Maintaining healthy ecosystems

Maintaining fully functioning natural systems, capable of repair and renewal.

In general, ecosystems have five main kinds of requirements: 1) appropriate physical environmental characteristics (such as climatic conditions or the presence of freshwater); 2) appropriate biotic conditions (the presence of certain food species, for example); 3) a minimum environmental quality (such as the absence of certain pollutants); 4) minimum spatial requirements for each species (to permit migration and to ensure adequate foraging opportunities, for example); and 5) sufficient opportunities for organisms to interact with other organisms of the same species (in order to facilitate reproduction and genetic exchange).

Disease and death are parts of the natural life processes and are necessary for maintaining the interplay of elements in nature. Some human-induced impacts may, however, result in damage that cannot be repaired or requires very lengthy recovery periods. Serious threats to a healthy natural environment are (1) intentional or accidental releases of alien organisms; (2) spread of diseases in wild plants and animals; (3) changes in climate (4) pollution.