TY - JOUR
T1 - Absence of microclimate selectivity in insectivorous birds of the Neotropical forest understory
AU - Pollock, Henry S.
AU - Cheviron, Zachary A.
AU - Agin, T. J.
AU - Brawn, Jeffrey D.
N1 - Funding Information:
We thank the Autoridad Nacional del Ambiente (ANAM) for providing research permits to work in the Republic of Panama and Smithsonian Tropical Research Institute, especially R. Urriola and A. Bilgray, for logistical support. Thanks to the various field assistants and volunteers, including D. Rincón Guarín, Z. Welty, J. Andrews, K. Bartowitz, and D. Forthman and family for the many hours of help in the field that made this research possible; to M. Wikelski for conceptual guidance in formulating the research; to C.E. Tarwater, J.P. Kelley, G.S. Bakken, and J.B. Williams for methodological support; to M.A. Patten, L.L. Powell, J. Stratford, M. Stager, N. Sly, P. Benham and two anonymous reviewers for helpful comments on the manuscript; to E. Welsh for help with figures; and to L. Powell, N. Cordeiro and J. Stratford for organizing this special issue. This research was supported in part by the Wilson Ornithological Society Paul A. Stewart Award , a Program in Ecology, Evolution and Conservation Biology Summer Research Grant , a University of Illinois Dissertation Travel Grant , the Environmental Science Program of the Smithsonian Tropical Research Institute , and a National Science Foundation Graduate Research Fellowship to HSP.
Publisher Copyright:
© 2014 Elsevier Ltd.
PY - 2015/8/1
Y1 - 2015/8/1
N2 - Local abiotic conditions (microclimates) vary spatially and selection of favorable microclimates within a habitat can influence an animal's energy budgets, behavior, and ultimately, fitness. Insectivorous birds that inhabit the understory of tropical forests may be especially sensitive to environmental variation and may select habitat based on microclimatic (e.g. temperature, humidity, light) conditions. Sensitivity to microclimate could contribute to the population declines of understory insectivores in response to forest fragmentation or degradation, which changes the physical structure of the forest, thereby increasing light intensity and temperature and decreasing humidity. To understand the role of microclimates in the habitat selection of understory insectivores, we characterized the microclimatic associations of nine species of understory insectivores at three sites along a precipitation gradient and across seasons in central Panama. We compared the distributions of microclimates selected by birds with microclimates at randomly chosen points within their home ranges to test for microclimate selectivity. We predicted that: (1) birds would select microclimates that are more humid, cooler, and less bright than random microclimates, (2) selectivity would be greater in hotter, drier habitats and (3) selectivity would be greatest in the dry season. We found no evidence of selectivity for the nine species we sampled on a seasonal or spatial basis. Microclimate variation was minimal in the forest understory at all sites, particularly in the wet season. Understory insectivores did not use microhabitats characterized by high light intensity, and may be sensitive to light, though the mechanism remains unclear. The lack of microclimate variation in the understory of tropical forests may have serious fitness consequences for understory insectivores due to increasing temperatures associated with climate change coupled with a lack of thermal refugia.
AB - Local abiotic conditions (microclimates) vary spatially and selection of favorable microclimates within a habitat can influence an animal's energy budgets, behavior, and ultimately, fitness. Insectivorous birds that inhabit the understory of tropical forests may be especially sensitive to environmental variation and may select habitat based on microclimatic (e.g. temperature, humidity, light) conditions. Sensitivity to microclimate could contribute to the population declines of understory insectivores in response to forest fragmentation or degradation, which changes the physical structure of the forest, thereby increasing light intensity and temperature and decreasing humidity. To understand the role of microclimates in the habitat selection of understory insectivores, we characterized the microclimatic associations of nine species of understory insectivores at three sites along a precipitation gradient and across seasons in central Panama. We compared the distributions of microclimates selected by birds with microclimates at randomly chosen points within their home ranges to test for microclimate selectivity. We predicted that: (1) birds would select microclimates that are more humid, cooler, and less bright than random microclimates, (2) selectivity would be greater in hotter, drier habitats and (3) selectivity would be greatest in the dry season. We found no evidence of selectivity for the nine species we sampled on a seasonal or spatial basis. Microclimate variation was minimal in the forest understory at all sites, particularly in the wet season. Understory insectivores did not use microhabitats characterized by high light intensity, and may be sensitive to light, though the mechanism remains unclear. The lack of microclimate variation in the understory of tropical forests may have serious fitness consequences for understory insectivores due to increasing temperatures associated with climate change coupled with a lack of thermal refugia.
KW - Habitat selection
KW - Light environments
KW - Microclimates
KW - Neotropics
KW - Radio-telemetry
KW - Understory insectivores
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U2 - 10.1016/j.biocon.2014.11.013
DO - 10.1016/j.biocon.2014.11.013
M3 - Article
AN - SCOPUS:84933057365
SN - 0006-3207
VL - 188
SP - 116
EP - 125
JO - Biological Conservation
JF - Biological Conservation
ER -