Inter‐ and intraspecific effects of body size on habitat use among sexually‐dimorphic macropodids

Abstract

Body size affects key life‐history parameters including dietary requirements and predation risk. We examined these effects on diel habitat use in a community of three sexually‐dimorphic macropodid marsupial species: western grey kangaroo Macropus fuliginosus, red‐necked wallaby M. rufogriseus and swamp wallaby Wallabia bicolor. In particular, our study seeks evidence of these effects operating concurrently at the intra‐ and interspecific levels. We used radio‐tracking to quantify habitat use and characterised each used location by recording the cover of plant functional groups and the presence of plant species. During nocturnal foraging periods we predicted that smaller animals (between and within species) should use habitats with higher‐quality forage, which is often less abundant, than larger animals, as metabolic demand scales with body size. During diurnal resting periods we predicted that smaller animals (between and within species), being more vulnerable to predation, should use greater concealment cover than larger animals. Western grey kangaroos and swamp wallabies behaved as predicted during foraging periods, but red‐necked wallabies did not, using more open, poorer‐quality habitats than expected. Only western grey kangaroos showed a within‐species effect on habitat use: the relatively smaller females foraged in higher‐quality patches. Habitats used by animals during the resting period generally offered greater concealment cover than those used during the foraging period, but there were no clear body size effects on the density of vegetation used. In our system, body size alone could not explain all of the observed patterns, suggesting that there may also be individual differences in habitat requirements influenced by factors such as reproductive costs, predation risk and social facilitation.

Leaf odour cues enable non‐random foraging by mammalian herbivores

“…(). This temporal pattern contrasts with assumptions that wallabies forage at night and rest during the day (Garnick, Di Stefano, Elgar, & Coulson, ), but this is likely to be context‐specific. Animals may rest during the day to avoid excessive heat (Dawson & Denny, ), and given our trials ran from autumn to spring, we suggest the cooler temperatures did not inhibit daytime foraging.…”

Social behaviour as a predominant driver of sexual, age-dependent and reproductive segregation in Mediterranean mouflon

“…habitat use, activity budget) of individuals with variable characteristics (sex, age, reproductive status). In addition, to explain segregation between sex and age classes, especially in hot environments, the WSH has been largely ignored, despite an increasing number of studies revealing specific behaviours in animals with contrasting body size, when facing adverse weather conditions (Alonso et al, 2016;Aublet, Festa-Bianchet, Bergero, & Bassano, 2009;Conradt et al, 2000;Garnick, Di Stefano, Elgar, & Coulson, 2014;Shrestha et al, 2014).…”

OpenDropOff: An open‐source, low‐cost drop‐off unit for animal‐borne devices

“…The eleventh device failed to detach after being damaged during what appeared to be a fatal koala fall from a tree, with an assessment of the OpenDropOff componentry suggesting that the device's timing circuit was damaged in the fall. Another device was deployed on a swamp wallaby in 2011, using similar methods as Di Stefano, Moyle, and Coulson () and Garnick, Di Stefano, Elgar, and Coulson (), as part of a study on macropod road ecology and successfully detached after 14 days. Here, the drop‐off componentry was housed within the main battery housing of the collar unit, consisting of a two‐part epoxy (Solid Cast 651, Solid Solutions) formed in a silicone mould.…”