Vegetation

Vegetation is an assemblage of plant species in addition to the ground cover they provide. it is a general term, without specific bit of reference to specific taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characteristics. it is for broader than the term flora which subject to species composition. Perhaps the closest synonym is plant community, but vegetation can, as well as often does, refer to a wider range of spatial scales than that term does, including scales as large as the global. Primeval redwood forests, coastal mangrove stands, sphagnum bogs, desert soil crusts, roadside weed patches, wheat fields, cultivated gardens and lawns; all are encompassed by the term vegetation.

The vegetation type is defined by characteristic dominant species, or a common aspect of the assemblage, such as an elevation range or environmental commonality. The contemporary ownership of vegetation approximates that of ecologist Frederic Clements' term earth cover, an expression still used by the Bureau of Land Management.

Dynamics

Like all the biological systems, plant communities are temporally and spatially dynamic; they modify at all possible scales. Dynamism in vegetation is defined primarily as reform in manner composition and/or vegetation structure.

Temporally, a large number of processes or events can draw change, but for sake of simplicity, they can be categorized roughly as either abrupt or gradual. Abrupt make adjustments to are generally returned to as disturbances; these add things like wildfires, high winds, landslides, floods, avalanches and the like. Their causes are commonly outside exogenous to the community—they are natural processes occurring mostly independently of the natural processes of the community such(a) as germination, growth, death, etc.. such(a) events can conform vegetation formation and composition very quickly and for long time periods, and they can make-up so over large areas. Very few ecosystems are without some type of disturbance as aand recurring element of the long term system dynamic. Fire and wind disturbances are particularly common throughout many vegetation kind worldwide. Fire is especially potent because of its ability to destroy non only well plants, but also the seeds, spores, and well meristems representing the potential next generation, and because of fire's affect on fauna populations, soil characteristics and other ecosystem elements and processes for further discussion of this topic see fire ecology.

Temporal change at a slower pace is ubiquitous; it comprises the field of ecological succession. Succession is the relatively unhurried change in appearance and taxonomic composition that arises as the vegetation itself modifies various environmental variables over time, including light, water and nutrient levels. These modifications change the suite of species near adapted to grow, represent and reproduce in an area, causing floristic changes. These floristic changes contribute to structural changes that are inherent in plant growth even in the absence of species changes especially where plants have a large maximum size, i.e. trees, causing behind and broadly predictable changes in the vegetation. Succession can be interrupted at any time by disturbance, develop the system either back to a previous state, or off on another trajectory altogether. Because of this, successional processes may or may non lead to some static, final state. Moreover, accurately predicting the characteristics of such a state, even whether it does arise, is not always possible. In short, vegetative communities are subject to numerous variables that together set limits on the predictability of future conditions.

As a general rule, the larger an area under consideration, the more likely the vegetation will be heterogeneous across it. Two main factors are at work. First, the temporal dynamics of disturbance and succession are increasingly unlikely to be in synchrony across any area as the size of that area increases. That is, different areas will be at different developmental stages due to different local histories, particularly their times since last major disturbance. This fact interacts with inherent environmental variability e.g. in soils, climate, topography, etc., which is also a function of area. Environmental variability constrains the suite of species that can occupy a given area, and the two factors together interact to create a mosaic of vegetation conditions across the landscape. Only in agricultural or horticultural systems does vegetation ever approach perfect uniformity. In natural systems, there is always heterogeneity, although its scale and intensity will vary widely..