BIOL 230 Lecture Notes - Lecture 6: Habitat Fragmentation, Intact Forest Landscape, Dont
Document Summary
Immigration only affects species richness if the species is not already represented, which becomes increasingly unlikely as the region fills up w/ species. Extinction becomes more likely as regions fills with species, as resources become scarce. Dynamic: continual change in the diversity of species. Equilibrium: when the has more or less than the seq value, there is a tendency to return to it. Larger areas receive more seeds and other propagules (yes. Larger areas have more resources -> post-immigration process. Larger areas have more births -> post-immigration process. Larger areas are more detectable by colonists (yes. Larger island -> rescue effect can save species. Smaller island -> less likely to have rescue effect, thus extinction. Graph: the larger the island, the higher the highest point of the island. Small islands most likely to be disturbed. Smaller islands could have lower immigration rates & higher extinction rates. Three explanations for species-area relationships: sampling effects, habitat diversity, island biogeography.
