Ecological issues related to wetland preservation, restoration, creation and assessment

A wide range of local, state, federal, and private programs are available to support the national (USA) policy of wetland ‘No Net Loss’. Implementation of programs, however, has resulted in the continued loss of natural wetlands on the premise that restored or created wetlands will replace the functions and values lost by destruction of natural wetlands. What are the ecological implications and consequences of these programs from a biodiversity and ecosystem perspective? From a biodiversity perspective, ongoing wetland protection policies may not be working because restored or created wetlands are often very different from natural wetlands. Wetland protection policies may also be inadequate to preserve and restore ecological processes such as nutrient cycling because they mostly focus on individual wetlands and ignore the fact that wetlands are integral parts of landscapes. Wetland mitigation projects, for example, often result in the exchange of one type of wetland for another and result in a loss of wetland functions at the landscape level. The most striking weakness in the current national wetlands policy is the lack of protection for ‘dry-end’ wetlands that are often the focus of debate for what is and what is not a wetland. From an ecological perspective, dry-end wetlands such as isolated seasonal wetlands and riparian wetlands associated with first order streams may be the most important landscape elements. They often support a high biodiversity and they are impacted by human activities more than other types of wetlands. The failings of current wetland protection and mitigation policies are also due, in part, to the lack of ecologically sound wetland assessment methods for guiding decision making processes. The ecologically based Hydrogeomorphic (HGM) approach to wetland assessment has the potential to be an effective tool in managing biodiversity and wetland ecosystem function in support of the national ‘No Net Loss’ policy.     

MULTI-FUNCTIONAL WETLAND DESIGN ADAPTIVE TO ENVIRONMENTAL CHANGES — WETLAND ECOSYSTEM CONSTRUCTION OF FURONGBA BAY IN HANFENG LAKE OF THE THREE GORGES RESERVOIR AREA

Hanfeng Lake, an inland lake formed by the seasonal water fluctuations due to the water storage and sluice in the Three Gorges Reservoir, was faced with ecological challenges such as water pollution, aquatic biodiversity loss, and changes in land use pattern. This article takes the wetland ecosystem construction in Furongba Bay, Hanfeng Lake as an example to explore approaches to designing multi-functional wetlands which could adapt to hydro-fluctuation and other environmental changes, by drawing from the ecological wisdoms of water regulation, conservancy, and utilization developed in the agrarian age of China to support a dynamic, multi-layered landscape of mutualism and co-evolution.     

运用社交媒体探索 基于自然解决方案中的 生态系统服务感知

Natural wetlands play a vital role in maintaining regional water balance, regulating regional climate, and maintaining biodiversity. Due to urban sprawl in China, the loss of natural wetlands has been dramatic. In recent years, nature-based solutions, including wetland parks, have been advocated to compensate for this loss and to reduce vulnerability and disaster risks. As a result, inspired by natural wetlands or building on existing wetland ecosystems, hundreds of wetland parks have been created in China over the last decade. Most research on ecosystem services of wetland parks has to date focused on technical perspectives, with only a few addressing public perception; the public’s perception of wetland parks is not well understood. This research used social media (i.e. Sina Weibo) to access large volumes of data and provide temporal and geographic granularity. A semantic analysis of microblogs was performed to understand how the public perceives the ecosystem services of wetland parks in Guangzhou. This study explored the public’s perceptions and compared these with the ecosystem services as communicated by professional institutions, and probed into the factors that affect these perceptions. The results showed that the top three ecosystem services perceived by both the general public and communicated by institutions are recreation, aesthetics, and refugia / habitat. There is a strong interconnection between the perceptions of recreation and aesthetics services. Flowering plant species and colored-leaf trees are the most important stimuli affecting perceptions of aesthetics services, and birds are key to the perception of refugia / habitat services. These results provide a basis for better aligning management of projects utilizing naturebased solutions, such as wetland parks, with expectations from the public.     

基于土地利用视角的区域生态风险指数评价方法分析

区域生态风险主要研究较大范围区域中各生态系统所承受的风险.区域生态风险细分为土壤、空气、水环境、噪声、生物多样性和经济美学等六类.土地利用变化直接改变着生态系统的结构和功能,影响生态过程,不同土地利用对区域生态环境的影响存在差异,可从区域土地利用视角出发,建立土地利用方式与生态影响类型和强度之间的经验联系,构建基于土地利用类型的生态风险指数,综合评价区域生态风险.采用层次分析方法,计算土地利用类型的生态风险影响强度.     

