Abstract
The spatial distribution and seasonal movement patterns of isolated populations of mountain goats (Oreamnos americanus) in the North Cascade range of Washington State is not fully understood. Determining harvest potential in these populations is challenging without a clear understanding of spatiotemporal movement, space use, and spatial overlap. Mountain goat populations in the North Cascades are fragmented and many have declined considerably from historic estimates. Identification of harvestable populations requires a clear understanding of population size, distribution, and movement. We investigated the population trends and spatial distribution of mountain goats in the Boulder River North Harvest Area in the Boulder River Wilderness of Washington State. We reviewed recent mountain goat population estimates and used Global Positioning System collar data to determine year-round and seasonal home range distributions, spatial overlap within these ranges, and proximity of mountain goats to roads and trails. We found 2 populations of mountain goats inhabiting the Whitehorse and Three Fingers Mountains in the Boulder River North Harvest Area. These 2 populations were spatially distinct and did not intermix during our study period. We also found mountain goats using exclusive areas seasonally on Whitehorse Peak. The Whitehorse population appeared to be more vulnerable to harvest than Three Fingers based on its proximity to roads and trails. This study provides space use and movement information on mountain goats in the North Cascades Range that can be used to improve harvest management of fragmented and isolated populations. Our results indicate that a re-evaluation of harvest level, harvest unit boundary, and monitoring strategy may be warranted for the Boulder River North mountain goat harvest area.
Space Use and Seasonal Movement of Isolated Mountain Goat Populations in the North Cascades, WA
