Browsing by Author "Pimm, SL"
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Item Open Access "Can we defy nature's end?" (vol 293, pg 2207, 2001)(SCIENCE, 2001-10-26) Pimm, SLItem 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, SLFurther 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.Item Open Access Disconnects in evaluating the relative effectiveness of conservation strategies(Conservation Biology, 2004-06-01) Saterson, KA; Christensen, NL; Jackson, RB; Kramer, RA; Pimm, SL; Smith, MD; Wiener, JBItem Open Access Habitat fragmentation and biodiversity conservation: key findings and future challenges(Landscape Ecology, 2016-02-01) Wilson, MC; Chen, XY; Corlett, RT; Didham, RK; Ding, P; Holt, RD; Holyoak, M; Hu, G; Hughes, AC; Jiang, L; Laurance, WF; Liu, J; Pimm, SL; Robinson, SK; Russo, SE; Si, X; Wilcove, DS; Wu, J; Yu, MItem Open Access On nestedness in ecological networks(Evolutionary Ecology Research, 2010-01-01) Joppa, LN; Montoya, JM; Solé, R; Sanderson, J; Pimm, SLQuestions: Are interaction patterns in species interaction networks different from what one expects by chance alone? In particular, are these networks nested - a pattern where resources taken by more specialized consumers form a proper subset of those taken by more generalized consumers? Organisms: Fifty-nine and 42 networks of mutualistic and host-parasitoid interactions, respectively. Analytical methods: For each network, the observed degree of nestedness is compared with the distribution of nestedness values derived from a collection of 1000 random networks. Those networks with nestedness values lower than 95% of all random values are considered 'unusually nested'. The analysis considers two different metrics of nestedness and five different network randomization algorithms, each of which differs in the ecological assumptions imposed. Results: Most ecological networks are unusually nested when compared with loosely constrained random networks. Comparisons with highly constrained networks temper these findings, but we still report a significant preponderance of nested networks (typically those with the most species). Conclusions: Bascompte et al. (2003) previously showed most observed mutualistic networks to be unusually nested. Later work using more ecologically realistic randomization algorithms cast doubt on those results. Across the largest set of species interactions considered to date, we conclude that an unexpectedly large number of interaction networks are patterned in a non-random manner. © 2010 Stuart L. Pimm.Item Open Access Relationship between giant panda populations and selected ecosystem services(Ecosystem Services, 2020-08-01) Zhang, J; Pimm, SL; Xu, W; Shi, X; Xiao, Y; Kong, L; Fan, X; Ouyang, ZThe Convention on Biological Diversity's Aichi Targets address both biodiversity and ecosystem services. We explore the relationship between giant panda populations and three ecosystem services: carbon sequestration, water retention, and soil retention. Do pandas prefer areas with higher than average values of these services? Areas may be good for pandas but not for these ecosystem services, and vice versa. Answering these questions can focus panda conservation. We map their spatial distribution and temporal changes from 2000 to 2015, by watershed, to target future protected areas for both pandas and these ecosystem services. Pandas occupy watersheds with above-average carbon sequestration and water retention. There is no tendency for pandas to be increasing in watersheds that have higher than average values of these ecosystem services or in watersheds where they are improving. Protected areas represented watersheds with higher than average values of these ecosystem services but without pandas only poorly. Watersheds with pandas do provide higher than average ecosystem services, but watersheds above average for these ecosystem services often lack pandas. Those areas might be potentially important for pandas, but obstacles block their way. We identified conservation areas combining habitats, population, activity range, and higher than average values of these ecosystem services and then proposed new protected areas.Item Open Access Seabird trophic position across three ocean regions tracks ecosystem differences(Frontiers in Marine Science, 2018-09-07) Gagné, TO; Hyrenbach, KD; Hagemann, ME; Bass, OL; Pimm, SL; MacDonald, M; Peck, B; Van Houtan, KSWe analyze recently collected feather tissues from two species of seabirds, the sooty tern (Onychoprion fuscatus) and brown noddy (Anous stolidus), in three ocean regions (North Atlantic, North Pacific, and South Pacific) with different human impacts. The species are similar morphologically and in the trophic levels from which they feed within each location. In contrast, we detect reliable differences in trophic position amongst the regions. Trophic position appears to decline as the intensity of commercial fishing increases, and is at its lowest in the Caribbean. The spatial gradient in trophic position we document in these regions exceeds those detected over specimens from the last 130 years in the Hawaiian Islands. Modeling suggests that climate velocity and human impacts on fish populations strongly align with these differences.Item 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, JORecent 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.Item Open Access What we need to know to prevent a mass extinction of plant species(Plants People Planet, 2021-01-01) Pimm, SLHuman actions are driving plant species to extinction at rates a hundred to a thousand times faster than normal. To prevent extinctions, it would be helpful to have a more comprehensive taxonomic catalogue and much greater knowledge of where plant species live. Addressing these questions must be a scientific priority. However, what we know at present is enough to effect practical conservation actions, such as protecting more land in biodiverse places, reconnecting fragmented habitats, and eliminating species introduced outside their native ranges. For the benefit of people and the planet, we can, and must act on what we know already, to prevent catastrophic plant extinctions. Summary: Continuing destruction of habitats—and especially tropical forests—the introduction of plant and herbivorous animal species outside their native ranges, and global climate disruption all contribute to the extinction of plant species. What can we do to prevent this? Do we have enough basic information to make effective conservation decisions? First, how many plant species are there? This question has an easy element—how many species we know now—and a much more difficult one—how many do we not know. Second, where are the concentrations of plant species? Third, where are the species we do not yet know? Fourth, what plant species have gone extinct, and where did they live? A related question is which species are threatened with extinction and where do they live? Fifth, how well can we map threats to species? For habitat loss, remote sensing provides satellite images globally and very frequently. It does so at a resolution that often displays individual trees and bushes. Sixth, supposing we had detailed answers to the previous questions, what are we doing to protect species? How well does the existing network of protected areas encompass species, especially those with the smallest ranges? Does that network allow for species moving upslope as the climate heats up? How well are managers doing in removing introduced species? Although answering these questions must be a scientific priority, we cannot wait until we have all the answers. We can, and indeed must, act on what we know already.