Vegetation

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These maps show a scale, or index of greenness, based on several factors: the number and type of plants, leafiness, and plant health. Where foliage is dense and plants are growing quickly, the index is high, represented in dark green. Regions with sparse vegetation and a low vegetation index are shown in tan. Based on measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite. Areas where there is no data are gray. [1]

Vegetation is an assemblage of plant species and the ground cover they provide. [2] It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characteristics. It is broader than the term flora which refers to species composition. Perhaps the closest synonym is plant community, but vegetation can, and 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.

Contents

The vegetation type is defined by characteristic dominant species, or a common aspect of the assemblage, such as an elevation range or environmental commonality. [3] The contemporary use of vegetation approximates that of ecologist Frederic Clements' term earth cover, an expression still used by the Bureau of Land Management.

Picture of Vegetative Environment Green Land 12.jpg
Picture of Vegetative Environment

History of definition

The distinction between vegetation (the general appearance of a community) and flora (the taxonomic composition of a community) was first made by Jules Thurmann (1849). Prior to this, the two terms (vegetation and flora) were used indiscriminately, [4] [5] and still are in some contexts. Augustin de Candolle (1820) also made a similar distinction but he used the terms "station" (habitat type) and "habitation" (botanical region). [6] [7] Later, the concept of vegetation would influence the usage of the term biome with the inclusion of the animal element. [8]

Other concepts similar to vegetation are "physiognomy of vegetation" (Humboldt, 1805, 1807) and "formation" (Grisebach, 1838, derived from "Vegetationsform", Martius, 1824). [5] [9] [10] [11] [12]

Departing from Linnean taxonomy, Humboldt established a new science, dividing plant geography between taxonomists who studied plants as taxa and geographers who studied plants as vegetation. [13] The physiognomic approach in the study of vegetation is common among biogeographers working on vegetation on a world scale, or when there is a lack of taxonomic knowledge of someplace (e.g., in the tropics, where biodiversity is commonly high). [14]

The concept of "vegetation type" is more ambiguous. The definition of a specific vegetation type may include not only physiognomy but also floristic and habitat aspects. [15] [16] Furthermore, the phytosociological approach in the study of vegetation relies upon a fundamental unit, the plant association, which is defined upon flora. [17]

An influential, clear and simple classification scheme for types of vegetation was produced by Wagner & von Sydow (1888). [18] [19] Other important works with a physiognomic approach includes Grisebach (1872), Warming (1895, 1909), Schimper (1898), Tansley and Chipp (1926), Rübel (1930), Burtt Davy (1938), Beard (1944, 1955), André Aubréville (1956, 1957), Trochain (1955, 1957), Küchler (1967), Ellenberg and Mueller-Dombois (1967) (see vegetation classification).

Classifications

Biomes classified by vegetation .mw-parser-output .legend{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .legend-color{display:inline-block;min-width:1.25em;height:1.25em;line-height:1.25;margin:1px 0;text-align:center;border:1px solid black;background-color:transparent;color:black}.mw-parser-output .legend-text{} Tundra Taiga Temperate broadleaf and mixed forest Temperate grasslands Subtropical moist forest Mediterranean Monsoon forest Desert Xeric shrubland Dry steppe Semi-desert Grass savanna Tree savanna Tropical and subtropical dry forest Tropical rainforest Alpine tundra Montane forest Vegetation-no-legend.PNG
Biomes classified by vegetation
   Tundra
   Taiga
   Desert

There are many approaches for the classification of vegetation (physiognomy, flora, ecology, etc.). [20] [21] [22] [23] Much of the work on vegetation classification comes from European and North American ecologists, and they have fundamentally different approaches. In North America, vegetation types are based on a combination of the following criteria: climate pattern, plant habit, phenology and/or growth form, and dominant species. In the current US standard (adopted by the Federal Geographic Data Committee (FGDC), and originally developed by UNESCO and The Nature Conservancy), the classification is hierarchical and incorporates the non-floristic criteria into the upper (most general) five levels and limited floristic criteria only into the lower (most specific) two levels. In Europe, classification often relies much more heavily, sometimes entirely, on floristic (species) composition alone, without explicit reference to climate, phenology or growth forms. It often emphasizes indicator or diagnostic species which may distinguish one classification from another.

