Ecological Niche; Types, Importance and Examples

Ecological niche can be defined the specific location where an organism lives or the role or function of a species within its environment or the interactions of a species with the biotic and abiotic factors that affect it.

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The term niche (plural: niches) originates from the French word nichier, meaning “to construct a nest,” and the Latin word nidus, meaning “nest.”

An ecological niche describes the interaction between a species and the biotic and abiotic factors that influence it.

Joseph Grinnell first introduced the concept of a niche in 1917, equating it to a species’ habitat. Later, Elton (1927) interpreted a niche as a species’ role within a trophic web, while Hutchinson (1957) defined it as the multidimensional space of resources a species can access and use.

Although niches have been defined in various ways, they are widely understood to relate to how an organism or population adapts to competition and resource distribution.

A niche specifically refers to the role or position of an organism or population within an ecosystem. Both biotic and abiotic factors in the ecosystem can influence a niche.

Ecologically, a niche can be defined as:

The specific location where an organism lives.
The role or function of a species within its environment.
The interactions of a species with the biotic and abiotic factors that affect it

Ecological niche, types of ecological niche and importance of ecological niche

Habitat and Niche

In ecology, a habitat refers to the physical location where an organism or a biological community naturally lives, such as a desert, forest, river, or mountain.
A habitat represents a physical space, a niche describes a species’ interaction with the elements of the ecosystem. An organism’s niche explains how it operates and survives within its environment.
A single habitat can contain numerous niches, supporting a variety of species simultaneously.
The concept of a ecological niche focuses on the role of a single species within a habitat, encompassing all its biological activities influenced by biotic and abiotic factors.

Niche Formation

Abiotic and biotic factors interact to shape an ecosystem’s niche. Natural selection influences which niches are favored by determining abiotic factors such as temperature, climate, and soil type.

Over time, species develop specialized traits that help them adapt to their environment. However, biological constraints like parasitism, competition, and predation can limit population size.

Competition for essential resources such as nutrients, space, light, and other necessities among coexisting species may restrict population growth in a habitat.
Predation can also reduce population size, depending on the number of predators and the intensity of predation.
In parasitism, the presence of parasites that use a species as their host and susceptibility to disease-causing infections further limit population growth.

As these factors change, ecosystem niches evolve and take on new forms.

Niche Segregation

Niche segrega t ion is the partitioning or separation of niche.
Niche segregation occurs due to natural selection, where each species occupies a specific niche, preventing two species from sharing the same one.
However, species can coexist by establishing separate ecological niches.
To avoid competition for limited resources, they must find ways to live together, such as through resource differentiation or niche partitioning.
Without such adaptation, natural selection will favor one species over the other, leading to the extinction of the less competitive species.

Niche Overlap

Niche overlap refers to two species using the same resources or environmental factors.
Often, ecological niches only partially overlap due to shared resources.

Vacant Niche

A vacant niche is one that is not yet occupied by a species, although the concept remains debated.
Ecological disturbances, such as forest fires or droughts, and evolutionary events, such as species failing to adapt, are generally considered the main causes of unoccupied niches.

Types of Ecological Niches

Ecological niche can be divided into different types viz, fundamental niche, realized niche, habitat or spatial niche, tropic niche and hypervolume niche.

Fundamental Niche

A species’ habitat encompasses the environmental conditions and resources necessary for its survival and reproduction.
Ecosystems are influenced by abiotic factors such as temperature, humidity, pH, and soil composition, as well as biotic factors like prey availability and interspecific interactions.
A species’ physiological tolerances and resource needs, in the absence of competition, can vary across time and space due to habitat diversity and environmental changes.
This variability shapes the species’ fundamental niche, allowing it to occupy a range of ecological roles within its ecosystem.

Realized Niche

Represents the specific environmental conditions and resources a species actively uses within its habitat.
It is typically more limited than the fundamental niche due to factors such as competition, predation, biotic interactions, and resource availability.
This reflects the portion of the fundamental niche that a species actually occupies, accounting for environmental and interspecies constraints.
It offers valuable insights into the ecological roles, distribution, and interactions of species within ecosystems.

