BISC 204 Lecture Notes - Lecture 18: Defaunation, Near Islands, Species Richness
8 Dec 2016
School
Department
Course
Professor
Document Summary
Bisc204 lecture 18: island biogeography and metapopulation theory. Equilibrium view of island species diversity - theory of island biogeography. This is the dynamic equilibrium theory that explains species richness of islands. Island richness is determined by colonization and extinction rates (# species through time) Richness increases with size and decreases with isolation as they are less likely to be colonized by species. Species diversity is balanced between the arrival of new colonists and extinction of existing species (rates, #spp/time) #spp/time just means the # of species through time. Immigrations rates of different species is high at 0 species. With a greater number of species, the probability of losing some due to extinction is higher. Dotted line in the middle shows where there immigration and extinction rates are in equilibrium. Demonstrates how smaller islands have higher rate of extinction (steeper slope) because they are smaller population sizes meaning they are more vulnerable to stochastic events wiping out species populations.
