Distribution of Diatoms in a Forested Stream Containing a Series of Interconnected Lakes

We explored the spatial variation in diatom communities withinthe Turkey Lakes Watershed (TLW). The TLW is a single watershed in an old growth sugar maple forest that contains an alternatingseries of stream and lake embayments. Near the outlet of each lake, we sampled pools and riffles to determine abundance and diversity of diatom communities along this hydrologic system. Diatom diversity, measured by Shannon-Weaver Index, richness andevenness, increased steadily downstream before eventually decreasing near the watershed outlet. Canonical CorrespondenceAnalysis indicated that diatom genera were correlated with streamchemistry. Upper reaches were the least productive, characterizedby lower pH (<7), higher N:P (113:1 to 124:1, dominated by complex forms of N), and high mean relative abundances of Eunotia spp., Tabellaria spp., and Pinnularia spp. Middle and lower reaches were more productive, characterized byhigher pH (>7), lower N:P (71:1 to 90:1, dominated by simple forms of N, e.g., nitrate-N), and high mean relative abundances of Cymbella spp. and Brachysira spp. Achnanthesminutissima (Kutz.) Hustedt, the most abundant species, and Navicula spp., Nitzschia spp., Gomphonema spp., and Frustrulia spp. were represented at all stream sites. Thisstudy revealed that within the TLW, a hydrologic system of the same stream order, the diatom community was influenced by a nutrient gradient, where the stream and its intervening lakes contributed to a shift from acidic, inorganic N-poor upper reaches to a circum-neutral, inorganic N-richer outlet. By imparting genera-specific stresses, stream flow (i.e. pools vs. riffles) further shaped the diatom community.     

TREE‐RING BASED RECONSTRUCTIONS OF INTERANNUAL TO DECADAL SCALE PRECIPITATION VARIABILITY FOR NORTHEASTERN UTAH SINCE 1226 A.D.1

ABSTRACT: Samples from 107 piñon pines (Pinns edulis) at four sites were used to develop a proxy record of annual (June to June) precipitation spanning the 1226 to 2001 AD interval for the Uinta Basin Watershed of northeastern Utah. The reconstruction reveals significant precipitation variability at interannual to decadal scales. Single‐year dry events before the instrumental period tended to be more severe than those after 1900. In general, decadal scale dry events were longer and more severe prior to 1900. In particular, dry events in the late 13th, 16th, and 18th Centuries surpass the magnitude and duration of droughts seen in the Uinta Basin after 1900. The last four decades of the 20th Century also represent one of the wettest periods in the reconstruction. The proxy record indicates that the instrumental record (approximately 1900 to the Present) underestimates the potential frequency and severity of severe, sustained droughts in this area, while over representing the prominence of wet episodes. In the longer record, the empirical probability of any decadal scale drought exceeding the duration of the 1954 through 1964 drought is 94 percent, while the probability for any wet event exceeding the duration of the 1965 through 1999 wet spell is only 1 percent. Hence, estimates of future water availability in the Uinta Basin and forecasts for exports to the Colorado River, based on the 1961 to 1990 and 1971 to 2000 “normal” periods, may be overly optimistic.     

Vegetation Type Conversion in Los Peñasquitos Lagoon,California: An Examination of the Role of Watershed Urbanization

Environmental Management - The objective of this study was to examine the role that watershed urbanization has played in changes to the vegetation types within Los Peñasquitos Lagoon, San...     

日本森林管理的最新发展——以日本神奈川县林业政策过程为例

为了追求更好的森林管理效果，对相关森林政策的实施，不是仅仅停留在传统的狭义的行政管理部门上，同时还要涉厦到经营者、市民以及当地居民等利益相关者。使他们都要以相互协调的方式参与到森林管理当中来。它是建立在一定的森林价值观基础上，基于科学原理井突破以往的技术层面而对森林进行的一系列更加合理的管理措施体系。本文以日本神奈川县的林业政策形成过程为例对森林治理问题进行了讨论。     

