There can be many or few species in vegetation. Structure refers to the absolute and relative abundances and other relationships of the species constituting the community. The total number of individuals of each species, or the rank order of abundance of the different species are examples of vegetation structure. Architecture refers to the arrangement in three dimensional space of any of the elements of a community.
Architecture can reflect the spatial distribution and clustering of species, of life forms of plants, or patches of vegetation. The term "succession" was coined when ecologists assumed that one community of plants gave way to another. Hence, communities succeeded one another. However, we now understand that communities may not always be discrete and that they may blend into one another gradually through time. In addition, there may not be a fixed sequence of species that necessarily has to occur in a region.
General tendencies in succession may appear, although the trends are often probabilistic and flexible. Succession occurs in all sorts of vegetation. Indeed in some cases, succession coverts one vegetation type to another. In some cases, succession takes place on new substrate that has few available nutrients or seeds and other sources of plants. For example, ponds may undergo succession through bogs to closed canopy forests. Mechanisms of succession in natural communities and their role in community stability and organization.
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Succession: A Closer Look. Dynamics of Predation. Ecological Consequences of Parasitism. Resource Partitioning and Why It Matters. Direct and Indirect Interactions. Keystone Species. Citation: Emery, S. Nature Education Knowledge 3 10 What do volcanoes, glaciers, sand dunes, storms, agriculture, and fire have in common?
They all initiate the process of succession in communities. Aa Aa Aa. The Role of Disturbance. Succession is one of the major themes of our Nature Trail. It is possible to observe both the on-going process of succession and the consequences of past succession events at almost any point along the trail. The rise and the decline of numerous species within our various communities illustrates both of the types of motive forces of succession: the impact of an established species to change a site's environmental conditions, and the impact of large external forces to suddenly alter the environmental nature of a site.
Both of these forces necessarily select for new species to become ascendant and possibly dominant within the ecosystem. Some specific examples of observable succession include: 1. The growth of hardwood trees including ash, poplar and oak within the red pine planting area.
The consequence of this hardwood tree growth is the increased shading and subsequent mortality of the sun loving red pines by the shade tolerant hardwood seedlings.
The shaded forest floor conditions generated by the pines prohibits the growth of sun-loving pine seedlings and allows the growth of the hardwoods. The consequence of the growth of the hardwoods is the decline and senescence of the pine forest. Observe the dead pine trees that have fallen. Observe the young hardwoods growing up beneath the still living pines. The raspberry thickets growing in the sun lit forest sections beneath the gaps in the canopy generated by wind-thrown trees.
Raspberry plants require sunlight to grow and thrive. Beneath the dense shade canopy particularly of the red pines but also beneath the dense stands of oaks, there is not sufficient sunlight for the raspberry's survival. However, in any place in which there has been a tree fall the raspberry canes have proliferated into dense thickets. You may observe this successional consequence of macro-ecosystem change within the red pine stand and all along the more open sections of the trail.
Within these raspberry thickets, by the way, are dense growths of hardwood seedlings. The raspberry plants are generating a protected "nursery" for these seedlings and are preventing a major browser of tree seedlings the white tailed deer from eating and destroying the young trees.
By providing these trees a shaded haven in which to grow the raspberry plants are setting up the future tree canopy which will extensively shade the future forest floor and consequently prevent the future growth of more raspberry plants! The succession "garden" plot.
This plot was established in April, please see the series of photographs on the "Succession Garden Plot" page. The initial plant community that was established within the boundaries of this plot was made up of those species that could tolerate the periodic mowing that "controlled" this "grass" ecosystem.
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