caa a22 4500 469106085 CHVBK 20180323133057.0 cr unu---uuuuu 170328e19920301xx s 000 0 eng 10.1007/BF00044404 doi (NATIONALLICENCE)springer-10.1007/BF00044404 Ecosystem stress and health: an expansion of the conceptual basis [Elektronische Daten] [Jurek Kolasa, Steward Pickett] The assessment of the ecosystem health and departures from it requires clarity of what the system, its structure, dynamics, and healthy conditions are. Available definitions provide inadequate tools to acquire this clarity and may lead to arbitrary diagnoses of ecosystem health but such diagnoses can be overturned on a variety of scientific, philosophical, or political grounds. Nested hierarchy of ecosystem structure compounds the difficulty in the assessment of stress and health because both states may occur simultaneously at different hierarchical levels: with stress at one level being a necessary condition of health at another. An approach based on a formal definition of system change is advanced. First, a conceptual model identifies a self-maintaining minimum interactive structure (MIS) at each level of ecosystem organization. Components of MIS are complementary, coordinated, and exchanging information — they are integrated. Function is defined as a contribution of a component to the maintenance of the whole. In this context health is viewed as persistence of the system at a given temporal and spatial scale. Impairment of the function is stress and is contrasted with change of system structure (loss, addition, or replacement of components of MIS) which is disturbance. Stress can be measured directly by changes of function or indirectly by changes in integration. Even though undesirable from the human point of view, a changed system may again be considered healthy. Kluwer Academic Publishers, 1992 definition (of stress) nationallicence ecosystem function nationallicence general theory nationallicence system organization nationallicence Kolasa Jurek Department of Biology, McMaster University, L8S 4K1, Hamilton, Ontario, Canada aut Pickett Steward Institute of Ecosystem Studies, Box AB, 12545, Millbrook, NY, U.S.A aut Journal of Aquatic Ecosystem Health Kluwer Academic Publishers 1/1(1992-03-01), 7-13 0925-1014 1:1<7 1992 1 10813 https://doi.org/10.1007/BF00044404 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00044404 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kolasa Jurek Department of Biology, McMaster University, L8S 4K1, Hamilton, Ontario, Canada aut NATIONALLICENCE 700 1- Pickett Steward Institute of Ecosystem Studies, Box AB, 12545, Millbrook, NY, U.S.A aut NATIONALLICENCE 773 0- Journal of Aquatic Ecosystem Health Kluwer Academic Publishers 1/1(1992-03-01), 7-13 0925-1014 1:1<7 1992 1 10813 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer