Selective herbivory by red-necked pademelon Thylogale thetis at rainforest margins: factors affecting predation rates

We examined browsing by red-necked pademelons (Thylogale thetis) on shoots of rainforest plants at areas of rainforest–grassland interface in the Lamington Plateau of southeast Queensland. Terminal shoots from nine species (three each of vines, trees and shrubs) were compared. The effects of five factors (plant species, site, distance from forest edge, habitat (grassland or forest) and time (trip) at two levels of exposure (caged or uncaged)) were also compared. Among the uncaged shoots, 98% showed signs of damage compared with 18% of the caged shoots. In general, shoot predation was higher in the grassland than in the forest and decreased with increasing distance away from the forest edge in both habitats. The three vine species were more heavily browsed than all other species. Browsing by red-necked pademelons is likely to influence regeneration near forest edges through direct death of seedlings as a result of predation and through altered competitive interactions resulting from selective herbivory. This effect, however, would be lower on seedlings within the forest habitat and would also reduce as seedlings establish themselves further from the forest edge into grassland habitat.