BIOL 2060 Lecture Notes - Lecture 20: Light Pollution, Pioneer Species, Intermediate Disturbance Hypothesis
19 Apr 2016
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Document Summary
Assumption of relatively constant environmental conditions: simple lab experiments, lotka-volterra competition model. Equilibrium: environment is treated as a constant conditions unchanging, balance of nature , competition can run its course, r-strategy species can grow in population size quickly but cannot compete with k- strategists. Non-equilibrium: environment is constantly changing, nature is adapting, disturbances can disrupt competition, r- and k-strategist species presence cycles/fluctuates. Disturbance is defined by its relativity to the average conditions. Any discrete event in time that disrupts population, community, or ecosystem structure and changes resources, substrate availability, or the physical environment. Intermediate disturbance hypothesis: species diversity will be highest when disturbance frequency is intermediate. K species won"t be able to exclude r species as disturbance will occasionally lower k species numbers so r species can recover. High frequency disturbance: low diversity end up with mostly/only r strategist. Only colonizer species can inhabit due to environment not staying constant enough for k species to grow.
