The habitat – that is, the space where an organism lives – and the biotic and abiotic factors that make possible their survival are the ecological niche of this living being.
The concept of a species’ habitat may be broad, such as the open ocean or coniferous forests of the Northern Hemisphere, as it may also be limited, such as the sebaceous glands of the skin of a mammal, in which certain species of mites live.
Each living being has a number of characteristics that allow it to occupy a particular habitat. Thus, for example, otters (a South American rodent species also known as a paddock) have a set of adaptations (claw feet, insulation skin, hydrodynamic body, prolonged diving capacity) that make rivers be their ideal habitat.
The ecological niche
The ecological niche of a living being is not only the physical space in which it lives, but rather that space and the biotic factors that work there: its prey, its predators, the places where it takes shelter and where it procreates. – In a way, the ecological niche corresponds to the role played by the living being in nature, including its relations with the other species that occupy that same habitat
Following the example of otters, it can be said that the ecological niche of these animals corresponds to that of a carnivore that lives associated with a watercourse, catches fish and requires clean water. Of course, this carnivore competes with other animals that also feed on fish, like certain aquatic snakes. In the same space, it is preferable not to coexist two species with the same ecological niche. They must always differ in some respect, otherwise the species would compete with each other and one would lead to the exclusion of the other.
The Niche and Adaptation
In a community, each species specializes in order to obtain what it needs for its survival; thus, each organism uses the environment in a specific way in relation to the other species that make up the community. This specialization reduces or eliminates competition among them, allowing the coexistence of several species in the same community.
The concept of ecological niche is useful to describe the differences of adaptation that exist between the diverse species.
Lamarck (1744-1829) and Darwin 1809-1882) were two scientists who studied the formation of living species and their adaptation to the environment, each of them elaborating their own theories.
The Niche and Specialization
According to the level of specialization, two types of species are distinguished:
- Specialist species: are those specialized in the use of a particular resource; therefore, are vulnerable to any change that occurs in relation to this resource. Specialist species are declining because they can not adapt to changes introduced by humans in the environment.
Ex: The tropical butterfly Heliconius melpomene lays its eggs only on passionflower leaves; When eggs hatch, the larvae have their only food in these leaves.
- Generalist species: they are less specialized ones, which have wider niches and are not so skillful, but adapt more easily to new situations. Generalist species are present in different habitats and are adapted to relatively different conditions.
Ex: Gull-Common is a species of abundant and widely distributed seabird. Their food includes everything from fish and marine invertebrates, eggs, insects and roundworms to carrion or even organic remains found in the trash produced by humans.