Patterns of resource selection by animals may be influenced by sex, and often change over a 24-h period. We used a dry sclerophyll landscape managed for commercial timber production to investigate the effects of sex and diel period on habitat selection by the swamp wallaby (Wallabia bicolor). We predicted that selection would be (i) affected by both sex and diel period; and (ii) positively related to lateral cover during the day, but to food resources at night. Non-metric multidimentional scaling indicated that some of the available habitats differed markedly with respect to visibility (an indicator of lateral cover), fern cover, forb cover, wallaby density and a forage quality index, providing the basis for non-random habitat selection. At the landscape scale, wallabies showed strong selection for 5-year-old regenerating sites, selected against 10-year-old regenerating sites and unharvested forest, and avoided recently harvested (3-10 months post-harvest) sites completely. At the scale of individual home ranges, a pooled male and female sample demonstrated selection for unharvested forest over recently harvested sites during both diurnal and nocturnal periods. A separate analysis showed that both sex and diel period influenced the selection of 5-and 10-year-old sites and the surrounding unharvested forest. Using a novel approach, we demonstrated that diurnal habitat selection by both sexes was negatively correlated with visibility, representing stronger selection for areas with more lateral cover. Nocturnal selection by females was positively correlated with values of a forage quality index, but this was not the case for males. We hypothesise that the observed patterns of selection were driven by the need to find food and avoid predators, but were also affected by the different reproductive strategies of males and females. Our results demonstrate the importance of incorporating factors such as sex and diel period into analyses of habitat selection.

Animals typically use habitat in a non-random way, but the factors influencing habitat selection may change throughout the 24-h cycle. In this study, we quantified resources at used and available locations to test two predictions about the fine-scale habitat selection of seven adult female swamp wallabies (Wallabia bicolor). We predicted that selection would be (i) non-random and (ii) differ between diurnal and nocturnal periods with respect to both food and shelter. Variables quantifying food abundance and lateral cover were recorded at 56 diurnal, 17 nocturnal and 143 randomly selected available locations. Logistic regression indicated that diurnal habitat selection was positively correlated with lateral cover, and the cover of trees, shrubs and forbs, whereas nocturnal selection was positively correlated with forb cover only. Diurnal locations had more lateral cover than nocturnal locations. The data were consistent with our first prediction, but only partially supported our second. At a fine scale, diurnal habitat selection was influenced by the co-availability of shelter and food resources, whereas nocturnal selection was influenced by food availability only, indicating that factors influencing habitat selection changed throughout the 24-h cycle.

Summary1. Viggers & Hearn (2005) examined the encroachment of native herbivores on to farmland. They presented kangaroo home range estimates and pasture biomass data for three sites in south-eastern Australia, then made broad management recommendations regarding the preservation of remnant habitat. 2. While Viggers & Hearn identified potentially important patterns, we believe that their data were neither sufficient nor appropriate to reveal the processes that underlie these patterns. 3. Specifically, their study was unreplicated at the land-use level, used inappropriate density estimates for their study populations, failed to measure resources adequately, used flawed methods of home range analysis, and demonstrated limited understanding of key concepts and of their study species and thus could not draw valid conclusions.

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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.