Abstract
Protected areas (PAs) are the cornerstones of global biodiversity conservation efforts, but to fulfil this role they must be effective at conserving the ecosystems and species that occur within their boundaries. Adequate monitoring datasets that allow comparing biodiversity between protected and unprotected sites are lacking in tropical regions. Here we use the largest citizen science biodiversity dataset – eBird – to quantify the extent to which protected areas in eight tropical forest biodiversity hotspots are effective at retaining bird diversity. We find generally positive effects of protection on the diversity of bird species that are forest-dependent, endemic to the hotspots, or threatened or Near Threatened, but not on overall bird species richness. Furthermore, we show that in most of the hotspots examined this benefit is driven by protected areas preventing both forest loss and degradation. Our results provide evidence that, on average, protected areas contribute measurably to conserving bird species in some of the world’s most diverse and threatened terrestrial ecosystems.
Highlights
Protected areas (PAs) are the cornerstones of global biodiversity conservation efforts, but to fulfil this role they must be effective at conserving the ecosystems and species that occur within their boundaries
We investigate the effectiveness of protected areas in eight tropical forest biodiversity hotspots across three continents (Fig. 1), which are the epicentres of the ongoing biodiversity crisis and regions where effective conservation efforts are the most urgent[11,21,22]
Given that species richness is an intuitive and widely used measure of biodiversity[27], these results may appear worrying, by suggesting that protected areas do not prevent local biodiversity loss. They agree with a wealth of previous evidence that overall species richness is not a suitable indicator of local biodiversity impact, as species that go locally extinct due to ecosystem alteration can be replaced by others—often of lower conservation concern—with no or little impact on overall species a AATLL AANNDD TTUUMM MMESS EEASS GGHAA IINNDD SSUUNN
Summary
Protected areas (PAs) are the cornerstones of global biodiversity conservation efforts, but to fulfil this role they must be effective at conserving the ecosystems and species that occur within their boundaries. Contrasting any protected and unprotected sites would not be an adequate counterfactual analysis, because it would conflate implementation effects (the difference protected areas have made) with location biases (differences between protected and unprotected sites prior to protected areas implementation)[5,6] Such location biases are inevitable because protected areas tend to be designated in regions of little economic interest (i.e. greater remoteness, higher altitudes, and lower agricultural suitability6,7), which are less likely to have suffered from human pressure both before and after protection. These differences can be statistically controlled for in counterfactual analyses of protected area effectiveness[8,9,10], but this requires large datasets on the spatial distribution of the biodiversity features of interest across many protected and unprotected sites. Evaluating protected area effectiveness in these regions is challenging, given that the detailed biodiversity datasets required for counterfactual analyses are typically unavailable[16]
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