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Do Community-Managed Forests Work? A Biodiversity Perspective
Community-managed reserves (CMRs) comprise the fastest-growing category of protected areas throughout the tropics. CMRs represent a compromise between advocates of nature conservation and advocates of human development. We ask whether CMRs succeed in achieving the goals of either. A fixed reserve area can produce only a finite resource supply, whereas human populations exploiting them tend to expand rapidly while adopting high-impact technologies to satisfy rising aspirations. Intentions behind the establishment of CMRs may be admirable, but represent an ideal rarely achieved. People tied to the natural forest subsist on income levels that are among the lowest in the Amazon. Limits of sustainable harvesting are often low and rarely known prior to reserve creation or respected thereafter, and resource exhaustion predictably follows. Unintended consequences typically emerge, such as overhunting of the seed dispersers, pollinators, and other animals that provide services essential to perpetuating the forest. CMRs are a low priority for governments, so mostly operate without enforcement, a laxity that encourages illegal forest conversion. Finally, the pull of markets can alter the "business plan" of a reserve overnight, as inhabitants switch to new activities. The reality is that we live in a hyperdynamic world of accelerating change in which past assumptions must continually be re-evaluated.
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Do Community-Managed Forests Work? A Biodiversity Perspective
Community-managed reserves (CMRs) comprise the fastest-growing category of protected areas throughout the tropics. CMRs represent a compromise between advocates of nature conservation and advocates of human development. We ask whether CMRs succeed in achieving the goals of either. A fixed reserve area can produce only a finite resource supply, whereas human populations exploiting them tend to expand rapidly while adopting high-impact technologies to satisfy rising aspirations. Intentions behind the establishment of CMRs may be admirable, but represent an ideal rarely achieved. People tied to the natural forest subsist on income levels that are among the lowest in the Amazon. Limits of sustainable harvesting are often low and rarely known prior to reserve creation or respected thereafter, and resource exhaustion predictably follows. Unintended consequences typically emerge, such as overhunting of the seed dispersers, pollinators, and other animals that provide services essential to perpetuating the forest. CMRs are a low priority for governments, so mostly operate without enforcement, a laxity that encourages illegal forest conversion. Finally, the pull of markets can alter the "business plan" of a reserve overnight, as inhabitants switch to new activities. The reality is that we live in a hyperdynamic world of accelerating change in which past assumptions must continually be re-evaluated.
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Saving the World's Terrestrial Megafauna
From the late Pleistocene to the Holocene and now the so-called Anthropocene, humans have been driving an ongoing series of species declines and extinctions (Dirzo et al. 2014). Large-bodied mammals are typically at a higher risk of extinction than smaller ones (Cardillo et al. 2005). However, in some circumstances, terrestrial megafauna populations have been able to recover some of their lost numbers because of strong conservation and political commitment, as well as human cultural changes (Chapron et al. 2014). Indeed, many would be in considerably worse predicaments in the absence of conservation action (Hoffmann et al. 2015). Nevertheless, most mammalian megafauna face dramatic range contractions and population declines. In fact, 59% of the world's largest carnivores (more than or equal to 15 kilograms, n = 27) and 60% of the world's largest herbivores (more than or equal to 100 kilograms, n = 74) are classified as threatened with extinction on the International Union for the Conservation of Nature (IUCN) Red List (supplemental tables S1 and S2). This situation is particularly dire in sub-Saharan Africa and Southeast Asia, home to the greatest diversity of extant megafauna (figure 1). Species at risk of extinction include some of the world's most iconic animals-such as gorillas, rhinos, and big cats (figure 2 top row)-and, unfortunately, they are vanishing just as science is discovering their essential ecological roles (Estes et al. 2011). Here, our objectives are to raise awareness of how these megafauna are imperiled (species in tables S1 and S2) and to stimulate broad interest in developing specific recommendations and concerted action to conserve them.