Habitat or Spatial Niche

In ecology, a habitat or spatial niche refers to the precise environmental conditions and resources a species needs for survival and reproduction.
These include factors like temperature, humidity, food supply, and shelter. Species evolve to occupy distinct niches within their habitats, adapting to efficiently use available resources while reducing competition with other organisms.
The millipede community living under a fallen log in a forest is shaped by the age and level of disturbance of the logs, which create diverse niches for various species.
The forest floor is primarily covered with maple-oak vegetation, and different millipede species inhabit distinct niches, such as under the log, beneath the bark, or within the leaf litter.

Trophic Niche

The trophic niche describes an organism’s role in its ecosystem based on its feeding behavior, interactions with other species, and position in the food web.
While two species may share the same habitat, their distinct feeding habits often place them in different functional roles or trophic levels.
For instance, in a pond ecosystem, the aquatic birds Corixa and Notonecta occupy separate trophic niches.
Notonecta is an active predator that hunts and feeds on other animals, whereas Corixa primarily consumes decaying vegetation.

Multifactor or Hypervolume Niche

This concept revolves around the unique adaptations of a population to various environmental factors.
Hutchinson (1957) introduced the idea of an n-dimensional hypervolume as a metaphor for describing a niche.
In this context, n represents the number of environmental variables (such as temperature, humidity, etc.) relevant to an organism within a specific space or hypervolume.
Due to the multitude of these factors, the niche is visualized as an n-dimensional hypervolume.

Importance of Ecological Niche

Species Coexistence: Ecological niches enable species to share habitats by reducing competition. Resource specialization and niche partitioning allow different organisms to utilize distinct resources or environmental conditions, ensuring their coexistence without direct rivalry.
Community Interactions: Ecologists study niches to explore how species interact within communities, examining factors like environmental adaptations, evolutionary traits, fitness strategies, and predator-prey relationships. This helps in understanding the intricate web of community dynamics.
Ecosystem Stability: Niches provide species with suitable roles and conditions to thrive, promoting biodiversity and maintaining ecosystem balance. Without them, ecosystems risk becoming imbalanced, leading to potential collapse.
Impact of Climate Change: As climate change alters habitats and resources, understanding ecological niches becomes critical. Shifts in temperature and conditions may force species to adapt, migrate, or face extinction, affecting community structure.
Biodiversity and Niches: The variety of niches in an ecosystem directly influences its biodiversity. More niches support greater species diversity, fostering complex and resilient ecosystems.

Examples of Ecological Niche

Kirtland’s warbler (Setophaga kirtlandii): Kirtland’s warbler is a small songbird with a highly specialized ecological niche. It exclusively nests in young jack pine trees (Pinus banksiana), which provide the dense, low branches and specific habitat structure needed for successful breeding. This dependence on a specific tree species limits its distribution.
Brown-headed cowbird (Molothrus ater): Cowbirds lay their eggs in nests built by other bird species and these host birds then incubate and raise the cowbird’s young, often at the expense of their own babies.
Cactus (Species of family Cactaceae): Cacti are adapted to dry environments with thick, water-storing stems that retain moisture during droughts. Their waxy skin reduces water loss, and spines replace leaves to minimize evaporation. Cacti also maximize sunlight exposure through their ribbed or columnar structure, enhancing photosynthesis while conserving water in harsh conditions.
Koalas (Phascolarctos cinereus): Koalas feed only on leaves from eucalyptus trees in Australia, are an example of a specialist species.
Prairie grasses (Bromus kalmii, Anthoxanthum hirtum, Sorghastrum nutans etc): Prairie grasses are characteristic species of grasslands, particularly in North America. These grasses are adapted to survive and thrive in environments with harsh conditions such as frequent grazing and periodic fires.
Archer fish (Toxotes chatareus): The archerfish (Toxotes spp.) has developed a remarkable adaptation to exploit an ecological niche that allows it to hunt for food both in the water and in the air above the water’s surface. This adaptation is a striking example of how an organism can use its environment creatively to access food sources that are otherwise out of reach for many aquatic animals.

