Ground vertebrate fauna of Perth's vegetation remnants: impact of 170 years of urbanization

Abstract

Ground vertebrates were surveyed on 34 vegetation remnants on the Swan Coastal Plain within the Perth metropolitan area. The remnants ranged from one hectare to nearly 340 ha and were sampled for at least 50 days during the year using pitfall traps. Six remnants were sampled in two or more successive years. Seven native, non-volant mammal, six introduced mammal, 11 amphibian and 43 reptile species were recorded. Native mammals are the most disadvantaged vertebrates in urban remnants with few species surviving the effects of long-term fragmentation. The herpetofauna is less affected, although snakes are generally rare. Marked annual variation occurred in lizard assemblages recorded on remnants sampled over consecutive years. On average, these remnants had a similarity in species composition of only 77% between years. Small remnants are important for conservation of reptile assemblages and there is a strong correlation between remnant area and species number for all reptile groups, except skinks. Remnants as small as one hectare retain viable populations of many reptiles, but need active management to exclude fire and predation. Regional biogeographic patterns are apparent in reptiles. Subregional patterns on the Swan Coastal Plain are associated with different soil types and the Swan River also creates a barrier across landforms. The diversity of reptile assemblages and variation in species trophic patterns indicate that many elements of the original food chain continue to operate in these urban environments.