Size distribution of all forest patches surveyed (left, N = 196) or not surveyed (right, N = 613,997 patches >0.25 ha) within the entire study region (∼252,669 km 2). Although this BSR has a long history of deforestation following 16 th-century European conquest, , ∼75% of its forest cover persisted until 1945, with deforestation in the mid 1970s spreading rapidly throughout the region following a peak of road-building. Within the entire biome, the Bahia Centre of Endemism is often considered to be one of the most species-rich, retaining the highest levels of local endemism, which is partly attributed to its stable forest refugia during late Pleistocene climatic extremes. Currently, ∼89.2% of the original forest cover (∼37,365,280 ha) of the four biogeographic subregions (BSRs) of the Atlantic Forest surveyed in this study have been converted to other land-uses and the remaining forest cover is heavily skewed to very small fragments (<10 ha) ( Fig. The once vast Atlantic Forest biome (∼1.5 million km 2) is one of the ‘hottest’ of the global biodiversity hotspots due to unrivalled numbers of endemic species and a relentless process of post-colonial deforestation. These secondary impacts can interact synergistically with the twin effects of reduced habitat area and increased isolation, thereby potentially exacerbating the rate of biodiversity loss within remaining forest fragments. In practice, tropical forest remnants persisting in real-world human-dominated landscapes coexist with a range of other forms of anthropogenic perturbations, including overhunting, timber extraction, surface fires, invasion of exotic species, and mesopredator release via removal of top-down control –. The consequences of both habitat loss and fragmentation to population extinctions in tropical forest landscapes remain poorly understood and largely based on unqualified theoretical conjectures derived from the species-area relationship. Tropical deforestation will continue to occupy the center of most 21 st-century conservation agendas due to its disproportionate role in local to regional scale extinctions in terrestrial ecosystems worldwide. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.įunding: The authors thank Brazilian Ministry of Environment/Probio for supporting fieldwork and Brazilian Ministry of Education/CAPES for PhD studentship of G. Received: MaAccepted: JPublished: August 14, 2012Ĭopyright: © Canale et al. PLoS ONE 7(8):Ĭentre National de la Recherche Scientifique, France
Hence, conventional species-area curves provided over-optimistic estimates of species persistence in that most forest fragments had lost species at a much faster rate than predicted by habitat loss alone.Ĭitation: Canale GR, Peres CA, Guidorizzi CE, Gatto CAF, Kierulff MCM (2012) Pervasive Defaunation of Forest Remnants in a Tropical Biodiversity Hotspot. Forest fragments were highly accessible to hunters and exposed to edge effects and fires, thereby severely diminishing the predictive power of species-area relationships, with the power model explaining only ∼9% of the variation in species richness per patch. On average, forest patches retained 3.9 out of 18 potential species occupancies, and geographic ranges had contracted to 0–14.4% of their former distributions, including five large-bodied species that had been extirpated at a regional scale. We uncovered a staggering rate of local extinctions in the mammal fauna, with only 767 from a possible 3,528 populations still persisting.
PERVASIVE DEFINITON PATCH
We scrutinized 8,846 person-years of local knowledge to derive patch occupancy data for 18 mammal species within 196 forest patches across a 252,669-km 2 study region of the Brazilian Atlantic Forest.
Here, we report unprecedented rates of local extinctions of medium to large-bodied mammals in one of the world's most important tropical biodiversity hotspots.
Tropical deforestation and forest fragmentation are among the most important biodiversity conservation issues worldwide, yet local extinctions of millions of animal and plant populations stranded in unprotected forest remnants remain poorly explained.
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