Avian life‐history determinants of local extinction risk in a hyper‐fragmented neotropical forest landscape

Abstract

The fact that species vary in their vulnerability to extinction is well documented, but the reasons for these differences remain poorly understood. Why should some species/families/guilds decline rapidly with increasing anthropogenic disturbance, while others either tolerate or proliferate in disturbed habitats? We investigated the bird species composition in 31 primary forest patches of varying size in a region of the Amazonian 'Arc of Deforestation' and assessed which species life-history traits predisposed individual species to extinction. Medium-sized non-flocking canopy frugivores/ominvores of low primary forest dependence were least likely to go extinct in small patches, while small-bodied flock-following primary-forest-dependent terrestrial insectivores were most fragmentation sensitive. We found highly idiosyncratic relationships between the minimum size of forest patches occupied by different species and their territory size requirements estimated based on other Amazonian studies. This suggests that avian assemblages in forest fragments primarily comprise species that either have good dispersal abilities or are highly tolerant to the non-forest matrix, rather than those whose minimum spatial requirements can be met by the size of available forest fragments.

Do insectivorous bird communities decline on land-bridge forest islands in Peninsular Malaysia?

“…We suggest that higher vagility and consequently increased dispersal amongst frugivores may explain this difference in persistence (Lees & Peres 2008, Sodhi et al 2004b. Being largely canopy birds, frugivores would be able to better tolerate microclimatic changes in fragments compared with many insectivores since canopy conditions are clearly more variable (Stratford & Robinson 2005).…”

Using avian functional traits to assess the impact of land-cover change on ecosystem processes linked to resilience in tropical forests

“…Of these, insectivores were the most frequent guild with 206 species in Santarém and 188 species in Paragominas, and frugivores were the second most speciose guild with 67 species in Santaré m and 72 species in Paragominas. We conducted all analyses separately on insectivores and frugivores because they respond differently to land-cover change and forest disturbance [49,52]. Full species lists and classifications are provided in the electronic supplementary material (dataset S1).…”

Avifauna da Reserva Biológica Municipal Poço D'Anta, Juiz de Fora, MG

“…Uma espécie, Pyrrhocoma ruficeps (Thraupidae) ainda necessita de mais esforços no sentido de confirmar sua ocorrência atual (Tabela 1), embora haja um espécime de P. ruficeps (Stotz et al 1996), sendo 208 espécies endêmicas (Brooks et al 1999). A última revisão da lista de espécies ameaçadas do Brasil indica que 98 dos 160 táxons de aves ocorrem principalmente na Mata Atlântica (Machado et al 2008). Em Minas Gerais ocorrem cerca de 764 espécies de aves, sendo 121 ameaçadas e 70 deficientes em dados (Fundação Biodiversitas 2007), onde muitas estão associadas ao bioma.…”

“…Embora as aves sejam organismos altamente móveis, o grupo não se encontra livre de tal devastação, já que muitas espécies são especialistas de habitat e incapazes de se dispersar por áreas abertas (Lees & Peres 2008). Assim, o efeito da perda de habitat eleva a probabilidade de extinção das espécies, ocasionando uma drástica redução da diversidade avifaunística.…”