The impact of warrens of the European rabbit (Oryctolagus cuniculus L.) on soil and ecological processes in a semi-arid Australian woodland

We examined the impact of the European rabbit (Oryctolagus cuniculus L.) on vegetation and soils of three microsites associated with rabbit warren complexes: the elevated mounds, the non-mound control areas, and an intermediate disturbed area. Mound surfaces supported significantly fewer plant species (n = 6.4) compared with control surfaces (n = 14.2). Mounds were typically raised structures with a local microrelief of 20 cm, and characterized by significantly more bare ground, and less litter and cryptogam cover, compared with the control surfaces. The flat micro-surfaces on the warrens were dominated by bare soils and lag gravel, whilst those on the control surfaces were dominated by cryptogams. Levels of dry and water-stable aggregation indicated that warren surfaces were significantly less stable than adjacent control surfaces. The results indicate that rabbit warrens are inherently unstable and erodible, and support a plant community of substantially reduced diversity and richness. Mechanical destruction of the warren, combined with destruction of the resident rabbit population is probably necessary to restabilize the area associated with the warrens. (C) 2001 Academic Press.