以SO2排放控制和排污权交易为例分析中国环境执政能力

从中国SO2污染控制政策的演变,以及近年来政府大力推动的排污权交易这一污染控制经济手段试点入手,全面揭示中国环境管理中存在的问题,并从中国政策过程特点以及环境管理的政府治理结构2个角度阐释问题根源.揭示的主要环境问题包括政策的可操作性、政策间的协调性差,政策相互冲突以及政策本身缺乏科学性的论证等问题.中国自上而下的政策过程以及利用后发优势学习引用其他国家经济的政策演变特点是造成这些问题的政策原因,而中央与地方之间关系、政府部门之间、国家环境保护总局内部机构安排等方面存在的问题则是这些问题的政府治理结构根源.最后,从短期、最大可行性角度出发,以国家环境保护总局的建设为主线提出解决问题的建议,强化国家环境保护总局政策制定、协调监督以及执法监管三方面的职能与能力建设.     

我国城市环境管理体制问题分析及对策研究

从环境管理体制的角度来研究城市化不可持续的问题,通过以政策过程为主线的分析认为:由于公众和媒体作用有限导致城市环境问题的辨识不足、责任界定环节中存在的各级政府以及各部门之间的职责不清、城市政策制定环节中的不科学性和不协调性以及城市政策执行和监督环节的低效等管理体制上的问题,是阻碍城市可持续发展的根源.最后针对城市环境管理体制中存在的突出问题提出政策建议,指出重点要从明确各级政府各部门的环境职责、完善城市环境决策机制、强化监督机制等方面促进城市的可持续发展.     

淮河流域水污染防治与“环境均衡”原则

分析淮河流域污染治理中出现的情况，提出“环境均衡”原则，建议建立经济补偿，相关地区和行业应承担同等的环境责任。     

降尺度与融合化：环境空间管控转型与体系优化——代“环境空间管控研究”专栏序言

由于经济增长与污染物排放增加尚未脱钩，当前中国环境保护与污染防治的结构性、根源性压力尚未根本缓解，在生产生活污染源头治理上仍然面临排污基数大、溢出效应强、空间跨度广等难题，亟需强化污染源管控精准落地、建立健全面向污染源头的环境空间管控体系，以降尺度与融合化空间管控形成更加精准、严格、高效的环境空间管控制度，系统提升环境空间治理效能.本文基于区域环境功能和环境承载力视角分析了环境空间管控体系的科学基点及优化逻辑，从降尺度建立分区分级管控体系、形成融合化环境管理机制、嵌入多层级国土空间规划体系、夯实环境空间管控信息化支撑等方面提出新时期环境空间管控转型与体系优化路径.此外，研究团队结合典型城市化地区和重点生态功能区的案例实证，从人类生产生活污染物排放过程和格局入手，按照"驱动机制解析—分区分类管控—环境效应评估"的主线设置了"环境空间管控研究"专栏，以期为污染物源头减排及环境空间管控技术方法探索、环境综合治理策略制定提供参考依据.     

Soil loss as a measure of carrying capacity in recreation environments

This article describes three applications of the Universal Soil Loss Equation for further defining differences between natural environments in terms of their suitabilities for recreation use. Physical capacity limits based upon vulnerability to erosion and loss of soil productivity are discussed. Examples include: (a) applications to site planning and comparison of existing campsites; (b) use of the methodology for setting limits of acceptable change; and (c) characterization of third-order or larger watersheds that compare ecological land type interpretations with those based upon application of the equation.     

Watershed management program on Santiago Island,Cape Verde

The Watershed Management Program (WMP) was put into operation in early 1985 on Santiago Island, Cape Verde, with the stated purpose, “to develop and protect the soil and water resources of the Program-designated watersheds … to stabilize the natural environment and increase agricultural production potential in the Program area.” The approach to soil and water conservation in the program has been to build erosion and flood control structures (engineering approach) and plant trees (biological approach) to decrease rill and gully erosion, trap sediment behind control structures, provide flood protection, increase infiltration, increase fuelwood and fodder production, and increase water supplies for irrigation. There have been many successes resulting from specific management activities, but flawed approach or implementation in a few key areas has acted to impede the program's complete success, including lack of a scientific basis for evaluating its impact on soil and water conservation; poor design, placement, and maintenance of some major hydraulic structures; inadequate intervention in stabilizing farmlands or education of farmers and landowners in the need for and benefits of agroforestry; and incomplete integration of engineering and biological approaches.