Resource heterogeneity influences home range area in the swamp wallaby Wallabia bicolor

Abstract

Home range area is influenced by the spatio‐temporal distribution of multiple resources, but current theoretical frameworks such as the habitat productivity and resource dispersion hypotheses fail to account for this adequately. We propose a conceptual framework for quantifying the influence of multiple resources on home range area where separate resources interact to form a continuous, multi‐dimensional resource surface exhibiting an emergent environmental pattern. We adopt the term resource heterogeneity to describe this pattern, and predict that home range area will be more closely correlated with resource heterogeneity than with simple additive or interactive effects of separate resources. Initially, we quantified resource heterogeneity as the geometric mean of resource abundance, and tested the performance of this index against simulated low, moderate and high heterogeneity scenarios. In all cases, the geometric mean reflected the modelled scenarios well, demonstrating its utility as a heterogeneity index. We then quantified shelter and food resources within the home ranges of swamp wallabies Wallabia bicolor, and used these data in a generalised linear mixed modelling framework to test our prediction. Based on Akaike's information criterion (AICc), the best model included the main effect of sex and the heterogeneity index. Although model selection uncertainty was relatively high (largest Akaike weight=0.37), the AICc value associated with the best model was 2.41 units less than the highest ranked model including shelter and food, indicating support for our prediction. Home range area was negatively correlated with resource heterogeneity, and males had larger home ranges than females (37.6 (28.5, 49.7) ha compared to 17.2 (13.6, 21.7) ha; mean and 95% CLs). We suggest that statistical models of home range area parameterised using an index of resource heterogeneity will often be superior to those that focus on a single resource, or fail to take the heterogeneity of multiple resources into account.

Effects of spatiotemporal resource heterogeneity on home range size of American beaver

“…a). The positive relationship between home range size and resource dispersion has been observed in mammalian carnivores (reviewed by Di Stefano et al ., ). Our results suggest that resource dispersion may also play an important role in determining home range sizes of mammalian herbivores.…”

“…Other studies have also suggested that beaver home range sizes were not related to age and body mass (Bloomquist et al, 2012). Natural log transformation was used to normalize home range sizes and to linearize relationships between raw home range and predictor variables (Di Stefano et al, 2011;Bloomquist et al, 2012).…”

“…For instance, increased habitat productivity would lead to a decrease in animal home range size (McNab, 1963). However, spatial distribution and configuration of resources may also play an important role in shaping movement patterns and space use of animals (Mueller & Fagan, 2008;Di Stefano et al, 2011).…”

Patchwork planet: the resource dispersion hypothesis, society, and the ecology of life

“…Using field data from swamp wallabys, Di Stefano et al (2011) report that home-range size decreases with resource heterogeneity, in terms of the spatio-temporal distribution of multiple resources. Because they interpreted RDH in terms solely of food resources, they judged it inadequate in the context of the wallabies' dependence on diverse resources.…”

Peer Review #2 of "Home range and use of diurnal shelters by the Etendeka round-eared sengi, a newly discovered Namibian endemic desert mammal (v0.1)"

“…We again hypothesize that prey availability may be the most important underlying factor in determining sengi density, and thus many home range characteristics. However, multiple factors may be involved (Di Stefano et al, 2011), including mate availability. Sauer (1973) suggested that shelters may have been limiting for M. flavicaudatus, although we doubt this was the case at our study site (Fig.1).…”