BIOL 1030 Lecture Notes - Lecture 29: Trophic Cascade, Herbivore, Human Hunting
19 Apr 2018
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Birch / fir forest (death of aspen) Immediately after a fire there are survivors . Some conifers have cones that are fire resistant. Immediately after a fire there are dispersers . Widely dispersed seeds are quick to arrive from other patches. These all tend to be species that grow well in open sun. Avoid competition by specializing on recent burns. Insect herbivory: spruce budworm eats fir, not cedar, outbreaks of budworm remove (patches of) fir. Trophic cascade: changes at one level of a food chain will ripple along the chain, affect populations several links removed, example: - reduced number of otters. If it"s kept below its carrying capacity, then the level below is not top limited must be limited by resources (bottom up: unpolluted lakes: Turbid water: ecological communities can exist in contrasting states, same place, different times. Clear lakes with many top predators vs.
