Effects of road clearings on movement patterns of understory rainforest birds in Central Amazonia

Laurance, Susan G. W.;Stouffer, Philip C.;Laurance, William F.

Abstract

The impacts of potential linear barriers such as roads, highways, and powerlines on rainforest fauna are poorly understood. In the central Brazilian Amazon, we compared the frequency of local (≤300 m-long) movements of understory birds within intact forest and across a 30-40 m wide road, over a two-year period. Rainforest regrowth had regenerated along some road verges, to the extent that a nearly complete canopy was formed in some areas, and we also assessed if this facilitated bird movement. Movement data were determined from 1212 recaptures of 3681 netted birds at six study sites. The road significantly inhibited total bird movement at five of the six sites. Bird foraging guilds varied in their responses to the road and different ages of regrowth. Movements of frugivores and edge/gap species were not inhibited at any site, whereas most forest-dependent insectivores (mixed-species flocks, terrestrial species, and army ant-followers) had markedly inhibited movements, except at sites with extensive regrowth. Solitary understory species were especially vulnerable, rarely crossing even roads overgrown by tall regrowth. For sensitive species, road-crossing movements were inhibited because individuals tended to avoid both edge-affected habitat near the road as well as the road-clearing itself. This study suggests that even narrow roads with low traffic volumes can reduce local movements of many insectivorous birds in Amazonia.

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Conservation Biology

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1523-1739

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Wiley-Blackwell

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DOI

10.1111/j.1523-1739.2004.00268.x