Sexual size dimorphism mediates effects of spatial resource variability on American black bear space use. (25th March 2015)

• Record Type: Journal Article
• Authors: Hiller, T. L.; Belant, J. L.; Beringer, J.
• Is Part Of: Journal of zoology. Volume 296:Number 3(2015:Jul.)
• Page Start: 200
• Page End: 207
• Publication Date: 2015-03-25
• Subjects: Zoology -- Periodicals; Zoologie -- Périodiques; 590.5
• DOI: 10.1111/jzo.12234
• Languages: English
• ISSNs: 0952-8369

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>The distribution of animals is influenced by numerous factors including spatial distribution and temporal availability of resources. We tested the spatial resource variability hypothesis (increasing landscape heterogeneity results in increasing amount of space use) and the temporal resource variability hypothesis (temporal variation in resources reduces amount of space use) using location data from radiomarked American black bears <italic>Ursus americanus</italic> in Missouri and Arkansas, USA. We used 95% utilization distributions (UDs) to define individual seasonal space use and constructed 22 models using covariates that described composition, spatial arrangement and diversity of land cover types (an index of heterogeneity or patchiness); seasonal hard mast production; and seasonal use of land cover to test our hypotheses using linear modeling and small‐sample Akaike information criterion (AIC<sub>c</sub>) model selection approaches. The AIC<sub>c</sub> best performing model supported the spatial resource variability hypothesis and included Shannon diversity index [95% confidence limit (CL) of coefficient = 1.56–2.42] and sex (male; 95% CL of coefficient = 0.05–0.49) as covariates that explained variation in transformed values of UD size. Predicted and observed values during model evaluation were highly correlated (<italic>r</italic> = 0.90). As land cover heterogeneity increased, UD size increased, likely a consequence of bears responding to greater patchiness to maintain sufficient resources. Further, the Shannon diversity index was greater for males <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgj1m9fjfn8" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math altimg="urn:x-wiley:09528369:media:jzo12234:jzo12234-math-5001" display="inline" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML" /></alternatives></inline-formula> than females <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgj1m9fjfk5" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math altimg="urn:x-wiley:09528369:media:jzo12234:jzo12234-math-5002" display="inline" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML" /></alternatives></inline-formula>, suggesting larger bodied males used larger areas to meet their higher energetic costs due to landscape fragmentation. Studies of resource hypotheses in solitary species should consider intraspecific allometric relationships such as sexual size dimorphism as has been addressed using group size in social species.</p> </abstract>