Large mammal population declines in Africa’s protected areas Ian D. Craigie a,c,e, * , Jonathan E.M. Baillie b , Andrew Balmford a , Chris Carbone c , Ben Collen c , Rhys E. Green a,d , Jon M. Hutton e a Conservation Science Group, Department of Zoology, University of Cambridge, CB2 3EJ, UK b Conservation Programmes, Zoological Society of London, NW1 4RY, UK c Institute of Zoology, Zoological Society of London, London, NW1 4RY, UK d Royal Society for the Protection of Birds, The Lodge, Sandy, SG19 2DL, UK e UNEP World Conservation Monitoring Centre, Cambridge, CB3 0DL, UK article info Article history: Received 14 March 2010 Received in revised form 1 June 2010 Accepted 8 June 2010 Available online 3 July 2010 Keywords: CBD 2010 Effectiveness Monitoring Parks Performance Time series abstract Protected areas (PAs) are the cornerstone of global conservation efforts but their performance in main- taining populations of their key species remains poorly documented. Here, we address this gap using a new database of 583 population abundance time series for 69 species of large mammals in 78 African PAs. Population abundance time series were aggregated to form a multi-species index of overall change in population abundance. The index reveals on average a 59% decline in population abundance between 1970 and 2005. Indices for different parts of Africa demonstrate large regional differences, with southern African PAs typically maintaining their populations and western African PAs suffering the most severe declines. These results indicate that African PAs have generally failed to mitigate human-induced threats to African large mammal populations, but they also show some successes. Further development of our index could help to measure future progress towards post-2010 targets for reducing biodiversity loss. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction National and international conservation strategies rely on pro- tected areas (PAs) to protect biodiversity from negative human im- pacts. Protected areas cover approximately 12.9% of the world’s land surface and have expanded in area fourfold over the past three decades (Chape et al., 2008). Given the high investment that has been made in PAs (Balmford et al., 2003) and their importance for conservation, it is crucial to document how effectively they are performing (Naughton-Treves et al., 2005). Yet despite calls to investigate this topic (Caro and Scholte, 2007) there are cur- rently few direct measures of terrestrial PA performance. Some studies of PA performance are based on management inputs and processes (Hockings et al., 2006; Leverington et al., 2008), but these measures have a poorly quantified relationship to biodiver- sity outcomes, thus currently limiting their utility. Other studies have investigated the degree to which PAs cover the geographic ranges of species (e.g. Rodrigues et al., 2004) or capture habitat diversity (e.g. Scott et al., 2001) but they do not measure their effi- cacy in protecting ecosystems or retaining species over the long term. Quantitative measurement of the conservation outcomes of PAs is urgently needed. The main measure of PA conservation performance developed to date is the extent to which PAs retain their natural habitat in relation to their surrounding areas (Bruner et al., 2001; Curran et al., 2004; Joppa et al., 2008; Nelson and Chomitz, 2009; Oliveira et al., 2007; Ostrom and Nagendra, 2006). This approach has been successfully applied to forested PAs, where remotely-sensed data can be used to compare forest cover inside and outside PAs. How- ever, such data have been of limited use in detecting the visually subtle but biologically important habitat modification and degra- dation occurring in environments such as savanna and grassland (Nagendra and Rocchini, 2008). Habitat-based measures are also unable to detect population declines due to direct species exploita- tion (e.g. bushmeat hunting – Brashares et al., 2004), or to out- breaks of diseases (e.g. ebola – Leroy et al., 2004). The need for quantitative measures of biodiversity outcomes in PAs is underscored by the Millennium Development Goals on envi- ronmental sustainability (MEA, 2005) and by the Convention on Biological Diversity (CBD – UNEP, 2002). In April 2002, 188 govern- ment Parties to the CBD agreed ‘‘to achieve by 2010 a significant reduction of the current rate of biodiversity loss” (CBD Decision 0006-3207/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.biocon.2010.06.007 * Corresponding author at: Conservation Science Group, Department of Zoology, University of Cambridge, CB2 3EJ, UK. Tel.: +44 7989 986477. E-mail addresses: idc28@cam.ac.uk, ian.craigie@ioz.ac.uk (I.D. Craigie), jonathan. baillie@ioz.ac.uk (J.E.M. Baillie), apb12@cam.ac.uk (A. Balmford), chris.carbone@ioz. ac.uk (C. Carbone), ben.collen@ioz.ac.uk (B. Collen), reg29@cam.ac.uk (R.E. Green), jon.hutton@unep-wcmc.org (J.M. Hutton). Biological Conservation 143 (2010) 2221–2228 Contents lists available at ScienceDirect Biological Conservation journal homepage: www.elsevier.com/locate/biocon