A global-level assessment of the effectiveness of protected areas at resisting anthropogenic pressures

Abstract

One-sixth of the global terrestrial surface now falls within protected areas (PAs), making it essential to understand how far they mitigate the increasing pressures on nature which characterize the Anthropocene. In by far the largest analysis of this question to date and not restricted to forested PAs, we compiled data from 12,315 PAs across 152 countries to investigate their ability to reduce human pressure and how this varies with socioeconomic and management circumstances. While many PAs show positive outcomes, strikingly we find that compared with matched unprotected areas, PAs have on average not reduced a compound index of pressure change over the past 15 y. Moreover, in tropical regions average pressure change from cropland conversion has increased inside PAs even more than in matched unprotected areas. However, our results also confirm previous studies restricted to forest PAs, where pressures are increasing, but less than in counterfactual areas. Our results also show that countries with high national-level development scores have experienced lower rates of pressure increase over the past 15 y within their PAs compared with a matched outside area. Our results caution against the rapid establishment of new PAs without simultaneously addressing the conditions needed to enable their success.

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.…”

Half of the world’s tree biodiversity is unprotected and is increasingly threatened by human activities

“…Conversely, the remaining half of these priority areas is not protected and largely located in places with high anthropogenic activities, thus, future conservation planning should be more based on restoration actions. Meanwhile, attention should also be paid to the increasing pressure within the existing protected areas (26,29,38), as rising human pressure is a risk in many places (e.g., the Serengeti-Mara ecosystem (66)), in addition to rising pressure from human-driven climate change (67) or extreme disturbance events such as mega-fires (68). From the aspect of tree biodiversity, the existing conservation priority frameworks are helpful for planning and implementing future PAs, especially the Global 200…”

“…Protected areas (PAs) are the primary conservation strategy for preventing biodiversity loss and preserving nature (24)(25)(26). In recent decades, the expansion of PAs has been considerable, with ~15% of the Earth's land now located within PAs (the World Database on Protected Areas, WDPA; https://livereport.protectedplanet.net/chapter-2, accessed on April 15, 2020).…”

“…Despite the rapid progress of PA expansion worldwide, research has found that current PAs do not overlap with certain regions that harbor otherwise high taxonomic diversity (e.g., mammals (27,28). Additionally, approximately one third of global PAs are experiencing intense human pressure (29), and this phenomenon is likely to continue globally as human activity increases near existing protected areas (26,30).…”