmental quality standard (or norm) for reindeer populations to evaluate their overall status and put complex variation and change into simple status categories (poor, medium, and good) based on sets of quantitative indicators for 1) population performance, genetic diversity, and health status; 2) available lichen resources; and 3) loss of seasonal habitat and connectivity. We implemented the environmental quality standard for 10 national and 14 smaller wild reindeer areas (populations) in Norway. Except for 1 area with good status, all others ranged from medium (n = 11) to poor quality (n = 12). More than half of the populations had medium (n = 7) or poor (n = 6) status for 1 or more population performance indicators, with negative trends in calf body mass and recruitment in several populations. High loss of genetic diversity gave poor status in 4 small and isolated populations, and 2 populations with chronic wasting disease scored poor on health status. The status of lichen resources was medium (n = 20) or good (n = 3), with 1 exception. However, lichen time series data were not available to evaluate temporal trends to assess overgrazing. Loss of connectivity (poor; n = 7) was more problematic than loss of seasonal habitat (n = 3). The poor availability of high-quality empirical data, particularly on population performance, has limited the ability to fully assess the conservation status of several small populations. The environmental quality standard provides an important step towards operationalizing management and aiding in securing the long-term conservation of wild reindeer. We discuss further improvements and the potential usefulness of this approach for other large mammals.

Animal space use, activity patterns, and habitat selection—and heterogeneity in these patterns—have important implications for where and when infectious diseases are transmitted. White-tailed deer (Odocoileus virginianus) are habitat generalists, with a high degree of heterogeneity in their movement ecology based on sex, age, season, and region. These heterogeneities have important implications for the transmission and management of chronic wasting disease (CWD), which is a deadly prion disease transmitted both directly and indirectly through the environment. As such, favored deer habitats may promote direct interactions between conspecifics or indirect spatial overlap and subsequent environmental transmission. However, little is known about how individual animal space use translates to actual spatial overlap between individuals, leaving uncertainty in how habitat shapes the risk of direct or environmental CWD transmission. In this study, we evaluated seasonal activity patterns, home ranges, and habitat selection for 596 white-tailed deer in southwest Wisconsin, USA, from 2017-2022. We also estimated seasonal encounter distributions—regions where a pair of deer were most likely to encounter each other—for all pairs of deer putatively in different social groups (between-group) in our study, and quantified seasonal variation in the habitat composition of these areas. We found that deer selection for crops, pasture, or grasslands was generally low, relative to forest, but was highest in the post-fawning (summer) and non-breeding (winter) seasons. We observed similar patterns for the habitat composition of encounter distributions, suggesting that crops, pasture, and grasslands may be attractive resources that facilitate between-group transmission. Site fidelity between years was generally high; combined with small female home ranges in the fawning season, this implies that females likely re-use the same small, high-quality fawning habitats from year to year. We found that attraction toward between-group individuals was low during the post-fawning season but high during the breeding (fall) and non-breeding seasons. These results suggest that space use and habitat selection could shape the risk of environmental transmission in the fawning and post-fawning seasons, social selection could favor direct transmission risk in the breeding season, and combined social and habitat selection may shape risk of both direct and environmental transmission during the non-breeding season. We provide a detailed picture of the physiological and social drivers of deer movement through the year, with implications for CWD transmission and management.