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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.
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.
Hybrid zones can form from secondary contact. A hybrid zone exists where the ranges of two interbreeding species or diverged intraspecific lineages meet and cross-fertilize. . Hybrid zones can form in situ due to the evolution of a new lineage [1] [page needed] but generally they result from secondary contact of the parental forms after a period of geographic isolation, which allowed their ...
Two zones can be distinguished in the Arctic tree line: [24] [25] a forest–tundra zone of scattered patches of krummholz or stunted trees, with larger trees along rivers and on sheltered sites set in a matrix of tundra; and "open boreal forest" or "lichen woodland", consisting of open groves of erect trees underlain by a carpet of Cladonia ...
1990 USDA Hardiness zone map detail for the northeast US. Zone 3a is light orange, zone 4b is light lavender. The area is a temperate broadleaf and mixed forests biome transition zone between the true boreal forest to the north and the Big Woods and Carolinian forest to the south, with characteristics of each.
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 ...
Biosphere 2, viewed from the thornscrub, a transition zone between Savannah and Desert (foreground) and Ocean (background) sections. A strategy of "species-packing" was practiced to ensure that food webs and ecological function could be maintained if some species did not survive.
Thresholds can be characterized as points or as zones. Zone-type thresholds imply a gradual shift or transition from one state to another rather than an abrupt change at a specific point. [ 2 ] Ecological thresholds have caught attention because many cases of catastrophic worsening of conditions have proved to be difficult or nearly impossible ...