Natural Recovery of Technogenic Landscapes in Open Larch Forests in Northeastern Russia

Studies on the vegetation and soil complexes in areas of the Kolyma River basin disturbed by mining, in the northeast of the Chukchi Peninsula, have been performed to reveal trends in natural restorative processes in posttechnogenic landscapes. Data on the flora, phytomass stock, chemical composition of plants pioneering in the overgrowing of disturbed areas, and physicochemical properties of soils and technogenic eluvia have been obtained. The results have shown that plant cover restoration in disturbed areas depends primarily on the type (genesis) of technogenic substrates, the content of fine earth in the surface layer, and the distance from natural plant complexes that serve as a source of seeds coming to the disturbed area.     

长江中上游护堤林发展土地潜力研究

护岸堤林建设是建设是长江中上游防护林体系建设林种空间布局与配置不可缺少的有机组成部分，具沿江而布及成连续林带的特点。其发展的土地潜力取决于岸堤线长度、林带建设宽度和建设地带内的土地利用现状结构等三个因素。研究结果表明：长江中上游研究江段护岸堤林发展土地数量潜力规模为２５１２３．４～４１９３８．９ｈｍ２，其中需造林绿化的宜林荒地地（第一类潜力）为８２１４．５～１３７５７．３ｈｍ２，需改造更新的疏灌林地和需加强抚育的未成林造林地（第二潜力）为５４０９．３～９０１５．５ｈｍ２，需退耕还林的耕地（第三类潜力）为１１４９９．６～１９１６６．１ｈｍ２。     

Regeneration of Native Trees in the Presence of Invasive Saltcedar in the Colorado River Delta, Mexico

Abstract:  Many riparian zones in the Sonoran Desert have been altered by elimination of the normal flood regime; such changes to the flow regime have contributed to the spread of saltcedar ( Tamarix ramosissma Ledeb.), an exotic, salt-tolerant shrub. It has been proposed that reestablishment of a natural flow regime on these rivers might permit passive restoration of native trees, without the need for aggressive saltcedar clearing programs. We tested this proposition in the Colorado River delta in Mexico, which has received a series of large-volume water releases from U.S. dams over the past 20 years. We mapped the vegetation of the delta riparian corridor through ground and aerial surveys (1999–2002) and satellite imagery (1992–2002) and related vegetation changes to river flood flows and fire events. Although saltcedar is still the dominant plant in the delta, native cottonwood (  Populus fremontii S. Wats.) and willow ( Salix gooddingii C. Ball) trees have regenerated multiple times because of frequent flood releases from U.S. dams since 1981. Tree populations are young and dynamic (ages 5–10 years). The primary cause of tree mortality between floods is fire. Biomass in the floodplain, as measured by the normalized difference vegetation index on satellite images, responds positively even to low-volume (but long-duration) flood events. Our results support the hypothesis that restoration of a pulse flood regime will regenerate native riparian vegetation despite the presence of a dominant invasive species, but fire management will be necessary to allow mature tree stands to develop.     

SURFACE WATER WITHDRAWAL ALLOCATION AND TRADING SYSTEMS FOR TRADITIONALLY RIPARLAN AREAS1

ABSTRACT: There is a growing need for water regulations in states traditionally managed by the riparian doctrine. Several states have passed water laws to control withdrawals from streams. Few, if any, however, have set up consistent and defensible methods for allocating water to users. This paper explores several methods for such allocations, examining each in detail and offering numerical examples that compare each on the basis of economic efficiency and effectiveness for maintaining critical stream‐flow standards. This work is part of a study to assess the vulnerability of Midwestern streams to climate change and, especially, surface supplied irrigation spawned by such climate change. The results suggest that it is possible to implement regulations that at once (1) are consistent with the riparian doctrine; (2) control the hydrological and ecological impacts of off stream withdrawals effectively; and (3) preserve the primary economic functions of those withdrawals, including minimizing economic risk. The results further suggest that trading of water permits improves the latter two objectives, but only if both the regulatory system and permit are well‐designed. On the other hand, in the absence of regulations, or under poorly designed regulations, streamflows, and therefore aquatic ecosystems, could be quite vulnerable.     

