Conférence de John WIENS (Univ of Arizona, Tucson)



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Le jeudi 30 mai 2013, à 11h00, dans la salle de conférences de l'OSUR, bâtiment 14b, Campus de Beaulieu, UR1.

Le jeudi 30 mai 2013, à 11h00, dans la salle de conférences de l'OSUR, bâtiment 14b, Campus de Beaulieu, UR1.
Niche evolution, niche conservatism, and the origins of biodiversity patterns

Résumé :
Niche conservatism is the tendency of species and populations to retain similar ecological traits over time. I will explore the idea that niche conservatism may be intimately related to both the gain and loss of biodiversity, in four sections. (1) First, I will address the role of niche conservatism in generating patterns of species richness, especially among habitats within a region. I will discuss the general processes that underlie patterns of species richness, then describe examples where high richness in some habitats is explained by the combination of niche conservatism (reducing dispersal between habitats) and the time-for-speciation effect (habitats that have been colonized longer accumulate more species over time). (2) I will describe a recent study quantifying the “evolutionary lag time” between when new environmental conditions develop in a region and when that new habitat is colonized by a given clade. The results show that it may take millions of years (or tens of millions of years) for species to adapt to novel climatic conditions. (3) I will describe an analysis directly comparing estimated rates of climatic niche evolution among species and rates of projected anthropogenic climate change. (4) Finally, I will discusss how climate change actually causes extinction, based on a review of what is known about the underlying mechanisms from empirical studies.

Contact : John WIENS




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