不同等级石漠化综合治理的植被恢复过程特征——以贵州省花江峡谷为例

通过对石漠化综合治理过程中植被群落结构特征的连续观测,对影响植被结构变化的主要因素以及植被结构随治理时间变化的规律进行了研究。同一等级石漠化中植被盖度、生物量、生物多样性随综合治理年限增加,其结构得到改善和提高,其中植被盖度、生物量增长幅度为50%~360%。受人为扰动及石漠化等级程度的双重影响,植被结构具有异质性,即人为干扰程度加强,生物多样性降低;随着石漠化等级程度的提高,植被盖度、生物量降低;而生物多样性却随着石漠化等级程度的提高而提高,这种反常现象归根于治理初期生态系统的紊乱。在综合治理过程中,应针对人为扰动方式、程度及石漠化等级程度采取相应措施。     

海口市南渡江河岸带生态修复策略与技术路径研究

河流作为自然界的一部分,是人类文明的摇篮,也是人类活动的重要区域.河岸带是河流生态系统的重要组成部分,在维系生态平衡中发挥着巨大作用.本文以南渡江河岸带生态修复为例,提出了河岸带的3种生态修复策略和5种生态修复模式,并对未来河流生态修复重点提出了相关建议,以期为国内河流生态修复与综合管理提供参考与借鉴.     

酸性矿山5种植被恢复措施下土壤碱性磷酸酶基因细菌群落特征及其与重金属关系

为揭示酸性矿山不同植被恢复措施下碱性磷酸酶基因（pho D）细菌群落特征及其与重金属的关系,以赣州龙南稀土矿区为研究区域,收集了5种植被（百喜草、香根草、桉树、玉兰、芥兰）的土壤,测量不同植被土壤理化性质和重金属含量,利用高通量测序技术分析16S rRNA细菌和pho D基因细菌多样性及其群落特征,并计算pho D基因细菌与重金属含量的相关性.结果表明：不同植被土壤存在Cd、As、Pb、Mn超过江西省背景值现象,其中桉树、香根草土壤Pb含量分别为背景值的5.96倍、4.4倍,桉树土壤Cd含量为背景值的2.6倍. pho D基因细菌多样性Chao1指数排序为百喜草<香根草<桉树<玉兰<芥兰.慢生根瘤菌属（Bradyrhizobium）、假单胞菌属（Pseudomonas）、链霉菌属（streptomyces）为主要pho D基因菌属.相关性分析结果表明,Cd、As、Mn含量与铵态氮、硝态氮呈显著正相关,Cd、As、Pb同pho D基因细菌Chao1指数呈显著负相关,pH、TN、OM、TP、AP与pho D基因细菌多样性呈显著正相关.Heatmap热图显示,新根瘤菌...     

基于生态安全格局的国土空间保护修复优化——以内蒙古呼包鄂地区为例

构建生态安全格局可为国土空间保护修复提供对策,以补充现有研究对国土空间优化实践指导的不足。以内蒙古呼包鄂地区为案例,识别城镇、生态源地,构建源地扩展阻力评价体系,通过最小累积阻力模型划分安全格局小区;基于电路理论识别国土空间保护修复重点区域（生态廊道、生态“夹点”、生态障碍点）,优化生态安全格局,提出国土空间保护修复建议,得到的主要结论有：研究区城镇源地适宜扩展区远小于生态源地,国土空间保护修复有较大潜力;安全格局小区中生态保育区生态空间面积最大,其次是优化缓冲区生态空间,生态防护区生活空间最小;识别135条生态廊道,12个生态“夹点”,6个生态障碍点,164个生态战略点,架构生态安全网络,形成“多核四区三带一屏一流域”的国土空间保护修复格局,以达到提升生态景观完整度与连通性、维护区域生态安全的目标。     

Optimal Environmental Management Strategy and Implementation for Groundwater Contamination Prevention and Restoration

An innovative management strategy is proposed for optimized and integrated environmental management for regional or national groundwater contamination prevention and restoration allied with consideration of sustainable development. This management strategy accounts for availability of limited resources, human health and ecological risks from groundwater contamination, costs for groundwater protection measures, beneficial uses and values from groundwater protection, and sustainable development. Six different categories of costs are identified with regard to groundwater prevention and restoration. In addition, different environmental impacts from groundwater contamination including human health and ecological risks are individually taken into account. System optimization principles are implemented to accomplish decision-makings on the optimal resources allocations of the available resources or budgets to different existing contaminated sites and projected contamination sites for a maximal risk reduction. Established management constraints such as budget limitations under different categories of costs are satisfied at the optimal solution. A stepwise optimization process is proposed in which the first step is to select optimally a limited number of sites where remediation or prevention measures will be taken, from all the existing contaminated and projected contamination sites, based on a total regionally or nationally available budget in a certain time frame such as 10 years. Then, several optimization steps determined year-by-year optimal distributions of the available yearly budgets for those selected sites. A hypothetical case study is presented to demonstrate a practical implementation of the management strategy. Several issues pertaining to groundwater contamination exposure and risk assessments and remediation cost evaluations are briefly discussed for adequately understanding implementations of the management strategy.     

