EEB 3408W Chapter Notes - Chapter 16: Niche Differentiation, Insular Biogeography, Gamma Diversity
2 Apr 2017
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Document Summary
Higher diversity when there are gradients that cause local communities to be different: latitudinal gradients. Time - tropics are older and have more species. Assumes all communities diversify over time so older have more species than youngers. General increase in environmental complexity at equator. More heterogenous and complex = more diversity. Selection in temperate zone is imposed by abiotic environment. More predators and parasites in tropics which prevents competitive displacement. Biotic interactions more important in mesic tropics. Allows specialization and evolution because species must have behavioural flexibility. Ultimately more diversity of all the dependent species. More groups originated in the tropics and specialized for climate. Most species are unable to disperse out of tropics because of niche conservatism. Greater time and area leads to higher richness. 1: area effect - increasing area allos increase habitats meaning more species. Increase in number of species with area is more rapid with isolated islands than expanding sample areas.
