Rattus-Lutreolus, Colonizer of Heathland After Fire in the Absence of Pseudomys Species

Abstract

The recolonization of heathland habitats by small mammals after wildfire was examined in Nadgee Nature Reserve, south-eastern New South Wales. The first native small mammal to arrive was R. lutreolus. Thickets of tall vegetation were very important and these were colonized via a network of runways leading from one thicket to another. R. lutreolus were reproductively active at a lower body weight on previously empty (marginal) heathland habitats than in preferred habitats. After fire, abundance and species diversity of small mammals increased as habitats aged and grew in complexity. Survival was best on the most structurally complex habitats. Different requirements of habitat and water are suggested as the main reasons R. lutreolus were first to colonize heathland, rather than R. fuscrpes. It is also proposed that the lack of competition from Pseudomys spp. may cause R. lutreolus to switch from the usual 'late regeneration niche' to an 'early' one. Past studies have proposed the reduction in burning since European settlement as a cause of the decline in several pseudomyine species. This paper proposes that too frequent burning may have the same result.