ENVS 1000U Lecture 8: Species Interactions and Community Ecology
4 Feb 2016
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Document Summary
Species interactions are the backbone of communities. One of the most important species interactions is who eats whom. Matter and energy move through the community. Trophic levels = rank in the feeding hierarchy: producers, consumers, detritivores and decomposers. Lecture 8: keystone species: have a strong or wide reaching impact far out of proportion to its abundance, removal of a keystone species has substantial ripple effects. Succession = predictable series of changes in a community following a disturbance. Primary succession = disturbance eliminates all vegetation and/or soil life: glaciers, drying lakes, volcanic lava. Pioneer species = the first species to arrive in a primary succession area (e. g. lichens: usually r-selected species. Secondary succession = a disturbance (e. g. fires, hurricanes, farming, logging) that dramatically alters, but does not destroy, all local organisms: remaining organisms form building blocks for next population species. Climax community = community resulting from successful succession: remains stable until another disturbance, usually k-selected species.
