Increasing Isolation of Protected Areas in Tropical Forests Over the Past Twenty Years

Abstract

Protected areas are one of the cornerstones for conserving the world's remaining biodiversity, most of which occurs in tropical forests. We use multiple sources of satellite data to estimate the extent of forest habitat and loss over the last 20 years within and surrounding 198 of the most highly protected areas (IUCN status 1 and 2) located throughout the world's tropical forests. In the early 1980s, surrounding habitat in the 50‐km unprotected or less highly protected “buffers” enhanced the protected areas' effective size and their capacity to conserve richness of forest‐obligate species above the hypothetical case of complete isolation. However, in nearly 70% of the surrounding buffers, the area of forest habitat declined during the last 20 years, while 25% experienced declines within their administrative boundaries. The loss of habitat occurred in all tropical regions, but protected areas in South and Southeast Asia were most severely affected because of relatively low surrounding forest habitat in the early 1980s and high subsequent loss, particularly in dry tropical forests. The future ability of protected areas to maintain current species richness depends on integrating reserve management within the land use dynamics of their larger regional settings.

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“…However, because we did not control for landscape characteristics ("matching") there is a possibility we are overestimating the effect of protection (Joppa & Pfaff, 2010;Joppa & Pfaff, 2011;. Although our results do confirm a well-known pattern that protected areas on the African continent and globally are becoming increasingly isolated by land clearing beyond their boundaries (DeFries et al, 2005;Bailey et al, 2016;Newmark, 2008). This is concerning since degradation around a protected area strongly predisposes it to future degradation within its borders (Laurance et al, 2012 Local communities were also engaged during the development of an updated management plan for NNR, and helped define NNR's vision for the next decade.…”

Simulating Forest Cover Changes of Bannerghatta National Park Based on a CA-Markov Model: A Remote Sensing Approach

“…While there is an abundance of literature on quantitative assessments of deforestation in and around PAs, more so for dwindling tropical forests [100,102,103], there is a growing literature on tropical reforestation and regrowth [13,14,[104][105][106] which necessitates evaluation of PAs for both deforestation and reforestation trends. Additionally, traditional methods of evaluating PAs have varied (comparison of inside versus outside PA, protected versus non protected forest, past trends versus future trends), but most of these studies still focus on assessing deforestation rates.…”

Role of Brazilian Amazon protected areas in climate change mitigation

“…The well-supported argument against using buffer zones for pairwise comparison made by this second group of studies is that landscape characteristics in sampled areas are not the same: areas in the interior of PAs usually are more remote (18) and thus are less likely to be deforested than areas in their exterior (12,16,17). Conclusions from these studies regarding the inhibitory effect of PAs on deforestation also vary, from a positive effect (9,10,15) that, however, is not seen in all PA groups (11) or a positive but modest effect (12,13,16,17) to no effect (14). As a result, the terms "de jure" and "de facto" have been used to qualify PA effects (11); the latter simply expresses a bias toward PA's more remote location.…”

“…Previous studies have quantified the effectiveness of these PAs in reducing deforestation (9)(10)(11), but the methods adopted to measure PA performance are somewhat controversial (12). We reviewed nine studies (9-17) of PA effects on tropical deforestation, summarizing their methods, assumptions, and main conclusions (Table S2).…”