BISC 204 Lecture Notes - Lecture 18: Johann Reinhold Forster, Insular Biogeography, Biogeography
12 Dec 2017
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Why study islands: small, simple, have discrete boundaries that are easy to understand, natural replication, many unique characteristics variations in size, shape, degree of isolation. Buffon"s law: environmentally similar but geographically isolated regions are comprised of distinct biotas. Johann reinhold forster: islands generally less diverse than mainland, diversity of plants increases with island area, availability of resources, habitat, and heat. Limited number of niches for species to occupy. Figure 1 species-area curves: by convention, we typically look at the log-log plot, but it"s easierto see a saturation point in the non- logged plot. The intersection between the lines for immigration rate and extinction rate tells you: Figure 2 rates of immigration and extinction help predict number of species found on an island. Equilibrium species richness is reached between rate of immigration of new species, and rate of extinction of established species. Before macarthur and wilson, it was thought that species composition on islands was static , or fixed .
