BSENEFICIAL USE POTENTIAL OF DRY WEATHER FLOW IN THE LAS VEGAS VALLEY,NEVADA1

ABSTRACT: Historically ephemeral washes in the Las Vegas Valley have become perennial streams in the urbanized area, and the primary source of these perennial flows appears to be the overirrigation of ornamental landscaping and turf. Overirrigation produces direct runoff to the washes via the streets and results in high ground water levels in some areas. Elevated ground water levels result in discharge to the washes because of changes in the natural balance of the hydrologic system and construction site and foundation dewatering. In recognition of the resource potential of these flows within the Las Vegas Valley, of the potential for dry weather flows to convey pollutants from the Valley to Lake Mead, and of the need to characterize dry weather flows under the stormwater discharge permit program, the quantity and quality of dry weather flow in Flamingo Wash was investigated during the period September 1990 through May 1993. This paper focuses on the resource potential of the flow (quantity and quality) as it relates to the interception and use of this water within the Valley. Economic and legal issues associated with the interception and use of this resource are not considered here.     

FACTORS CONTROLLING RUNOFF NUTRIENT LOSS FROM CULTIVATED LAND IN EASTERN SOUTH DAKOTA1

ABSTRACT A stepwise multiple regression was used to evaluate the relative importance of antecedent-, event-, and high-intensity-precipitation amounts; runoff volume; and precipitation nutrient contents and concentrations in determining nutrient losses in runoff. Plots were fertilized at high, medium, and low rates and had cultivation ridges oriented up-and-down slope or on the contour. Runoff volume was the important factor in determining the loss of NO₃, soluble PO₄, total PO₄, and soluble K ions in runoff from fallow, corn, or soybean plots. NH₄-N loss was controlled mainly by the precipitation content and antecedet precipitation since fertilizer had been applied. Nutrient losses were greater from plots fertilized at the high rate and from plots with cultivation ridges oriented up-and-down slope rather than on the contour.     

SOIL EROSION AWARENESS AND USE OF CONSERVATION TILLAGE FOR WATER QUALITY CONTROL1

Water pollution through loss of topsoil from farmland continues to be a major problem, despite nearly 50 years of providing farmers technical and financial assistance for soil and water conservation. The technology for controlling erosion and water pollution is available, but farmers have been slow in implementing control practices. Past research has shown that farmers tend to be unaware of the seriousness of the erosion problem on their own operations. Using a random sample of farmers from central Iowa, the relationship is examined between awareness of a soil erosion problem and the use of conservation tillage. Results indicate that awareness of a soil erosion problem effects the use of conservation tillage, and that awareness can be enhanced by experiential educational strategies such as the development and implementation of a soil and water conservation plan.     

浅谈卧龙特区梯级电站建设对自然保护区的影响

根据笔者参加卧龙特区梯级电站规划中了解到的一些情况,首先阐述了保护区的自然环境和社会环境以及在此背景上造成的当前大熊猫的处境。接着分析了梯级电站建设可能带来的生态效益、经济效益和社会效益。同时,又估计到会带来的一些不利影响,重点是对大熊猫的生存环境方面。最后,从加强自然保护角度建议对方案中在核心区布置的一些梯级电站应持慎重态度,并提了几点保护措施。     

Balancing urban development and endangered species: The coachella valley habitat conservation plan

Habitat conservation plans (HCPs) permitted under Section 10(A) of the federal Endangered Species Act, have been increasingly used to overcome conflicts between urban development and species conservation. This article profiles one such HCP, the Coachella Valley (CA) Fringe-Toed Lizard Habitat Conservation Plan. The second HCP officially approved by the US Fish and Wildlife Service, the Coachella Valley case is frequently cited as a model for resolving conservation and development conflicts. The article begins with a discussion of the use of HCPs, and then provides a detailed discussion of Coachella Valley experience, its history, specific provisions, and success to date. A final section examines whether Coachella Valley does in fact represent a positive model. It is argued that the HCP has been less than fully successful and leaves unresolved a series of fundamental ethical and policy questions concerning the protection of endangered species. Funding for this report was provided by the National Fish and Wildlife Foundation. Any opinions, findings, conclusions, or recommendations are those of the author and do not necessarily represent the views of the Foundation.     

