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We used the landscape model PAYSAGE to demonstrate the use of GIS and simulation models for ecosystem management over a portion of Mitkof Island in the Tongass National Forest. The objectives of the study were to: 1) depict the natural heterogeneity in environment and resource distributions across the study area; 2) quantify changes in vegetation and vertebrate habitats (brown creeper, orange-crowned warbler, marten) during the period of commercial timber harvest (1954 to the present); and 3) simulate likely long-term changes in vegetation and vertebrate habitat under three management scenarios – the Tongass Forest Plan, the wildlife habitat conservation strategy, and the Pacific Fisheries Task Force strategy. The results indicated that productive forest lands and vertebrate habitats are naturally patchy in the study area due to topography and climate. This natural fragmentation was exacerbated by past logging, which targeted high-productivity old growth stands. This stand type was reduced in area by 76 per cent from 1954 to 1994. Patch density and mean patch size decreased during this time while mean nearest neighbour distance increased. Simulations of the three management scenarios for a 200-year period projected relatively minor differences in landscape patterns among the scenarios. This is because the forest plan scenario is relatively restrictive in timber harvest and because most of the area protected in the other two scenarios does nor currently support old growth. We discuss the role of decision-support tools such as PAYSAGE in adaptive ecosystem management and evaluate limitations of the model. 相似文献
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A comparison between planetary-wave flow regimes and blocking 总被引：1，自引：0，他引：1
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LOUISE JOHNSON 《New Zealand geographer》2003,59(1):17-26
This paper will briefly examine employment trends in regional Australia before focusing on one manufacturing, coastal region ‐ Geelong, Victoria –over the 1990s. It will consider the experience of a differentiated sample of women as they enter (and re‐enter) the one sphere of economic activity seen by many as the economic future of cities and regions ‐the service sector. Interviews detailed women's employment histories and experiences but despite the complexity of their multiple locations, this paper will argue that it is their disadvantaged positions as women workers that is fundamental in shaping that experience, regardless of how it is complicated by age, ethnicity or disability. 相似文献