The diet of the Bridled nailtail wallaby (Onychogalea fraenata). II Overlap in dietry niche breadth and plant preferences with the black-striped wallaby (Macropus dorsalis) and domestic cattle

Abstract

Patterns of dietary selection were examined in the rare bridled nailtail wallaby (Onychogalea fraenata) and compared with those of the black-striped wallaby (Macropus dorsalis) and cattle on the Taunton Scientific Reserve in central Queensland. These two species were considered as possible competitors of 0, fraenata. The dietary niche breadth, the similarity of diet to resources, of 0. fraenata was always narrower than those of the larger species. However, the niche breadths of all species broadened significantly during the driest seasonal conditions, which accounts for the increased dietary overlaps previously reported in these conditions. An analysis of dietary preferences (electivities) showed that 0. fraenata had a high preference for herbaceous plants (forbs and malvaceous species), whereas M. dorsalis and cattle had high preference for grass. During dry conditions the preferred diet of 0. fraenata was considerably different to its actual diet, indicating that the diet was suboptimal. This pattern was not as pronounced in the other herbivores, suggesting that 0. fraenata could be at a competitive disadvantage during these conditions in its last refuge.