Linking landscape characteristics to local grizzly bear abundance using multiple detection methods in a hierarchical model

Animal Conservation
By: , and 

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Abstract

Few studies link habitat to grizzly bear Ursus arctos abundance and these have not accounted for the variation in detection or spatial autocorrelation. We collected and genotyped bear hair in and around Glacier National Park in northwestern Montana during the summer of 2000. We developed a hierarchical Markov chain Monte Carlo model that extends the existing occupancy and count models by accounting for (1) spatially explicit variables that we hypothesized might influence abundance; (2) separate sub-models of detection probability for two distinct sampling methods (hair traps and rub trees) targeting different segments of the population; (3) covariates to explain variation in each sub-model of detection; (4) a conditional autoregressive term to account for spatial autocorrelation; (5) weights to identify most important variables. Road density and per cent mesic habitat best explained variation in female grizzly bear abundance; spatial autocorrelation was not supported. More female bears were predicted in places with lower road density and with more mesic habitat. Detection rates of females increased with rub tree sampling effort. Road density best explained variation in male grizzly bear abundance and spatial autocorrelation was supported. More male bears were predicted in areas of low road density. Detection rates of males increased with rub tree and hair trap sampling effort and decreased over the sampling period. We provide a new method to (1) incorporate multiple detection methods into hierarchical models of abundance; (2) determine whether spatial autocorrelation should be included in final models. Our results suggest that the influence of landscape variables is consistent between habitat selection and abundance in this system.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Linking landscape characteristics to local grizzly bear abundance using multiple detection methods in a hierarchical model
Series title Animal Conservation
DOI 10.1111/j.1469-1795.2011.00471.x
Volume 14
Issue 6
Year Published 2011
Language English
Publisher ZSL
Contributing office(s) Northern Rocky Mountain Science Center
Description 13 p.
First page 652
Last page 664