省级区域耕地保有量测算研究——以江苏省为例

预测了江苏省耕地供给变化趋势和耕地需求量。根据预测结果，对耕地供需平衡情况进行了判断，分析了不同的耕地集约利用水平、耕地种植结构对耕地供需平衡的影响耕地的供需状况。以此为依据，确定了区域粮食供应的优选策略。在此基础上，从区间估计的角度，探讨了耕地保有量的确定思路与方法，确定了江苏省规划期内不同时间阶段的耕地保有量区间，即到2010年耕地保有量应维持439．7-473．0万hm^2，2020年耕地保有量应维持420．8-458．4万hm^2。     

ECOSYSTEM MANAGEMENT AND THE CONSERVATION OF AQUATIC BIODWERSITY AND ECOLOGICAL INTEGRITY1

ABSTRACT: Ecologically effective ecosystem management will require the development of a robust logic, rationale, and framework for addressing the inherent limitations of scientific understanding. It must incorporate a strategy for avoiding irreversible or large-scale environmental mistakes that arise from social and political forces that tend to promote fragmented, uncritical, short-sighted, inflexible, and overly optimistic assessments of resource status, management capabilities, and the consequences of decisions and policies. Aquatic resources are vulnerable to the effects of human activities catchment-wide, and many of the landscape changes humans routinely induce cause irreversible damage (e.g., some species introductions, extinctions of ecotypes and species) or give rise to cumulative, long-term, large-scale biological and cultural consequences (e.g., accelerated erosion and sedimentation, deforestation, toxic contamination of sediments). In aquatic ecosystems, biotic impoverishment and environmental disruption caused by past management and natural events profoundly constrain the ability of future management to maintain biodiversity and restore historical ecosystem functions and values. To provide for rational, adaptive progress in ecosystem management and to reduce the risk of irreversible and unanticipated consequences, managers and scientists must identify catchments and aquatic networks where ecological integrity has been least damaged by prior management, and jointly develop means to ensure their protection as reservoirs of natural biodiversity, keystones for regional restoration, management models, monitoring benchmarks, and resources for ecological research.     

APPLICATION OF A HYDROLOGIC MODEL FOR LAND USE PLANNING IN FLORIDA1

ABSTRACT: An environmental simulation model of the Upper St. Johns River Basin, Florida, has been developed in order to predict hydrologic responses under proposed management plans. Land use projections for each of 19 hydrologic planning units are provided by a linear programming analysis of agricultural activities. Inputs to the model include rainfall, runoff, evapotranspiration (ET), aquifer properties, topography, soil types, and vegetative patterns. A water balance is developed in the uplands based on infiltration, ET, surface runoff, and groundwater flow. Valley continuity is based on stage-volume relationship for inflows and outflows and a variable roughness coefficient dependent on vegetative patterns. Land use changes form the basis for predicting hydroperiod variation under alternative management schemes. Plans are ranked according to two criteria, deviation from a natural hydroperiod and flood or drought control provided. Results indicate that (1) a single reservoir without irrigation and (2) floodplain preservation plans are superior to (3) multiple reservoir with irrigation and (4) uncontrolled floodplain plans with regard to both criteria.     

The Maintenance of Landscape Health in the Midst of Land Use Change

Land use design that recognizes the landscape attributes that characterize homeostatic health can emphasize them during land use change. The attributes of landscape health are the working mechanisms of all open systems, and can be observed in the homeostatic behavior of forests, deserts and floodplains. These attributes are openness, self-regulation, storage and diversity. The attributes of health comprise criteria for evaluating and guiding land use. To maintain landscape health, land use design can maintain and restore these mechanisms during change of moderate pace and scale.     

土地利用弹性规划研究

从功能、理论基础、规划重点、程序内容、实施及评价等方面对土地利用弹性规划进行了全面探讨,认为土地利用弹性规划的意义在于充分考虑经济发展中的不确定因素,解决传统规划存在的不合理刚性问题.弹性规划主要建立在不确定理论与需求引致理论的基础上,规划的重点即解决建设用地时间与空间配置的弹性问题.程序内容在遵循一般规划规律的同时具有鲜明特色,即注重分析不确定信息,并对相应的用地问题进行超前安排;弹性规划实施评价以实施的难易度、经济度和效益为标准.     

SOUND POLICY OR SMOKE AND MIRRORS: DOES ECOSYSTEM MANAGEMENT MAKE SENSE?1

ABSTRACT: Protection of ecosystems as entities on the landscape has attracted a wide range of support. Ecosystem-based public policies are claimed to be more effective, efficient, and scientifically sound than other approaches to environmental and natural resource policy. The ecosystem concept was never intended to serve as a public policy guide or to determine landscape units for land management purposes. This paper critically examines the use of the ecosystem concept in public policy and land use management and analyzes the proposed rule to manage the National Forest System according to ecosystem management principles. The concept is found to be unsuitable as a basis for guiding environmental and natural resource public policies in general while the proposed rule to manage the national forests according to ecosystem management principles is shown to be incoherent.     

PLANNING UNDEVELOPED LAKESHORE1

ABSTRACT: Private lakeshore development usually precedes establishment of public lake access. As a result, the best access areas are often occupied before public access is provided. The public then has a problem to provide access for nonriparian citizens. This problem can be anticipated and prevented by classifying undeveloped lakeshore areas according to suitability for both private and public uses, and incorporating appropriate recommendations into the municipal, comprehensive land use plan. To accomplish this, a site evaluation system has been developed which numerically rates the lakeshore for each of four public uses: public beaches, picnic areas, boat access areas, and public marinas; and two private uses: private marinas and vacation homes. Ratings are developed for: slope, soil suitability, shoreland type, water quality, site location, scenery, and road access. These ratings are combined with a statement of public goals developed from attitude surveys to produce a lakeshore land use plan. The plan recommends that lakeshore areas best suited for private development are so used, and areas best suited for public use are reserved for that purpose. This site evaluation system is demonstrated by a case study on Lake Champlain in Ferrisburg, Vermont.