FREQUENTLY ASKED QUESTIONS (FAQS)

Define ecological niche.

What is niche segregation.

Niche segregation is is the partitioning or separation of niche which involves species dividing ecological roles to reduce competition. Through natural selection, each species occupies a distinct niche, enabling coexistence. Resource differentiation and niche partitioning help avoid competition for limited resources. Without adaptation, one species outcompetes the other, potentially leading to the extinction of the less competitive species.

Define niche overlap.

Niche overlap refers to two species using the same resources or environmental factors. Often, ecological niches only partially overlap due to shared resources.

What is vacant niche?

A vacant niche is one that is not yet occupied by a species, although the concept remains debated. Ecological disturbances, such as forest fires or droughts, and evolutionary events, such as species failing to adapt, are generally considered the main causes of unoccupied niches.

List out the types of ecological niches.

Ecological niche can be divided into following types:
1. Fundamental niche
2. Realized niche
3. Habitat or spatial niche
4. Tropic niche
5. Hypervolume or multifactor niche.

Point out the importance of ecological niche.

Species Coexistence: Ecological niches enable species to share habitats by reducing competition. Resource specialization and niche partitioning allow different organisms to utilize distinct resources or environmental conditions, ensuring their coexistence without direct rivalry.
Community Interactions: Ecologists study niches to explore how species interact within communities, examining factors like environmental adaptations, evolutionary traits, fitness strategies, and predator-prey relationships. This helps in understanding the intricate web of community dynamics.
Ecosystem Stability: Niches provide species with suitable roles and conditions to thrive, promoting biodiversity and maintaining ecosystem balance. Without them, ecosystems risk becoming imbalanced, leading to potential collapse.
Impact of Climate Change: As climate change alters habitats and resources, understanding ecological niches becomes critical. Shifts in temperature and conditions may force species to adapt, migrate, or face extinction, affecting community structure.
Biodiversity and Niches: The variety of niches in an ecosystem directly influences its biodiversity. More niches support greater species diversity, fostering complex and resilient ecosystems.

Examples of ecological niches in ecosystem.

Kirtland’s warbler (Setophaga kirtlandii): Kirtland’s warbler is a small songbird with a highly specialized ecological niche. It exclusively nests in young jack pine trees (Pinus banksiana), which provide the dense, low branches and specific habitat structure needed for successful breeding. This dependence on a specific tree species limits its distribution.
Brown-headed cowbird (Molothrus ater): Cowbirds lay their eggs in nests built by other bird species and these host birds then incubate and raise the cowbird’s young, often at the expense of their own babies.
Cactus (Species of family Cactaceae): Cacti are adapted to dry environments with thick, water-storing stems that retain moisture during droughts. Their waxy skin reduces water loss, and spines replace leaves to minimize evaporation. Cacti also maximize sunlight exposure through their ribbed or columnar structure, enhancing photosynthesis while conserving water in harsh conditions.
Koalas (Phascolarctos cinereus): Koalas feed only on leaves from eucalyptus trees in Australia, are an example of a specialist species.
Prairie grasses (Bromus kalmii, Anthoxanthum hirtum, Sorghastrum nutans etc): Prairie grasses are characteristic species of grasslands, particularly in North America. These grasses are adapted to survive and thrive in environments with harsh conditions such as frequent grazing and periodic fires.
Archer fish (Toxotes chatareus): The archerfish (Toxotes spp.) has developed a remarkable adaptation to exploit an ecological niche that allows it to hunt for food both in the water and in the air above the water’s surface. This adaptation is a striking example of how an organism can use its environment creatively to access food sources that are otherwise out of reach for many aquatic animals.