Body size and spatial scales in avian response to landscapes: a meta-analysis

Authors


D. H. Thornton, School of Environment, Washington State Univ., PO Box 642812, Pullman, WA 99164-2812, USA, and Panthera, 8 West 40th Street, New York, NY 10018, USA. E-mail: dthornton@panthera.org

Abstract

Response of species to their environment is dependent on the scales that individuals interact with landscapes. Several life-history traits have been suggested to influence scales of response to landscapes, but little empirical work has addressed this issue, limiting our ability to predict the relevant scale(s) at which species respond to their environment. Body size is frequently hypothesized to be relevant for predicting the effects of landscape structure on species given correlations between body size and various measures of mobility or perceptual range, yet evidence of this relationship remains equivocal. We conducted a meta-analysis of 22 studies to address the question of whether body size is related to the characteristic scale at which bird species respond to landscape structure. On the basis of correlation coefficients and linear mixed models, we show that body size is positively related to the characteristic scale of response to landscapes. The strength of this relationship is less than body size – dispersal allometries, suggesting that response to landscapes may be influenced, in part, by factors other than dispersal (e.g. territory size). However, the strength of the observed body size – scale relationship may have been affected by several factors, including limitations in the range of body sizes and landscape extents tested. Our findings suggest that life-history traits mediate aspects of the scales at which species respond to the landscape and contribute to developing a more predictive framework for investigating scalar relationships in nature.

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