Ecological Succession
Community diversity: number of species/number of individualsthe “species richness” of a community
Succession is a shift in community composition over timespecies richness or diversity change during succession: ? usually starts with low diversity of r-strategists with high tolerance for harsh abiotic conditions ? early pioneers facilitate further settling by “conditioning” the habitat (e.g. change of soil quality) ? conditioning of the habitat might inhibit pioneers’ ability to grow ? pioneers will be replaced by other species ? community becomes usually more diverse ? increasing share of K-strategists as habitat/environment become more stable over time; eventually diversity decreases again
Keystone species have particularly strong effect on community composition because they alter the habitat or prevent dominance