Human impact on the environment is evident globally, including within the most biodiverse areas. Of particular conservation importance is human impact on the world’s remaining wild areas, which contain the largest intact land parcels relatively free of human influence. Larger, intact areas are essential to the conservation of many habitats and species, which other smaller, fragmented areas cannot support. Here, we use the human footprint index to measure the extent of human impact on the world’s last wild areas —between 1993 and 2009— and to determine if protected areas have been effective in preserving land from further human impact. Specifically, we use the quasi-experimental matching technique to compare human footprint inside and outside protected areas, in each of the world’s biomes.
Results/Conclusions
In general, we found that the increases in human footprint were lower inside than outside protected areas; however, in half of the biomes examined, the differences were insignificant. Moreover, the increases in human footprint were higher in tropical than temperate regions, suggesting that wild areas in the tropics — a region that harbors much of the planet’s biodiversity — are under greater human pressure. Furthermore, upon analysis of IUCN protected area categories, we found no relationship between the increases in human footprint and the IUCN level of protected areas. Our findings suggest that protected areas alone are unlikely to be ubiquitously successful in preserving wild areas. To achieve protection, it is important to address the drivers of human impact within wild areas and to improve environmental governance.