An analytical approach for simulating effects of avalanches on mountain goat population dynamics: Implications for management and conservation

Kevin White; Taal Levi; Eran W. Hood; Gabriel J. Wolken; Erich H. Peitzsch; Yves Buhler; Katreen Wikstrom Jones; Chris Darimont

USGS · 70258327

An analytical approach for simulating effects of avalanches on mountain goat population dynamics: Implications for management and conservation

Kevin White·Taal Levi·Eran W. Hood·Gabriel J. Wolken·Erich H. Peitzsch·Yves Buhler·Katreen Wikstrom Jones·Chris Darimont

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Abstract

Mountain environments with snow avalanche hazard cover about 6% of Earth’s land area and occur on all continents. Whereas human risks associated with avalanche hazard have been widely studied, little is known about how avalanche activity affects population dynamics in mountain wildlife. Globally, 32 species of mountain ungulates across 70 countries occupy avalanche-prone terrain. Avalanches comprise the leading cause of mortality in coastal Alaskan mountain goats (mean = 36%, range = 23 - 65%, depending on area), and disproportionately remove prime-aged individuals from populations. The implications of such rates and patterns of mortality on population growth rate are likely to be significant given the species’ low reproductive productivity, but further clarity is needed. To fill this knowledge gap, we developed a sex- and age-specific population modeling approach that integrates both reproduction and mortality to simulate the effects of avalanche-caused mortality on population growth rate across a range of empirically-observed states of avalanche-caused mortality (minimum, mean, maximum). Simulations were conducted to illustrate model functionality, and also provide insight about potential avalanche impacts on population demographic processes. For example, when severe avalanche years occur populations can experience significant additive mortality and declines (up to 15%). Due to low reproductive rates and slow life-history strategy of the species, such impacts can lead to long demographic recovery times (up to 11 years). From a species conservation perspective, such impacts are striking, and highlight the utility of employing a quantitative modeling approach to predict possible effects of avalanches on mountain ungulate population dynamics and viability. Our work explicitly builds upon recent findings about the importance of avalanches on mountain-adapted animal populations, and associated implications for the cultural and ecological communities that depend on them.

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Source-reported bounding extent: 55° to 59.65495767270383° latitude; -138° to -130° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Kevin White, Taal Levi, Eran W. Hood, Gabriel J. Wolken, Erich H. Peitzsch, Yves Buhler, Katreen Wikstrom Jones, Chris Darimont. 2024. An analytical approach for simulating effects of avalanches on mountain goat population dynamics: Implications for management and conservation. https://pubs.usgs.gov/publication/70258327

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