Elk migration influences the risk of disease spillover in the Greater Yellowstone Ecosystem
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Title
Elk migration influences the risk of disease spillover in the Greater Yellowstone Ecosystem
Description
- Wildlife migrations provide important ecosystem services, but they are declining. Within the Greater Yellowstone Ecosystem (GYE), some elk Cervus canadensis herds are losing migratory tendencies, which may increase spatiotemporal overlap between elk and livestock (domestic bison Bison bison and cattle Bos taurus), potentially exacerbating pathogen transmission risk.
- We combined disease, movement, demographic and environmental data from eight elk herds in the GYE to examine the differential risk of brucellosis transmission (through aborted foetuses) from migrant and resident elk to livestock.
- For both migrants and residents, we found that transmission risk from elk to livestock occurred almost exclusively on private ranchlands as opposed to state or federal grazing allotments. Weather variability affected the estimated distribution of spillover risk from migrant elk to livestock, with a 7%–12% increase in migrant abortions on private ranchlands during years with heavier snowfall. In contrast, weather variability did not affect spillover risk from resident elk.
- Migrant elk were responsible for the majority (68%) of disease spillover risk to livestock because they occurred in greater numbers than resident elk. On a per-capita basis, however, our analyses suggested that resident elk disproportionately contributed to spillover risk. In five of seven herds, we estimated that the per-capita spillover risk was greater from residents than from migrants. Averaged across herds, an individual resident elk was 23% more likely than an individual migrant elk to abort on private ranchlands.
- Our results demonstrate links between migration behaviour, spillover risk and environmental variability, and highlight the utility of integrating models of pathogen transmission and host movement to generate new insights about the role of migration in disease spillover risk. Furthermore, they add to the accumulating body of evidence across taxa that suggests that migrants and residents should be considered separately during investigations of wildlife disease ecology. Finally, our findings have applied implications for elk and brucellosis in the GYE. They suggest that managers should prioritize actions that maintain spatial separation of elk and livestock on private ranchlands during years when snowpack persists into the risk period.
Bibliographic Citation
Rayl, N.D., J.A. Merkle, K.M. Proffitt, E.S. Almberg, J.D. Jones, J.A. Gude, and P.C. Cross. 2021. Elk migration influences the risk of disease spillover in the Greater Yellowstone Ecosystem. Journal of Animal Ecology 90:1264-1275. https://doi.org/10.1111/1365-2656.13452
Creator
Rayl, Nathaniel D.
Merkle, Jerod A.
Proffitt, Kelly M.
Almberg, Emily S.
Jones, Jennifer D.
Gude, Justin A.
Cross, Paul C.
Subject
Brucellosis Brucella abortus
Cross-species pathogen spillover
Elk Cervus canadensis
Human–wildlife conflict
Partial migration
Resource selection function
Wildlife disease
Extent
12 pages
Date Created
2021-02-25
Type
Article
Format
application/pdf
Language
English
Is Part Of
Journal of Animal Ecology
Collection
Citation
Rayl, Nathaniel D. et al., “Elk migration influences the risk of disease spillover in the Greater Yellowstone Ecosystem,” CPW Digital Collections, accessed February 5, 2025, https://cpw.cvlcollections.org/items/show/256.