Dr. Manju Bhaskar discusses the ecological niche concept. An ecological niche describes a species' functional role and position based on factors like resources, predators, habitat characteristics. G. Evelyn Hutchinson described the fundamental niche, being all conditions a species can survive in alone, and the realized niche, being conditions after interactions with other species. Niches allow populations to persist by reducing competition and filling different roles in food webs and ecosystems. Understanding niches provides insights into community composition and species responses to one another.

1. Dr. Manju Bhaskar
Assistant Professor
Department of Zoology
D. B. S. College (CSJM University)
Kanpur 208006
Email: drmanjubhaskar19@gmail.com
Niche
Concept

2. • Ecological Niche: It is the functional role and position of a
species in its environment that describes how the species
distribution of resources and competitors or predators.
• ‘The total of the adaptations of an organismic unit’
• Niches identify the 'role of an organism in its community’, or ‘the way a
species makes its living’.
Joseph Grinnell introduced the term.
• Data on niches can be used to:
Make comparisons of the composition and organization of
communities.
Examine shifts in the behavior or ecology of one species in
response to another species. (In particular, niche shifts are
commonly used to study interspecific competition, based on
Gause’s Principle of Competitive Exclusion).

3. Ecological niche describe
 The range of conditions necessary for persistence of the species
 Its ecological role in the ecosystem.
The ecological niche was defined by a place a species can take in nature,
determined by its
Abiotic requirements
Food Preferences
Microhabitat Characteristics (for example a foliage layer)
Diurnal and Seasonal specialization
Predation Avoidance
This functional niche refers to a species position in trophic chains and food
food webs, and the concept is thus especially relevant for ecosystem ecology.

4. • 1957, Zoologist G. Evelyn Hutchinson
describe two forms of Niche
• Fundamental Niche
Fundamental niche is the entire set of
conditions under which an animal
(population, species) can survive and
reproduce itself.
It is focused on the conditions in which
a species could exist with no ecological
interactions.
• Realized Niche
Realized niche is the set of conditions
actually used by given animal (pop,
species), after interactions with other
species (predation and especially
competition) have been taken into
account.
It considered the population’s existence
Fitness (for individual) or
Population Growth Rate is zero
outside the fundamental niche

6. Biotic Factors affecting a species' niche include
Food Availability
Predators.
Abiotic Factors affecting ecological niche include
 Temperature
 Landscape characteristics
 Soil Nutrients
 Light
Non-Living factors.

7. Realized Niche
Fundamental
Niche

8. Birds in New Zealand
• Because New Zealand is an island separated from the rest of the world, it is utilized by
by some unique plants and animals as a niche.
• It includes few animals that are capable of flying or swimming, considering the distance
distance of this place from the rest of the world.
• Historically, in the absence of animals, the native animals like flying birds of the place
place filled these niches.
• The flying birds were the first known predators of this place. However, due to the absence
of land animals, these birds eventually flew down on the land to fill up the niche,
eventually becoming flightless.
• Large birds like the Giant Moa grew up to 12 ft in height and about 500lb in weight, in the
place of large mammals.
• Birds like Kiwi live on land occupying niches of small mammals like mice and moles,
feeding on seeds and insects.
• The common birds present in New Zealand are South Island takahē, the Kakapo Parrot, and
the Giant Moa.

9. Panda Bears
• Panda bears have specialized niches where they have a limited diet, primarily
feeding on bamboo.
• Pandas do not move very far to reserve the very little energy they gather from such
bamboos.
• In order to preserve the available energy, they do not indulge in interspecific
or intraspecific competition.
• These are also no natural predators and they reproduce about once in two
years to keep the population small in order to avoid the competition.
• Their niche is specialized, which is why it is also highly sensitive to human
activities.
• They feed and live mostly around the bamboo trees which are increasingly
destroyed by humans for farmland or mining.
• These are now mostly limited to temperate or humid bamboo forests of South
Western China.

10. Ecologists use the concept of the ecological niche to help understand
how communities relate to environmental conditions, fitness,
predator-prey interactions in communities. This becomes ever
as climate change affects community ecology.
Ecological niches allow species to exist in their environment. Under the
right conditions, the species will thrive and play a unique role. Without
the ecological niches, there would be less biodiversity, and the ecosystem
would not be in balance.
Interspecies competition: Ecologists refer to coexistence when
ecological niches. Two competing species cannot exist in one ecological
niche. This is due to limited resources.
Competition affects the fitness of species, and can lead to evolutionary
changes. An example of interspecies competition is an animal that
forages for pollen or nectar from a specific plant species, competing with
other such animals.
In the case of some species of ants, the insects will compete for nests and

11. The degree and type of niche overlap can
be used to assess interspecific
competition.
If niches overlap, and resources are
limiting, then competition is currently
occurring.
Abutting niches are an (indirect)
indication that competition may have
lead to niche divergence in the past.
Niche Overlap

14. Importance of Ecological
Niches
• Ecological niches are important for species, as they allow them to
function without high competition for shared, limited resources.
• Importance of ecological niches for an ecosystem when the species
occupying it ceases to exist in it.
• For example, the lack of bees has been seen to cause low fruit yields in
greenhouses, due to a lack of pollination. Similarly, we can understand
that if bee populations severely decrease on our planet, we might have
problems growing sufficient food in the future.
• The data gained from niche modeling has widespread applications,
including in conservation projects and for planning ecological reserves.

15. • Some of the important theories and principles related to ecological niches
include:
• The Competitive Exclusion Principle
• The competitive exclusion principle states that in an ecosystem, two
species cannot continue to occupy the same niche forever.
resources will lead to competition, which will force one or both species to
adapt to either occupy a different niche or cease to exist.
• This phenomenon is especially prominent in relation to invasive species,
which may occupy the same niche as an indigenous species, and can drive the
local species to extinction.
• In R* Theory, multiple species cannot exist with the same resources unless
they differentiate their niches. When resource density is at its lowest, those
species populations most limited by the resource will be competitively
excluded.
• In P* Theory, consumers can exist at high density due to having shared
enemies.

16. Referen
ces
• Ecological niche Jitka Polechová & David Storch DOI: 10.1016/B978-0-12-
409548-9.11113-3
• DOI: 10.13140/RG.2.2.33675.39208
• https://doi.org/10.3389/fmicb.2020.01942
• https://biologydictionary.net/niche/
• https://pediaa.com/difference-between-fundamental-niche-and-realized-
niche/
• https://slideplayer.com/slide/14926288/
• https://slidetodoc.com/marine-ecosystems-and-biodiversity-the-
connection-between-environment/