In the FGDC standard, the hierarchy levels, from most general to most specific, are: system, class, subclass, group, formation, alliance, and association. The lowest level, or association, is thus the most precisely defined, and incorporates the names of the dominant one to three (usually two) species of a type. An example of a vegetation type defined at the level of class might be "Forest, canopy cover > 60%"; at the level of a formation as "Winter-rain, broad-leaved, evergreen, sclerophyllous, closed-canopy forest"; at the level of alliance as "Arbutus menziesii forest"; and at the level of association as "Arbutus menziesii-Lithocarpus dense flora forest", referring to Pacific madrone-tanoak forests which occur in California and Oregon, US. In practice, the levels of the alliance and/or an association are the most often used, particularly in vegetation mapping, just as the Latin binomial is most often used in discussing particular species in taxonomy and in general communication.

Dynamics

Like all biological systems, plant communities are temporally and spatially dynamic; they change at all possible scales. Dynamism in vegetation is defined primarily as changes in species composition and structure.

Temporal dynamics

Vegetation types at the time of Last Glacial Maximum Last Glacial Maximum Vegetation Map.svg
Vegetation types at the time of Last Glacial Maximum

Temporally, many processes or events can cause change, but for the sake of simplicity, they can be categorized roughly as abrupt or gradual. Abrupt changes are generally referred to as disturbances; these include things like wildfires, high winds, landslides, floods, avalanches and the like. Their causes are usually external (exogenous) to the community—they are natural processes occurring (mostly) independently of the natural processes of the community (such as germination, growth, death, etc.). Such events can change vegetation structure and composition very quickly and for long periods, and they can do so over large areas. Very few ecosystems are without some disturbance as a regular and recurring part of the long-term system dynamic. Fire and wind disturbances are prevalent throughout many vegetation types worldwide. Fire is particularly potent because of its ability to destroy not only living plants but also the seeds, spores, and living meristems representing the potential next generation, and because of fire's impact 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 ecological succession field. Succession is the relatively gradual structure and taxonomic composition change that arises as the vegetation modifies various environmental variables over time, including light, water, and nutrient levels. These modifications change the suite of species most adapted to grow, survive, and reproduce in an area, causing floristic changes. These floristic changes contribute to structural changes inherent in plant growth even in the absence of species changes (especially where plants have a large maximum size, i.e., trees), causing slow and broadly predictable changes in the vegetation. Succession can be interrupted at any time by disturbance, setting the system back to a previous state or off on another trajectory altogether. Because of this, successional processes may or may not lead to some static, final state. Moreover, accurately predicting the characteristics of such a state, even if it does arise, is not always possible. In short, vegetative communities are subject to many variables that set limits on future conditions' predictability.

Spatial dynamics

Generally, the larger an area under consideration, the more likely the vegetation will be heterogeneous. 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. Different areas will be at various developmental stages due to other local histories, particularly their times since the last significant disturbance. This fact interacts with inherent environmental variability (e.g., in soils, climate, topography, etc.), also a function of area. Environmental variability constrains the suite of species that can occupy a given area, and the two factors interact to create a mosaic of vegetation conditions across the landscape. Only in agricultural or horticultural systems does vegetation ever approach perfect uniformity. There is always heterogeneity in natural systems, although its scale and intensity will vary widely.

See also

Related Research Articles

<span class="mw-page-title-main">Biome</span> Biogeographical unit with a particular biological community

A biome is a distinct geographical region with specific climate, vegetation, and animal life. It consists of a biological community that has formed in response to its physical environment and regional climate. Biomes may span more than one continent. A biome encompasses multiple ecosystems within its boundaries. It can also comprise a variety of habitats.

<span class="mw-page-title-main">Biogeography</span> Study of distribution of species

Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, isolation and habitat area. Phytogeography is the branch of biogeography that studies the distribution of plants. Zoogeography is the branch that studies distribution of animals. Mycogeography is the branch that studies distribution of fungi, such as mushrooms.

Ecological classification or ecological typology is the classification of land or water into geographical units that represent variation in one or more ecological features. Traditional approaches focus on geology, topography, biogeography, soils, vegetation, climate conditions, living species, habitats, water resources, and sometimes also anthropic factors. Most approaches pursue the cartographical delineation or regionalisation of distinct areas for mapping and planning.

<span class="mw-page-title-main">Grassland</span> Area with vegetation dominated by grasses

A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur naturally on all continents except Antarctica and are found in most ecoregions of the Earth. Furthermore, grasslands are one of the largest biomes on Earth and dominate the landscape worldwide. There are different types of grasslands: natural grasslands, semi-natural grasslands, and agricultural grasslands. They cover 31–69% of the Earth's land area.

