Factors Determining the Distribution of Animals and Plants in Freshwaters

Many factors affect the presence or absence of organisms and plants in freshwaters. These can be categorized as:

(a) natural dispersion; (b) abiotic factors; (c) biotic factors.

The biotic factors can be significant locally in determining whether a species occurs or not. Species may be precluded by predation, competition, or lack of suitable food resources or habitat. These factors are considered in Chapter 4. In this chapter the importance of natural dispersion and the abiotic factors are discussed.