. Elements of ecology. Ecology. it becomes drier and is also changed chemically. In time certain smaller spe- cies of trees invade the area, taking the place of the shrubs, and eventually full- sized forest trees will dominate the scene. Various stages in such a succession are shown in Fig. The existence of zonation in a com- munity does not necessarily mean that succession is going on since distinct hori- zontal subdivisions may occur in a static community, as described in the previous chapter. Furthermore, the change in the vegetation is not always self-induced but may be caused by out
. Elements of ecology. Ecology. it becomes drier and is also changed chemically. In time certain smaller spe- cies of trees invade the area, taking the place of the shrubs, and eventually full- sized forest trees will dominate the scene. Various stages in such a succession are shown in Fig. The existence of zonation in a com- munity does not necessarily mean that succession is going on since distinct hori- zontal subdivisions may occur in a static community, as described in the previous chapter. Furthermore, the change in the vegetation is not always self-induced but may be caused by outside influences. Sometimes the conversion of a swamp to dry land is brought about primarily by a lowering of the water table caused by a physiographic change. But in other in- stances, as in the situation described in the preceding paragraph, the vegetation itself is chiefly responsible for building up the land as ecological succession goes forward. At the same time that the vegetation is undergoing these profound changes in the hydrarch succession, the animal life of the community is correspondingly altered. Fish, beavers, and muskrats will gradually be excluded and terrestrial vertebrates will enter. Less conspicuous but just as significant will be the mani- festations of succession among the in- vertebrates and the microorganisms. These trends in the animal members of the community are indicated schemati- cally in Fig. for a hydrosere in Illi- nois. The changes in bird species asso- ciated with a hydrarch succession are shown in Table 19. The changes in the Fig. Five methods by which vegetation invades deeper water from the pond margin: (a) spike rush, (b) tussock sedge, (c) loosestrife, (d) cat-tail flag, and (e) sphagnum and heath. (Needham & Lloyd, 1937, Copyright, Cornell Univ. Press.) 433. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustra
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Keywords: ., bookcentury1900, bookpublishernewyorkwiley, booksubjectecology
