Ecological niche

1. Ecological Niche
Dr Praveen Koushley
Department of Botany
JST Govt. P. G. College, Balaghat (MP)

2. BACKGROUND YEAR
HISTORICAL TREATMENT of the
ECOLOGICAL NICHE
Joseph Grinnell 1917 the habitats and habits of birds
Charles Elton 1927
the species' place in the biological
environment, its relationship to food and
predators.
G.F. Gause 1934
the intensity of competition between
species suggest the degree to which
their niches overlapped
David Lack 1947
realized that niche relationships could
provide a basis for evolutionary
diversification of species
G.E.Hutchinson 1959
was the first to define the niche concept
formally as the activity range of each
species along every dimension of the
environment.

3. The total requirements of a species for all
resources and physical conditions determine where
it can live and how abundant it can be at any one
place within its range. These requirements are
termed abstractly the ECOLOGICAL NICHE
G.E. Hutchinson (1958) suggested that
the niche could be modeled as an
imaginary space with many dimensions, in
which each dimension or axis represents
the range of some environmental condition
or resource that is required by the species.

4. the niche of a plant might include the range of
temperatures that it can tolerate,
the intensity of light required for
photosynthesis,
specific humidity regimes,
and minimum quantities of
essential soil nutrients for uptake
• A useful extension of the niche concept is the
distinction between fundamental and realized niches
(Figure 9g-1). The fundamental niche of a species
includes the total range of environmental conditions
that are suitable for existence without the influence of
interspecific competition or predation from other
species. The realized niche describes that part of the
fundamental niche actually occupied by the species.

5. • Figure 9g-1: The following diagram shows a hypothetical situation
where a species distribution is controlled by just two
environmental variables: temperature and moisture. The green
and yellow areas describe the combinations of temperature and
moisture that the species requires for survival and reproduction in
its habitat. This resource space is known as the fundamental
niche. The green area describes the actual combinations of these
two variables that the species utilizes in its habitat. This subset of
the fundamental niche is known as the realized niche.

6. The ecological niche of an organism depends
not only on where it lives but also on what it
does. By analogy, it may be said that the
habitat is the organism's "address", and the
niche is its "profession", biologically speaking.
Odum - Fundamentals of
Ecology - W B Saunders 1959