ACCURACY AND PRECISION OF NRCS MODELS FOR SMALL WATERSHEDS1

ABSTRACT: In the last 30 years, the National Resource Conservation Service's TR‐55 and TR‐20 models have seen a dramatic increase in use for stormwater management purposes. This paper reviews some of the data that were originally used to develop these models and tests how well the models estimate annual series peak runoff rates for the same watersheds using longer historical data record lengths. The paper also explores differences between TR‐55 and TR‐20 peak runoff rate estimates and time of concentration methods. It was found that of the 37 watersheds tested, 25 were either over‐ or under‐predicting the actual historical watershed runoff rates by more than 30 percent. The results of this study indicate that these NRCS models should not be used to model small wooded watersheds less than 20 acres. This would be especially true if the watershed consisted of an area without a clearly defined outlet channel. This study also supports the need for regulators to allow educated hydrologists to alter pre‐packaged model parameters or results more easily than is currently permitted.     

Agroforestry as alternative land-use production systems for the tropics

The science of agroforestry has progressed significantly during the past three decades. This article describes and documents various prominent traditional agroforestry systems. In-depth research on interactive processes of some agrisilvicultural systems have been undertaken and quantified. It has been found that the presence of woody species can enhance nutrient cycling, and can improve soil productivity, soil conservation and soil biotic andfaunal activities. In simultaneous systems however, their presence can also cause competition with the associated food crops. Most agroforestry systems constitute ecologically and bio-physically sustainable land use systems. Some are highly sustainable and economically viable, in particular the highly complex and specialized types, such as the damar and rubber agroforests in Indonesia. Agroforestry systems have potential uses in stabilization of sloping lands and buffer zones around forest reserves, for recovering degraded lands, and for improving the productivity of the bush fallow system. Despite rapid progress in biophysical research, field application of the science of agroforestry is still minimal. This article examines the possibilities of exploring the multiple contributions of trees to food security, rural income generation, diversity of products and ecosystem conservation within sustainable agroforestry contexts. Research efforts in the new millennium need to focus more on practical research and also on socio-economic and policy factors that can enhance beneficial application of the science in the near future to smallholder farmers in the tropics.     

Awareness of environmental legislation as a deterrent for wildlife crime: A case with Masaai pastoralists,poison use and the Kenya Wildlife Act

Illegal wildlife crime is a global phenomenon, accelerating the ongoing biodiversity crisis. In the Old World, and particularly in Africa, illegal use of poisons to eliminate carnivores is the main driver of the continental vulture crisis. Knowledge about the underlying source and drivers of this threat is lacking for most areas, including Kenya, a global vulture and biodiversity hotspot. An extensive questionnaire survey of over 1300 respondents was run, using a specialized questioning technique and quantitative analytical approaches. Results show that, while pastoralists have a positive attitude towards vultures, over 20% of them use poisons to eliminate predators. Poisoning was largely driven by livestock losses to predators, and by negative attitude towards predators. Poisoning was less prevalent among respondents aware of the Kenya Wildlife Act. Overall, we suggest that a combination of top-down, e.g. legislation, and bottom-up (such as corrals or compensation) along with awareness campaigns may help reduce poisoning on the ground.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01695-8.     

Trophic state, ecosystem efficiency and biodiversity of transitional aquatic ecosystems: analysis of environmental quality based on different benthic indicators

Estuaries and coastal lagoons are characterized by a strong spatial and temporal variability of physicochemical characteristics and productivity patterns. In these environments, the magnitude and direction of the ecological responses to inorganic nutrient increase (i.e. eutrophication) are difficult to predict. In the framework of the project, New Indicators of Trophic state and environmental quality of marine coastal ecosystems and transitional environments (NITIDA), we analysed benthic indicators of trophic state, ecosystem efficiency, and environmental quality in four different transitional environments. The trophic state of the sediments was assessed in terms of quantity and bioavailability of sediment organic C pools; ecosystem efficiency was determined in terms of the prokaryote efficiency in exploiting enzymatycally degraded organic C; environmental quality was determined in terms of meiofaunal diversity. Here, we provide a synopsis of the results obtained and a meta-analysis of the scores assessments obtained using the different ecological indicators of environmental quality and demonstrate that trophic state, ecosystem efficiency, and biodiversity in transitional ecosystems are closely linked. We conclude that the assessment of the environmental quality of transitional ecosystems should be based upon a battery of trophic state indicators and 'sensors' of ecosystem functioning, efficiency, and quality.     

