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Edges and Ecotones: Characteristics and Explanation

Grade 7
Jun 14, 2023

Edges and Ecotones


Biome and types of biome:

The term “biome” describes the group of plants and animals that coexist naturally in a region and frequently exhibit similar characteristics specific to that region.

It is the largest geographic biotic unit and contains a number of communities with names derived from the dominating geographical characteristics of the area, such as grasslands, deserts, or forests. We can determine the type of life that exists in a biome by looking at factors such as temperature, soil, and water.

Terrestrial, freshwater, and marine biomes are the three types into which biomes can be divided. Grasslands, deserts, and tropical forests are examples of terrestrial biomes. Polar freshwaters, large lakes, tropical and subtropical coastal rivers, temperate coastal rivers, and many more are examples of freshwater biomes. Marine biomes include tropical coral, continental shelves, and kelp forests.



Terrestrial and aquatic biome

Biome boundaries are not usually clearly drawn. In the case of grassland and forest biomes, transitional or transient zones are considered.



A zone of junction or transition between two biomes is known as an ecotone.

The ecotone is the area where two communities meet and integrate.


Mangrove forests, for example, serve as an ecotone between a marine and terrestrial ecosystem.

Other examples are grassland (between forest and desert), estuary (between freshwater and saltwater), and riverbank or marshland (between terrestrial and aquatic biomes).

An ecotone is a zone where an ecosystem (or community) rapidly transitions from one to the other. Landscape ecologists frequently research this essential aspect of landscapes. Long portions of this zone can be found crossing two different ecosystems, and it is here that both ecosystems’ characteristics can be observed. As a result, it creates a totally distinct ecosystem.

A sudden change in the environment might lead to the formation of ecotones.

In nature, there are many examples. The change from a forest to a grassland ecosystem is a prime example of an ecotone. You often observe a slow change in the forest’s tree composition as temperature and rainfall conditions vary. The forest will abruptly give way to a grassland’s wide-open areas.


Another illustration of a transition from a terrestrial to an aquatic habitat is a floodplain. One of the most significant ecotones in nature is formed by the section of the bank where these two ecosystems converge.

Ecotones can also exist within an ecosystem. In the habitats of elephants, this is typical. Elephants prefer to break up the forest by stomping when they move, turning the area into grassland along their path. They repeatedly take the same route (creating elephant corridors), eventually ensuring that there is no vegetation there. The final outcome will resemble this:


Characteristics of Ecotone

Ecotones are of importance to ecologists because they indicate a change in the living conditions, including habitats and niches, in addition to being a physical transition from one ecosystem to another. Organisms from both populations experience increasing environmental pressures along this ecotone.

  • It could be narrow (between grassland and forest) or wide (between forest and desert).
  • In comparison to the nearby ecosystems, its conditions are intermediate. Thus, it is a zone of tension. For instance, a deer (a terrestrial animal) cannot survive in a region with damp marshlands (the ecotone between terrestrial and aquatic ecosystems). The same deer will also struggle to survive near the ecotone where a forest and grassland meet since there aren’t enough open spaces. It is not as good at keeping an eye out for predators as it is on wide grasslands.
  • As we move away from a community or ecosystem, the quantity and population density of the species within that community typically decreases.
  • Some organisms in a well-developed ecotone are completely distinct from those in the nearby communities.
  • The zone can offer other organisms an opportunity. This possibility is a result of several living situations being close to one another. In nature, diversity promotes stability. Because ecotones have more complex plant and landscape characteristics, a wide variety of creatures can coexist there. Terrestrial species, for example, will approach the riverbank to consume water. Because they can eat fish in these ecotones, birds frequently flourish there.
  • Both natural and artificial ecotones exist. For example, a man-made ecotone exists between an agricultural field and a forest.

Characteristics of ecotone


When there is no clear border between two ecosystems in terms of species composition, an ecocline is formed, which is a region where change occurs gradually yet continuously.

Ecocline occurs when abiotic parameters like altitude, temperature (thermocline), salinity (halocline), depth, etc., gradually vary.

An ecotone is a gradient shift in the physicochemical characteristics between two ecosystems, whereas an ecocline is a specific new zone created by the union of two identical ecosystems.

Ecocline transitions contain a wider variety of plant species because they are less distinctive, have more stable conditions within them, and are less unstable.

The species diversity is smaller, circumstances are less stable, and ecotone transitions are more noticeable.


Edge Effect

The term “edge effect” describes the changes in population or community structures that take place at the intersection of two ecosystems.

The edge effect refers to the fact that these areas typically have a higher diversity of species. These species are referred to as edge species.

Birds are particularly susceptible to the edge effect in terrestrial habitats.

For instance, the ecotone between the forest and the desert has a higher bird density.

Edge Effect

Edge species

Along the ecotones, density and biodiversity are higher due to the higher number of landscape elements, the complexity of the vegetation, and mixed ecological characteristics. This phenomenon is called the edge effect.

For instance, there are typically more bird species along land-water ecotones. Similar to this, there are more fish species in the ecotones created by seas and rivers (deltas or estuaries).

Edge species refer to the new variety of species that live around edges and are unique. The typical edge species in floodplain ecotones are amphibians. The majority of their everyday tasks can be completed along these edges.

Species that are associated with ecotones are called edge species, and those not found in ecotones are called interior species.

White-tailed Deer, for example, require grassland for grazing but a forest for shelter.

Edge species

There are certain species that are only “edge species” periodically. In nature, seasonal edge species are fairly prevalent. For example, certain fish species migrate from the ocean to estuaries to spawn. Water turtles are another unusual species that visit beaches to deposit their eggs and then return to the sea when their young are ready. Some other species can be found in settings that are both on edge and inside. One example is the squirrel. The definition of an edge species is particularly challenging because of this shift in the spatial and temporal behaviors of organisms.

Importance of Edges and Ecotones

  • Ecotones are advantageous for mobile animals in particular because they allow them to visit several environments quickly.

Because of the conditions they support, ecotones and edges are special. They are extremely vulnerable places of biodiversity since they can sustain such a wide variety of organisms. These environments are harsh and delicate, and even minor alterations could have severe effects on the creatures that inhabit them.

  • For animals looking for a place to nest or food, they also offer a wonderful site to lay their eggs or nourishment.
  • They serve as a way for the transfer of genes from one population to another due to the greater genetic diversity that is available.
  • They can serve as a buffer zone, protecting the nearby ecosystems from potential harm. A wetland, for example, can trap pollutants and keep them from leaking into rivers.
  • Ecotones are also another sensitive indicator of climate change on a global scale. Climate change is assumed to be the cause of shifting ecological boundary lines. Thus, ecotones are currently the subject of increased research among scientists and environmentalists.
  • Edges also provide favorable settings for human interest. The ground is highly fertile along the river-land ecotone. It is also close to a water supply that is readily available. The development of agricultural land is highly advantageous under these circumstances.

Future ecologists will continue to focus a lot of their research on ecotones and margins since it is crucial to their development, preservation, and restoration in order to sustain the enormous biodiversity they support, as well as a variety of economic activities.

Importance of Edges and Ecotones

Edges and Ecotones


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