Browsing by Author "Jenkins, CN"

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Open Access
Deforestation risks posed by oil palm expansion in the Peruvian Amazon
(Environmental Research Letters, 2018-11-01) Vijay, V; Reid, CD; Finer, M; Jenkins, CN; Pimm, SL
Further expansion of agriculture in the tropics is likely to accelerate the loss of biodiversity. One crop of concern to conservation is African oil palm (Elaeis guineensis). We examined recent deforestation associated with oil palm in the Peruvian Amazon within the context of the region's other crops. We found more area under oil palm cultivation (845 km2) than did previous studies. While this comprises less than 4% of the cropland in the region, it accounted for 11% of the deforestation from agricultural expansion from 2007-2013. Patches of oil palm agriculture were larger and more spatially clustered than for other crops, potentially increasing their impact on local habitat fragmentation. Modeling deforestation risk for oil palm expansion using climatic and edaphic factors showed that sites at lower elevations, with higher precipitation, and lower slopes than those typically used for intensive agriculture are at long-term risk of deforestation from oil palm agriculture. Within areas at long-term risks, based on CART models, areas near urban centers, roads, and previously deforested areas are at greatest short-term risk of deforestation. Existing protected areas and officially recognized indigenous territories cover large areas at long-term risk of deforestation for oil palm (>40%). Less than 7% of these areas are under strict (IUCN I-IV) protection. Based on these findings, we suggest targeted monitoring for oil palm deforestation as well as strengthening and expanding protected areas to conserve specific habitats.
Open Access
The biodiversity of species and their rates of extinction, distribution, and protection.
(Science (New York, N.Y.), 2014-05) Pimm, SL; Jenkins, CN; Abell, R; Brooks, TM; Gittleman, JL; Joppa, LN; Raven, PH; Roberts, CM; Sexton, JO
Recent studies clarify where the most vulnerable species live, where and how humanity changes the planet, and how this drives extinctions. We assess key statistics about species, their distribution, and their status. Most are undescribed. Those we know best have large geographical ranges and are often common within them. Most known species have small ranges. The numbers of small-ranged species are increasing quickly, even in well-known taxa. They are geographically concentrated and are disproportionately likely to be threatened or already extinct. Current rates of extinction are about 1000 times the likely background rate of extinction. Future rates depend on many factors and are poised to increase. Although there has been rapid progress in developing protected areas, such efforts are not ecologically representative, nor do they optimally protect biodiversity.
Open Access
Volume and Geographical Distribution of Ecological Research in the Andes and the Amazon, 1995-2008
(2011) Pitman, NCA; Widmer, J; Jenkins, CN; Stocks, G; Seales, L; Paniagua, F; Bruna, EM
The Andes range and the Amazon basin represent the most diverse biological community on earth and the largest tropical forest on earth, respectively, but they are historically understudied by biologists. In this paper we provide the first quantitative description of the volume and geographical distribution of ecological research in these regions. We compiled a dataset of all articles based on the Andes and Amazon regions published in two prominent international tropical ecology journals between 1995 and 2008. During this period, the number of scientific articles based on research in the Amazon was half that based on research in Central America, while the Andes scored among the least-studied of all tropical regions. Brazil was the leading base for Amazonian studies and Ecuador the primary location for Andean studies, but Ecuador led both categories and Brazil came last when research effort was standardized by area. Most Amazonian research took place in three regions—Manaus, southeastern Peru, and eastern Ecuador—with ~31 percent of all papers coming from four field stations in those regions. Andean research focused overwhelmingly on the northern Andes. Research in the Andes range and the Amazon basin remains scattered, patchy, and far below its potential. We propose steps that funding agencies can take to increase research output and reduce geographical bias in the study of South America's richest ecosystems.