In the course of evolution, different creatures have adapted to a wide variety of habitats and conditions and developed their unique ecological niche. That’s why almost üTo find life everywhere on earth: in the deepest seas, in the highest mountains and in the driest deserts. Despite the seemingly hostile conditions in these places, there are species that can live perfectly in these places with the resources available there.
Ecological niche definition
the ecological niche is the relationship structure of a certain species with the biotic and abiotic environmental factors relevant to it. It therefore describes the sum of the interactions that a species has with the factors of its environment and other living beings in its habitat.
During evolution, the different species have adapted to the resources available to them and the prevailing environmental conditions. This resulted in specific relationships for the different species. These make it clear which resources the species needs and how it uses them.
The formation of these ecological niches is called niche designated.
In other words, the ecological niche of a species is the sum of all relationships that it has with its environment.
It is an ecological niche, not a spatial niche or an actual place!
As different species each develop their own ecological niche, it is possible for them to live together and survive in ecosystems. Depending on the environmental conditions an ecosystem offers, the number of species or the number of possible ecological niches changes. In very extreme habitats, such as deserts or high mountains, there are far fewer ecological niches that could be occupied than, for example, in coral reefs and tropical rainforests.
Ecological Niche: Factors
Many different factors and dimensions can play a role in the ecological niche. Species can interact with abiotic environmental factors such as temperature and food sources, but also with biotic factors such as enemies and competitors. Due to the large number of factors, only part of the relationship structure, i.e. individual factors, can be considered.
For example, if food is considered, food niche spoken. This is then about the respective food supply and how this is used in comparison to or despite food competitors.
biotic factors
Biotic environmental factors include:
- predators or predators
- parasites
- competitors
abiotic factors
Abiotic environmental factors include:
- food sources
- temperature and humidity
- nesting sites
- sleeping places and hiding places
- hibernation quarters
- soil condition
- water availability
- activity times
Ecological niche: niche overlap
Every ecological niche in the world exists only once. However, there are species with almost identical ecological niches and sometimes strong niche overlaps. If there is only one of these overlaps, for example in breeding sites and a clear separation in other important dimensions, such as food sources, this overlap will be tolerated to some extent by the competing species.
However, this tolerance range varies greatly from case to case and the maximum possible tolerated niche overlap is therefore difficult to determine.
In general, however, the more overlaps in ecological niches there are between two species, the more pronounced the competition between these two species.
Ecological niche: competition
The factor of interspecific competition plays an important role in the ecological niche. This competition is between two different species and mostly for example for food, breeding grounds or habitat. For now, the competition leads to a disadvantage for both sides. Later, the weaker species will be replaced by the stronger ones or even die out.
competitive exclusion principle
That competitive exclusion principle states that two species with the same ecological requirements, i.e. a very similar ecological niche, living in the same biotope, are always in direct competition with each other. The more competitive species then displaces the less competitive species. This process is also referred to as outcompeting. The weaker and then displaced species then adapts to new, different circumstances, i.e. changes its ecological niche and thus avoids further competition (avoidance of competition).
Two species with a very similar ecological niche cannot therefore coexist in one habitat. However, as soon as one of the species changes or adapts its ecological niche, coexistence is possible.
Ultimately, competition leads to all species living in a biotope forming their own species-specific ecological niches, so it drives niche formation. The development of new niches does not only lead to a large one diversity or species diversity as a whole, but also to the fact that the available resources can usually be divided well among the competing species.
Ecological niche: congruence and divergence
It can happen that two different species form a similar ecological niche, even though the two species are only very distant relatives and can also be found in geographically different places. This case is called congruence designated.
Congruence was found, for example, in Australian marsupial moles and moles in Europe and in African spurges and South American cacti.
Of divergence one speaks against it when it comes to a divergence of very closely related species. Due to environmental conditions, these species can develop traits that differ greatly from each other. Relatively closely related, but they remain.
A divergence can be observed, for example, in the desert fox and the red fox. The desert fox has evolved different characteristics due to desert environmental conditions, but still remains quite closely related to the red fox.
Ecological niche: concepts
A distinction can also be made between the concepts of the fundamental niche and the real niche.
fundamental niche
The perfect environmental conditions for a species without any restrictions, such as by competitors, in which they could exploit their full potential is called fundamental niche (fundamental niches).
In nature, however, there are always limitations, for example due to competitors, so that fundamental niches can only exist under laboratory conditions.
real niche
the real niche (realized niche) forms that part of the fundamental niche that is actually occupied by the specific species in reality. It is therefore the fundamental niche constrained by reality.
The realized niche refers to the concrete factors of the ecosystem and, above all, to the interrelationships to other species and their own conspecificsfor example through competition for resources.
The number of constraints that the fundamental niche experiences in nature affects the niche breadth of the realized niche.
Niche breadth: generalists and specialists
The sum of different resources that a species can use is called niche width designated.
Ecological niches can be quite narrow or even be very wide.
Can be divided into species with a wide range of niches generalists and those with a rather narrow niche breadth that specialists.
generalists
Species that belong to the generalists have a broad ecological niche, they are accordingly not dependent on special living conditions and resources and can adapt better to changes. For example, food generalists have many different food sources.
Pigs, for example, are among the food generalists – they are omnivores, so they have a variety of food sources.
specialists
The specialists have a rather narrow niche width, they are mostly of very dependent on specific living conditions and resources. In terms of food niche, this means that they only own and are committed to a very specific food source.
Koalas, for example, are among the food specialists – they feed exclusively on eucalyptus.
Whether a species develops into a generalist or a specialist depends on the prevailing niche conditions. For example, if there are many different food sources, the species will probably develop into generalists, but if there are only few food sources or strong competition, the result is often a development into specialists.
However, even after the formation of the ecological niche, change is still possible. If, for example, new food sources open up, for example because a competitor is gone, there will be one niche expansion. However, when fewer food sources are available due to more competition, it leads to a specialization or agreement of the niche.
Ecological niche example: desert fox
Each species, both plant and animal, has its own specific ecological niche. There are therefore an almost infinite number of examples of ecological niches. Below is the example of desert fox.
Of the desert fox (Fennec) lives in sandy deserts in North Africa. Over time, its physique and behavior have adapted perfectly to the environmental conditions, to life in deserts: it is comparatively tiny, agile and agile. In addition, it has very large ears in order to be able to dissipate excess heat.
Desert foxes are the world’s smallest wild dogs.
Desert foxes mostly live in pairs and with their young and are crepuscular and nocturnal to escape the heat of the day. They belong to the omnivores, so they are food generalists. Desert foxes mainly eat small animals, such as mice and insects, but also tubers and fruits. They also get their fluids from food and are not required to drink.
Desert foxes have enlarged tympanic cavities, allowing them to pick up deep sounds, like insects moving in the sand, which they can then dig for purposefully.
The enemies of the desert fox are mainly humans. They are still hunted for their fur and also sold as pets. Among the predators are in particular hyenas and jackals. Desert foxes are also considered to be the definitive hosts of various parasites, such as various tapeworms.
Ecological niche hazard
Various interventions in ecosystems or in nature as a whole can damage the ecological niches of living beings.
These include, for example:
- the consequences of the climate catastrophe
- fertilizers and pesticides
- Alien species that harm or displace native species (invasive species)
Overall, the ecological niches of the specialists are faster…