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- Rosser, J. Barkley, et al.
(författare)
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Discontinuous change in multilevel hierarchical systems
- 1994
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Ingår i: Systems Research and Behavioral Science (Systems Research). - : John Wiley & Sons Ltd. - 1092-7026. - 9781840649895 ; 11:3, s. 77-93
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Tidskriftsartikel (refereegranskat)abstract
- We examine sources and dynamics of discontinuous changes in discrete multi-level hierarchical ecological-economic systems. We hypothesize the anagenetic moment, the creation of a new level of hierarchy, as arising from variable entrainment at some level. Bottom-up as well as top-down dynamics are studied and competing theories of the sources of such discontinuities are reviewed. Implications for the analysis of complex ecological-economic systems are considered depending on whether they are characterized by single hierarchy, bi-hierarchy, or matrix hierarchy relationships.
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- Colding, Johan, et al.
(författare)
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The relations among threatened species, their protection, and taboos
- 1997
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Ingår i: Conservation Ecology. - 1195-5449. ; 1:1
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Tidskriftsartikel (refereegranskat)abstract
- We analyzed the role of taboos for the protection of species listed as "threatened" by the World Conservation Union (IUCN), and also for species known to be endemic and keystone. The study was limited to taboos that totally avoid or prohibit any use of particular species and their populations. We call them specific-species taboos. Through a literature review, 70 currently existing examples of specific-species taboos were identified and analyzed. The species avoided were grouped into biological classes. Threat categories were determined for each species, based on the IUCN Red Data Book. We found that ≃ 30% of the identified taboos prohibit any use of species listed as threatened by IUCN. Of the specific-species taboos, 60% are set on reptiles and mammals. In these two classes, ≃ 50% of the species are threatened, representing all of the threatened species in our analysis, with the exception of one bird species. Both endemic and keystone species that are important for ecosystem functions are avoided by specific-species taboos. Specific-species taboos have important ecological ramifications for the protection of threatened and ecologically important populations of species. We do not suggest that specific-species taboos are placed on species because they are, or have been, endangered; instead, we emphasize that species are avoided for a variety of other reasons. It is urgent to identify and analyze resource practices and social mechanisms of traditional societies, such as taboos, and to investigate their possible ecological significance. Although it may provide insights of value for conservation, not only of species,
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| 7. |
- Rockström, Johan, et al.
(författare)
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Linkages among water vapour flows, food production and terrestrial ecosystem services.
- 1999
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Ingår i: Conservation Ecology. - Ottawa : Carleton University for The Resiliance Alliance. - 1195-5449. ; 3:2
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Tidskriftsartikel (refereegranskat)abstract
- Global freshwater assessments have not addressed the linkages among water vapor flows, agricultural food production, and terrestrial ecosystem services. We perform the first bottom-up estimate of continental water vapor flows, subdivided into the major terrestrial biomes, and arrive at a total continental water vapor flow of 70,000 km3/yr (ranging from 56,000 to 84,000 km3/yr). Of this flow, 90% is attributed to forests, including woodlands (40,000 km3/yr), wetlands (1400 km3/yr), grasslands (15,100 km3/yr), and croplands (6800 km3/yr). These terrestrial biomes sustain society with essential welfare-supporting ecosystem services, including food production. By analyzing the freshwater requirements of an increasing demand for food in the year 2025, we discover a critical trade-off between flows of water vapor for food production and for other welfare-supporting ecosystem services. To reduce the risk of unintentional welfare losses, this trade-off must become embedded in intentional ecohydrological landscape management
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