Ecological Niche

Ecological niche The ecological niche describes the role an organism plays in its environment. It consists of: The species habitat. The organisms activity, the period of time it is active. The resources it obtains from the environment. Eg. A pukeko lives in marsh areas. It feeds of small insects and grasses.

Fundamental niche and realised niche The fundamental niche of a species includes the total range of environmental conditions that are suitable for existence without the influence of interspecific competition or predation from other species. The realized niche describes that part of the fundamental niche actually occupied by the species.

Niche differences Organisms can be identified as either Generalists Organisms with a broad niche Eat lots of types of food Live in many types of environments Eg. house mice Specialists Organisms with a narrow niche Eat a narrow range of food items Live in few, specific types of habitats Eg. panda bear

Law of tolerance The law of tolerance states that for every abiotic factor, an organism has a range of tolerance within which it can survive.

Habitat The habitat provides the organism with the following resources: Mating sites Food and water Nesting sites Shelter from climate extremes Predator avoidance Organisms may or may nit have the adaptations to exploit all the available resources successfully.

What determines where species can live? All species have requirements for many factors/conditions. Abiotic factors – non-living factors; ex. temperature, precipitation, pH Biotic factors – other species; ex. prey species, competing species For each of these factors, species exhibit a range of tolerance. For example, a fish species may only be found within a pH range of 4.5 to 6 in lakes.

Competition When two species use the same resources, they are said to compete and their interaction = competition. ex. lions and hyenas compete for food in Africa Competition does not necessarily involve contact; interaction may be only by means of effects on the resources. No two organisms can occupy exactly the same niche at the same time