Local richness along gradients in the Siskiyou herb flora: R. H. Whittaker revisited.
Ecology
; 92(1): 108-20, 2011 Jan.
Article
em En
| MEDLINE
| ID: mdl-21560681
ABSTRACT
In his classic study in the Siskiyou Mountains (Oregon, USA), one of the most botanically rich forested regions in North America, R. H. Whittaker (1960) foreshadowed many modern ideas on the multivariate control of local species richness along environmental gradients related to productivity. Using a structural equation model to analyze his data, which were never previously statistically analyzed, we demonstrate that Whittaker was remarkably accurate in concluding that local herb richness in these late-seral forests is explained to a large extent by three major abiotic gradients (soils, topography, and elevation), and in turn, by the effects of these gradients on tree densities and the numbers of individual herbs. However, while Whittaker also clearly appreciated the significance of large-scale evolutionary and biogeographic influences on community composition, he did not fully articulate the more recent concept that variation in the species richness of local communities could be explained in part by variation in the sizes of regional species pools. Our model of his data is among the first to use estimates of regional species pool size to explain variation in local community richness along productivity-related gradients. We find that regional pool size, combined with a modest number of other interacting abiotic and biotic factors, explains most of the variation in local herb richness in the Siskiyou biodiversity hotspot.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Plantas
/
Solo
/
Árvores
/
Ecossistema
/
Altitude
Tipo de estudo:
Prognostic_studies
País/Região como assunto:
America do norte
Idioma:
En
Revista:
Ecology
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Estados Unidos