DAT BIO Ch. 14- Ecology

Terms in this set (100)

begins in habitats where communities were entirely or partially destroyed by some kind of
damaging event. For example, secondary succession begins in habitats damaged by fire, floods, insect devastations,
overgrazing, and forest clear-cutting and in disturbed areas such as abandoned agricultural fields, vacant lots, roadsides,
and construction sites. Because these habitats previously supported life, secondary succession, unlike primary
succession, begins on substrates that already bear soil. In addition, the soil contains a native seed bank. Two examples
of secondary succession follow:
• Succession on abandoned cropland (called old-field succession) typically begins with the germination of
r-selected species from seeds already in the soil (such as grasses and weeds). The trees that ultimately follow
are region specific. In some regions of the eastern United States, pines take root next, followed by various
hardwoods such as oak, hickory, and dogwood.
• Succession in lakes and ponds begins with a body of water, progresses to a marsh-like state, then a meadow,
and finally to a climax community of native vegetation. Sand and silt (carried in by a river) and decomposed
vegetation contribute to the filling of the lake. Submerged vegetation is established first, followed by emergent
vegetation whose leaves may cover the water surface. Grasses, sedges, rushes, and cattails take root at the
perimeter of the lake. Eventually, the lake fills with sediment and vegetation and is subsequently replaced by a
meadow of grasses and herbs. In many mountain regions, the meadow is replaced by shrubs and native trees,
eventually becoming a part of the surrounding coniferous forest.