Avian life-history determinants of local extinction risk in a hyper-fragmented neotropical forest landscape A. C. Lees & C. A. Peres Centre for Ecology Evolution and Conservation, School of Environmental Sciences, University of East Anglia, Norwich, UK Keywords Brazil; birds; life history; conservation; rainforest; habitat fragmentation; extinction risk. Correspondence Alexander C. Lees, Centre for Ecology Evolution and Conservation, School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK. Email: a.lees@uea.ac.uk Received 10 September 2007; accepted 20 January 2008 doi:10.1111/j.1469-1795.2008.00162.x Abstract The fact that species vary in their vulnerability to extinction is well documented, but the reasons for these differences remain poorly understood. Why should some species/families/guilds decline rapidly with increasing anthropogenic disturbance, while others either tolerate or proliferate in disturbed habitats? We investigated the bird species composition in 31 primary forest patches of varying size in a region of the Amazonian ‘Arc of Deforestation’ and assessed which species life-history traits predisposed individual species to extinction. Medium-sized non-flocking canopy frugivores/ominvores of low primary forest dependence were least likely to go extinct in small patches, while small-bodied flock-following primary-forest-depen- dent terrestrial insectivores were most fragmentation sensitive. We found highly idiosyncratic relationships between the minimum size of forest patches occupied by different species and their territory size requirements estimated based on other Amazonian studies. This suggests that avian assemblages in forest fragments primarily comprise species that either have good dispersal abilities or are highly tolerant to the non-forest matrix, rather than those whose minimum spatial requirements can be met by the size of available forest fragments. Introduction Conservation biologists have invested considerable effort identifying the life-history traits that render certain species, guilds, families or communities vulnerable to extinction (see reviews in McKinney, 1997; Purvis et al., 2000; Henle et al., 2004). Identifying traits associated with increased extinction risk may facilitate the protection of species sensitive to disturbance (Lindenmayer et al., 2002; Martin & Possi- ngham, 2005). Birds are often used as a model taxonomic group as they (1) form a diverse assemblage for which key life-history attributes are better known than for any other group; (2) are relatively easy to survey; (3) occupy spatial scales amenable to human perceptions. Despite recent macroecological progress in our understanding of the rela- tionship between sensitivity to anthropogenic disturbance and life-history traits on a global or continental scale (e.g. Purvis et al., 2000; Fagan et al., 2001; O’Grady et al., 2004), few studies have investigated these relationships at the level of local assemblages within a given landscape. Traits com- monly linked to local extinction proneness include geo- graphic range size, population size and variability, body mass and life-history specialization. According to the classi- fication scheme of Vos et al. (2001), species least vulnerable to fragmentation should be generalist species with high densities, small spatial requirements, high mobility and short generation times. Although a considerable body of work on traits related to extinction risk focuses on population persistence following habitat fragmentation (e.g. Blake, 1991; Laurance, 1991; Terborgh et al., 1997; Davies, Gascon & Margules, 2001), the entire southern Amazonian region has received little attention. Gage et al. (2004) used a comparative macroeco- logical modelling approach to investigate the threat of extinction to Neotropical birds, and for the southern Ama- zonian region concluded that the only weak predictors of threat were body size (larger species being more threatened) and number of habitats (species occupying more habitats being less threatened). The Brazilian Amazon contains about 40% of the world’s remaining tropical rainforest and is subject to the world’s highest absolute tropical deforestation rate, currently aver- aging nearly 2 million hectares per year (INPE, 2007). Despite this, lowland Amazonia is not widely recognized as an area of current avian conservation priority (Fjelds˚a & Rahbek, 1998), on account of its low levels of endemicity – containing only five endemic bird areas (EBAs), of which two are on the western fringe close to the Andes (Statters- field et al., 1998). Moreover, with habitat loss and fragmen- tation accelerating right across the continent, species threatened in the near future will also include many that are not currently considered to be range restricted. The Amazon is however an excellent model region in which to study the relationship between sensitivity to disturbance and life-history traits because of (1) its recent history of anthro- pogenic habitat fragmentation and degradation and (2) it is a vast, relatively uniform region with few endemics (there- fore avoiding the confounding problems associated with Animal Conservation 11 (2008) 128–137 c  2008 The Authors. Journal compilation c  2008 The Zoological Society of London 128 Animal Conservation. Print ISSN 1367-9430