In ecology, the thumb rule is that of conserving interrelationships. Human activity that threatens the future existence of other species may be an ecological disaster since it would in turn affect other species also. These interrelationships are taken care of within the concept of carrying capacity. Carrying capacity is a concept which limits the potential ability of natural resources and species to withstand human intervention. It may be described as a test of the ability of land, water and air to keep itself usable and toxin-free despite pollution and effluent discharges and harmful developments over it.
The famous American wildlife conservation ecologist Aldo Leopold described ‘carrying capacity’ in 1933 as a saturation point at which the numbers of a particular species of grazing animals approached the point where grasslands could support no more individuals without a general and continuing decline in the quality of the pasture land. While chemical fertilizers, insecticides and pesticides increase crop yield, their use beyond the carrying capacity of land may destroy crops. This is equally true for the effluent discharges into rivers, ponds and other wetlands. The wetlands sustain life forms and complete ecosystems which in turn support larger ecosystems.
Carrying capacity also refers to the number of individuals who can be supported in a given area within the limits of natural resources, and without degrading the social, cultural and economic environment for the present and future generations. The carrying capacity for any given area is not fixed.