Projected Climate Change Effects on Winterkill in Shallow Lakes in the Northern United States

2 was obtained from the output of the Canadian Climate Center General Circulation Model. To illustrate the effect of projected climate change on lake DO characteristics, we present herein DO information simulated, respectively, with inputs of past climate conditions (1961–1979) and with a projected 2 × CO₂ climate scenario, as well as differences of those values. Specific parameters obtained were minimum under-ice and lake bottom DO concentration in winter, duration of under-ice anoxic conditions (<0.1 mg/liter) and low DO conditions (<3 mg/liter), and percentage of anoxic and low DO lake volumes during the ice cover period. Under current climate conditions winterkill occurs typically in shallow eutrophic lakes of the northern contiguous United States. Climate warming is projected to eliminate winterkill in these lakes. This would be a positive effect of climate warming. Fish species under ice may still experience periods of stress and zero growth due to low DO (<3 mg/liter) conditions under projected climate warming.     

Riparian Vegetation and Water Chemistry in a Basin Under Semiarid Mediterranean Climate, Andarax River, Spain

A study has been made of the relationships between the characteristics of the riparian vegetation (floristic composition, structure and diversity) and the spatial–temporal variation of the quality of the stream waters in a basin under a semiarid Mediterranean climate in the southeastern Iberian Peninsula. The plant communities of the high reaches present greater specific richness and diversity (S _mean= 7.0 ± 3.4 and H′_mean= 2.0 ± 0.7) than do those of the middle and low reaches (S _mean= 4.5 ± 1.6 and H′_mean= 1.8 ± 0.6). One zone reached the highest specific richness (S= 12, H′= 3.2), which, apart from being situated in the intermediate stretch of the basin, represents a transitional state (ecotone) between the Salix and Tamarix communities. The characteristics of the waters analyzed indicate very high rates of erosion and runoff due to the nature of the soils (easily eroded marls) and to agricultural expansion and mining since the 16th century. The present-day riparian vegetation is not adequate to absorb the nitrates added to the basin by crop fertilization, reaching extremely high values, particularly during the dry period (between 1.2 and 42.5 mg/liter). Sewage dumping at three sampling stations did not appear to affect the specific composition of the woody vegetation. In the zones with watercourses, water salinity was low during the period of greater water flow, but considerably higher in the dry season (the upper limit was some 1.2 mS/m), resulting in a predominance of salt cedars over willows. Three types of saltcedar areas were distinguished: subhalophilous, which barely changes its chemical composition over the season; halophilous, which develops over strongly mineralized waters and markedly alters in chemical composition during the dry season; and hyperhalophilous, where salinity is extraordinarily high and quite constant throughout the year. A direct relationship was found between the dominance of Tamarix africana and abundance of NaCl.     

Benefit–Cost Analysis of StormwaterQuality Improvements

The major purpose of this paper is to explore the potential value of benefit–cost evaluation for stormwater quality management decisions at a local level. A preliminary benefit–cost analysis (BCA) screening method is used for maximum extent practicable (MEP) analysis, identifying promising management practices, and identifying societal and economic tradeoffs for local stormwater problems. Ballona Creek, a major urban storm drain in Los Angeles, California, USA, is used to illustrate the practicality of the benefit–cost evaluation. The Ballona Creek example demonstrates the economic limits of stormwater management in an urban region and attests to the value of coordinated basinwide management compared to uncoordinated management by individual landowners. Evaluation results suggest that in urban areas, the benefit of stormwater quality improvements might be far greater if accompanied by comprehensive redesign of drainage networks and neighboring land uses. In this case, benefit–cost analysis is found to be useful for evaluating and understanding stormwater management alternatives despite the uncertainties in characterizing stormwater quality and the effects of stormwater management on improving receiving water quality.     

The Effects of Irrigation on Revegetation of Semi-Arid Coastal Sage Scrub in Southern California

Artemisia californica, represented nearly 100% of the species present at the end of two growing seasons. Irrigation may speed revegetation under some conditions, but was not very effective in establishing natural vegetation structure.     

A Mediation Case for Resolving the Energy and Environment Dispute at Aliağa-İzmir, Turkey

A mediation exercise to resolve the ongoing dispute against these power plant projects at Aliağa was recommended and participated in by the author in 1997. In this article the basis of the continuing environmental concern about the feared impacts of the new power plants, procedure, and results of this mediation are mentioned. The basis of the “energy versus environment” dispute in Aliağa are introduced. Mediation exercise and its end results have been criticized.     

