Lec7EEMB2W08

Lec7EEMB2W08 - Community Ecology Community: Two or more...

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1 Community Ecology Community: Two or more populations living in the same geographic area Community Characteristics - Trophic structure - Species Diversity - Dominance - Growth form and structure Species Diversity : Species richness + Species evenness How are species numbers determined and why do they vary? Species richness = The number of species in a community Species evenness = The relative abundance of species in a community 90% 5% 5% 33% 33% 33% Community #1 Community #2 Community Ecology Species Diversity : Species richness + Species evenness How are species numbers determined and why do they vary? Species richness = The number of species in a community Species evenness = The relative abundance of species in a community 90% 5% 5% 33% 33% 33% Community #1 Community #2 Community Ecology Community #2 is more diverse (higher species diversity) Community #1 and #2 have the same species richness Community #2 is more even than community #1 Diversity Indices: Diversity indices are designed to combine both species richness and evenness into an assessment of species diversity The most commonly used index of species diversity (H) S i = 1 H = - P i ln P i M Shannon - Weaver Diversity Index: Community Ecology For a given species richness (H) increases with species evenness For a given species evenness (H) increases with species richness
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This note was uploaded on 04/07/2008 for the course EEMB 2 taught by Professor Evan during the Winter '07 term at UCSB.

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Lec7EEMB2W08 - Community Ecology Community: Two or more...

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