Human‐influenced streamflow during extreme drought: identifying driving forces,modifiers, and impacts in an urbanized catchment in central Poland

This study investigates the response of the streamflow to an extremely hot and dry summer 2015 in the urbanized catchment of the Utrata River in central Poland. The objectives were to: reveal changes in the flow regime, assess anomalies in summer river flows, estimate the natural and wastewater effluent contribution and provide an ecological context for the in‐stream conditions. The mean annual flow rate in the period 1996–2015 increased by 0.61 m³/s as compared to 1951–1970. The mean annual wastewater inflow rate to the river in 2015 was approximately 0.770 m³/s, constituting 39% of the observed flow. Almost the entire period of August this contribution approached 100%. The optimum river water temperature threshold for warm‐water fish species was exceeded. Streamflow modifications are attributed to an increase of wastewater discharge, urban impact through an increase in imperviousness, and the variability of climatic driving forces.     

ENVIRONMENTAL FLOW SETTING IN ENGLAND AND WALES: STRATEGIES FOR MANAGING ABSTRACTION IN CATCHMENTS

This paper describes the evolution of methods to set environmental flows in England and Wales. Problems and challenges are reviewed in the context of recent legislative developments, and examples are given of different conceptual approaches. Scenario-based approaches have evolved as a pragmatic means to resolve competing uses of water; in contrast, approaches based on ecological objectives aim to meet more consistent goals. Where rivers or associated wetlands have been designated under national or European conservation legislation, broad ecological objectives are already under discussion. Furthermore, the European Water Framework Directive now requires good ecological status, or its equivalent, to be reached in all waters. Recently, the Environment Agency has developed a new process for managing abstractions in England and Wales; this includes a common methodology for the setting of environmental flows using objective methods.     

Securing water and wastewater systems: global perspectives

There has been long‐standing concern that water systems are vulnerable to man‐made and natural threats. In the United States, after the events of 11 September 2001, government planners focused on the possibility that the nation's critical infrastructure may be vulnerable to terrorist attacks. However, as demonstrated in this paper, there are many other factors that influence water supply security including lack of water resource availability, threats from point and nonpoint source pollution to water‐related ecosystems, and impact of climate change. In order to meet water security threats, there is a need to balance human and environmental water needs while at the same time safeguarding essential ecosystem services and biodiversity. Integrated water resources management may help achieve this balance. Examples are presented, which illustrate the diversity of water security throughout the world.     

基于森林景观恢复策略的庄园遗产景观设计探寻——以荷兰海德兰省巴克塞比克地区为例

庄园遗产景观是指包含花园和农业用地的历史乡村庄园集群。在气候变化、工业发展和快速城市化的背景下,庄园遗产景观正面临水生态环境失衡、空间碎片化和文化特征消失等挑战,而这些挑战只能从区域规划尺度去应对。以荷兰海德兰省巴克塞比克地区为例,在考虑地方景观异同的同时,以景观自身特性为基底,结合未来发展趋势,进一步诠释了一种旨在提升庄园遗产景观韧性的多尺度景观设计方法。发现森林砍伐为地域空间变化的主要因素之一,它对水系统与生态多样性造成了负面影响。基于在区域尺度上对庄园遗产景观历史发展的分析,森林景观恢复(FLR)作为主要设计策略,旨在从不同尺度上对“退化的”景观进行生态功能修复并提升人类福祉。这种新的空间设计方法将在不同尺度上促进文化遗产景观发展。     

Avifaunal Richness and Abundance Along an Urban Rural Gradient with Emphasis on Vegetative and Anthropogenic Attributes in Tiruchirappalli,India