Dive Operator Use Patterns in the Designated No-Take Zones of the Florida Keys National Marine Sanctuary (FKNMS)

/ The Florida Keys National Marine Sanctuary (FKNMS), created by Congress in 1990, addressed the issue of resource protection partly by proposing 26 "no-take" zones. These areas, discussed in the 1995 Draft Management Plan, disallowed all extractive activities, and four of the zones also prohibited diving and snorkeling. Furthermore, the Draft Management Plan considered recreational carrying capacity, proposing that use densities be studied and eventually limited in high-use and sensitive areas. Conducted with 62 commercial dive operators from the Florida Keys in 1995-96, this study uses geographic information systems (GIS) to determine the extent of FKNMS zone use by dive operators, assess the regional importance of FKNMS zones to operators, and compare management strategies by which to allow use while minimizing impacts to the coral reef resource. Dive operators took almost 70% of their total trips and 77% of their total divers to FKNMS zones in 1995. Although zone use is generally related to the proximity of dive locations, dive operators do rely disproportionately on single sites in certain regions. The resulting profiles demonstrate that management strategies need to consider disproportionate use, as well as the average number of users per trip, to effectively protect the region's environmental resources. In addition to implementing a carrying capacity plan, the FKNMS should consider a limited-entry system for dive operators.     

Comparing Landslide Maps: A Case Study in the Upper Tiber River Basin, Central Italy

/ The preparation of landslide maps is an important step in any landslide hazard assessment. Landslides maps are prepared around the world, but little effort is made to assess their reliability, outline their main characteristics, and pinpoint their limitations. In order to redress this imbalance, the results of a long-term research project in the Upper Tiber River basin in central Italy are used to compare reconnaissance and detailed landslide inventory maps, statistical and geomorphologically based density maps, and landslide hazard maps obtained by multivariate statistical modeling. An attempt is made to discuss advantages and limitations of the available maps, outlining possible applications for decision-makers, land developers, and environmental and civil defence agencies. The Tiber experiment has confirmed that landslides can be cost-effectively mapped by interpreting aerial photographs coupled with field surveys and that errors and uncertainties associated with the inventory can be quantified. The experiment has shown that GIS makes it easy to prepare landslide density maps and facilitates the production of statistically based landslide hazard models. The former supply an overview of the distribution of landslides that is easily comprehended but do not provide insight on the causes of instability. The latter, giving insight into the causes of instability, are diagnostically powerful, but are difficult to prepare and exploit.     

The Use of Cluster Analysis in Distinguishing Farmland Prone to Residential Development: A Case Study of Sterling, Massachusetts

k -means nonhierarchical cluster analysis using farm size, slope, and distance to the nearest city center and highway as surrogates of farmland conversion. Discriminant analysis showed that the two groups derived from the cluster analysis were 98.8% accurate (P < 0.0000). Results from the statistical analysis may serve as a starting point for the identification of individual farms prone to residential development. To explain the driving forces of farmland conversion to residential uses, interviews should be conducted with farmers, landowners, and land buyers. The use of multivariate statistical techniques to identify farms in jeopardy of residential development, in conjunction with qualitative assessments that explain the probability of development of individual farms, may prove a useful strategy to understand and predict farmland conversion.     

Environmental Accountability: Who's Kidding Whom?

International declarations and charters have been produced to encourage and support higher education institutions (HEIs) to address their environmental responsibilities. This paper discusses the results of a critical examination of a range of international HEIs that have signed the global environmental Talloires Declaration. It also assesses the Talloires Secretariat (University Leaders for a Sustainable Future, ULSF) and the extent to which this has been a primary stimulus. An international survey was undertaken and the results presented in a discursive format in order to highlight key driving forces, barriers, and opportunities for environmental responsibility in HEIs. Analysis reveals that they occur on two distinct and evolving levels: the macro national framework level and the micro institutional framework level. Survey responses revealed that none of the HEIs have an embedded institutional environmental culture and most did not have all the micro institutional mechanisms in place for an integrated university-wide environmental response. Many of the institutional barriers to environmental responsibility occurred as a result of this lack of strategy. The most significant institutional opportunity cited was enthusiastic individuals, particularly those at senior management or directorate level, and these individuals were found to be a key driving force. Results also showed that environmental reporting along the lines developed by the private sector is a flexible mechanism that can stimulate progress internally and externally and can be cost effectively disseminated via the World Wide Web. Moreover the survey results indicate that ULSF is not currently a primary stimulus for institution wide action.     

A Methodological Approach for Designating Management Zones in Mount Spil National Park, Turkey

/ This study was undertaken to (1) determine the suitability of ecosystems within Mount Spil National Park (Turkey) to human activities by a systematic zoning procedure, and (2) provide the basis for developing sound management strategies based on natural-cultural resource attributes of the park. After assessing natural-cultural resources and human activity requirements, the suitability of three zones (Strict Protection Zone, SPZ; Restricted Use Zone, RUZ; and Recreation and Administration Zone, RAZ) for proposed human activities/land uses was determined in order to maintain ecological sustainability and integrity through a weighting-ranking methodology, based on a grid cell resolution of 1 km x 1 km. Results showed that out of the three management zones, the RUZ in which the recreational activities that do not require physical developments are allowed constituted 82% of the park area as the first priority management zone. The proposed zoning procedure is believed to be a key step to improve management for both the study area and other national parks with the similar landscape features.