Appendix B
Selected Definitions
KEY TERMS1
adaptation — Societal strategies for managing ecosystems to maintain ecosystems and ecosystem services in the face of environmental change that cannot be avoided. (In this report, adaptation refers to societies’ and ecosystems’ ability to adapt to climate change and other environmental stressors, as opposed to the ecological meaning of the process of change established by natural selection, or a biological character that gives increased Darwinian fitness.) (EB, p. 17)
biodiversity/biological diversity — Species, genetic, and ecosystem diversity in an area, sometimes including associated abiotic components such as landscape features, drainage systems, and climate. (EB, p. 377)
complex adaptive systems — Systems made up of individual agents, whose interactions have macroscopic consequences that feed back to influence individual behaviors.2 (Levin, 1998)
ecosystem functioning — The rate, level, or temporal dynamics of one or more ecosystem processes, such as primary production, total plant biomass, or nutrient gain, loss, or concentration. (EB, p. 109)
1 Most definitions are from Levin, S., ed., 2001. Encyclopedia of Biodiversity. Academic Press: 4666 pages. Cited in definitions as “EB,” with page number.
2 Levin, S. 1998. Ecosystems and the Biosphere as Complex Adaptive Systems. Ecosystems 1(5):431–436.
ecosystem services — The wide array of conditions and processes through which ecosystems, and their biodiversity, confer benefits on humanity; these conditions and processes include the production of goods, life-support functions, life-fulfilling conditions, and preservation of options. (EB, p. 353)
evolution — The morphological or genetic change in species over time. Small changes that do not lead to reproductive isolation among members of a group are referred to as microevolution. Speciation, or the generation of new species, is generally referred to as macroevolution. (EB, p. 393)
ex situ — Literally, away from the site or location; in this context, referring to conservation efforts elsewhere than the natural habitat; for example, in botanical gardens. (EB, p. 645)
functional diversity — The range and value of the species and organismal traits that influence ecosystem functioning. (EB, p. 109)
invasive species — Introduced species that establish self-maintaining populations and spread, with and without human assistance, into new areas where they frustrate human intentions in production and natural landscapes. (EB, p. 501)
mitigation — The implementation of measures designed to avoid, reduce or eliminate the undesirable effects of a proposed action on the environment. (CEQ Regulations for Implementing the National Environmental Protection Act, Sec. 1508.20)