Urban expansion and human migration from rural to urban locations have complex relationships with environmental change. Habitat fragmentation, loss of biodiversity and vegetation changes are some of the most common impacts of urbanisation. In many Indian cities, the urban core is characterised by historical human settlements with narrow lanes and packed commercial establishments, while urbanisation that occurred after 1970s preferred spacing between the dwellings with more greenery or urban forestry. As urbanisation progresses, the urban fringes have more scope for incorporating environmental concerns and conservation. In this study, we measured species richness and abundance of birds within varied urban habitats and landscapes along the urban–rural gradient in Tiruchirappalli, India. We also tried to determine the linkage between bird diversity and landscape attributes including anthropogenic factors. Our observations showed that within urban areas, certain landscapes favoured species richness while many habitats are unfriendly for species but encouraged homogenisation. As we move from urban core towards rural gradient, the species richness increased; however, it is not uniform in all peripheral directions. Interestingly, the urban fringes at certain pockets had richness equivalent to rural locations. Species richness positively correlated with vegetation cover while built cover, noise, vehicular movement and pedestrians had negative impacts. As the urban fringes are in various stages of development, they have more scope for integrating ecological and biodiversity considerations and in this aspect wetlands, riverine farmlands and urban forests may play a crucial role in retaining native birds and also supporting migratory bird species.     

Effect of constructed wetlands receiving agricultural return flows on disinfection byproduct precursors

The effects of wetland treatment on disinfection byproduct precursors were evaluated for six constructed wetlands receiving agricultural return flows in the Central Valley of California. Wetlands varied in size, age, vegetation, hydrologic residence time (0.9-20 days) and water management (continuous flow vs. flood pulse). The effects of wetland treatment were determined by analyzing input and outflow waters for dissolved organic carbon concentration and quality, bromide concentration, and formation potentials for nine disinfection byproduct species, including trihalomethanes, haloacetronitriles, chloral hydrate, and haloketones. We hypothesized that hydraulic residence time was a key factor governing differences in disinfection byproduct precursors. Small wetlands (<3 ha) with short hydraulic residence times (<2 days) did not produce significant changes in disinfection byproduct precursor concentrations with respect to the agricultural return flows input to the wetlands. In these wetlands hydraulic residence times were not long enough to promote processes that adversely affect dissolved organic carbon and bromide quantity, such as evapoconcentration and leaching from vegetation. Thus, less negative effects were associated with disinfection byproduct formation. In contrast, larger wetlands (>100 ha) with long hydraulic residence times (>10 days) resulted in higher dissolved organic carbon and bromide levels, increasing disinfection byproduct formation by factors ranging between 1.7 and 10.2 compared to agricultural return flows. Results from this study provide important information for optimizing the design and management of constructed wetlands to effectively combine control of disinfection byproduct precursors with other water quality parameters.     

高密度城市环境的生态设计--高雄洲仔湿地的城市生态思考

本文探讨了位于自然、城市和基础设施彼此相互混杂景观中的城市湿地的生态设计方法(?)相对于远离城市的自然环境湿地(?)洲仔湿地的恢复可以说是一个如何将“自然引入城市”的典范。洲仔湿地邻近高雄高速铁路站,周围环绕不断发展中的高密度住宅群。在这个特殊的地理位置中,却具有丰富的景观多样性和贯穿全区的生态流。为解决在湿地恢复过程中所遇到的三个问题(自然与人类行为之间的冲突;野生生物生境和城市公园之间的冲突;自然与城市基础设施之间的冲突),提出了三个城市生态愿景,重新定义了“人地关系”,同时也提出了在高密度城市居住环境中,设计可以作为生态介入的观点。     

Reduction of fecal indicator bacteria (FIB) in the Ballona Wetlands saltwater marsh (Los Angeles County, California, USA) with implications for restoration actions

A benefit of wetland preservation and restoration is the ecosystem service of improving water quality, typically assessed based on bacterial loading. The Ballona Wetlands, a degraded salt marsh of approximately 100 ac located on the southern border of Marina Del Rey (Los Angeles County, California, USA) are currently the focus of publicly funded restoration planning. The wetlands receive tidal water, usually contaminated with fecal indicator bacteria (FIB: total and fecal coliforms, Escherichia coli, enterococci) from the adjacent Ballona Creek and Estuary. During the summer of 2007, two 24-h studies were conducted to determine FIB tidal dynamics within the wetland. Measurements of water flow and mean FIB concentrations (n = 3) were measured every 1.5 h to determine total FIB load estimates. FIB loading rates (MPN/s) were greatest during flood tides as water entered the wetlands, and then again during spring tide conditions when sediments were resuspended during swifter spring ebb flows. During daylight hours, the wetland acted as a sink for these bacteria as loads diminished, presumably by sunlight and other processes. Conversely, during late afternoon and night, the wetlands shifted to being a source as excess FIB departed on ebb flows. Therefore, the wetlands act as both a source and sink for FIB depending on tidal conditions and exposure to sunlight. Future restoration actions would result in a tradeoff - increased tidal channels offer a greater surface area for FIB inactivation, but also would result in a greater volume of FIB-contaminated resuspended sediments carried out of the wetlands on stronger ebb flows. As levels of FIB in Ballona Creek and Estuary diminish through recently established regulatory actions, the wetlands could shift into a greater sink for FIB.     

