Ecological Integrity

Environmental stress refers to physical, chemical, and biological constraints on the productivity of species and the development of ecosystems. When they increase or decrease in intensity, stressors elicit ecological responses. Stressors can be natural environmental factors, or they can be associated with the activities of humans. Some environmental stressors are relatively local in their influence, while others are regional or global in scope. Stressors are challenges to ecological integrity.

Species and ecosystems have some capacity to tolerate changes in the intensity of environmental stressors, an attribute known as resistance. However, there are limits to resistance, which represent thresholds of tolerance. When these thresholds are exceeded, substantial ecological changes occur in response to further increases in the intensity of environmental stress.

Environmental stressors can be categorized as follows: