With climate warming, the ranges of many boreal species are expected to shift northward and to fragment in southern peripheral ranges. To understand the conservation implications of losing southern populations, we examined range-wide genetic diversity of the snowshoe hare (Lepus americanus), an important prey species that drives boreal ecosystem dynamics. We analysed microsatellite (8 loci) and mitochondrial DNA sequence (cytochrome b and control region) variation in almost 1000 snowshoe hares. A hierarchical structure analysis of the microsatellite data suggests initial subdivision in two groups, Boreal and southwestern. The southwestern group further splits into Greater Pacific Northwest and U.S. Rockies. The genealogical information retrieved from mtDNA is congruent with the three highly differentiated and divergent groups of snowshoe hares. These groups can correspond with evolutionarily significant units that might have evolved in separate refugia south and east of the Pleistocene ice sheets. Genetic diversity was highest at mid-latitudes of the species' range, and genetic uniqueness was greatest in southern populations, consistent with substructuring inferred from both mtDNA and microsatellite analyses at finer levels of analysis. Surprisingly, snowshoe hares in the Greater Pacific Northwest mtDNA lineage were more closely related to black-tailed jackrabbits (Lepus californicus) than to other snowshoe hares, which may result from secondary introgression or shared ancestral polymorphism. Given the genetic distinctiveness of southern populations and minimal gene flow with their northern neighbours, fragmentation and loss of southern boreal habitats could mean loss of many unique alleles and reduced evolutionary potential.

Hybridization drives the evolutionary trajectory of many species or local populations, and assessing the geographic extent and genetic impact of interspecific gene flow may provide invaluable clues to understand population divergence or the adaptive relevance of admixture. In North America, hares (Lepus spp.) are key species for ecosystem dynamics and their evolutionary history may have been affected by hybridization. Here we reconstructed the speciation history of the three most widespread hares in North America - the snowshoe hare (Lepus americanus), the white-tailed jackrabbit (L. townsendii) and the black-tailed jackrabbit (L. californicus) - by analysing sequence variation at eight nuclear markers and one mitochondrial DNA (mtDNA) locus (6240 bp; 94 specimens). A multilocus-multispecies coalescent-based phylogeny suggests that L. americanus diverged ~2.7 Ma and that L. californicus and L. townsendii split more recently (~1.2 Ma). Within L. americanus, a deep history of cryptic divergence (~2.0 Ma) was inferred, which coincides with major speciation events in other North American species. While the isolation-with-migration model suggested that nuclear gene flow was generally rare or absent among species or major genetic groups, coalescent simulations of mtDNA divergence revealed historical mtDNA introgression from L. californicus into the Pacific Northwest populations of L. americanus. This finding marks a history of past reticulation between these species, which may have affected other parts of the genome and influence the adaptive potential of hares during climate change.

Allometric foraging theory suggests that herbivores of greatly differing size should co-exist through niche segregation, but a few studies of large-small herbivore foraging relationships have reported competitive interactions. This study addresses the potential roles of habitat productivity and large herbivore grazing intensities on large-small herbivore foraging interactions. We examined effects of different intensity simulated grazing treatments on forage abundance and quality for Utah prairie dogs (Cynomys parvidens) in a low productivity ecosystem, and consequent effects on prairie dog individual growth rates, foraging preferences, and activity budgets. We hypothesized that simulated grazing would have predominantly facilitative impacts on Utah prairie dogs, as was found for black-tailed prairie dogs in higher productivity ecosystems. To test this hypothesis, we measured the effects of simulated grazing on forage nitrogen, digestibility, and biomass. Simulated grazing increased average forage nitrogen and digestibility while decreasing forage biomass. These effects were associated with reduced individual growth rates, increased juvenile foraging time, and reduced juvenile vigilance. Results suggest that the negative effects of reduced vegetation biomass greatly outweighed positive treatment effects in this study. However, prairie dogs in the moderate intensity defoliation treatment showed some preference for "grazed" plots over "ungrazed" plots, and this preference increased with time. Our study lends support to the idea that habitat productivity and herbivore densities may mediate shifts between facilitative and competitive interactions between different-sized herbivores.