Distribution of inland wetlands with sulfidic sediments in the Murray-Darling Basin, Australia

This project examined the extent of sulfidic sediments in freshwater wetlands of the Murray-Darling Basin, Australia. We sampled 81 wetlands throughout the basin with methods previously developed for the analysis of coastal acid sulfate soils. Sulfidic sediments are generally regarded as a coastal phenomenon. We tested the hypothesis that elevated concentrations of mineral sulfides may also accumulate in sediments of inland wetlands. Of the 81 wetlands sampled, 17 (21%) contained reduced sulfur in sediments at concentrations above suggested trigger values. Most of the affected wetlands were adjacent to the Murray River, with only several associated with other major river catchments. Reduced sulfur in the sediments was positively correlated with sulfate concentrations in the overlying water column. This represents a concern for wetland managers because of the increasing desire to return wetlands to a more natural wetting and drying cycle to improve wetland health. However, during drying, sulfidic sediments oxidise and produce acid, which may exceed the buffering capacity of the system and ultimately harm aquatic life. Therefore, if sulfidic sediments are present, a drying phase should only be reinstated after careful consideration of the potential acidification risks. This study verified that sulfidic sediments can occur in freshwater wetlands in concentrations that could pose an ecological risk if mismanaged.     

国土空间规划背景下市县生态保护重要性 评价实践探索——以武汉市江夏区为例

开展生态保护重要性评价，从空间上明确生态保护的重要区域是生态保护政策落实的关键。“双评价”指南中的生态保护重要性评价主要针对省级尺度，缺乏市县尺度的修正和细化方法。以武汉市江夏区为例，探索了国土空间规划背景下市县生态保护重要性评价方法：基于江夏区地域特征，选择水土保持、水源涵养、生物多样性维护、水土流失敏感性和内涝风险构建评价指标体系；从“物种”维度优化生物多样性维护评价方法并利用Info WorksICM水动力模型探索内涝风险评价方法；综合单项评价结果得到初判结果；结合政策性生态保护线、自然保护地和重要自然要素修正初判结果。结果表明：江夏区生态保护极重要、重要空间面积分别为565和220km~2，占区域总面积的34.2%和13.3%。     

Ecological network analysis of an urban water metabolic system: Model development, and a case study for Beijing

Using ecological network analysis, we analyzed the network structure and ecological relationships in an urban water metabolic system. We developed an ecological network model for the system, and used Beijing as an example of analysis based on the model. We used network throughflow analysis to determine the flows among components, and measured both indirect and direct flows. Using a network utility matrix, we determined the relationships and degrees of mutualism among six compartments - 1) local environment, 2) rainwater collection, 3) industry, 4) agriculture, 5) domestic sector, and 6) wastewater recycling - which represent producer, consumer, and reducer trophic levels. The capacity of producers to provide water for Beijing decreased from 2003 to 2007, and consumer demand for water decreased due to decreasing industrial and agricultural demand; the recycling capacity of reducers also improved, decreasing the discharge pressure on the environment. The ecological relationships associated with the local environment or the wastewater recycling sector changed little from 2003 to 2007. From 2003 to 2005, the main changes in the ecological relationships among components of Beijing's water metabolic system mostly occurred between the local environment, the industrial and agricultural sectors, and the domestic sector, but by 2006 and 2007, the major change was between the local environment, the agricultural sector, and the industrial sector. The other ecological relationships did not change during the study period. Although Beijing's mutualism indices remained generally stable, the ecological relationships among compartments changed greatly. Our analysis revealed ways to further optimize this system and the relationships among compartments, thereby optimizing future urban water resources development.     

