Diet of four rock‐dwelling macropods in the Australian monsoon tropics

Abstract

An unusually high diversity of macropods inhabit the rocky areas in the monsoon tropics of the Northern Territory, Australia, yet the mechanisms that allow their niche separation are not clear. Previous studies suggest that the nabarlek, Petrogale concinna, may have a more grazing diet than the short-eared rock-wallaby, Petrogale brachyotis, with whom it coexists. Thus, diet may be an important mechanism of niche separation between these species. We examined the diet of the four sympatric species (the black wallaroo Macropus bernardus, common wallaroo Macropus robustus, P. brachyotis and P. concinna ) to determine whether there are differences in the dominant plant groups eaten by the species across the landscape and with season. Diets were determined with a macroscopic analysis of the seed and fruit content of scats and an analysis of the 12 C to 13 C isotope ratios of scats using mass spectrometry. In the dry season the rock-wallaby species predominantly consumed browse and/or forbs, and the larger wallaroos predominantly consumed grass. However, there was large variation across the landscape in the dry season diets of P. brachyotis, M. bernardus and M. robustus ; including high proportions of grass eaten at some sites and high proportions of browse at other sites. In the wet season, greater proportions of grass were eaten by P. brachyotis and M. bernardus than in the dry season. Generally, there was little evidence to support the previous suggestion that P. concinna is more of a grazer than P. brachyotis , but there was some evidence than M. bernardus consumes greater amounts of browse and/or forbs than M. robustus .

Using carbon isotope analysis of the diet of two introduced Australian megaherbivores to understand Pleistocene megafaunal extinctions

“…Wet season (W) and dry season (D) values, estimated from dung δ 13 C are shown. Superscript numbers indicate the data sources (1, Telfer & Bowman, 2006; 2, Murphy & Bowman, 2007a). For comparative purposes, the approximate body mass for each species (Strahan, 1995) is shown in the top panel.…”

“…The largest marsupial browsers (rock wallabies, < 5 kg) are restricted to habitats associated with rocky outcrops in the savanna biome (Freeland et al. , 1988; Telfer & Bowman, 2006), and there is evidence that the savanna matrix presents a barrier to their spread (Telfer et al. , 2008).…”

Dietary classification of extant kangaroos and their relatives (Marsupialia: Macropodoidea)

“…Griffiths & Barker 1966;Hollis et al 1986;Dawson et al 2004), faeces (e.g. Horsup & Marsh 1992;Telfer & Bowman 2006;McMillan et al 2010), feeding observations (Taylor 1980;Lundie-Jenkins et al 1993) and indigenous knowledge (Burbidge et al 1988;Telfer & Garde 2006). Horsup & Marsh 1992;Telfer & Bowman 2006;McMillan et al 2010), feeding observations (Taylor 1980;Lundie-Jenkins et al 1993) and indigenous knowledge (Burbidge et al 1988;Telfer & Garde 2006).…”

Comparative dietary ecology of two congeneric marsupial folivores

“…Various methods exist for estimating folivore diet, including microhistological analysis of gut and/or faecal contents (Storr 1961;Norbury 1988), direct observations of feeding (Proctor-Gray 1984) and stable isotope analysis of faeces (Telfer & Bowman 2006). Microhistological analysis of faeces is commonly employed to examine folivore diet as it is noninvasive, inexpensive and repeatable.…”