Across much of Asia protected areas have a dual objective of conserving biodiversity and supporting rural and indigenous livelihoods. For the red panda Ailurus fulgens and other sensitive species of concern, even limited anthropogenic disturbance may influence their use of protected areas. We quantified the prevalence of timber collection and livestock grazing, and their impacts on red panda habitat use, in Phrumsengla National Park, Bhutan. Red pandas used sites with at least 20% bamboo cover, as evidenced by presence of their faecal pellets. They avoided sites disturbed by livestock, regardless of bamboo availability. Timber collection itself was not an important predictor of red panda presence but bamboo may be harvested opportunistically from sites where timber is collected. Conservation efforts for the red panda should not rely on protected areas alone but should explicitly consider and mitigate impacts of anthropogenic disturbances in protected areas.

Forest fires fundamentally shape the habitats available for wildlife. Current predictions for fire under a warming climate suggest larger and more severe fires may occur, thus challenging scientists and managers to understand and predict impacts of fire on focal species, especially species of management concern. Snowshoe hares (Lepus americanus Erxleben) are a common and important prey animal in boreal forests and are the primary prey for the US federally threatened Canada lynx (Lynx canadensis Kerr), so understanding hare dynamics in post-fire landscapes is critical for managing lynx. We collected habitat and fecal pellet data from 114 sites across three natural burn treatments (mature forest, 1988 Red Bench burn, and 1994 Adair and Howling burns) to evaluate impacts of fire and fire-habitat interactions on snowshoe hare in Glacier National Park, Montana, USA. We found that hare numbers were low throughout the park, with hares absent at 17 % of surveyed sites and occurring at densities above 0.5 hares ha−1 (a commonly suggested threshold for supporting Canada lynx) at only 7 % of sites. Hare densities were variable but 10 to 20 times higher in regenerating lodgepole pine (Pinus contorta Douglas ex Loudon) stands of 1988 Red Bench burn compared to lodgepole stands in other burn treatments. In stands dominated by other tree species, we found little difference in hare densities across burn treatments. Regardless of burn history or dominant canopy type, percent canopy cover was positively associated with hare relative abundance. Hare densities also increased with percent understory cover up to 80 % cover, beyond which they began to decline. The regular occurrence of wildfires in Glacier National Park, with 2003 being a particularly large fire year (the largest since 1910), suggest that hare and lynx distribution and abundance within the park may shift substantially in the coming decades as these animals respond to changing spatiotemporal patterns of regenerating forest.

Public agencies sometimes seek outside guidance when capacity to achieve their mission is limited. Through a cooperative agreement and collaborations with the U.S. National Park Service (NPS), we developed recommendations for a conservation program for migratory species. Although NPS manages ∼ 36 million hectares of land and water in 401 units, there is no centralized program to conserve wild animals reliant on NPS units that also migrate hundreds to thousands of kilometers beyond parks. Migrations are imperiled by habitat destruction, unsustainable harvest, climate change, and other impediments. A successful program to counter these challenges requires public support, national and international outreach, and flourishing migrant populations. We recommended two initial steps. First, in the short term, launch or build on a suite of projects for high-profile migratory species that can serve as proof to demonstrate the centrality of NPS units to conservation at different scales. Second, over the longer term, build new capacity to conserve migratory species. Capacity building will entail increasing the limited knowledge among park staff about how and where species or populations migrate, conditions that enable migration, and identifying species' needs and resolving them both within and beyond parks. Building capacity will also require ensuring that park superintendents and staff at all levels support conservation beyond statutory borders. Until additional diverse stakeholders and a broader American public realize what can be lost and do more to protect it and engage more with land management agencies to implement actions that facilitate conservation, long distance migrations are increasingly likely to become phenomena of the past.

Understanding population dynamics requires reliable estimates of population density, yet this basic information is often surprisingly difficult to obtain. With rare or difficult‐to‐capture species, genetic surveys from noninvasive collection of hair or scat has proved cost‐efficient for estimating densities. Here, we explored whether noninvasive genetic sampling (NGS) also offers promise for sampling a relatively common species, the snowshoe hare (Lepus americanus Erxleben, 1777), in comparison with traditional live trapping. We optimized a protocol for single‐session NGS sampling of hares. We compared spatial capture–recapture population estimates from live trapping to estimates derived from NGS, and assessed NGS costs. NGS provided population estimates similar to those derived from live trapping, but a higher density of sampling plots was required for NGS. The optimal NGS protocol for our study entailed deploying 160 sampling plots for 4 days and genotyping one pellet per plot. NGS laboratory costs ranged from approximately $670 to $3000 USD per field site. While live trapping does not incur laboratory costs, its field costs can be considerably higher than for NGS, especially when study sites are difficult to access. We conclude that NGS can work for common species, but that it will require field and laboratory pilot testing to develop cost‐effective sampling protocols.

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