The role of protected areas in mitigating human impact in the world’s last wilderness areas

Abstract

Human impact on the environment is evident across the planet, including its most biodiverse areas. Of particular interest is the impact on the world's last wilderness areas, in which the largest patches of land relatively free from human influence remain. Here, we use the human footprint index to measure the extent to which the world's last wilderness areas have been impacted by human activities-between the years 1993 and 2009-and whether protected areas have been effective in reducing human impact. We found that overall the increase in human footprint was higher in tropical than temperate regions. Moreover, although on average the increase was lower inside protected areas than outside, in half of the fourteen biomes examined the differences were insignificant. Although reasons varied, protected areas alone are unlikely to be ubiquitously successful in protecting wilderness areas. To achieve protection, it is important to address loss and improve environmental governance.

Effectiveness of protected areas in conserving tropical forest birds

“…In this study, we found that protected areas are effective in the sense that they perform better than comparable unprotected sites. We have, however, not demonstrated that they are sufficiently effective to halt habitat loss and degradation (which previous studies found to be ongoing and sometimes increasing within protected areas [17][18][19] ) nor that they halt population declines (which are still ongoing within many protected areas [35][36][37] ). Furthermore, our analysis does not address whether protected areas are sufficient in terms of their extent or representativeness (while previous studies attest that they are not 38,39 ).…”

“…5c; Supplementary Table 1). The last is the reciprocal result of two recent studies showing lower levels of human pressure within protected areas when compared with appropriate counterfactuals in tropical forests 18,19 .…”

“…Yet, evaluating protected area effectiveness in these regions is particularly challenging, given that the detailed biodiversity datasets required for counterfactual analyses are typically unavailable 16 . Among the few analyses investigating biodiversity outcomes of tropical protected areas, most focused on protected area effects on land cover, finding that they mitigate both forest loss and forest degradation 10,[17][18][19] . While such analyses are possible using ex situ remote sensing data, investigating effectiveness in terms of species outcomes requires data collected in situ.…”

Effectiveness of protected areas in conserving tropical forest birds

“…In this study, we found that protected areas are effective in the sense that they perform better than comparable unprotected sites. We have, however, not demonstrated that they are sufficiently effective to halt habitat loss and degradation (which previous studies found to be ongoing and sometimes increasing within protected areas [23][24][25] ) nor that they halt population declines (which are still ongoing within many protected areas [41][42][43] ). Furthermore, our analysis does not address whether protected areas are sufficient in terms of their extent of coverage or their representativeness (while previous studies attest that they are not 2,44 ).…”

“…Yet, evaluating protected area effectiveness in these regions is particularly challenging, given that the detailed biodiversity datasets required for counterfactual analyses are typically unavailable 22 . Among the few analyses investigating biodiversity outcomes of tropical protected areas, most focused on protected areas effects on habitats, finding that they mitigate both forest loss and forest degradation 18,[23][24][25] . While such analyses can utilise remote sensing data, investigating effectiveness in terms of species outcomes essentially requires data collected in situ.…”