An Evaluation of the Influence of Natural Science in Regional-Scale Restoration Projects

Regional-scale restoration is a tool of growing importance in environmental management, and the number, scope, and complexity of restoration programs is increasing. Although the importance of natural science to the success of such projects generally is recognized, the actual use of natural science in these programs rarely has been evaluated. We used techniques of program evaluation to examine the use of natural science in six American and three Western European regional-scale restoration programs. Our results suggest that ensuring the technical rigor and directed application of the science is important to program development and delivery. However, the influence of science may be constrained if strategies for its integration into the broader program are lacking. Consequently, the influence of natural science in restoration programs is greatest when formal mechanisms exist for incorporating science into programs, for example, via a framework for integration of science and policy. Our evaluation proposes a model that can be used to enhance the influence of natural science in regional-scale restoration programs in the United States and elsewhere.     

地下水污染的原位值复技术——PRB法

原位修复地下水污染技术,具有经济、高效等特点.国外大量研究表明,此技术可以有效去除地下水中的重金属和有机污染物.本文主要介绍了原位修复技术中的PRB方法及其特点,并通过实验验证了其对地下水中重金属、有机物和三氮等污染物的去除效果,以此为基础,讨论了在我国开发应用该技术的前景及应注意的问题.     

富营养化浅水湖泊稳态转换理论与生态恢复探讨

从清水稳态与浊水稳态转换的过程、稳态阈值、稳态恢复力等方面介绍了浅水湖泊的稳态转换理论,总结了浊水稳态与清水稳态恢复力的影响因素,以及清水稳态与浊水稳态相互转换的驱动力,分析了富营养化引起的植物群落演替和稳态转换的过程.根据稳态转换理论和太湖五里湖的生态恢复实践,提出以改善生境条件为稳态转换驱动力进行生态恢复,并阐述了降低营养盐浓度、提高水体透明度、清除某些鱼类、改善基底、调节水位、软围隔消浪等生境改善措施.      

Modeling Effects of Natural Flow Restoration on Metals Fate and Transport in a Mountain Stream Impacted by Mine Waste1

Abstract: The effects of natural flow restoration on metals fate and transport in the Upper Tenmile Creek Watershed, Montana, were modeled using the Water Quality Analysis Simulation Program developed by the U.S. Environmental Protection Agency (USEPA). This 50‐km² watershed has over 150 historic abandoned mines, including mine waste rock and tailings, as well as adits discharging acid mine drainage, and is the primary drinking water supply for the City of Helena. Water supply diversions almost completely dewater some stream reaches during summer low flows, but the city is considering a new drinking water source and restoration of natural flows in Tenmile Creek as part of acid mine drainage remediation and broader aquatic habitat restoration. One dimensional steady‐state simulation of total recoverable cadmium, copper, lead, and zinc in the mainstem was performed, and the model was calibrated to June 2000 base‐flow data. Representative low‐flows in August and high‐flow snowmelt conditions in June were modeled using mean monthly natural flow estimates from the U.S. Geological Survey and representative USEPA metals concentrations data. The modeling showed that total recoverable metals concentrations, and especially loads, can vary significantly among input locations and over time in the watershed. Some data gaps limit evaluation of variability and increase uncertainty in several locations. Model results indicated, however, that natural low‐ and high‐flow restoration by itself can reduce some metals concentrations in the mainstem compared to June 2000 values, which were influenced by significant water diversion. Some values (such as Zn) may still exceed standards during natural August low flow due to the remaining high concentrations and loads in the primary inputs to the mainstem. Others (such as Cu) can increase during high flow due to remaining mine waste sources and loading of particulate Cu associated with erosion and transport of solids. Greater than 50% reduction in concentrations and loads from some of the main tributaries may be necessary to meet all standards, especially for potential particulate loads with higher flows in June.     

Perceptions of Wood in Rivers and Challenges for Stream Restoration in the United States

This article reports a study of the public perception of large wood in rivers and streams in the United States. Large wood is an element of freshwater aquatic ecosystems that has attracted much scientific interest in recent years because of its value in biological and geomorphological processes. At the heart of the issue is the nature of the relationship between scientific recognition of the ecological and geomorphological benefits of wood in rivers, management practices utilizing wood for river remediation progress, and public perceptions of in-channel wood. Surveys of students’ perceptions of riverscapes with and without large wood in the states of Colorado, Connecticut, Georgia, Illinois, Iowa, Missouri, Oregon, and Texas suggest that many individuals in the United States adhere to traditionally negative views of wood. Except for students in Oregon, most respondents considered photographs of riverscapes with wood to be less aesthetically pleasing and needing more improvement than rivers without wood. Analysis of reasons given for improvement needs suggest that Oregon students are concerned with improving channels without wood for fauna habitat, whereas respondents elsewhere focused on the need for cleaning wood-rich channels for flood risk management. These results underscore the importance of public education to increase awareness of the geomorphological and ecological significance of wood in stream systems. This awareness should foster more positive attitudes toward wood. An integrated program of research, education, and policy is advocated to bridge the gap between scientific knowledge and public perception for effective management and restoration of river systems with wood.