Linkages between biodiversity conservation and global climate change in small island developing States (SIDS)

Global climate change is an important cause of biodiversity loss. The conservation, sustainable management and use of biodiversity resources are key factors that can be effectively used to minimize the adverse impacts of global climate change. Efforts to understand and address the linkages between global climate change and biodiversity loss are both urgent and timely. Integrating responses related to these two global environmental challenges is especially relevant for small island developing States (SIDS) because the adverse impacts of climate change can impose severe stresses on biodiversity resources that are fragile, vulnerable and already under stress and the people who depend upon them. This paper argues that comprehensive assessments of adverse impacts of global climate change on the biodiversity resources of SIDS, and an improved understanding of relevant climate change related adaptation measures and sustainable energy policies (that are based on the principles of conservation, sustainable management and use of biodiversity resources) will enable SIDS to become more resilient and to develop better response capacities.     

Mixing Zone Characterization of Two Transition Terrain Streams With Tracers1

Abstract: For most wastewater discharges to streams, the effluent creates a plume that becomes less distinct as it mixes with the receiving water. Constant‐discharge tracer studies were used to characterize the plume or physical mixing zone (PMZ) at two similar transition terrain streams. At both sites, the laterally unmixed PMZs did not extend across the entire stream and mixing occurred relatively quickly. The observed plumes were significantly smaller than the regulatory mixing zone (RMZ) allowed by the State of Colorado. At Site 1 mixing occurred within a much shorter distance due to the presence of a riffle zone located a few meters downstream of the discharge point. Interpretation of field data with an analytical model suggests that the effective transverse dispersion coefficient (k_z) for the riffle zone at Site 1 (～1 m²/s) was significantly higher than the average value over the longer nonriffle section at Site 2 (～0.01 m²/s). These results imply that to achieve the fastest mixing in transition terrain streams, thereby minimizing the size of the PMZ, discharge outfalls should be located upstream and close to riffle zones.     

AN ASSESSMENT OF USES MADE OF A MULTIPURPOSE RESERVOIR'

ABSTRACT: Data were collected from residents of a rural community at two time periods to assess attitudes toward uses made of a reservoir which had been recently constructed in the area. The findings revealed that attitudes became significantly more favorable for flood control, water supply, and recreation uses of the reservoir. Attitudes toward fish and wildlife conservation use were not significantly different over time but these uses were perceived positively at both time periods. The data were also analyzed in the context of a vested interest perspective using cross-sectional design. The findings demonstrated that the theoretical model used to guide the investigation was quite useful in predicting attitudes toward the four uses examined.     

ENVIRONMENTAL DESIGNS FOR STREAMBANK PROTECTION PROJECTS1

ABSTRACT: Streambank protection projects are intended to prevent streambank erosion, thereby preventing streambank failure and maintaining a desirable channel alignment. Streambank erosion is a natural process of unaltered, dynamic river systems, and protection projects seek to impose stability on this natural system. The environmental impacts of such projects are primarily changes to terrestrial and aquatic habitats and to aesthetics. Adverse environmental impacts have been minimized and enhancement of existing habitat and aesthetics have been achieved through the development of new, innovative designs or modifications to existing designs and through use of construction and maintenance practices that promote habitat and aesthetics. Designs based on channel flow characteristics, e.g., revetments using a variety of structural materials, can result in preservation of wildlife habitat by reducing the use of structural protection by matching the erosion potential of flow at the bank with the protection capability of the materials used. Designs based on streambed stabilization prevent bank failure caused by bank undermining, result in preservation or establishment of streamside vegetation, and enhance aesthetics. Protection schemes that manage and preserve floodplains, berms, and riparian areas preserve the natural condition of the floodplain area. Designs based on deflection of erosive flows, e.g., dikes, minimize disturbance to the bank vegetation and create low-velocity aquatic habitats. Use of vegetation for bank protection is most effective when used in combination with structural components. Construction and maintenance practices can be scheduled and modified to minimize impacts to floodplain areas and to enhance wildlife habitat while preserving the integrity of the protection structure.     

Vegetation and soil recovery in wilderness campsites closed to visitor use

Recreational use of wilderness results in impacts to vegetation and soil in trails and campsites. Traditionally, campsite impact studies have compared campsites receiving various levels of use with unused control areas. Field studies in Sequoia National Park, California, indicate that the degree of impact to vegetation and soils also varies within campsites. The central areas of campsites, where trampling is concentrated, show lower plant species diversity, differences in relative species cover, more highly compacted soils, and lower soil nutrient concentrations than do peripheral, moderately trampled, and untrampled areas within the same campsite. Three years after closure to visitor use, the central areas show less increase in mean foliar plant cover, and soils remain more highly compacted than in previously moderately trampled areas of the same sites. Changes in relative species cover over time are used to assess both resiliency to trampling and species composition recovery within campsites closed to visitor use.     

Spatial and temporal changes in Louisiana's Barataria Basin marshes, 1945–1980

A computerized geographic information system with site-specific change-detection capabilities was developed to document amounts, rates, locations, and sequences of loss of coastal marsh to open water in Barataria Basin, Louisiana, USA. Land-water interpretations based on 1945, 1956, 1969, and 1980 aerial photographs were used as input, and a modified version of the Earth Resources Laboratory Applications Software developed by the National Aeronautics and Space Administration was used as a spatial data base management system. Analysis of these data sets indicates that rates of marsh loss have increased from 0.36% per year in the 1945–56 period, to 1.03% per year in 1956–69, and to 1.96% per year in 1969–80. The patterns of marsh loss indicate that the combination of processes causing degradation of the marsh surface does not affect all areas uniformly. Marsh loss rates have been highest where freshwater marshes have been subject to saltwater intrusion. The increase in the wetland loss rates corresponds to accelerated rates of subsidence and canal dredging and to a cumulative increase in the area of canals and spoil deposits.     

环境风险规制的经济成本及次生影响——决策中需要重视的向度

环境风险是社会经济发展的副产物,是市场外部性的表现,需要公共部门的参与解决.然而环境风险的应对并非没有代价,这种代价既包括规制的经济成本,也包括其带来的次生影响.我国经济发展到目前的阶段,政府和公众都非常关注环境风险,并出台了大量的规制性政策对其进行治理.如何在实现环境治理目标的同时,合理控制经济成本、尽量减少次生影响是提升环境治理效能的重要命题,本文针对这一问题进行了探讨.主要对规制的经济成本和次生影响等关键概念做了辨析,对规制的经济成本和次生影响在我国被忽略的可能原因进行了分析,对他国应对这一问题所采取的措施开展了讨论.最后提出在我国针对重大环境规制性政策开展规制影响评估的建议.