The world is filled with a wide variety of organisms that each play their important roles in balancing the ecosystem and the world as a whole. Organisms, such as bacteria, are responsible for both good and bad functions in the ecosystem. Like bacteria, other life forms have both positive and negative effects on the ecosystem and other organisms; however every organisms plays a role in maintaining a healthy planet. The term ecological niche refers to the role an organism plays in their ecosystem. In the following, we will be delving deeper into what defines an ecological niche as well as discussing some important examples.
What is an ecological niche? Ecological niche definition
In the field of ecology, a niche describes an organism's role within its community. An organism's ecological niche is comprised of its interactions with its community and the environmental conditions needed for it to stay alive. An organism's role in its community can be as a predator, a prey, or even a scavenger. Each organism has a role in its environment, therefore each organism has an ecological niche. Niches are determined by both the biotic and abiotic factors of environment. 1 The term ecological niche is mostly used when dealing with living animals since it involves the interactions of the organisms within their ecosystem.
Biotic Factor: Factors that influence an organisms niche like food ability and predators.
Niches involve the flow of energy between species, which is why it is important to understand the role an organism plays in their ecosystem. If a niche is left vacant due to a particular species going extinct or migrating to another ecosystem, another species can take its place.1 Some organisms can create unique niches to ensure that their species do not get replaced. This reduces their competition with other species for resources and survival. Despite being able to create specialized roles for themselves, organisms need to be capable of adapting to the changes in their ecosystem to ensure that they do not go extinct. This is the reason why many species usually adapt in order to survive under a wide range of temperatures, climates, and conditions.
Ecological niches come in various types, and contain various combinations of factors and variables that make them unique from other niches. Biotic and abiotic factors used by a given species to survive make up the specie's fundamental niche, while factors that limit the species population from thriving are known as limiting factors.1 Examples of limiting factors are competition for resources needed for survival and predators.1 Organisms must withstand the limiting factors within their ecosystem to survive and maintain their niches.
Types of ecological niche
Niches can be of three types: spatial or habitat, trophic, and multidimensional. Spatial niches refer to the physical area within the habitat that the species lives in. Different species can exist within the same ecosystem due to spatial niche partitioning. This phenomenon allows different species to occupy their own section within their ecosystem. Figure 1 depicts the concept of spatial niche partitioning. In additional to spatial partitioning, animals can also form barriers via dietary partitioning. Dietary partitioning can separate different species based on the food that they eat.1 For example an animal's height can allow it to secure its food. An example of this can be seen when looking at the giraffe. Since giraffes have extremely long necks, they can eat leaves at the top of a large tree while shorter animals like zebras and deer can eat leaves on the lower end of the tree.
Trophic niches refer to the trophic level that the species occupies in the food chain. Animals on the lower end of the food chain are separated from animals on the higher end of the food chain. According the food web, organisms can be producers, primary consumers, secondary consumers, tertiary consumers, quaternary consumers and decomposers.1 Quaternary consumers are animals at the top of the food chain and usually eat tertiary and even secondary consumers. Producers are organisms that generate energy from the sun via photosynthesis. These organisms do not need to consume other organisms to survive because they create their own energy through a process called photosynthesis. Similarly, decomposers eat dead organisms of all trophic levels. See Figure 2 for a depiction of the food web.
Photosynthesis is the process by which plants and other organisms convert sun light into energy that their cells can use to survive. The series of complex processes required for photosynthesis occurs in the chloroplast.
Lastly, multidimensional niches consist of the concept of a fundamental niche and the limiting factors that exist.1 A fundamental niche refers to what an organisms niche would be in the absence of limiting factors like competition. Species who have similar lifestyles such as rabbits and groundhogs often compete for resources and spatial niches that allow them to maintain their lifestyle. When two or more different species compete for the same niche they are said to be engaged in interspecific competition. An organisms fundamental niche in combination with the limiting factors associated with the niche is known as the realized or multidimensional niche. Let's take a look at some examples of ecological niches below.
Ecological niche example
There are a wide range of ecological niches found all throughout the world. Ecological niches come in a vast variety of characteristics that make it harder or easier for an organism to survive. An example of an ecological niche can be seen in desert plants. The desert is known to be a dry and unfruitful ecosystem and only the toughest organisms can survive there. Desert plants such as cacti have adapted to their harsh spatial niche by storing water in their bodies and growing long roots to maximize the amount of water they can take in. The ecological niche of desert plants has little interspecific competition since not many organisms can survive in the desert.
What is the importance of ecological niches?
Ecologists use ecological niches to help understand how communities and ecosystems relate to environmental conditions, trait evolutions, and predator prey interactions within certain communities.1 As climate change becomes a more pressing issue, the study of ecological niches has become more important.1 Ecological niches allow different species to coexist within a given environment.1 Without ecological niches, there would be less biodiversity and the ecosystem would not be as balanced.1
As previously mentioned, an ecological niche is unique to each species. Competition among species affects the fitness of a species and can lead to evolutionary changes. Ecologists use the competition exclusion principle to understand how species coexist in the same environment. The competition exclusion principle indicates that two species cannot exist in the same ecological niche. This is due to a limited amount of resources.
Competition among species for an ecological niche leads to evolutionary changes of the losing organisms in order for that species to have a new ecological niche. If the losing species does not adapt, they can risk becoming extinct due to the lack of resources needed for its survival.
The R* Theory indicates that multiple species cannot exist with the same resources unless they grow to have different niches.1 When there is a low level of resources such as during a drought, the losing species will be competitively excluded unless they adapt to their environmental changes.
Similarly, the P* Theory states that consumers such as deer, rabbits, and zebras can coexist when the level of resources are high due to having shared predators.1 When multiple species have the same predator, it is easier for them to coexist in the same ecological niche.
Ecological niche of insects
Like animals, insects also have ecological niches. For example, flies function to eat decaying flesh which can alert other animals that food is nearby. Another ecological niche example can be seen when looking at bees. Bees gather pollen and nectar from flowers in order to make their food, known as honey. When bees leave their hive, they travel to various flowers to gather pollen.
As bees move from flower to flower, they introduce pollen from the previous flower to the new flower, which helps to create new flowers through the process of pollination. Since bees use pollen to make their food, they must compete with other animals for pollen. The major competitor species for bees are hummingbirds. Hummingbirds and bees both love nectar. Since hummingbirds only feed individually and bees feed in large groups, bees often out compete hummingbirds for flowers.
There are many ecological niches in the earth's ecosystem and each species' niche contributes to a balanced and healthy earth.
Ecological Niche - Key takeaways
- Niches can be of three types: spatial or habitat, trophic, and multidimensional.
- Niches are determined by both the biotic and abiotic factors of environment.
- Trophic niches refer to the trophic level that the species occupied in the food chain.
- Spatial niches refer to the physical area within the habitat that the species lives in.
- The R* Theory indicates that multiple species cannot exist with the same resources unless they grow to have different niches.