Rates of species loss from Amazonian forest fragments

Ferraz, Gonçalo; Russell, G. B.; Stouffer, Philip C.; Bierregaard, Richard O.; Pimm, Stuart L.; Lovejoy, Thomas Ε.

doi:10.1073/pnas.2336195100

Cited by 300 publications

(297 citation statements)

References 31 publications

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“…Species can obviously linger in small habitat fragments for decades before they expire, as evidenced by the rediscovery of species thought extinct for up to a century (see supporting information for examples). We suggest that bird extinctions among doomed species have a half-life of Ϸ50 years (25,26). So, perhaps three-quarters of these species, 1,250, will likely go extinct this century (24), a number very similar to the number Birdlife considers to be at risk.…”

Section: Resultsmentioning

confidence: 87%

Human impacts on the rates of recent, present, and future bird extinctions

Pimm

Raven

Peterson

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

274

213

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Unqualified, the statement that Ϸ1.3% of the Ϸ10,000 presently known bird species have become extinct since A.D. 1500 yields an estimate of Ϸ26 extinctions per million species per year (or 26 E͞MSY). This is higher than the benchmark rate of Ϸ1 E͞MSY before human impacts, but is a serious underestimate. First, Polynesian expansion across the Pacific also exterminated many species well before European explorations. Second, three factors increase the rate: (i) The number of known extinctions before 1800 is increasing as taxonomists describe new species from skeletal remains. (ii) One should calculate extinction rates over the years since taxonomists described the species. Most bird species were described only after 1850. (iii) Some species are probably extinct; there is reluctance to declare them so prematurely. Thus corrected, recent extinction rates are Ϸ100 E͞MSY. In the last decades, the rate is <50 E͞MSY, but would be 150 E͞MSY were it not for conservation efforts. Increasing numbers of extinctions are on continents, whereas previously most were on islands. We predict a 21st century rate of Ϸ1,000 E͞MSY. Extinction threatens 12% of bird species; another 12% have small geographical ranges and live where human actions rapidly destroy their habitats. If present forest losses continue, extinction rates will reach 1,500 E͞MSY by the century's end. Invasive species, expanding human technologies, and global change will harm additional species. Birds are poor models for predicting extinction rates for other taxa. Human actions threaten higher fractions of other well known taxa than they do birds. Moreover, people take special efforts to protect birds.

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Section: Resultsmentioning

confidence: 87%

Human impacts on the rates of recent, present, and future bird extinctions

Pimm

Raven

Peterson

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

274

213

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“…Por exemplo, na amazônia central, fragmentos com menos de 100ha perderam metade das espécies de pássaros de sub-bosque em apenas 15 anos (Ferraz et al 2003). reduções na riqueza de espécies com a fragmentação foram observadas numa grande gama de grupos taxonômicos incluindo primatas (rylands & Keuroghlian 1988), pássaros de subosque (stouffer & Bierregaard 1995a;Ferraz et al 2003), borboletas umbrófilas (Brown & Hutchings 1997), cupins (souza & Brown 1994, besouros (Klein 1989) abelhas euglossinae (Powell & Powell 1987) e formigas (carvalho & Vasconcelos 1999, Vasconcelos et al 2006.…”

Section: Efeitos De áReaunclassified

Consequências ecológicas da fragmentação florestal na amazônia

2009

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RESUMOum grande número de trabalhos tem sido desenvolvido com o intuito de determinar as conseqüências ecológicas da fragmentação florestal na Amazônia e aqui apresentamos uma síntese dos principais resultados destes trabalhos. A fragmentação da floresta tem múltiplos efeitos sobre a biota amazônica, podendo alterar a diversidade e a composição das comunidades nos fragmentos e mudar processos ecológicos como a polinização, a ciclagem de nutrientes e o estoque de carbono. as mudanças ecológicas que ocorrem em função do isolamento são em geral proporcionais ao tamanho do fragmento. conseqüentemente, fragmentos pequenos tendem a ter menos espécies como um todo (menor riqueza de espécies) e menor densidade de espécies por unidade de área do que fragmentos grandes. Os fragmentos de floresta na Amazônia parecem ser particularmente vulneráveis aos efeitos de borda. Sob condições naturais as bordas são raras nas florestas tropicais, mas quando a floresta é fragmentada a quantidade de bordas aumenta dramaticamente. Estas novas bordas são artificiais, criando uma transição abrupta entre a floresta e a área alterada adjacente. Nas florestas de terra-firme da Amazônia central, um dos efeitos de borda mais proeminentes é o aumento na taxa de mortalidade de árvores, que causa um aumento na incidência de clareiras no dossel próximo às bordas. os efeitos de borda também causam alterações nos gradientes físicos e na abundância das espécies nos fragmentos. Em geral as espécies que são mais vulneráveis à fragmentação florestal tendem a responder negativamente à formação de bordas, necessitam de áreas extensas, e/ou não são tolerantes a matriz (isto é, o mosaico de habitats modificados que circundam os fragmentos de floresta), enquanto que as espécies que são resilientes aos efeitos da fragmentação florestal geralmente têm características opostas. Palavras-chave: Biodiversidade, conservação, dinâmica florestal, fragmentação do habitat, floresta tropical. ABSTRACT ECOLOGICAL CONSEQUENCES OF FOREST FRAGMENTATION IN THE AMAZON.Many studies have analyzed the ecological consequences of forest fragmentation on amazonian forests and the results of these studies are summarized here. Habitat fragmentation has extensive effects on amazon rainforests, affecting diversity and community composition in the resulting fragments, and also affecting ecological processes like pollination, nutrient cycling, and carbon fixation. The ecological changes resulting from fragmentation are generally of inverse proportional magnitude to the size of the fragment area. consequently, smaller fragments are usually less species-rich and have fewer species per area than do larger forest fragments. Forest fragments in the amazon seem to be particularly prone to edge effects. Fragmentation dramatically increases edges of tropical forests: new edges are artificial and abrupt, forming a stark boundary between the forest and the surrounding, altered landscape. one of the most striking effects is a dramatic increase in the Oecologia Brasiliensis

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“…Figure 2). This arises because many large mammals (Lovejoy et al 1986), primates (Rylands and Keuroghlian 1988, Schwartzkopf and Rylands 1989, Gilbert and Setz 2001, understory birds (Stouffer and Bierregaard 1995b, Stratford and Stouffer 1999, Ferraz et al 2003, and even certain beetle, ant, bee, termite, and butterfly species (Powell and Powell 1987, Vasconcelos 1988, Klein 1989, Souza and Brown 1994, Brown and Hutchings 1997, Didham 1997a) are highly sensitive to fragment area. A number of these species have disappeared from even the largest (100 ha) fragments in the study area.…”

Section: Area Effectsmentioning

confidence: 99%

Ecosystem decay of Amazonian forest fragments: implications for conservation

Laurance

Stability of Tropical Rainforest Margins

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Rates of species loss from Amazonian forest fragments

Cited by 300 publications

References 31 publications

Human impacts on the rates of recent, present, and future bird extinctions

Human impacts on the rates of recent, present, and future bird extinctions

Consequências ecológicas da fragmentação florestal na amazônia

Ecosystem decay of Amazonian forest fragments: implications for conservation

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