The importance of ecological scale for wildlife conservation in naturally fragmented environments: A case study of the brush-tailed rock-wallaby (Petrogale penicillata) J.V. Murray a,b, * , S. Low Choy c , C.A. McAlpine b,d , H.P. Possingham a,b , A.W. Goldizen a,b a School of Integrative Biology, University of Queensland, Brisbane, Qld 4072, Australia b The Ecology Centre, School of Integrative Biology, University of Queensland, Brisbane, Qld 4072, Australia c School of Mathematical Sciences, Queensland University of Technology, Brisbane, Qld 4000, Australia d Centre for Remote Sensing and Spatial Information Science, School of Geographical Sciences and Architecture, University of Queensland, Brisbane, Qld 4072, Australia ARTICLE INFO Article history: Received 16 December 2006 Received in revised form 22 May 2007 Keywords: Scale Habitat complexity Species–environment relationship Landscape context Classification trees Stratification ABSTRACT Determining the ecologically relevant spatial scales for predicting species occurrences is an important concept when determining species–environment relationships. Therefore spe- cies distribution modelling should consider all ecologically relevant spatial scales. While several recent studies have addressed this problem in artificially fragmented landscapes, few studies have researched relevant ecological scales for organisms that also live in nat- urally fragmented landscapes. This situation is exemplified by the Australian rock-walla- bies’ preference for rugged terrain and we addressed the issue of scale using the threatened brush-tailed rock-wallaby (Petrogale penicillata) in eastern Australia. We sur- veyed for brush-tailed rock-wallabies at 200 sites in southeast Queensland, collecting potentially influential site level and landscape level variables. We applied classification trees at either scale to capture a hierarchy of relationships between the explanatory vari- ables and brush-tailed rock-wallaby presence/absence. Habitat complexity at the site level and geology at the landscape level were the best predictors of where we observed brush- tailed rock-wallabies. Our study showed that the distribution of the species is affected by both site scale and landscape scale factors, reinforcing the need for a multi-scale approach to understanding the relationship between a species and its environment. We demonstrate that careful design of data collection, using coarse scale spatial datasets and finer scale field data, can provide useful information for identifying the ecologically relevant scales for studying species–environment relationships. Our study highlights the need to deter- mine patterns of environmental influence at multiple scales to conserve specialist species such as the brush-tailed rock-wallaby in naturally fragmented landscapes. Ó 2007 Published by Elsevier Ltd. 1. Introduction Determining the ecologically relevant spatial scales for pre- dicting the distribution and abundance of organisms is a fun- damental goal in ecology (Donovan et al., 1987; Clark et al., 1993; Orrock et al., 2000). Ecological theory proposes that wildlife populations can be studied within a hierarchy of lev- els of ecological organisation (Bissonette, 1997; Saab, 1999; 0006-3207/$ - see front matter Ó 2007 Published by Elsevier Ltd. doi:10.1016/j.biocon.2007.07.020 * Corresponding author. Address: School of Integrative Biology, University of Queensland, Brisbane, Qld 4072, Australia E-mail addresses: j.murray@sols.uq.edu.au (J.V. Murray), s.lowchoy@qut.edu.au (S. Low Choy), c.mcalpine@uq.edu.au (C.A. McAlpine), h.possingham@uq.edu.au (H.P. Possingham), a.goldizen@uq.edu.au (A.W. Goldizen). BIOLOGICAL CONSERVATION 141 (2008) 7 – 22 available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/biocon