Ecotone

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Reed beds are a common form of lakeside ecotone. The beds tend to accumulate organic matter which is then colonised by trees, forcing the reeds further into the lake. Blick vom Lons Turm HemmelsdorferSee Ausfluss aalbek.jpg
Reed beds are a common form of lakeside ecotone. The beds tend to accumulate organic matter which is then colonised by trees, forcing the reeds further into the lake.

An ecotone is a transitional vegetation area between two biological communities, [1] where two communities meet and integrate. [2] examples include transition between grassland and forest, estuaries and lagoon, freshwater and water etc. It may be narrow or wide, and it may be local (the zone between a field and forest) or regional (the transition between forest and grassland ecosystems). [3] An ecotone may appear on the ground as a gradual blending of the two communities across a broad area, or it may manifest itself as a sharp boundary line.

Contents

Etymology

The word ecotone was coined (and its etymology given) in 1904 in "The Development and Structure of Vegetation" (Lincoln, Nebraska: Botanical Seminar) by Frederic E. Clements. It is formed as a combination of ecology plus -tone, from the Greek tonos or tension – in other words, a place where ecologies are in tension.

Features

Fig.1 & 2 show simple ecotones with equal and homogeneous surfaces in both cases. Fig.3 shows an inclusion of each medium in the other, creating multiple ecotones, which are shown in a more complex form in figure 4. Fig. 5 & 6 show the edges of forests or banks treated in such a way as to lengthen the ecotone considerably without excessively modifying the environment. Fig.7 shows a common interpenetration of media (such as that found at the edge of a forest). Fig.8 shows an ecotone that could have been formed by an animal modifying its environment. EcotoneLamiotCommons4.jpg
Fig.1 & 2 show simple ecotones with equal and homogeneous surfaces in both cases. Fig.3 shows an inclusion of each medium in the other, creating multiple ecotones, which are shown in a more complex form in figure 4. Fig. 5 & 6 show the edges of forests or banks treated in such a way as to lengthen the ecotone considerably without excessively modifying the environment. Fig.7 shows a common interpenetration of media (such as that found at the edge of a forest). Fig.8 shows an ecotone that could have been formed by an animal modifying its environment.

There are several distinguishing features of an ecotone. First, an ecotone can have a sharp vegetation transition, with a distinct line between two communities. [4] For example, a change in colors of grasses or plant life can indicate an ecotone. Second, a change in physiognomy (physical appearance of a plant species) can be a key indicator. Water bodies, such as estuaries, can also have a region of transition, and the boundary is characterized by the differences in heights of the macrophytes or plant species present in the areas because this distinguishes the two areas' accessibility to light. [5] Scientists look at color variations and changes in plant height. Third, a change of species can signal an ecotone. There will be specific organisms on one side of an ecotone or the other.

Other factors can illustrate or obscure an ecotone, for example, migration and the establishment of new plants. These are known as spatial mass effects, which are noticeable because some organisms will not be able to form self-sustaining populations if they cross the ecotone. If different species can survive in both communities of the two biomes, then the ecotone is considered to have species richness; ecologists measure this when studying the food chain and success of organisms. Lastly, the abundance of introduced species in an ecotone can reveal the type of biome or efficiency of the two communities sharing space. [6] Because an ecotone is the zone in which two communities integrate, many different forms of life have to live together and compete for space. Therefore, an ecotone can create a diverse ecosystem.

