Biology 3445F Lecture Notes - Lecture 4: Logistic Function, Insular Biogeography, Power Law
Document Summary
Whittaker provided foundation for measuring diversity at different spatial scales whereby diversity could be. Levels of diversity divided in three ways: alpha diversity: local patch, beta: variation among patches, gamma: regional area. Multiplicative: = * means beta diversity is independent of species richness. Additive: = + more intuitive measure of dissimilarity between patches, beta diversity has units associated with it. Beta diversity: the variation in species composition among sites in a geographic region. Any process that increases beta diversity (while alpha remains constant) has a corresponding increase in gamma diversity. Image: system 2 is much less similar than system 1, therefore beta diversity is higher. As dispersal increases, more species of the regional pool are present in local communities lowers beta diversity as patches become homogenized. Picture below: levels of diversity increasing spatial scales as you move down: hierarchical framework for processes influencing biodiversity space-time continuum. Species-area relationship (sars): you will find more species if you sample a larger area.
