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Bark beetle outbreaks have impacted millions of acres of conifer forests in Colorado and across western North America, which has altered forest structure and function. These alterations may have significant impacts on the ability of forests to fulfill resource requirements for species that utilize them or modify how they use forests to meet these needs. Ungulates in the southern Rocky Mountains utilize conifer forests to fulfill different aspects of their ecologies. However, there is currently a limited understanding of the unique impacts bark beetle outbreaks have on each species. Using GPS location data for mule deer (Odocoilus hemionus), elk (Cervus canadensis), and bighorn sheep (Ovis canadensis) we created third and fourth order resource selection functions using a use-availability framework. Measures of the beetle kill, along with topographic covariates, were derived from remotely sensed data. Preliminary results suggest that measures of outbreak age, size, severity, and heterogeneity all impact ungulate use of forested areas, however these patterns vary across scale and by species. General trends indicate that older and more severe patches of beetle kill forests with moderate outbreak heterogeneity are selected for by ungulates. Understanding the dynamics of ungulate resource selection under these circumstances is critical to inform both wildlife and forest management strategies, as the impacts of beetle-kill continue to evolve and expand across the west.
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A 2000-year record of fecal biomarkers reveals past herbivore presence and impacts in a catchment in northern Yellowstone National Park, USA
Molecular biomarkers preserved in lake sediments are increasingly used to develop records of past organism occurrence. When linked with traditional paleoecological methods, analysis of molecular biomarkers can yield new insights into the roles of herbivores and other animals in long-term ecosystem dynamics. We sought to determine whether fecal steroids in lake sediments could be used to reconstruct past ungulate use and dominant taxa in a small catchment in northern Yellowstone National Park. To do so, we characterized the fecal steroid profiles of a selection of North American ungulates historically present in the Yellowstone region (bison, elk, moose, mule deer, and pronghorn) and compared them with those of sediments from a small lake in the Yellowstone Northern Range. Analysis of a set of fecal steroids from herbivore dung (Δ5-sterols, 5α-stanols, 5β-stanols, epi5β-stanols, stanones, and bile acids) differentiated moose, pronghorn, and mule deer, whereas bison and elk were partially differentiated. Our results show that bison and/or elk were the primary ungulates in the watershed over the pastc. 2300 years. Fecal steroid influxes reached historically unprecedented levels during the early and middle 20thcentury, possibly indicating high local use by ungulates. Comparison of fecal steroid influxes with pollen and diatom data suggests that elevated ungulate presence may have contributed to decreased forage taxa (Poaceae,Artemisia, andSalix), relative to long-term averages, and possibly increased lake production. Our results reflect past change within a single watershed, and extending this approach to a network of sites could provide much-needed information on past herbivore communities, use, and environmental influences in Yellowstone National Park and elsewhere.
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- Award ID(s):
- 2149482
- PAR ID:
- 10583369
- Editor(s):
- Khamesipour, Faham
- Publisher / Repository:
- Public Library of Science
- Date Published:
- Journal Name:
- PLOS ONE
- Volume:
- 19
- Issue:
- 10
- ISSN:
- 1932-6203
- Page Range / eLocation ID:
- e0311950
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1371/journal.pone.0311950
