Spatial mosaics of small animal communities across habitat and vegetation cover in semiarid Australia

Abstract

The fluctuating environment of arid lands drives spatial and temporal variation in resource availability and habitat suitability for animals. Patches of vegetative growth may create refuges that allow populations to persist when resources are scarce. Yet the links between fine-scale spatial variation and animal abundance are not well known. Here, we examine whether spatial variation in habitat and microhabitat create spatial mosaics in animal abundance. We surveyed ground-dwelling vertebrates and invertebrates in two adjacent habitats in semiarid Australia (cracking clay floodplains and rocky gibber), and across variation in microhabitat (vegetation cover). There was considerable variation in vegetation cover, creating fine-scale spatial mosaics of microhabitats. However, animal community composition did not vary significantly across the two main habitats. At the microhabitat level, numbers of spiders and reptiles were positively associated with woody vegetation cover. Vegetation cover did not significantly impact other taxonomic groups or overall community composition. The results show that response to microhabitats by animal populations is taxon-specific. Woody shrubs may provide a more reliable or more detectable microhabitat refuge compared to grasses for particular taxa. Informed wildlife conservation in arid lands requires investigating taxon-specific habitat and microhabitat associations, as well as the scale and persistence of these associations.