Formation

Changes in the physical environment may produce a sharp boundary, as in the example of the interface between areas of forest and cleared land. Elsewhere, a more gradually blended interface area will be found, where species from each community will be found together as well as unique local species. Mountain ranges often create such ecotones, due to the wide variety of climatic conditions experienced on their slopes. They may also provide a boundary between species due to the obstructive nature of their terrain. Mont Ventoux in France is a good example, marking the boundary between the flora and fauna of northern and southern France. [7] Most wetlands are ecotones. The spatial variation of ecotones often form due to disturbances, creating patches that separate patches of vegetation. Different intensity of disturbances can cause landslides, land shifts, or movement of sediment that can create these vegetation patches and ecotones. [8]

Plants in competition extend themselves on one side of the ecotone as far as their ability to maintain themselves allows. Beyond this competitors of the adjacent community take over. As a result, the ecotone represents a shift in dominance. Ecotones are particularly significant for mobile animals, as they can exploit more than one set of habitats within a short distance. The ecotone contains not only species common to the communities on both sides; it may also include a number of highly adaptable species that tend to colonize such transitional areas. [3] The phenomenon of increased variety of plants as well as animals at the community junction is called the edge effect and is essentially due to a locally broader range of suitable environmental conditions or ecological niches.

Ecotones and ecoclines

An ecotone is often associated with an ecocline: a "physical transition zone" between two systems. The ecotone and ecocline concepts are sometimes confused: an ecocline can signal an ecotone chemically (ex: pH or salinity gradient), or microclimatically (hydrothermal gradient) between two ecosystems.

In contrast:

Examples

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">Ecoregion</span> Ecologically and geographically defined area that is smaller than a bioregion

An ecoregion is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural communities and species. The biodiversity of flora, fauna and ecosystems that characterise an ecoregion tends to be distinct from that of other ecoregions. In theory, biodiversity or conservation ecoregions are relatively large areas of land or water where the probability of encountering different species and communities at any given point remains relatively constant, within an acceptable range of variation . Ecoregions are also known as "ecozones", although that term may also refer to biogeographic realms.

<span class="mw-page-title-main">Edge effects</span> Ecological concept

In ecology, edge effects are changes in population or community structures that occur at the boundary of two or more habitats. Areas with small habitat fragments exhibit especially pronounced edge effects that may extend throughout the range. As the edge effects increase, the boundary habitat allows for greater biodiversity.

<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, such as 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">Savanna</span> Mixed woodland-grassland ecosystem

A savanna or savannah is a mixed woodland-grassland biome and ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of grasses. Four savanna forms exist; savanna woodland where trees and shrubs form a light canopy, tree savanna with scattered trees and shrubs, shrub savanna with distributed shrubs, and grass savanna where trees and shrubs are mostly nonexistent.

<span class="mw-page-title-main">Alpine tundra</span> Biome found at high altitudes

Alpine tundra is a type of natural region or biome that does not contain trees because it is at high elevation, with an associated harsh climate. As the latitude of a location approaches the poles, the threshold elevation for alpine tundra gets lower until it reaches sea level, and alpine tundra merges with polar tundra.

<span class="mw-page-title-main">Landscape ecology</span> Science of relationships between ecological processes in the environment and particular ecosystems

Landscape ecology is the science of studying and improving relationships between ecological processes in the environment and particular ecosystems. This is done within a variety of landscape scales, development spatial patterns, and organizational levels of research and policy. Landscape ecology can be described as the science of "landscape diversity" as the synergetic result of biodiversity and geodiversity.

This glossary of ecology is a list of definitions of terms and concepts in ecology and related fields. For more specific definitions from other glossaries related to ecology, see Glossary of biology, Glossary of evolutionary biology, and Glossary of environmental science.

<span class="mw-page-title-main">Tree line</span> Edge of the habitat at which trees are capable of growing

The tree line is the edge of a habitat at which trees are capable of growing and beyond which they are not. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions. The tree line is sometimes distinguished from a lower timberline, which is the line below which trees form a forest with a closed canopy.

<span class="mw-page-title-main">Environmental gradient</span>

An environmental gradient, or climate gradient, is a change in abiotic (non-living) factors through space. Environmental gradients can be related to factors such as altitude, depth, temperature, soil humidity and precipitation. Often times, a multitude of biotic (living) factors are closely related to these gradients; as a result of a change in an environmental gradient, factors such as species abundance, population density, morphology, primary productivity, predation, and local adaptation may be impacted.

