BIOSC 0370 Lecture Notes - Lecture 22: Seral Community, Species Richness, Radiocarbon Dating
22 Dec 2015
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Document Summary
Community succession: the ecology of change (ch 19) It"s possible to look back in time by examining pollen preserved in lake sediments: carbon dating: identifies age of pollen in each layer, helps determine changes in plant species composition. Can occur rapidly after disturbance b/c of short generation time of dominant species. Caused by vulnerability to herbivores, not competition: sea lettuce dominates on disturbed boulders, and the lettuce eaten by crabs, so boulders attract crabs. Rapid b/c organisms can move downstream from sites that are less disturbed. During drought, little succession w/ brief episodes of rapid change. Consistent pattern of succession: initial rapid increase in species richness, then plateau, then small decline. Early successional species high dispersal, rapid growth, early reproduction traits. Late successional species enhanced competitive ability traits. Spruce seeds could grow in earlier seral stages, so facilitation is not the mechanism driving its abundance. Few spruce seeds arrived to colonize pioneer & low-shrub stages.
