Journal of Tropical Ecology

Research Article

Responses of Amazonian rain forest birds to habitat modification

Andrew D. Johnsa1 p1

a1 Departamento Zoologia, Museu Paraense Emílio Goeldi, Belém, Pará, Brazil

Abstract

Bird species were surveyed in a variety of habitat types in a lightly populated area of western Brazilian Amazonia. Habitats surveyed were untagged forest, selectively logged forest, ‘capoeira’ (scrub regenerating on cleared land), cropfields, and an isolated 35 ha forest ‘island’. All habitats were within a few kilometres of each other. Many bird species were found to occur in all or most habitats, although the similarlity of the species assemblages dropped with increasing levels of disturbance of the natural vegetation. Certain understorey insectivores common in untagged forest were rarely observed in other habitats; disturbed areas contained higher numbers of flycalching insectivores or birds feeding on both insects and fruit, some of which were open-country rather than forest species. The avifauna of the forest ‘island’ was more similar to that of regenerating scrub than to that of tall forest, and the persistence of forest species was attributed to their ability to move to and from nearby continuous forest areas.

Levantamentos da avifauna de uma variedade de tipos de habitats foram conduzidos numa área de baixa densidade populacional da Amazônia Brasilcira ocidental. Habitats Icvanlados incluiram mata primária, meta com corte seletivo, capoeira, agro-mosaicos, e uma ‘ilha’ de mata dc 35-ha, os quais ocuparam uma área de 15 km2. Muitas espécics de aves ocorram na maioria ou todos os tipos de habitats, mas a semelhança do conjunto, de espécies diminuiu com o aumento do nível de perlurbação da vegetacao. Cerlos insertívoros de sub-bosque comuns em mala primária foram raramente obscrvados em oulros habitats; áreas perturbadas continham um núimero maior de espécies predando em insetos alados ou alimentando-se de frutos c insetos, algumas das quais cram lipicas de habitats abertos ao inves dc mata. A avifauna da ilha de mata foi mais scmclhante a de capocira do que a de mata alta, e a persistencia das especies de mata foi atribuida a capacidade dessas especies de se deslocar da mata continua á habitats adjaccntcs a vice-e-versa.

(Accepted January 31 1991)

Correspondence:

p1 Current address: Makerere University Biological Field Station, PO Box 10066, Kampala, Uganda