BIOL 1070 Lecture Notes - Intermediate Disturbance Hypothesis, Woodlot, Competitive Exclusion Principle
8 Mar 2014
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Document Summary
Competitive exclusion: one of the species disappears from that area. Character displacement: both species continue to exist, but they diverge to occupy slightly different ecological niches within the shared habitat. Co-existence at reduced carrying capacity: both species continue to live in the area, but at lower numbers of individuals per species. Deciduous: dominant here because of seasonal temperature variation and even precipitation among the seasons. Outcompete conifers in summer because larger leaves means greater photosynthetic capacity. Population at time two=population at time one +births - deaths+ immigrants-emigrants. Intermediate disturbance hypothesis: predicts that the highest species richness occurs at an intermediate level of natural disturbance. Low levels of disturbance result in a low amount of habitats, whereas high levels of disturbance eliminate too many habitats to support diversity. Floods, forest fire etc. are large, infrequent disturbances that are often catastrophic. Natural disturbances play an important role in shaping landscapes and influencing ecosystem processes.