<span class="mw-page-title-main">Ecological succession</span> Process of change in the species structure of an ecological community over time

Ecological succession is the process of change in the species that make up an ecological community over time.

A phytochorion, in phytogeography, is a geographic area with a relatively uniform composition of plant species. Adjacent phytochoria do not usually have a sharp boundary, but rather a soft one, a transitional area in which many species from both regions overlap. The region of overlap is called a vegetation tension zone.

<span class="mw-page-title-main">Forest dynamics</span> Biotic and abiotic ecosystem influences

Forest dynamics are the underlying physical and biological forces that shape and change a forest ecosystem. The continuous state of change in forests can be summarized with two basic elements: disturbance and succession.

<span class="mw-page-title-main">Raunkiær plant life-form</span> Types of plant form as defined by Christen Raunkiær

The Raunkiær system is a system for categorizing plants using life-form categories, devised by Danish botanist Christen C. Raunkiær and later extended by various authors.

Phytosociology, also known as phytocoenology or simply plant sociology, is the study of groups of species of plant that are usually found together. Phytosociology aims to empirically describe the vegetative environment of a given territory. A specific community of plants is considered a social unit, the product of definite conditions, present and past, and can exist only when such conditions are met. In phyto-sociology, such a unit is known as a phytocoenosis. A phytocoenosis is more commonly known as a plant community, and consists of the sum of all plants in a given area. It is a subset of a biocoenosis, which consists of all organisms in a given area. More strictly speaking, a phytocoenosis is a set of plants in area that are interacting with each other through competition or other ecological processes. Coenoses are not equivalent to ecosystems, which consist of organisms and the physical environment that they interact with. A phytocoensis has a distribution which can be mapped. Phytosociology has a system for describing and classifying these phytocoenoses in a hierarchy, known as syntaxonomy, and this system has a nomenclature. The science is most advanced in Europe, Africa and Asia.

<span class="mw-page-title-main">Secondary succession</span> Redevelopment of an encology after an event that changes it radically

Secondary succession is the secondary ecological succession of a plant's life. As opposed to the first, primary succession, secondary succession is a process started by an event that reduces an already established ecosystem to a smaller population of species, and as such secondary succession occurs on preexisting soil whereas primary succession usually occurs in a place lacking soil. Many factors can affect secondary succession, such as trophic interaction, initial composition, and competition-colonization trade-offs. The factors that control the increase in abundance of a species during succession may be determined mainly by seed production and dispersal, micro climate; landscape structure ; bulk density, pH, and soil texture.

<span class="mw-page-title-main">Disturbance (ecology)</span> Temporary change in environmental conditions that causes a pronounced change in an ecosystem

In ecology, a disturbance is a temporary change in environmental conditions that causes a pronounced change in an ecosystem. Disturbances often act quickly and with great effect, to alter the physical structure or arrangement of biotic and abiotic elements. A disturbance can also occur over a long period of time and can impact the biodiversity within an ecosystem.

Phytogeography or botanical geography is the branch of biogeography that is concerned with the geographic distribution of plant species and their influence on the earth's surface. Phytogeography is concerned with all aspects of plant distribution, from the controls on the distribution of individual species ranges to the factors that govern the composition of entire communities and floras. Geobotany, by contrast, focuses on the geographic space's influence on plants.

Plant life-form schemes constitute a way of classifying plants alternatively to the ordinary species-genus-family scientific classification. In colloquial speech, plants may be classified as trees, shrubs, herbs, etc. The scientific use of life-form schemes emphasizes plant function in the ecosystem and that the same function or "adaptedness" to the environment may be achieved in a number of ways, i.e. plant species that are closely related phylogenetically may have widely different life-form, for example Adoxa moschatellina and Sambucus nigra are from the same family, but the former is a small herbaceous plant and the latter is a shrub or tree. Conversely, unrelated species may share a life-form through convergent evolution.

A fire regime is the pattern, frequency, and intensity of the bushfires and wildfires that prevail in an area over long periods of time. It is an integral part of fire ecology, and renewal for certain types of ecosystems. A fire regime describes the spatial and temporal patterns and ecosystem impacts of fire on the landscape, and provides an integrative approach to identifying the impacts of fire at an ecosystem or landscape level. If fires are too frequent, plants may be killed before they have matured, or before they have set sufficient seed to ensure population recovery. If fires are too infrequent, plants may mature, senesce, and die without ever releasing their seed.

