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Enigmatic declines in bird numbers in lowland forest of eastern Ecuador may be a consequence of climate change.

ABSTRACT: Bird populations have declined in many parts of the world but most of those declines can be attributed to effects of human activities (e.g., habitat fragmentation); declines in areas unaffected by human activities are not common. We have been sampling bird populations at an undisturbed site in lowland forest of eastern Ecuador annually since 2001 using a combination of mist nets and direct observations on two 100-ha plots. Bird numbers fluctuated on both plots during the first 8 years but did not show a consistent pattern of change. Since about 2008, numbers of birds on both plots have declined; capture rates in 2014 were ?40% less than at the start of the study and observation rates were ?50% less. Both understory and canopy species declined in abundance. Overall, insectivores showed the most pronounced declines but declines varied among trophic groups. The period from 2008 onward also was a period of stronger La Niña events which, at this study site, are associated with increased rainfall. The mechanism for the declines is not known but likely reflects a combination of reduced reproductive success coupled with reduced survival associated with changing climate.

SUBMITTER: Blake JG

PROVIDER: S-EPMC4558082 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Enigmatic declines in bird numbers in lowland forest of eastern Ecuador may be a consequence of climate change.

Blake John G JG Loiselle Bette A BA

PeerJ 20150811

Bird populations have declined in many parts of the world but most of those declines can be attributed to effects of human activities (e.g., habitat fragmentation); declines in areas unaffected by human activities are not common. We have been sampling bird populations at an undisturbed site in lowland forest of eastern Ecuador annually since 2001 using a combination of mist nets and direct observations on two 100-ha plots. Bird numbers fluctuated on both plots during the first 8 years but did no ...[more]

PMID: 26339554

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Enigmatic declines in bird numbers in lowland forest of eastern Ecuador may be a consequence of climate change.

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Enigmatic declines in bird numbers in lowland forest of eastern Ecuador may be a consequence of climate change.

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