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Saving the World's Terrestrial Megafauna
In: Ripple , W J , Chapron , G , López-Bao , J V , Durant , S M , Macdonald , D W , Lindsey , P A , Bennett , E L , Beschta , R L , Bruskotter , J T , Campos-Arceiz , A , Corlett , R T , Darimont , C T , Dickman , A J , Dirzo , R , Dublin , H T , Estes , J A , Everatt , K T , Goswami , V R , Galetti , M , Hayward , M , Hedges , S , Hoffmann , M , Hunter , L T B , Kerley , G I H , Letnic , M , Levi , T , Maisels , F , Morrison , J C , Nelson , M P , Newsome , T M , Painter , L , Pringle , R M , Sandom , C J , Terborgh , J , Treves , A , Van Valkenburgh , B , Vucetich , J A , Wirsing , A J , Wallach , A D , Wolf , C , Woodroffe , R , Young , H & Zhang , L 2016 , ' Saving the World's Terrestrial Megafauna ' , BioScience , vol. 66 , no. 10 , pp. 807-812 . https://doi.org/10.1093/biosci/biw092
From the late Pleistocene to the Holocene and now the so-called Anthropocene, humans have been driving an ongoing series of species declines and extinctions (Dirzo et al. 2014). Large-bodied mammals are typically at a higher risk of extinction than smaller ones (Cardillo et al. 2005). However, in some circumstances, terrestrial megafauna populations have been able to recover some of their lost numbers because of strong conservation and political commitment, as well as human cultural changes (Chapron et al. 2014). Indeed, many would be in considerably worse predicaments in the absence of conservation action (Hoffmann et al. 2015). Nevertheless, most mammalian megafauna face dramatic range contractions and population declines. In fact, 59% of the world's largest carnivores (more than or equal to 15 kilograms, n = 27) and 60% of the world's largest herbivores (more than or equal to 100 kilograms, n = 74) are classified as threatened with extinction on the International Union for the Conservation of Nature (IUCN) Red List (supplemental tables S1 and S2). This situation is particularly dire in sub-Saharan Africa and Southeast Asia, home to the greatest diversity of extant megafauna (figure 1). Species at risk of extinction include some of the world's most iconic animals—such as gorillas, rhinos, and big cats (figure 2 top row)—and, unfortunately, they are vanishing just as science is discovering their essential ecological roles (Estes et al. 2011). Here, our objectives are to raise awareness of how these megafauna are imperiled (species in tables S1 and S2) and to stimulate broad interest in developing specific recommendations and concerted action to conserve them.
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Biased-corrected richness estimates for the Amazonian tree flora
This paper is the result of the work of hundreds of different scientists and research institutions in the Amazon over the past 80 years. Without their hard work this analysis would have been impossible. We thank Charles Zartman for the use of plots from Jutai. HtS, VFG, and RS were supported by grant 407232/2013-3 - PVE - MEC/MCTI/CAPES/CNPq/FAPs; PIP had support for this work from CNPq (productivity grant 310885/2017-5) and FAPESP (research grant #09/53413-5); RAFL was supported by the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 795114; CB was supported by grant FAPESP 95/3058-0 - CRS 068/96 WWF Brasil - The Body Shop; DS, JFM, JE, PP and JC benefited from an "Investissement d'Avenir" grant managed by the Agence Nationale de la Recherche (CEBA: ANR-10-LABX-25-01); HLQ/MAP/JLLM received financial supported by MCT/CNPq/CT-INFRA/GEOMA #550373/2010-1 and # 457515/2012-0, and JLLM were supported by grant CAPES/PDSE # 88881.135761/2016-01 and CAPES/Fapespa #1530801; The Brazilian National Research Council (CNPq) provided a productivity grant to EMV (Grant 308040/2017-1); Floristic identification in plots in the RAINFOR forest monitoring network have been supported by the Natural Environment Research Council (grants NE/B503384/1, NE/ D01025X/1, NE/ I02982X/1, NE/F005806/1, NE/D005590/1 and NE/I028122/1) and the Gordon and Betty Moore Foundation; BMF is funded by FAPESP grant 2016/25086-3. BSM, BHMJ and OLP were supported by grants CNPq/CAPES/ FAPS/BC-Newton Fund #441244/2016-5 and FAPEMAT/0589267/2016; TWH was funded by National Science Foundation grant DEB-1556338.The 25-ha Long-Term Ecological Research Project of Amacayacu is a collaborative project of the Instituto Amazónico de Investigaciones Científicas Sinchi and the Universidad Nacional de Colombia Sede Medellín, in partnership with the Unidad de Manejo Especial de Parques Naturales Nacionales and the Center for Tropical Forest Science of the Smithsonian Tropical Research Institute (CTFS). The Amacayacu Forest Dynamics Plot is part of the Center for Tropical Forest Science, a global network of large-scale demographic tree plots. We acknowledge the Director and staff of the Amacayacu National Park for supporting and maintaining the project in this National Park. ; Amazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come. ; Publisher PDF ; Peer reviewed
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