Plant ecology is a subdiscipline of ecology which studies the distribution and abundance of plants, the interactions among and between members of plant species, and their interactions with their environment. Plant ecology has its roots both in plant geography and in studies of the interactions between individual plants, populations of plants, plant communities, and their respective environments.
Broadly speaking, the scope of plant ecology encompasses plant ecophysiology, plant population ecology, community ecology, ecosystem ecology and landscape ecology.
Most plants are rooted in the soil, and often they reproduce vegetatively in a way that makes it difficult to distinguish individual plants of the same species. These characteristic features of plants necessitate a somewhat different scientific methodology than that used in, say, animal ecology though the different subdisciplines of plant ecology remain integrated with ecosystem ecology.
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When plants grow close to other plants they may compete for resources, such as light, water and nutrients, that are needed for plant growth. Plants may compete for a single growth-limiting resource e.g. light in agricultural systems with sufficient water and nutrients, but in most natural ecosystems plants probably are adapted to respond to the environment in such a way that they are colimited by several resources, e.g. light, phosphorus and nitrogen at the same time.[1]
In principle, it is possible to examine competition at the level of the limiting resources if a detailed knowledge of the physiological processes of the competing plants is available. However, in most terrestrial ecological studies, there is only little information on the uptake and dynamics of the resources that limit the growth of different plant species, and, instead, competition is inferred from observed negative effects of neighbouring plants without knowing precisely which resources the plants were competing for.
Facilitation among neighboring plants may act by reducing the negative impacts of a stressful environment, and in general, facilitation is more likely to occur in physically stressful environments than in favorable environments, where competition may be the most important interaction among species
An important ecological function of plants is that they produce organic compounds for herbivores in the bottom of the food web. Oppositely, herbivory is an important source of disturbance for many plant species, and they have evolved many different forms of defensive physical structures and chemical compounds to prevent herbivory.
Plant communities are broadly distributed into biomes based on the structure of dominant plant species. Biomes are determined by regional climates, namely temperature and precipitation, and follow general latitudinal trends. Within biomes, there may be many ecological communities, which are impacted not only by climate and a variety of smaller-scale features, including soils, hydrology, and disturbance regime.
In the same way that plant communities vary at differing latitudes, plant communities vary with elevation. Communities at high elevations often resemble those found at higher latitudes.
The ecological success of a plant species in a specific environment may be quantified by its abundance, and depending on the life form of the plant different measures of abundance may be relevant, e.g. density, biomass, or plant cover.
The change in the abundance of a plant species may be due to both abiotic factors, e.g. climate change, or biotic factors, e.g herbivory or interspecific competition.
Whether a plant species is present at a local area depends on the processes of colonisation and local extinction. The probaility of colonisation decreases with distance to neighboring habitats where the species is present and increases with plant abundance and fecundity in neighboring habitats and the dispersal distance of the species. The probability of local extinction decreases with abundance (both living plants and seeds in the soil seed bank).
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