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An ecotone may be narrow or wide, and it may be local (the zone between a field and forest) or regional (the transition between forest and grassland ecosystems). [3] An ecotone may appear on the ground as a gradual blending of the two communities across a broad area, or it may manifest itself as a sharp boundary line.
Humans have had several effects on the flood pulse. Through ecosystem alterations such as dams, debris removal, channelization, levees, navigation, irrigation, contamination, logging, fire suppression, species introduction, and agricultural runoff, humans have contributed to the destruction of wetlands and the extinction of species.
By this view, the topography in the ball-and-cup model is not static, as it is in the community perspective. This is a fundamental difference between the two perspectives. Although the mechanisms of community and ecosystem perspectives are different, the empirical evidence required for documentation of alternative stable states is the same. In ...
Gleason argued that species distributions responded individualistically to environmental factors, and communities were best regarded as artifacts of the juxtaposition of species distributions. Gleason's ideas, first published in 1926, were largely ignored until the late 1950s. Two quotes illustrate the contrasting views of Clements and Gleason.
The transition zone is the part of Earth's mantle that is located between the lower and the upper mantle, most strictly between the seismic-discontinuity depths of about 410 to 660 kilometres (250 to 410 mi), but more broadly defined as the zone encompassing those discontinuities, i.e., between about 300 and 850 kilometres (190 and 530 mi) depth. [1]
The annual rainfall typically falls between 1,600 and 2,000 mm, although there are areas in the Dahomey Gap that receive 1,000 mm or less annually. [4] [8] The Guinean savanna mosaic represents a critical ecological transition zone between the dense, evergreen rainforests to the south and the more open, tree-dotted savannas to the north.
One example of primary succession takes place after a volcano has erupted. The lava flows into the ocean and hardens into new land. The resulting barren land is first colonized by pioneer organisms, like algae, which pave the way for later, less hardy plants, such as hardwood trees, by facilitating pedogenesis, especially through the biotic acceleration of weathering and the addition of ...
Biotic homogenization is the process by which two or more spatially distributed ecological communities become increasingly similar over time. This process may be genetic, taxonomic, or functional, and it leads to a loss of beta (β) diversity. [1]