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Recent population trends of mountain goats in the Olympic Mountains, Washington

Northwest Science

By:
, , , , , , and
DOI: 10.3955/046.086.0403

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Abstract

Mountain goats (Oreamnos americanus) were introduced in Washington's Olympic Mountains during the 1920s. The population subsequently increased in numbers and expanded in range, leading to concerns by the 1970s over the potential effects of non-native mountain goats on high-elevation plant communities in Olympic National Park. The National Park Service (NPS) transplanted mountain goats from the Olympic Mountains to other ranges between 1981 and 1989 as a means to manage overabundant populations, and began monitoring population trends of mountain goats in 1983. We estimated population abundance of mountain goats during 18–25 July 2011, the sixth survey of the time series, to assess current population status and responses of the population to past management. We surveyed 39 sample units, comprising 39% of the 59,615-ha survey area. We estimated a population of 344 ± 72 (90% confidence interval [CI]) mountain goats in the survey area. Retrospective analysis of the 2004 survey, accounting for differences in survey area boundaries and methods of estimating aerial detection biases, indicated that the population increased at an average annual rate of 4.9% since the last survey. That is the first population growth observed since the cessation of population control measures in 1990. We postulate that differences in population trends observed in western, eastern, and southern sections of the survey zone reflected, in part, a variable influence of climate change across the precipitation gradient in the Olympic Mountains.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Recent population trends of mountain goats in the Olympic Mountains, Washington
Series title:
Northwest Science
DOI:
10.3955/046.086.0403
Volume
86
Issue:
4
Year Published:
2012
Language:
English
Publisher:
Northwest Scientific Association
Publisher location:
http://www.northwestscience.org/
Contributing office(s):
Forest and Rangeland Ecosystem Science Center
Description:
12 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Northwest Science
First page:
264
Last page:
275
Country:
United States
State:
Washington
Other Geospatial:
Olympic Mountains