Multiple-resource modeling as a tool for conservation: Its applicability in Mexico

The current Mexican environmental law provides the legal basis for comprehensive land-use planning. Under the law, development of natural ecosystems must combine goals, policies, and practices towards the sustainable use of natural resources and the protection of biological diversity. Thus, ecosystem manipulation must be able to counter fragmentation of natural ecosystems and isolation of natural reserves, while providing for human needs. Assessment of the potential of natural ecosystems and management impacts are required. Multiple-resource simulation is an assessment and land-use planning tool that permits managers and decision makers to comply with the law, providing a flexible, user-oriented system that can meet the needs of managers, conservationists, and researchers. A multiple-resource model and an example of how it can be applied to meet planning needs is presented for discussion.     

Ecological principles,biodiversity, and the electric utility industry

The synthetic field of conservation biology uses principles derived from many different disciplines to address biodiversity issues. Many of these principles have come from ecology, and two simple ones that seem to relate to many issues involving the utility industry are: (1) Everything is interconnected (and should usually stay that way), and (2) We can never do merely one thing. The first principle can be applied to both the biotic and physical environments that are impacted by industrial activities. Habitat fragmentation and the loss of physical and biotic connectedness that results are frequently associated with transmission rights-of-way. These problems can be reduced—or even turned into conservation benefits—by careful planning and creative management. The second principle applies to the utility industry's programs to deal with carbon released by burning fossil fuels. Ecological knowledge can allow these programs to contribute to the preservation of biodiversity in addition to addressing a pollution problem. Without careful ecological analyses, industry could easily create new problems while implementing solutions to old ones.     

鄱阳湖湿地植被的生物多样性及其保护和利用

鄱阳湖是我国最大的天然淡水湖泊，湖区湿地面积２６９８ｋｍ＾２，是我国湿地生态系统中植物资源及植被类型最丰富的地区之一。该处分布高等植物７５科２００余属３５０余种，湿地植被依其生态环境和群落特征可划分为水生群落、沼泽、草甸、沙洲４类型６０余个群系，保护与合理地持续利用这些植物群落是有效的保护和发展鄱阳湖湿地生态环境的根本途径。为些就切实制定鄱阳湖湿地总体规划，建立包括整个湖区面积在内的湿地生态系统自     

洪泽湖湿地资源保护与可持续利用研究

洪泽湖湿地生物多样性比较丰富，湿地植被群丛多样，重点保护鸟类种类众多，种群数量大。调查结果显示：洪泽湖湿地共鉴定出浮游植物165种、水生高等植物81种、浮游动物91种、底栖动物69种、鱼类102种、鸟类194种。我们研究了洪泽湖湿地的大气、河流、湖泊环境质量，在分析洪泽湖湿地的破坏程度和原因后，提出了洪泽湖湿地保护对策和可持续利用途径。     

生物多样性——人类持续发展的自然基础的研究

生物多样性保护成为当前国际社会普遍关注的焦点问题之一,是因为生物多样性的急剧丧失已在削弱未来人类持续发展的基础。本文从基因、物种和生态系统三个层次分析了生物多样性的性质和价值以及人类生存与发展的意义。指出生物多样性丧失的主要推动力是人类所采取的非持续的生活方式和发展模式,生物多样性的丧失已成为人类持续发展的主要障碍。在分析、总结我国生物多样性保护的成就与问题的基础上,提出了中国生物多样性保护战略。