Species Distribution - Abiotic and Biotic Factors

Abiotic and Biotic Factors

The distribution of species into clumped, uniform, or random depends on different abiotic and biotic factors. Any non-living chemical or physical factor in the environment is considered an abiotic factor. There are three main types of abiotic factors: climatic factors consist of sunlight, atmosphere, humidity, temperature, and salinity; edaphic factors are abiotic factors regarding soil, such as the coarseness of soil, local geology, soil pH, and aeration; and social factors include land use and water availability. An example of the effects of abiotic factors on species distribution can be seen in drier areas, where most individuals of a species will gather around water sources, forming a clumped distribution.

Biotic factors, such as predation, disease, and competition for resources such as food, water, and mates, can also affect how a species is distributed. A biotic factor is any behavior of an organism that affects another organism, such as a predator consuming its prey. For example, biotic factors in a quail’s environment would include their prey (insects and seeds), competition from other quail, and their predators, such as the coyote. An advantage of a herd, community, or other clumped distribution allows a population to detect predators earlier, at a greater distance, and potentially mount an effective defense. Due to limited resources, populations may be evenly distributed to minimize competition, as is found in forests, where competition for sunlight produces an even distribution of trees.