Freshwater ecosystems are a subset of Earth's aquatic ecosystems. They include lakes, ponds, rivers, streams, springs, bogs, and wetlands. They can be contrasted with marine ecosystems, which have a larger salt content. Freshwater habitats can be classified by different factors, including temperature, light penetration, nutrients, and vegetation. There are three basic types of freshwater ecosystems: Lentic, lotic and wetlands. Freshwater ecosystems contain 41% of the world's known fish species.

<span class="mw-page-title-main">Guinean forest–savanna mosaic</span> Tropical forest, savanna, and grassland ecoregion in West Africa

The Guinean forest-savanna, also known as the Guinean forest-savanna transition, is a distinctive ecological region located in West Africa. It stretches across several countries including Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Togo, Benin, Nigeria, and Cameroon. This region is characterized by a unique blend of forested areas and savannas, creating a diverse and dynamic landscape.

<span class="mw-page-title-main">Community (ecology)</span> Associated populations of species in a given area

In ecology, a community is a group or association of populations of two or more different species occupying the same geographical area at the same time, also known as a biocoenosis, biotic community, biological community, ecological community, or life assemblage. The term community has a variety of uses. In its simplest form it refers to groups of organisms in a specific place or time, for example, "the fish community of Lake Ontario before industrialization".

Altitudinal zonation in mountainous regions describes the natural layering of ecosystems that occurs at distinct elevations due to varying environmental conditions. Temperature, humidity, soil composition, and solar radiation are important factors in determining altitudinal zones, which consequently support different vegetation and animal species. Altitudinal zonation was first hypothesized by geographer Alexander von Humboldt who noticed that temperature drops with increasing elevation. Zonation also occurs in intertidal and marine environments, as well as on shorelines and in wetlands. Scientist C. Hart Merriam observed that changes in vegetation and animals in altitudinal zones map onto changes expected with increased latitude in his concept of life zones. Today, altitudinal zonation represents a core concept in mountain research.

<span class="mw-page-title-main">Barren vegetation</span> Area of land where plant growth may be limited

Barren vegetation describes an area of land where plant growth may be sparse, stunted, and/or contain limited biodiversity. Environmental conditions such as toxic or infertile soil, high winds, coastal salt-spray, and climatic conditions are often key factors in poor plant growth and development. Barren vegetation can be categorized depending on the climate, geology, and geographic location of a specific area.

Tropical ecology is the study of the relationships between the biotic and abiotic components of the tropics, or the area of the Earth that lies between the Tropic of Cancer and the Tropic of Capricorn. The tropical climate experiences hot, humid weather and rainfall year-round. While many might associate the region solely with the rainforests, the tropics are home to a wide variety of ecosystems that boast a great wealth of biodiversity, from exotic animal species to seldom-found flora. Tropical ecology began with the work of early English naturalists and eventually saw the establishment of research stations throughout the tropics devoted to exploring and documenting these exotic landscapes. The burgeoning ecological study of the tropics has led to increased conservation education and programs devoted to the climate. Tropical ecology provides a wealth of natural resources to humans, this includes contributing to the carbon cycle, with the ability to store 50% of carbon emissions as well as turnover 40% of global oxygen. However, despite the natural services provided by tropical ecology, deforestation is a threat of tropical rainforests. Any plant of interest can be exploited for commercial reasons and extraction of these specific plant species can be at a rapid rate without time for healthy regeneration. Most of the global plant biodiversity is hosted in tropical areas, however studies in this area is mostly covered by scientist from Northern countries. Inclusion of scientist from countries where rainforest is present is heavily encouraged because it extends global knowledge and research which advances scientific contributions, benefiting tropical ecology.

