COMMUNITY ECOLOGY - ORIGINAL RESEARCH Effects of wildfire, rainfall and region on desert lizard assemblages: the importance of multi-scale processes Louise A. Pastro • Christopher R. Dickman • Mike Letnic Received: 20 October 2012 / Accepted: 4 March 2013 Ó Springer-Verlag Berlin Heidelberg 2013 Abstract Vertebrate populations are influenced by envi- ronmental processes that operate at a range of spatial and temporal scales. Wildfire is a disturbance that can affect vertebrate populations across large spatial scales, although vertebrate responses are frequently influenced by processes operating at smaller spatial scales such as topography, interspecific interactions and regional history. Here, we investigate the effects of a broad-scale wildfire on lizard assemblages in a desert region. We predicted that a rainfall gradient within the region affected by the wildfire would influence lizard responses to the fire by encouraging post- fire succession to proceed more rapidly in high-rainfall areas, and would be enabled in turn by more rapid vege- tation recovery. To test our prediction, we censused lizards, measured rainfall, undertook vegetation surveys and sam- pled invertebrate abundance across burnt and unburnt habitat ecotones within three regional areas situated along a gradient of long-term annual rainfall. Lizard diversity was not affected by fire or region and lizard abundance was influenced only by region. Lizard assemblage composition was also only influenced by region, but this did not relate to differences in rainfall or habitat as we had predicted. Regional differences in lizard assemblages related instead to food availability. The observed differences also likely reflected regional differences in the strength of biotic interactions with predators and changes in land use. Our study shows that assemblage responses to a disturbance were not uniform within a large desert region and instead were influenced by other environmental processes operat- ing simultaneously at multiple temporal and spatial scales. Keywords Disturbance Á Fire Á Food Á Habitat accommodation Á Succession Introduction The distributions and abundances of animals often are influenced by a range of drivers that operate at different spatial scales (Harte et al. 2005; Haythornthwaite and Dickman 2006). At the largest scale, factors such as cli- mate and geography are most important. These in turn interact with processes operating at smaller scales, such as food and habitat availability, disturbances such as fires and storm events, interspecific interactions and human land use, so that the same global drivers will have different effects in different regions (Peters et al. 2004; Bestelmeyer et al. 2011). Wildfires in particular are an important determinant of animal distributions and the effects of these fires can be influenced by a range of multi-scale processes such as climate and rainfall patterns, fire history, habitat charac- teristics and predation pressure (Nimmo et al. 2012). Cli- mate change is predicted to drive shifts in rainfall regimes and increase the occurrence and intensity of wildfire events in many regions around the globe, providing an imperative Communicated by Raoul Van Damme. Electronic supplementary material The online version of this article (doi:10.1007/s00442-013-2642-7) contains supplementary material, which is available to authorized users. L. A. Pastro (&) Á C. R. Dickman Desert Ecology Research Group, School of Biological Sciences, University of Sydney, Heydon-Laurence Building A08, Sydney, NSW 2006, Australia e-mail: louise.pastro@sydney.edu.au M. Letnic Australian Wetlands, Rivers and Landscapes Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia e-mail: M.letnic@unsw.edu.au 123 Oecologia DOI 10.1007/s00442-013-2642-7