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- Title
Influential factors for natal dispersal in an avian island metapopulation.
- Authors
Wilson, Amy G.; Arcese, Peter
- Abstract
Dispersal is a key parameter in evolutionary, demographic and conservation theory, but the factors influencing dispersal between populations are rarely known, and the contribution of immigrants to population stability remains uncertain. Using dispersal data from nine island populations of song sparrows, we show that female and male immigrants responded differently to population structure: in females, immigration varied with adult sex ratio; whereas immigration by males was more influenced by population density. These patterns are consistent with the hypothesis that intra-sexual competition for breeding resources influenced recruitment patterns. Immigrants often constituted a substantial fraction of local population size, and in six cases immigration by females prevented the extirpation of that sex from the island. Breeding vacancies and extirpations may have been more likely in females because their apparent survival was lower than in males. Local recruitment and immigration varied markedly among islands, perhaps as consequence of island size and isolation. Overall, our results suggest that immigration varied with local demography in a sex-specific way, stabilized population numbers and reduced extinction rates in the smallest populations.
- Subjects
ANIMAL dispersal; BIRD behavior; EVOLUTIONARY economics; DEMOGRAPHY; DEMOGRAPHIC change; SEX ratio; POPULATION density; ANIMAL sexual behavior; BIOLOGICAL extinction; BIRDS
- Publication
Journal of Avian Biology, 2008, Vol 39, Issue 3, p341
- ISSN
0908-8857
- Publication type
Article
- DOI
10.1111/j.0908-8857.2008.04239.x