面向可持续发展的海岸带综合管理研究

本文以可持续发展为目标，从海岸带综合管理问题入手，进一步分析了海岸带系统的可持续性，阐述了海岸带综合管理的方法论，提出了海岸带综合管理的内涵、原则、任务与技术方法。     

三峡库区香溪河消落带植被多样性及分布格局研究

研究三峡大坝蓄水10 a后香溪河消落带不同高程区域植被的物种组成、群落多样性及其空间分布特征,旨在为库区消落带生态修复中的物种选择、植被群落重建提供依据。研究结果发现:(1)香溪河消落带植被以一年生草本植物为主,物种组成比较简单。植物种群空间分布分析表明,优势种种群均属于聚集分布;(2)随着高程的增加,α多样性指数中Patrick丰富度、Shannon-wiener多样性和Pielou均匀度呈增加趋势,而Simpson优势度则与其它三个指数相反呈递减的趋势;而β多样性指数中Cody指数、Wilson-Shmida指数、Jaccard指数和Sorenson 指数均呈增加趋势;(3)推荐狗牙根、马唐、狗尾草和香附子4种植物作为三峡库区香溪河消落带植被恢复的备选草本物种。     

重化工园区循环经济评价指标体系构建及应用研究

为了切实推进重化工园区的循环经济发展,首先需要对其循环经济发展水平进行评价。采用层次分析法等方法理论,研究提出有针对性和可操作性的重化工园区循环经济评价指标体系,并根据构建的计算模型,对某重化工园区2012年循环经济发展水平进行分析评价。     

我国部分城市大气颗粒物中多环芳烃的分布特征

主要研究中国大气颗粒物中多环芳烃污染状况,对多环芳烃的浓度水平、时间和空间分布、组成及在不同粒径颗粒物上的分布特征进行了综述.北方城市大气颗粒物中多环芳烃的浓度普遍高于南方城市.大气颗粒物中多环芳烃以4～6环为主,占多环芳烃总量的60％～ 80％.大多数多环芳烃分布于细粒子中,且多环芳烃在PM2.5中的分布占在PM1o中分布的70％以上.多环芳烃质量浓度有明显的季节变化特征,多数研究中多环芳烃浓度从高到低的季节变化规律为冬季、秋季、春季、夏季.不同功能区大气颗粒物中多环芳烃污染,城区高于郊区,交通区和工业区高于商业区、居住区和文化区.     

山谷地区埋地天然气管道泄漏三维数值模拟

针对山谷地区埋地天然气泄漏问题,建立三维泄漏模型,将管道模型建立于土壤下,给出山谷地区风随海拔高度变化边界条件,在此基础上对山谷地区高含硫天然气泄漏问题进行六组模拟。结果表明:六组工况下硫化氢的危险区域全部大于甲烷的危险区域,突显出天然气泄漏问题中硫化氢的危害性之大。风速对危险范围的影响很大,在山谷地形条件下危险范围大小与风速大小成反比,且风速越大,危险范围越小。三个泄漏口方向中漏口斜向上45°时空气中泄漏气体的总质量分数最大,扩散的范围最大,但部分范围内并未达到泄漏气体的危险浓度,危险范围比实际扩散范围要小,漏口斜向下45°时危险区域是最大的,漏口水平介于中间。     

A Geospatial Methodology to Identify Locations of Concentrated Runoff from Agricultural Fields

A geospatial methodology has been developed that utilizes high resolution lidar‐derived DEMs to help track runoff from agricultural fields and identify areas of potential concentrated flow through vegetated riparian areas in the Coastal Plain of Virginia. Points of concentrated flow are identified across 74 agricultural fields within the Virginia portion of the Chesapeake Bay watershed. On average, 70% of the surface area of the agricultural fields analyzed drains through less than 20 m of the field margin, and on average 81% of the field surface area drains through 1% or less of the field margin. Within the riparian buffer, locations that were predicted by the geospatial model to have high levels of concentrated flow were found to exhibit evidence of channelization. Results indicate that flow concentration and channelized flow through vegetated riparian areas may be common along the margin of agricultural fields, resulting in vegetated riparian areas that are less effective at sediment trapping than assumed. Additional results suggest that the regulations governing the location and width of vegetated riparian may not be sufficient to achieve goals for reducing sediment and nutrient runoff from nonpoint agricultural sources. Combined with the increasing availability of lidar‐derived DEMs, the geospatial model presented has the potential to advance management practices aimed at reducing nonpoint source pollution leaving agricultural fields.