Raptorial birds and environmental gradients in the southern Neotropics: A test of species-richness hypotheses

We investigated the spatial patterns of raptor species richness in the southern Neotropics and tested three hypotheses that were most likely to explain spatial variations: ambient energy, productivity and habitat heterogeneity. We used non-linear regression analysis and eliminated alternative hypoth...

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Autor principal:	Bellocq, Maria Isabel
Publicado:	2005
Materias:	Birds Neotropics Raptors Spatial patterns Species-richness hypotheses bioenergetics environmental gradient habitat structure productivity raptor species richness Aves Raptores
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14429985_v30_n8_p892_Bellocq http://hdl.handle.net/20.500.12110/paper_14429985_v30_n8_p892_Bellocq
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_14429985_v30_n8_p892_Bellocq
record_format	dspace
spelling	paper:paper_14429985_v30_n8_p892_Bellocq2025-07-30T18:51:48Z Raptorial birds and environmental gradients in the southern Neotropics: A test of species-richness hypotheses Bellocq, Maria Isabel Birds Neotropics Raptors Spatial patterns Species-richness hypotheses bioenergetics environmental gradient habitat structure productivity raptor species richness Aves Raptores We investigated the spatial patterns of raptor species richness in the southern Neotropics and tested three hypotheses that were most likely to explain spatial variations: ambient energy, productivity and habitat heterogeneity. We used non-linear regression analysis and eliminated alternative hypotheses by finding the best single environmental predictor of raptor species richness among potential evapotranspiration (PET), actual evapotranspiration (AET), mean annual temperature and precipitation and vegetation structure coefficient. As expected, the number of raptor species decreases monotonically as latitude increases. Raptor species richness was significantly correlated with each of the environmental factors considered in this study, reflecting covariation of climatic and habitat descriptors. Correlation coefficients showed positive associations between species richness and each single environmental variable. Mean annual temperature was the strongest environmental predictor of raptor species richness (explaining 82% of the variance), consistent with the ambient energy hypothesis. Another descriptor of ambient energy (PET) explained 75% of the spatial variation. Both the AET and the vegetation structure coefficient explained 77% of the spatial variation in richness. The spatial clusters of extreme residuals identified the subtropical rainforests and the and heights and low plateaux of the study area as regions where local environmental conditions appear to interfere with the general trend identified by the model at the regional scale. Fil:Bellocq, M.I. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2005 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14429985_v30_n8_p892_Bellocq http://hdl.handle.net/20.500.12110/paper_14429985_v30_n8_p892_Bellocq
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Birds Neotropics Raptors Spatial patterns Species-richness hypotheses bioenergetics environmental gradient habitat structure productivity raptor species richness Aves Raptores
spellingShingle	Birds Neotropics Raptors Spatial patterns Species-richness hypotheses bioenergetics environmental gradient habitat structure productivity raptor species richness Aves Raptores Bellocq, Maria Isabel Raptorial birds and environmental gradients in the southern Neotropics: A test of species-richness hypotheses
topic_facet	Birds Neotropics Raptors Spatial patterns Species-richness hypotheses bioenergetics environmental gradient habitat structure productivity raptor species richness Aves Raptores
description	We investigated the spatial patterns of raptor species richness in the southern Neotropics and tested three hypotheses that were most likely to explain spatial variations: ambient energy, productivity and habitat heterogeneity. We used non-linear regression analysis and eliminated alternative hypotheses by finding the best single environmental predictor of raptor species richness among potential evapotranspiration (PET), actual evapotranspiration (AET), mean annual temperature and precipitation and vegetation structure coefficient. As expected, the number of raptor species decreases monotonically as latitude increases. Raptor species richness was significantly correlated with each of the environmental factors considered in this study, reflecting covariation of climatic and habitat descriptors. Correlation coefficients showed positive associations between species richness and each single environmental variable. Mean annual temperature was the strongest environmental predictor of raptor species richness (explaining 82% of the variance), consistent with the ambient energy hypothesis. Another descriptor of ambient energy (PET) explained 75% of the spatial variation. Both the AET and the vegetation structure coefficient explained 77% of the spatial variation in richness. The spatial clusters of extreme residuals identified the subtropical rainforests and the and heights and low plateaux of the study area as regions where local environmental conditions appear to interfere with the general trend identified by the model at the regional scale.
author	Bellocq, Maria Isabel
author_facet	Bellocq, Maria Isabel
author_sort	Bellocq, Maria Isabel
title	Raptorial birds and environmental gradients in the southern Neotropics: A test of species-richness hypotheses
title_short	Raptorial birds and environmental gradients in the southern Neotropics: A test of species-richness hypotheses
title_full	Raptorial birds and environmental gradients in the southern Neotropics: A test of species-richness hypotheses
title_fullStr	Raptorial birds and environmental gradients in the southern Neotropics: A test of species-richness hypotheses
title_full_unstemmed	Raptorial birds and environmental gradients in the southern Neotropics: A test of species-richness hypotheses
title_sort	raptorial birds and environmental gradients in the southern neotropics: a test of species-richness hypotheses
publishDate	2005
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14429985_v30_n8_p892_Bellocq http://hdl.handle.net/20.500.12110/paper_14429985_v30_n8_p892_Bellocq
work_keys_str_mv	AT bellocqmariaisabel raptorialbirdsandenvironmentalgradientsinthesouthernneotropicsatestofspeciesrichnesshypotheses
_version_	1840324509751574528

Raptorial birds and environmental gradients in the southern Neotropics: A test of species-richness hypotheses

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