BIO120H1 Lecture Notes - Lecture 9: Intermediate Disturbance Hypothesis, Sclerophyll, Pinus Rigida
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BIO120H1 Full Course Notes
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Lecture 9: spatial ecology, plant communities, and disturbance. Community dynamics: predictable successional change in plant communities. Pioneer species get in first (from dispersal or seed bank in soil) Soil-building processes and shade thought to be critical (some have more shade than the other) Happens at many levels, but most heavily studied in human-impacted landscapes in eastern north america, esp. Old field means it was once agriculture and now it"s left alone. Vegetation changes spontaneously as the vegetation itself modifies the environment. Not driven by human, doesn"t require any interference. Species that get in first (when there are no plants) are pioneer species. Ends at climax stage, stable equilibrium, no more change. Primary succession ; new substrate created, no pre-existing vegetation. Disturbance: discrete event that causes abrupt change in ecosystem, community, population; sets back succession e. g. fire, windstorm, logging, agriculture. Primary succession on new lava flows kilauea volcano, hawaii. Seeds and spores blow in, hardy pioneer plants can establish themselves.
