Ecotone is known to be a transitional area, which is present between two ecosystem or two different pleasant communities like forest and grassland. They are known to be of great environmental importance as they often contain those species which are not found in the overlapping communities. They are home to many flora and fauna as they have an area transition between two ecosystems and biomes. They may also exist along a broad belt or in a small pocket, such as a forest clearing, where two local communities blend together.
Some of the very known examples of ecotones are marshlands (between dry and wet ecosystems), mangrove forests (between terrestrial and marine ecosystems), grasslands (between desert and forest), and estuaries (between saltwater and freshwater). Mountain ranges can also create ecotones due to the changes in the climatic conditions on the slopes. Ecotone can also be seen in the area where one water body meets with another water body like estuaries and lagoons or at the boundary line between water and land like marshes.
Freshwater and Marine Ecotones
Both of these ecotones are differentiated on the basis of the presence of large plants that rise from the roots attached to the submerged substrate and because of this reason they are found in areas where ample light is available at the bottom of the basin to permit growth.
Characteristics of Ecotones
Some of the major characteristic features of ecotones are discussed below:
A. They can be natural or man-made. Example: agriculture field and forest (it is a man-made one).
B. They may vary in size from narrow to wide.
C. They are known to be zones of tension as they show conditions intermediate to the bordering ecosystems.
D. They may also contain those species which are totally different from those found in the bordering systems.
Importance of Ecotones
Ecotones have so many important roles in the ecosystem, some of them are listed below:
A. Ecotones show greater variation in an organism.
B. They provide a comfortable habitat for different organisms i.e. by providing space for nesting for those animals who roam here and there in search of food or a place for a nest.
C. They act as a bridge or mode of transportation of gene flow from one population to another as they show larger genetic diversity.
D. They offer protections to the bordering of an ecosystem from various damages and that's why they are known to be the buffer zone.
E. Ecotones also show sensitivity toward global climate change. Climatic changes take place because of the shifting of boundaries between ecosystems.
The zone in which there is a continuous change from one ecosystem to another in the absence of a sharp boundary between the two in terms of species composition is called an ecoline.
The flow of an ecoline occurs across the environmental gradient, like gradual change in abiotic factors such as altitude, temperature, salinity, depth and many more.
Edge Effect – Edge Species
When there is a change in population size or community structure that occurs at the boundary of two habitats then it is known as the edge effect. It is seen that sometimes the population density of some species in the ecotone is higher than any other community and this effect is known to be an edge effect. And edge species are those which occur primarily or most abundantly in the edge zone.
In the case of the terrestrial ecosystem, mainly birds show edge effects. For example, the population density of birds is greater in the ecotone between the forest and the desert.
Formation of Ecotones
When there is any kind of change in the physical environment then, in that case, they may produce sharp boundaries, as an example of the interface between areas of forest and cleared land. Mainly mountain ranges are responsible for the formation of such ecotones as they show a wide variety of climatic conditions experienced on their slope ranges. A terrain acts as an obstructive boundary which provides a boundary between species. The most common example of this condition is seen in Mont Ventoux in France as it acts as a boundary between the flora and fauna of northern and southern France.