Evolution and ecology of birds on islands: Trends and prospects

Authors
Citation
J. Blondel, Evolution and ecology of birds on islands: Trends and prospects, VIE MILIEU, 50(4), 2000, pp. 205-220
Citations number
152
Language
INGLESE
art.tipo
Review
Categorie Soggetti
Environment/Ecology
Journal title
VIE ET MILIEU-LIFE AND ENVIRONMENT
ISSN journal
0240-8759 → ACNP
Volume
50
Issue
4
Year of publication
2000
Pages
205 - 220
Database
ISI
SICI code
0240-8759(200012)50:4<205:EAEOBO>2.0.ZU;2-B
Abstract
This paper reviews ecological and evolutionary processes that operate among and within insular communities, species and populations. Being basically n on-evolutionary the MacArthur and Wilson's paradigm of island biogeography holds well in explaining processes that operate on the short ecological tim e, and proved to be helpful in explaining such issues as colonisation-extin ction processes, species richness at equilibrium and species turnover. But several limitations make it insufficient as a modern tool for explaining ev olutionary changes on islands. Colonising an island necessarily entails rap id evolutionary changes as a response to both non-selective and selective e volution. This results in a cascade of changes of life history traits, the so-called insular syndrome. Components of this syndrome include changes in morphology (size and shape), demography (age-specific fecundity, survival, dispersal) and behaviour. Shifts in behaviour are among the most spectacula r features in insular vertebrates. Surprisingly few systematic and broad-sc ale analyses of demographic changes on islands have been designed to docume nt the classical tenet of evolutionary shifts from high reproductive rates and short life span towards the opposite combination of life history traits as a result of high intraspecific competition in crowded insular populatio ns. Examples of shifts in life history traits are given from a detailed cas e study on the biology of Blue tits in the island of Corsica, and most of t hese changes fit the predictions of an insular syndrome. An interesting tre nd resulting from shift from dispersal to sedentariness and habitat fidelit y in islands is the potential far population differentiation at much smalle r spatial scales than an mainland regions. This results in enhancing within -species diversity which counterbalances the species impoverishment of insu lar biotas. Although ecological adjustments and evolutionary changes make i nsular communities self-regulating assemblages of species that are resistan t face to the risks of spontaneous extinction and invasion, insular communi ties are among the most vulnerable biota on Earth. The most important threa ts to island birds are discussed and some directions are given for promotin g studies that could contribute to fill the most important gaps in our know ledge on evolution on islands and contribute to conservation issues.