Table 1.

Illustrative definitions of ecological and biotic integrity

Source	Primary context	Definition
Karr and Dudley 1981	Regulation of freshwater systems through the U.S. Clean Water Act	“The capability of supporting and maintaining a balanced, integrated, adaptive community of organisms having a species composition, diversity, and functional organization comparable to that of natural habitat of the region.”
		“A system possessing integrity can withstand, and recover from, most perturbations imposed by natural environmental processes, as well as many major disruptions induced by man.”
Canada National Parks Act (S.C. 2000, c. 32, s. 2)	Management of national parks	“A condition that is determined to be characteristic of its natural region and likely to persist, including abiotic components and the composition and abundance of native species and biological communities, rates of change and supporting processes.”
Miller 2000; Ulanowicz 2000	Integration of environment, conservation, and health in a sustainable development context, shared mutual self-interest, and biophilia	Four key attributes: “(1) System health … the continued successful functioning of the community, (2) the capacity to withstand stress, (3) an undiminished ‘optimum capacity’ for the greatest possible ongoing development options, and (4) the continued ability for ongoing change and development, unconstrained by human interruptions.”
Parrish et al. 2003	Management of protected areas	“The ability of an ecological system to support and maintain a community of organisms that has species composition, diversity, and functional organization comparable to those of natural habitats within a region.” “The dominant ecological characteristics of a system or species … can withstand and recover from most perturbations imposed by natural environmental dynamics or human disruptions.”
This paper	Management of multiple-use lands	The extent to which the composition, structure, and function of an ecosystem fall within their natural range of variation.