Repository logo

Browsing by Author "Berger, Joel, advisor"

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Bats, elephants, and their food: a conservation perspective on trophic interactions in the Namib Desert
    (Colorado State University. Libraries, 2019) Laverty, Theresa Marie, author; Berger, Joel, advisor; Crooks, Kevin, committee member; Wittemyer, George, committee member; Teel, Tara, committee member
    To view the abstract, please see the full text of the document.
  • Thumbnail Image
    ItemOpen Access
    Ecological consequences of warming climes for cold-adapted species – evidence from mountain goats
    (Colorado State University. Libraries, 2023) Hayes, Forest Parker, author; Berger, Joel, advisor; Bailey, Larissa L., committee member; Wilson, Kenneth R., committee member; McGrath, Daniel, committee member
    Global climate change from human activity is changing ecological communities at unprecedented rates. Coupled with recent and extraordinary loss of biodiversity, assessing the consequences for vulnerable species – and effecting proactive conservation – will be fundamental to stymieing these losses. Among the areas most strongly impacted by these changes are montane regions, which are warming at rates 2–5x the global average. Within those, cold-adapted organisms are among the most strongly impacted as they may experience thermal stress at moderate temperatures. Past species- and taxa-level responses to warming environs includes numerous concentrated extirpations at the southern peripheries of distributional ranges during the late Pleistocene. Less clear are localized capacities of cold-adapted species to mitigate thermal challenges against warming temperatures, especially through proximate behavioral and physiological adjustments. In this dissertation, I address three key tendrils of the ecological consequences of warming climes for cold-adapted species. First, I evaluate the role of snow patches in mediating the physiological impacts of warming temperatures. Despite strong associations between many taxa and cold environs, great uncertainty remains about the biological benefits, if any, of using persistent snow during summer months. Contrary to the prevalent hypothesis that persistent snow provides thermal relief for cold-adapted species, I demonstrate that use of snow patches facilitates insect avoidance and not thermoregulatory gains. While the duration and spatial extent of snow declines globally as the climate warms, its diminishing availability is likely to have substantive impacts to populations given a general pattern of associations between insects and temperatures at high elevations and latitudes. Next, I evaluate changes in spatial use relative to high temperatures and the influence of snow on resource selection. While thermal challenges to persistence are well evidenced through historical extirpations, attention to near-term shifts in resource use and snow as a driver of summer resource selection remains under-investigated. I found strong shifts in resource selection during periods of high temperature, with increased selection for cooler habitats, little effect from snow, and evidence of ecological tradeoffs in avoidance of heat. These results point to possible demographic consequences of changing behavior and illustrate the importance of proactive consideration of changing patterns of use in management policies. Finally, I evaluate the importance of climate refugia and human translocation for the applied conservation of biodiversity. Despite a long history of relocating wildlife, translocations outside native ranges have rarely been conducted for conservation and populations introduced beyond their native ranges have seldom contributed to in situ species conservation within native ranges. Herein, I identify three cases of introductions to climate refugia and highlight the untapped conservation value of existing populations outside of native ranges. I report species in these refugia offer not only a reservoir for reintroductions but also a buffer against temperature-driven distributional change and may prove invaluable in stymieing current and future loss of biodiversity under continued climate challenges. In concert, this dissertation addresses physiological and geographical consequences of warming climes for cold-adapted species, identifies the need for proactive conservation, and highlights one avenue through which meaningful conservation benefits may be achieved.