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Power of sign surveys to monitor population trend

Ecological Applications

By:
, , , and
DOI:10.2307/1941877

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Abstract

The urgent need for an effective monitoring scheme for grizzly bear (Ursus arctos) populations led us to investigate the effort required to detect changes in populations of low—density dispersed animals, using sign (mainly scats and tracks) they leave on trails. We surveyed trails in Glacier National Park for bear tracks and scats during five consecutive years. Using these data, we modeled the occurrence of bear sign on trails, then estimated the power of various sampling schemes. Specifically, we explored the power of bear sign surveys to detect a 20% decline in sign occurrence. Realistic sampling schemes appear feasible if the density of sign is high enough, and we provide guidelines for designs with adequate replication to monitor long—term trends of dispersed populations using sign occurrences on trails.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Power of sign surveys to monitor population trend
Series title:
Ecological Applications
DOI:
10.2307/1941877
Volume:
2
Issue:
4
Year Published:
1992
Language:
English
Publisher:
Ecological Society of America
Description:
9 p.
First page:
422
Last page:
430