<span class="mw-page-title-main">Plant community</span> Collection of native photosynthetic organisms

A plant community is a collection or association of plant species within a designated geographical unit, which forms a relatively uniform patch, distinguishable from neighboring patches of different vegetation types. The components of each plant community are influenced by soil type, topography, climate and human disturbance. In many cases there are several soil types present within a given plant community. This is because the soil type within an area is influenced by two factors, the rate at which water infiltrates or exits the soil, as well as the rate at which organic matter enters or decays from the soil. Plant communities are studied substantially by ecologists, due to providing information on the effects of dispersal, tolerance to environmental conditions, and response to disturbance of a variety of plant species, information valuable to the comprehension of various plant community dynamics.

<span class="mw-page-title-main">Plant ecology</span> The study of effect of the environment on the abundance and distribution of plants

Plant ecology is a subdiscipline of ecology that studies the distribution and abundance of plants, the effects of environmental factors upon the abundance of plants, and the interactions among plants and between plants and other organisms. Examples of these are the distribution of temperate deciduous forests in North America, the effects of drought or flooding upon plant survival, and competition among desert plants for water, or effects of herds of grazing animals upon the composition of grasslands.

Vegetation classification is the process of classifying and mapping the vegetation over an area of the Earth's surface. Vegetation classification is often performed by state based agencies as part of land use, resource and environmental management. Many different methods of vegetation classification have been used. In general, there has been a shift from structural classification used by forestry for the mapping of timber resources, to floristic community mapping for biodiversity management. Whereas older forestry-based schemes considered factors such as height, species and density of the woody canopy, floristic community mapping shifts the emphasis onto ecological factors such as climate, soil type and floristic associations. Classification mapping is usually now done using geographic information systems (GIS) software.

<span class="mw-page-title-main">Ecosystem Functional Type</span>

Ecosystem Functional Type (EFT) is an ecological concept to characterize ecosystem functioning. Ecosystem Functional Types are defined as groups of ecosystems or patches of the land surface that share similar dynamics of matter and energy exchanges between the biota and the physical environment. The EFT concept is analogous to the Plant Functional Types (PFTs) concept, but defined at a higher level of the biological organization. As plant species can be grouped according to common functional characteristics, ecosystems can be grouped according to their common functional behavior.

<span class="mw-page-title-main">Biomes in Brazil</span>

According to IBGE (2004), Brazil has its territory occupied by six terrestrial biomes and one marine biome.

