Difference Between Fundamental Niche and Realized Niche

The main difference between fundamental niche and realized niche is that the fundamental niche is any type of environmental condition in which a particular species can live whereas the realized niche is where the species actually live. In a fundamental niche, there is no competition for resources or predators while in a realized niche, there is a competition for both resources and predators. 

Fundamental niche and realized niche are two types of environmental positions in an ecosystem that can be occupied by a particular species. 

Key Areas Covered 

1. What is a Fundamental Niche
     – Definition, Characteristics, Examples
2. What is a Realized Niche
     – Definition, Characteristics, Examples
3. What are the Similarities Between Fundamental Niche and Realized Niche
     – Outline of Common Features
4. What is the Difference Between Fundamental Niche and Realized Niche
     – Comparison of Key Differences

Key Terms 

Competition, Ecosystem, Fundamental Niche, Pre and Post Competitive Niche, Realized Niche, Resources

What is a Fundamental Niche 

Fundamental niche or pre-competitive niche is the range of environmental conditions in which a particular species can live. This means it defines a collection of conditions and sources in which the species can survive, grow, and reproduce. The organisms in the species can take the maximum advantage of both biotic and abiotic factors in the ecosystem of the fundamental niche since there is no competition for resources and predators.  

Figure 1: A male Red-winged Blackbird in Chicago, Illinois, USA

As an example, the male red-winged blackbird holds the prime real estate in the marshes in the early spring. However, with the seasonal progress, tri-color blackbirds, which are more aggressive move, into the marshes and take over the best territory. Hence, before the arrival of the tri-color blackbird, the marshes are a fundamental niche for the male red-winged blackbird. 

What is a Realized Niche 

Realized niche or post-competitive niche is the range of environmental conditions in which the species actually live. It is always smaller than the corresponding fundamental niche of the species and is considered as a subset of the fundamental niche. When the species in the fundamental niche has to face various interactions and pressure from the environment, it is forced to move into a small niche, the realized niche. Also, it is considered that with the growth of the realized niche, the corresponding fundamental niche also grows accordingly.  

Figure 2: A Coyote

As an example, wolves ranged across North America competing well with coyotes for food and territory. With the arrival of European settlers to the continent, the hunting reduced the wolf population, letting coyotes enjoy a wide range of environment.  

Similarities Between Fundamental Niche and Realized Niche 

• Fundamental niche and realized niche are two types of positions of the ecosystem occupied by a particular species. 

Difference Between Fundamental Niche and Realized Niche 

Definition 

Fundamental niche refers to a niche of an organism given that there are no limiting factors on the environment or resources the organism can use while a realized niche refers to a niche a viable population of a species occupies in the presence of competitor species. This explains the basic difference between fundamental niche and realized niche.

Also Called 

The fundamental niche is also called pre-competitive niche while a realized niche is called post-competitive niche.  

Existence 

Fundamental niche is a type of theoretical niche while a realized niche is where the species actually lives.

Size 

Furthermore, the fundamental niche is large in size while the realized niche is small in size. 

Roles of Species 

Also, the fundamental niche elaborates on various roles of a particular species while a realized niche elaborates on what the species actually do. 

Competition for Resources 

There is no competition in a fundamental niche either for resources or predators while a competition occurs for both resources and predators in a realized niche. This is an important difference between fundamental niche and realized niche.

Conclusion 

Fundamental niche is a theoretical niche that includes any type of ecological positions in which a particular species can live. On the other hand, realized niche is the actual ecosystem where the species live. In addition, there is no environmental pressure in the fundamental niche and when the pressure occurs either from predators or limited resources, the species moves to the realized niche. The main difference between fundamental niche and realized niche is where the species live and the type of environmental pressure.

Reference:

1. Gauthier, Nicholas. “Fundamental Niche: Definition & Example.” Study.com, Study.com, Available Here    
2. Gauthier, Nicholas. “Realized Niche: Example & Definition.” Study.com, Study.com, Available Here 

Image Courtesy:

1. “Agelaius phoeniceus -Chicago, Illinois, USA -male-8” By John Picken from Chicago, USA – Red-winged Blackbird (CC BY 2.0) via Commons Wikimedia   
2. “Kojote2010 cut” By Kojote2010.JPG: JoernHaukederivative work: Kürschner (talk) – Kojote2010.JPG (CC BY-SA 3.0) via Commons Wikimedia