Ecology: Population Regulation

Population regulation is a basic process related to most phenomena in ecology: regulation arises as a result of potentially stabilizing density-dependent processes, even when brought about by non-equilibrium mechanisms (Murdoch, 1994).

No population continues to grow indefinitely. Specifically, populations that exhibit exponential growth eventually succumb to the limitations brought about by the environment. As a population’s density changes, a naturally-occurring series of interactions which are environmentally controlled form between members of the population, thus regulating the population size. These interactions include a wide variety of mechanisms relating to physiological, morphological and behavioral adaptations (Smith & Smith, 2012).

The Concept of Logistic Population Growth

According to Smith (1966), a concept popularized in 1978 by English clergyman and economist Thomas Robert Malthus states that births, deaths and movements influence both the number of organisms in a given area and the growth of the population itself. Like the individuals that make up a population, the population itself starts as a small unit and continues to expand until it comes to a point where it is at a certain level of equilibrium with the environment. In its initial colonization of an unoccupied habitat, it grows geometrically in proportion to its numbers as it finds itself in an area where the environmental conditions are constant and the resources excessive. However, as the population increases, the detrimental effects of an increasing population density begin to slow down growth rate.

Because resources are limited, exponential growth cannot be sustained indefinitely. The maximum population size that can be sustained for a particular enviro...

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...ompetition, dominant individuals claim sufficient resources for growth and reproduction. Others produce no offspring or perish. Competition can involve interference among individuals or indirect interactions via exploitation of resources.

Comp, Growth and Devt

Competition for scarce resources can decrease or retard growth and development. Up to a point, plants respond to competition by modifying form and size.

Competition and Mortality

A common response to high population density is reduced survival. Mortality functions to increase resource availability for the remaining individuals, allowing for increased growth.

Competition and Reproduction

High population density and competition can also function to delay reproduction in animals and reduce fecundity in both plants and animals.

Smith, Thomas M. , and Robert Leo Smith. Elements of Ecology. Pearson , print.2012