References

  1. ↑ "Global Maps". earthobservatory.nasa.gov. 8 May 2018. Archived from the original on 11 July 2017. Retrieved 8 May 2018.
  2. ↑ Burrows, Colin J. (1990). Processes of vegetation change. London: Unwin Hyman. p.  1. ISBN   978-0045800131.
  3. ↑ Introduction to California Plant Life; Robert Ornduff, Phyllis M. Faber, Todd Keeler-Wolf; 2003 ed.; p. 112
  4. ↑ Thurmann, Jules (1849). Essai de phytostatique appliqué à la chaîne du Jura et aux contrées voisines, ou Étude de la dispersion des plantes vasculaires envisagée principalement quant à l'influence des roches soujacentes. Berne: Jent et Gassmann.
  5. 1 2 Martins, F. R. & Batalha, M. A. (2011). Formas de vida, espectro biológico de Raunkiaer e fisionomia da vegetação. In: Felfili, J. M., Eisenlohr, P. V.; Fiuza de Melo, M. M. R.; Andrade, L. A.; Meira Neto, J. A. A. (Org.). Fitossociologia no Brasil: métodos e estudos de caso. Vol. 1. Viçosa: Editora UFV. p. 44-85. "Archived copy" (PDF). Archived (PDF) from the original on 2016-09-24. Retrieved 2016-08-25.{{cite web}}: CS1 maint: archived copy as title (link). Earlier version, 2003, "Archived copy" (PDF). Archived (PDF) from the original on 2016-08-27. Retrieved 2016-08-25.{{cite web}}: CS1 maint: archived copy as title (link).
  6. ↑ Candolle, Augustin Pyramus de (1820). "Essai élémentaire de géographie botanique". Dictionnare des Sciences Naturelles (in French). 18. Flevrault, Strasbourg.
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  8. ↑ Coutinho, L. M. (2006). O conceito de bioma. Acta Bot. Bras. 20(1): 13-23, Coutinho, Leopoldo Magno (2006). "O conceito de bioma". Acta Botanica Brasilica. 20: 13–23. doi: 10.1590/S0102-33062006000100002 ..
  9. ↑ Humboldt, Alexander von; Bonpland, Aimé (1805). Essai sur la géographie des plantes : accompagné d'un tableau physique des régions équinoxiales, fondé sur des mesures exécutées, depuis le dixième degré de latitude boréale jusqu'au dixième degré de latitude australe, pendant les années 1799, 1800, 1801, 1802 et 1803 (in French). Paris: Chez Levrault, Schoell et compagnie, libraires.
  10. ↑ Humboldt, Alexander von; Bonpland, Aimé (1807). Ideen zu einer Geographie der Pflanzen : nebst einem Naturgemälde der Tropenländer : auf Beobachtungen und Messungen gegründet, welche vom 10ten Grade nördlicher bis zum 10ten Grade südlicher Breite, in den Jahren 1799, 1800, 1801, 1802 und 1803 angestellt worden sind (in German). Tübingen: Bey F.G. Cotta.
  11. ↑ Garcke, Aug.; Schlechtendal, D. F. L. von (1838). Linnaea : Ein Journal für die Botanik in ihrem ganzen Umfange (in German). Vol. 12. Berlin: F. Dümmler.
  12. ↑ Martius, C. F. P. von. 1824. Die Physiognomie des Pflanzenreiches in Brasilien. Eine Rede, gelesen in der am 14. Febr. 1824 gehaltnen Sitzung der Königlichen Bayerischen Akademie der Wissenschaften. München, Lindauer, Archived 2016-10-12 at the Wayback Machine .
  13. ↑ Ebach, M.C. (2015). Origins of biogeography. The role of biological classification in early plant and animal geography. Dordrecht: Springer, p. 89, .
  14. ↑ Beard, J.S. (1978). Whittaker, R. H. (ed.). Classification of Plant Communities. Springer Science & Business Media. pp. 33–64. ISBN   978-94-009-9183-5.
  15. ↑ Eiten, George (June 1992). "How names are used for vegetation". Journal of Vegetation Science. 3 (3): 419–424. Bibcode:1992JVegS...3..419E. doi:10.2307/3235768. JSTOR   3235768.
  16. ↑ Walter, B. M. T. (2006). Fitofisionomias do bioma Cerrado: síntese terminológica e relações florísticas. Doctoral dissertation, Universidade de Brasília, p. 10, "Archived copy" (PDF). Archived (PDF) from the original on 2016-08-26. Retrieved 2016-08-26.{{cite web}}: CS1 maint: archived copy as title (link).
  17. ↑ Rizzini, C.T. 1997. Tratado de fitogeografia do Brasil: aspectos ecológicos, sociológicos e florísticos. 2 ed. Rio de Janeiro: Âmbito Cultural Edições, p. 7-11.
  18. ↑ Cox, C. Barry; Moore, Peter D.; Ladle, Richard J. (2016-05-31). Biogeography: An Ecological and Evolutionary Approach. John Wiley & Sons. p. 20. ISBN   978-1-118-96858-1.
  19. ↑ "Sydow-Wagners Methodischer Schul-Atlas (1888-1944)". www.atlassen.info. Retrieved 2023-02-07.
  20. ↑ de Laubenfels, D. J. 1975. Mapping the World's Vegetation: Regionalization of Formation and Flora. Syracuse University Press: Syracuse, NY.
  21. ↑ Küchler, A. W.; Zonneveld, I. S. (2012-12-06). Vegetation mapping. Springer Science & Business Media. pp. 67–80. ISBN   978-94-009-3083-4.
  22. ↑ Sharma, P. D. (2012). Ecology And Environment. Rastogi Publications. p. 140. ISBN   978-81-7133-905-1.
  23. ↑ Mueller-Dombois, D. (1984). Woodwell, G. M. (ed.). "Classification and Mapping of Plant Communities: a Review with Emphasis on Tropical Vegetation" (PDF). bse.carnegiescience.edu. New York: J Wiley and Sons. pp. 21–88. Archived from the original (PDF) on July 17, 2010. Retrieved 2023-02-07.

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Classification

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