毕节地区各土类水土保持树种的Fuzzy评价

根据毕节地区16个主要造林树种的生态生物学特性,结合本区气候和土壤生态条件,运用 Fuzzy 二级评价模型,对各土类水土保持树种的适宜程度进行了综合评价。     

Contour Farming Based on Natural Vegetative Strips: Expanding the Scope for Increased Food Crop Production on Sloping Lands in Asia

In the agriculture of the future, there is a compelling place for agroecologically-based practices alongside practices based on the best available chemical, genetic, and engineering components. This paper explores this issue in the context of the development and spread of a conservation farming system based on natural vegetative contour buffer strips in smallholder production systems in southeast Asia. Farmers adapted contour hedgerow farming practices into a simpler, buffer-strip system as a labor-saving measure to conserve soil and sustain yields on steeply sloping cropland in Claveria, Mindanao, Philippines. Permanent-ridge tillage systems were also adapted to smallholder farming systems by researchers. Natural vegetative buffer strips resulted in gradually increasing yields, with an estimated benefit of 0.5t/ha/crop. They were seen to increase land values, facilitate investment in more intensive and profitable cropping systems, and expand the land base for food crop agriculture. They induced an institutional innovation of farmer-led Landcare organizations, which have spread this and other agroforestry practices to thousands of households in the southern Philippines.     

A Framework of Lessons Learned from Community-Based Marine Reserves and Its Effectiveness in Guiding a New Coastal Management Initiative in the Philippines

Community-based coastal resource management has been widely applied within the Philippines. However, small-scale community-based reserves are often inefficient owing to management inadequacies arising because of a lack of local support or enforcement or poor design. Because there are many potential pitfalls during the establishment of even small community-based reserves, it is important for coastal managers, communities, and facilitating institutions to have access to a summary of the key factors for success. Reviewing relevant literature, we present a framework of lessons learned during the establishment of protected areas, mainly in the Philippines. The framework contains summary guidance on the importance of (1) an island location, (2) small community population size, (3) minimal effect of land-based development, (4) application of a bottom-up approach, (5) an external facilitating institution, (6) acquisition of title, (7) use of a scientific information database, (8) stakeholder involvement, (9) the establishment of legislation, (10) community empowerment, (11) alternative livelihood schemes, (12) surveillance, (13) tangible management results, (14) continued involvement of external groups after reserve establishment, and (15) small-scale project expansion.These framework components guided the establishment of a community-based protected area at Danjugan Island, Negros Occidental, Philippines. This case study showed that the framework was a useful guide that led to establishing and implementing a community-based marine reserve. Evaluation of the reserve using standard criteria developed for the Philippines shows that the Danjugan Island protected area can be considered successful and sustainable. At Danjugan Island, all of the lessons synthesized in the framework were important and should be considered elsewhere, even for relatively small projects. As shown in previous projects in the Philippines, local involvement and stewardship of the protected area appeared particularly important for its successful implementation. The involvement of external organizations also seemed to have a key role in the success of the Danjugan Island project by guiding local decision-makers in the sociobiological principles of establishing protected areas. However, the relative importance of each component of the framework will vary between coastal management initiatives both within the Philippines and across the wider Asian region.Published on line     

Value to wildlife of urban-agricultural parks: a case study from Rome urban area

Urban-agricultural parks could have some advantages to wildlife because of less intensive agricultural procedures, absence of hunting pressure, and reduced human disturbance. In this study, the breeding and wintering bird communities and the small mammal community in an urban-agricultural park of Rome were compared to those of a close urban park and a close agricultural area just outside the city. The aim was to assess the best destination and management of wildlife in natural areas at the urban–rural interface. Richness and diversity of bird communities were higher in the urban-agricultural park. Due to habitat features and probably human disturbances, but not to urbanization, predation, and competition factors, the urban park drastically reduces the abundance of decreasing open-land bird species. Abundance of these species was not significantly different in the urban-agricultural park and in the agricultural area. In the urban-agricultural and urban park, bird and mammal pest species were more abundant than they were in the agricultural area. Regarding decreasing abundance of small mammal species, no significant difference among the study areas was observed. Urban-agricultural park is a better choice than urban park for wildlife. Thus, a higher number of preserved urban natural areas should be devoted to urban-agricultural parks. However, to increase the abundance of open-land species and in general wildlife, a less intensive management of cultivated and pasture patches is necessary.     

PROFILE: Tourism Contribution to Agro-Ecosystems Conservation: The Case of Lesbos Island, Greece

The objective of this study was to investigate the impact of tourism activities on olive tree cultivation and the human population of the island of Lesbos. The presence or absence of tourism is related with the maintenance or abandonment of olive tree cultivation and population changes for each community. A spatial segregation of the island is evident, related to tourist development, olive tree cultivation, and population change. The results of the study demonstrate that in communities where tourism plays an important role olive tree cultivation is preserved and the population is stable. The preservation of the agro-ecosystem is assured while the olive groves remain productive. Simultaneously, the landscape, which provides specific attractions for tourism, is not altered.