Small mammal and reptile persistence in desert grasslands during a period of low rainfall – Part 1

Abstract

The abundance of Australia's arid zone vertebrates is typically driven by fluctuations in rainfall, which dictate productivity across functional groups. Many species fluctuate from highly abundant during high rainfall periods to low abundance during low rainfall periods. Although these fluctuations are well documented, little is known regarding the factors affecting fauna persistence during periods of low rainfall. We examined the relationship between several influential factors and the richness and abundance of nocturnal small mammal and reptiles in the spinifex sand plains of central Australia. The study was conducted during a period of low rainfall following the decline of most vertebrate species in the area. Mammals showed species-specific responses, with varying dependencies on cover and climatic factors, whilst reptiles showed a surprisingly limited response to resource abundances and rainfall. The most consistent factor associated with small mammal and reptile abundances was the presence of large predators. Cats had greater suppressive effects on small mammals whilst reptiles declined with greater wild dog presence. These results likely represent a combination of selective foraging and seasonal fluctuations in activity of the two predators. Our results highlight the importance of controlling predator numbers during low rainfall periods to reduce their potential suppressive effects.