Determinantes ecológicos do risco de extinção: abundância local, amplitude de nicho, capacidade de dispersão e a resposta das espécies de pequenos mamíferos à fragmentação florestal no Planalto Atlântico Paulista / Ecological determinants of extinction risk: local abundance, niche breadth, dispersal ability and response of small mammals to forest fragmentation at the Atlantic Plateau of São Paulo

AUTOR(ES)

Thais Kubik Martins

FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

25/11/2011

RESUMO

Anthropogenic disturbances, particularly habitat loss and fragmentation, are considered the main causes of the increased extinction rates observed in the last decades. Since the risk of extinction is extremely variable among species, the ecological determinants of the chance of extinction have been in the center of the debates in the ecological literature. Ecological traits associated with rarity, as niche breadth and local abundance, and dispersal ability are recurrently mentioned in the literature as the main determinants of the risk of local extinction. Using data on occurrence in fragments, continuous forest and areas of agriculture, and on capture-recapture in three 2-ha grids in continuous forest, in the Atlantic Plateau of São Paulo, we investigate the effects of these three ecological traits on the risk of local extinction in small mammals. We used a model selection approach and the Akaike criterion (AICc) to evaluate which of the existing hypotheses on the relationship of these traits with the extinction risk is most plausible. Two model selections were run: one considering the three traits and seven species, and another considering only niche breadth and local abundance and 18 species. The results from both selections point to niche breadth as the main determinant of the risk of local extinction. Local abundance was secondarily important, with a positive effect on extinction risk, which is stronger among the species with smaller niche breadth. This result is consistent with the idea that local abundance is influenced by species degree of ecological specialization and competitive ability, which is negatively related to colonization ability through a trade-off. As dispersal ability varied little among studied species, and colonization ability is also determined by population growth rate, it is possible that the risk of extinction among habitat specialist small mammals is secondarily defined by population growth rate

ASSUNTO(S)

Área de vida capacidade de deslocamento demanda conflitante endangered species especialização ecológica espécies ameaçadas fragmentação de habitat habitat fragmentation habitat loss habitat requirements home range movement movimento perda de habitat raridade rarity requerimentos de habitat trade-off ecological specialization

Documentos Relacionados

• Efeitos da fragmentação da floresta na diversidade e abundância de anfíbios anuros e lagartos de serapilheira em uma paisagem do Planalto Atlântico de São Paulo.
• Small mammals of the Atlantic Forest of the Atlantic Plateau of São Paulo: an evaluation of the threat of extinction and the response to alterations in context and remnant size
• Breadth, Depth and Agreement among Provincial Formularies in Canada
• Abundance, density and population size of game mammals and birds of Ilha do Cardoso State Park, SP, Brazil.
• Abundância, Riqueza, Análise Faunística e Efeitos da Fragmentação Florestal em Calliphoridae (Diptera) na Reserva Biológica do Tinguá, Nova Iguaçu, Brasil.