Establishing hydroecological relationships to manage the impacts of groundwater abstraction

Despite the pressing environmental, economic and social issues surrounding water abstraction, scientific methods for managing its ecological impacts remain in their infancy. In this paper, we demonstrate statistically significant relationships between in‐stream ecological condition using macroinvertebrates and the hydrological effect of groundwater abstraction on surface water flows in streams originating from Permo‐Triassic sandstone aquifers in the English midlands. Ecological condition was most strongly correlated to the effect of abstraction on medium‐low flows (Q₇₅) compared with effects at other flows, water quality, habitat or seasonal effects. Ecological impacts occurred when the effect of abstraction on Q₇₅ flows exceeded 60%. The same relationships were shown among individual macroinvertebrate taxa, validating the biological responses. The hydroecological model has provided a scientific basis for making local decisions on investigation sites and has helped to focus resources to areas at risk of not meeting Good Ecological Status under the Water Framework Directive because of abstraction.     

城市小微湿地特征与价值研究——以南昌中心城区为例

小微湿地是城市景观中的重要组成部分,研究其空间分布特征,并从文化与生态2个方面定量估算其服务价值对引导改善城市人居环境具有重要意义.以南昌市中心城区小微湿地为研究对象,借助ArcGIS平台开展小微湿地的空间核密度分析,揭示小微湿地的空间分布特征;以条件价值法(CVM)、影子工程法(SPA)和市场价值法(MVM)等分别计...     

A Configurable Agent‐Based Crowd Model with Generic Behavior Effect Representation Mechanism

Most of the existing crowd models were designed for specific behaviors or scenarios (e.g., emergency evacuations and bi‐directional crowd flows). Significant modifications were often required to accommodate new behaviors or new scenarios. This article proposed a generic crowd model with the flexibility to incorporate different behaviors under different scenarios. At the higher level of the proposed crowd model, the agent‐based modeling method was used to enable the individual heterogeneity and decision making. At the lower level, a unified mechanism to represent the effects of different individual behaviors was introduced. A core formula with seven generic parameters (i.e., agent's position, target's position, behavior angle, effect of base speed, agent factor, target factor, and distance factor) has been developed to form the basis of the unified mechanism. This article also presented a Behavior Library that consisted of a set of basic behaviors that were able to construct complex behaviors through their combinations. To demonstrate the capability of the model in various scenarios, the following simulations have been implemented and discussed: queuing at an exit, bi‐directional pedestrian walk flow, evacuation in a building, and consensus decision making in a large group.     

THOUGHTS ON ECOLOGICAL WATERSHED PLANNING UNDER THE TERRITORIAL SPATIAL PLANNING

The author firstly points out several problems that commonly exist in China’s watersheds and the urgent need for multidisciplinary collaboration in ecological planning. The theories and practices on watershed ecological planning are reviewed respectively from the aspects of waterway planning, natural river and wetland protection, ecological baseflow recovery, nonpoint source pollution reduction, and biodiversity protection. The author suggests that if we could reserve multi-functional ecological zone in the new territorial spatial planning by multidisciplinary collaboration, ecological goals including flood control, water quality improvement, ecological base flow provision, and biodiversity protection could be achieved. In this comprehensive solution, only when water bodies and associated habitats such as the ground and underground, upstream and downstream, and rivers and banks are coordinated as a whole, it will generate multiple ecological benefits. Finally, the author believes that planners and designers have the ability to solve ecological problems. To fulfill this vision, we must call for collaboration between land planning and ecological watershed planning in the process of territorial spatial planning.     

兼顾鱼类保护与发电需求的秦岭湑水河 观音峡电站段生态修复设计

随着中国生态文明建设的推进,自然保护地内的建 坝河流生态系统修复逐渐受到重视。秦岭作为生物多样性保护 热点地区和中央水塔,其淡水生物多样性保护地位十分重要。 针对秦岭湑水河珍稀洄游鱼类保护的目标,探讨了恢复河流连 通性的多种方案,借助HEC-RAS软件模拟及结果分析,运用 水文学、河流生态学、生态水工学、风景园林学的思路与方 法,探讨通过拆除观音峡水库大坝同时保留一定发电功能的方 法来恢复自然流淌河流、维护珍稀鱼类的生态过程,并且兼顾 发电与社会经济发展的可能性策略。