<span class="mw-page-title-main">Riparian-zone restoration</span> Ecological restoration of river banks and floodplains

Riparian-zone restoration is the ecological restoration of riparian-zonehabitats of streams, rivers, springs, lakes, floodplains, and other hydrologic ecologies. A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the fifteen terrestrial biomes of the earth; the habitats of plant and animal communities along the margins and river banks are called riparian vegetation, characterized by aquatic plants and animals that favor them. Riparian zones are significant in ecology, environmental management, and civil engineering because of their role in soil conservation, their habitat biodiversity, and the influence they have on fauna and aquatic ecosystems, including grassland, woodland, wetland or sub-surface features such as water tables. In some regions the terms riparian woodland, riparian forest, riparian buffer zone, or riparian strip are used to characterize a riparian zone.

<span class="mw-page-title-main">Montane ecosystems</span> Ecosystems found in mountains

Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial factor in shaping plant community, biodiversity, metabolic processes and ecosystem dynamics for montane ecosystems. Dense montane forests are common at moderate elevations, due to moderate temperatures and high rainfall. At higher elevations, the climate is harsher, with lower temperatures and higher winds, preventing the growth of trees and causing the plant community to transition to montane grasslands and shrublands or alpine tundra. Due to the unique climate conditions of montane ecosystems, they contain increased numbers of endemic species. Montane ecosystems also exhibit variation in ecosystem services, which include carbon storage and water supply.

<span class="mw-page-title-main">Biogeographic classification of India</span>

Biogeographic classification of India is the division of India according to biogeographic characteristics. Biogeography is the study of the distribution of species (biology), organisms, and ecosystems in geographic space and through geological time. India has a rich heritage of natural diversity. India ranks fourth in Asia and tenth in the world amongst the top 17 mega-diverse countries in the world. India harbours nearly 11% of the world's floral diversity comprising over 17500 documented flowering plants, 6200 endemic species, 7500 medicinal plants and 246 globally threatened species in only 2.4% of world's land area. India is also home to four biodiversity hotspots—Andaman & Nicobar Islands, Eastern Himalaya, Indo-Burma region, and the Western Ghats. Hence the importance of biogeographical study of India's natural heritage.

The Southern Siberian rainforest is an area of temperate rainforest in South Central Siberia that occurs primarily along the Altai and Sayan mountain ranges in Khakassia and Tuva as well as a small area in the Khamar-Daban Mountains near Lake Baikal in Buryatia. The forest encompasses a total area of approximately 6,000 square kilometres (2,300 sq mi). The larger portion of the forest in the Altai and Sayan Mountains runs across a latitude range that encompasses between 51.5 degrees to 56 degrees north latitude, and a longitude range running between 86 degrees to 95 degrees east longitude. The region overlaps with the Golden Mountains of Altai World Heritage Site. Ecological zones range from hemiboreal forest to a forest-steppe ecotone and include a wider variety of plant species than surrounding areas.

