Niche expansion and the niche variation hypothesis: does the degree of individual variation increase in depauperate assemblages?
Am Nat
; 172(6): 868-77, 2008 Dec.
Article
em En
| MEDLINE
| ID: mdl-18950275
ABSTRACT
The niche expansion and niche variation hypotheses predict that release from interspecific competition will promote niche expansion in depauperate assemblages. Niche expansion can occur by different mechanisms, including an increase in within-individual, among-individual, or bimodal variation (sexual dimorphism). Here we explore whether populations with larger niche breadth have a higher degree of diet variation. We also test whether populations from depauperate lizard assemblages differ in dietary resource use with respect to variation within and/or among individuals and sexual dimorphism. We found support for the niche expansion and niche variation hypotheses. Populations in assemblages with low phylogenetic diversity had a higher degree of individual variation, suggesting a tendency for niche expansion. We also found evidence suggesting that the mechanism causing niche expansion is an increase in variation among individuals rather than an increase in within-individual variation or an increase in bimodal variation due to sexual dimorphism.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Adaptação Biológica
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Caracteres Sexuais
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Ecossistema
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Dieta
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Lagartos
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Modelos Teóricos
Idioma:
En
Ano de publicação:
2008
Tipo de documento:
Article