Although 12% of the planet's surface is protected, the global protected area network fails to encompass about a quarter of threatened vertebrate species that are in dire need of protection (Rodrigues et al. 2004). This result suggests that there may be a need to designate more protected areas, especially in the tropics where two-thirds of global biodiversity resides. Protected areas (reserves or national and regional parks) may be the only hope for retaining a reasonable proportion of residual tropical biodiversity (Bruner et al. 2001). However, major ongoing land conversion in the tropics will exert a massive negative impact on its biodiversity by the year 2100 (Sala et al. 2000). This anthropogenic land conversion is not limited to areas under no legal protection, as shown by DeFries et al. (2005). Using satellite imagery, they determined the habitat loss between the early 1980s and 2001 in 198 protected areas across the tropics that are critical for biodiversity (due to large size, a high level of protection and the presence of intact forests within the administrative boundary). Forest loss within and outside ‘buffer’ areas (the surrounding 50 km) was determined. Of the protected areas surveyed, 25% lost forests within their administrative boundaries, with 70% of them losing forests even in buffer areas. Buffer areas are critical as they dampen the negative effect of invasive species, fire and hunting in the protected areas.