Ecotone, Ecological Niche

 

 

  • An Ecotone is a transitional area of vegetation between two different plant communities, such as forest and grassland.
    • It has some of the characteristics of each bordering biological community and often contains species not found in the overlapping communities

Features

    • An ecotone can have a sharp vegetation transition, with a distinct line between two communities
      • For example, a change in colours of grasses or plant life can indicate an ecotone
    • A change in physiognomy (physical appearance of a plant species) can be a key indicator
      • Example, Water bodies, such as estuaries, can have a region of transition, and the boundary is characterized by the differences in heights of the plant species present in the areas because this distinguishes the two areas’ accessibility to light
    • A change of species can signal an ecotone.
      • There will be specific organisms on one side of an ecotone or the other.
    • The abundance of introduced species in an ecotone can reveal the type of biome or efficiency of the two communities sharing space.
      • 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
    • An ecotone may exist along a broad belt or in a small pocket, such as a forest clearing, where two local communities blend together
      • The influence of the two bordering communities on each other is known as the edge effect

Examples of Ecotone

    • The Mangrove Forests represent an ecotone between Marine and Terrestrial ecosystem
    • The Grasslands represent an ecotone between desert and forest
    • The Estuaries represent an ecotone between saltwater and freshwater\

Significance of ecotones

    • Ecotones are the biological analogues of buffer states. They act as buffer regions when catastrophic conditions strike and protect the adjacent ecosystem from any prospective dangers.
      • For instance, if a tsunami hits a coast, it’s usually the mangrove vegetation that acts as the shock absorbers. It prevents a massive amount of danger from infiltrating the terrestrial region
    • Ecotones act as biodiversity hotspots between two ecosystems. As such, this area is of high environmental and scientific importance.
      • Because this region borders two well-defined ecosystems, it promotes gene flow from one community to another, thereby giving rise to interesting variations. As such, ecotones hold evolutionary significance for researchers

 

  • An ecological niche refers to the interrelationship of a species with all the biotic and abiotic factors affecting it
    • It describes how an organism or population responds to the distribution of resources and competitors (for example, by growing when resources are abundant, and when predators, parasites and pathogens are scarce) and how it in turn alters those same factors (for example, limiting access to resources by other organisms, acting as a food source for predators and a consumer of prey)
  • A Niche is unique for a species, which means no two species have exact identical Niches
  • If we should have to conserve species in its native habitat, we should have knowledge about the niche requirements of the species and should ensure that all requirements of its niche are fulfilled
Clarity Check: <em>Niche vs Habitat</em>
  • In ecology, a habitat is a place where an organism or a biological population normally (or is adapted to) live(s), reside(s), or occur(s). It may be a forest, a river, a mountain, or a dessert.
  • While habitat is a geographical place, a niche is the relationship of a species with the components of an ecosystem
  • Thus, a habitat may consist of many niches and could support various species at a given time.

Niche Formation

    • Both abiotic and biotic factors help shape the niche of an ecosystem.
      • Abiotic factors, such as temperature, climate, and soil type, of an ecosystem will help form the niches, while natural selection works to set which niches would be favoured and not.
      • Through time, the species eventually develop special features that help them adapt to their environment

Examples

    • Xerophytic plants
      • These have developed several adaptations to living in dry ecological niches
      • The adaptations have evolved to help save water stored in the plant and to prevent water loss
      • Other adaptations that xerophytic plants use include the ability to move or fold up their leaves, dropping their leaves during dry periods, a waxy coating to prevent evaporation (called the cuticle) and thick hairy leaf coverings
      • Plants usually open their stomata during the day and close them at night. Succulents do the opposite in order to reduce water loss during the heat of the day.