References

  1. ↑ Senft, Amanda (2009). Species Diversity Patterns at Ecotones (PDF). University of North Carolina. Archived from the original (Master's thesis) on 2011-09-30. Retrieved 2011-01-07.
  2. ↑ Pearl, Solomon Eldra; Berg, Linda R.; Martin, Diana W. (2011). Biology. Belmont, California: Brooks/Cole.[ page needed ]
  3. 1 2 Smith, Robert Leo (1974). Ecology and Field Biology (2nd ed.). Harper & Row. p.  251. ISBN   978-0-06-500976-7.
  4. ↑ The Editors of Encyclopædia Britannica. "Ecotone." Encyclopædia Britannica, Encyclopædia Britannica, inc., 23 Jan. 2012, www.britannica.com/science/ecotone.
  5. ↑ Janauer, G.A (1997). "Macrophytes, hydrology, and aquatic ecotones: A GIS-supported ecological survey". Aquatic Botany. 58 (3–4): 379–91. doi:10.1016/S0304-3770(97)00047-8.
  6. ↑ Walker, Susan; Wilson, J. Bastow; Steel, John B; Rapson, G.L; Smith, Benjamin; King, Warren McG; Cottam, Yvette H (2003). "Properties of ecotones: Evidence from five ecotones objectively determined from a coastal vegetation gradient". Journal of Vegetation Science. 14 (4): 579–90. doi: 10.1111/j.1654-1103.2003.tb02185.x .
  7. ↑ Kubisch, P; Leuschner, C; Coners, H; Gruber, A; Hertel, D (2017). "Fine Root Abundance and Dynamics of Stone Pine (Pinus cembra) at the Alpine Treeline Is Not Impaired by Self-shading". Front Plant Sci. 8: 602. doi: 10.3389/fpls.2017.00602 . PMC   5395556 . PMID   28469633.
  8. ↑ Swanson, F. J.; Wondzell, S. M.; Grant, G. E. (1992). "Landforms, Disturbance, and Ecotones" (PDF). Landscape Boundaries. Ecological Studies. 92: 304–323. doi:10.1007/978-1-4612-2804-2_15. ISBN   978-1-4612-7677-7 . Retrieved 11 November 2022.
  9. ↑ Maarel, Eddy (1990). "Ecotones and ecoclines are different". Journal of Vegetation Science. 1 (1): 135–8. doi:10.2307/3236065. JSTOR   3236065.
  10. 1 2 Backeus, Ingvar (1993). "Ecotone Versus Ecocline: Vegetation Zonation and Dynamics Around a Small Reservoir in Tanzania". Journal of Biogeography. 20 (2): 209–18. doi:10.2307/2845672. JSTOR   2845672.
  11. ↑ Brownstein, G; Johns, C; Fletcher, A; Pritchard, D; Erskine, P. D (2015). "Ecotones as indicators: Boundary properties in wetland-woodland transition zones". Community Ecology. 16 (2): 235–43. doi: 10.1556/168.2015.16.2.11 .
  12. 1 2 Smith, Deborah R (2011). "Asian Honeybees and Mitochondrial DNA". Honeybees of Asia. pp. 69–93. doi:10.1007/978-3-642-16422-4_4. ISBN   978-3-642-16421-7.
  13. 1 2 Hughes, Jennifer B; Round, Philip D; Woodruff, David S (2003). "The Indochinese-Sundaic faunal transition at the Isthmus of Kra: An analysis of resident forest bird species distributions". Journal of Biogeography. 30 (4): 569–80. doi:10.1046/j.1365-2699.2003.00847.x. S2CID   55953315.
  14. ↑ Theeraapisakkun, M; Klinbunga, S; Sittipraneed, S (2010). "Development of a species-diagnostic marker and its application for population genetics studies of the stingless bee Trigona collina in Thailand". Genetics and Molecular Research. 9 (2): 919–30. doi: 10.4238/vol9-2gmr775 . PMID   20486087.
  15. ↑ Alfano, Niccolò; Michaux, Johan; Morand, Serge; Aplin, Ken; Tsangaras, Kyriakos; Löber, Ulrike; Fabre, Pierre-Henri; Fitriana, Yuli; Semiadi, Gono; Ishida, Yasuko; Helgen, Kristofer M; Roca, Alfred L; Eiden, Maribeth V; Greenwood, Alex D (2016). "Endogenous Gibbon Ape Leukemia Virus Identified in a Rodent (Melomys burtoni subsp.) from Wallacea (Indonesia)". Journal of Virology. 90 (18): 8169–80. doi:10.1128/JVI.00723-16. PMC   5008096 . PMID   27384662.
  16. ↑ Tanzler, R; Toussaint, E. F. A; Suhardjono, Y. R; Balke, M; Riedel, A (2014). "Multiple transgressions of Wallace's Line explain diversity of flightless Trigonopterus weevils on Bali". Proceedings of the Royal Society B: Biological Sciences. 281 (1782): 20132528. doi:10.1098/rspb.2013.2528. PMC   3973253 . PMID   24648218.
  17. ↑ Steve Nadis (11 June 2016). "Life on the edge". New Scientist.
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