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{Habitat & Ecological Niche} |
“The habitat of an Organism is the place where it lives, or the place where
one would go to find it.” Habitat is also defined as
“The sum total of environmental factors of an individual,
population or community in locality.” Thus, the habitat of the water “backswimmer” Notonecta is
the swallow vegetation-choked areas (Littoral
Zone) of ponds & lakes; that is where one would go to collect this
particular organism.
Habitat commonly refers to a large area or
the place occupied by entire community. E.g.: - Pond, Lake, River, Estuary, Ocean, Forest, Desert, Grassland, Wood-land etc. Like the habitat of the
sand sage grassland community is the series of sandy soil occurring along the
north sides of rivers in the Southern Great Plains region of the United States.
However, it
may be as smaller as a Burrow, Bark of tree or intestine of an Ant.
On the other
hand “Ecological Niche, is a more inclusive term that includes not only
the physical space occupied by an organism but also its functional role in the
community (e.g.: - its trophic position)
and its position in environmental
gradients of temperature, moisture, pH, Soil and other condition of
existence.” Grinnel (1971) used term Niche.
These three
aspects of the ecological niche can be conveniently designated as the: -
1. Spatial or Habitat Niche: It refers to the Physical Space occupied by an organism.
E.g. Distribution of seven species of Millipedes in forest floor of a Maple Oak
forest (O’Neill, 1971).
2. Trophic Niche:
It deals with the trophic position
of an organism.
E.g. Notonecta & Corixa live in the same aquatic habitat i.e. Pond, but are of different trophic niche.
Notonecta is a Predator while Corixa feeds largely on decaying vegetation.
3. Multidimensional or Hyper volume niche: It’s considered as “abstract
n-dimensional inhabitant hype volume (By G.E.Hutchinson, 1965).
Consequently,
the ecological niche of an organism depends not only on where it lives but also
on what it does (how it transforms energy, behaves, responds to and modifies
its physical & biotic environment)
& how it is constrained by other species.
By analogy, Ecologist
E.P.Odum said that “the Habitat is the organism’s address and
the Niche is its Profession.”
