Changes in biotic communities developing from freshwater wetland sediments under experimental salinity and water regimes

1. Reduction in diversity of both freshwater aquatic and terrestrial ecosystems has been attributed to salinity increase and such increases are a symptom of changes to land use. Hydrological alteration to ground and surface water are likely to be associated with salinity increase and its influence on biodiversity. However the combined effects of salinity and hydrology on aquatic biodiversity have not been elucidated fully in either field or experimental situations. 2. The effect of salinity and water regime on the biota in sediments from seven wetlands from inland south‐eastern Australia was tested experimentally using germination of aquatic plant seeds (five salinity and two water levels) and emergence of zooplankton eggs (five salinity levels). Salinity levels were <300, 1000, 2000, 3000, 5000 mg L^?1 and water regimes were damp (waterlogged) and submerged. 3. Aquatic plant germination and zooplankton hatching was not consistent for all seven wetland sediments. Four of the wetland sediments, Narran Lakes, Gwydir Wetlands, Macquarie Marshes and Billybung Lagoon showed similar responses to salinity and water regime but the other three wetland sediments from Lake Cowal, Great Cumbung Swamp and Darling Anabranch did not. 4. As salinity increased above 1000 mg L^?1 there was a decrease in the species richness and the abundance of biota germinating or hatching from sediment from four of the wetlands. 5. Salinity had a particularly strong effect in reducing germination from sediments in damp conditions when compared to the flooded conditions. In parallel, salts accumulated in the sediment in damp conditions but did not in flooded conditions. 6. There is potential for increasing salinity in freshwater rivers and wetlands to decrease the species richness of aquatic communities and thus of the wetland community as a whole, resulting in loss of wetland biodiversity. This reduction in diversity varies between wetlands and is at least partly related to hydrology. For aquatic plants the reduction in diversity will be more marked for plants germinating from seed banks at the edges of wetlands where plants are not completely submerged than for the same seed bank germinating in submerged conditions.     

Longitudinal evaluation of vegetation richness and cover at wetland compensation sites: implications for regulatory monitoring under the Clean Water Act

There has been regulatory concern over the appropriate length of time to monitor wetland sites restored or created as compensation for impacts permitted by a U.S. Clean Water Act permit. However there is very little longitudinal research on wetland compensation sites, and conclusions on compensation site development are usually drawn from the analysis of a chronosequence of sites of different ages. This approach has limitations, given the extent of changes in wetland compensation practices and performance standards over the past few decades. In this study we conducted vegetation surveys of 22 wetland compensation sites in a rapidly developing part of the Minneapolis-St. Paul metropolitan area in 1997 and 2010. We present data on changes over time in floristic richness and cover at the site level and at the level of wetland community type within each site. Our findings do not support the assumption that wetland compensation sites progress on a trajectory toward increasing diversity, floristic quality, or native cover over time. We find that, when data from all sites are considered together, emergent communities have suffered significant declines in both floristic quality and native plant cover, while wet meadow communities have gained species richness but not species diversity. There is some evidence that site richness and cover characteristics are converging toward a regional mean over time, as the species composition of wet meadows became significantly more similar over the survey period, and all community types have significant increases in woody cover. Our study suggests the importance of selecting appropriate compensation sites that avoid foreseeable hydrologic stresses, and does not support the position that 5 years of monitoring can assure the ongoing biotic integrity of wetland compensation sites.     

Distribution and status of the medicinal leech (Hirudo medicinalis L.) in Turkey

A survey of all the major potential habitats in western Turkey showed that medicinal leeches, Hirudo medicinalis L., are widely distributed over the country and are not rare. They occur in practically all suitable habitats and the only region where they were found to be absent is that of the large river deltas in the south of the country (Çukurova deltas, Göksu delta). There may be zoogeographic reasons for this (Taurus mountains barrier). The application of a semi-quantitative survey method using collecting efficiency (number of leeches collected per hour by a single person) allowed a rapid assessment to be made of its status in a large number of wetlands. Leech density varied considerably from wetland to wetland, and the results enabled a ranking of the Turkish wetlands to be made according to their importance for medicinal leeches. Taking both the leech density and the size of leech habitats into account, the largest populations were identified on the Black Sea coast (Kizilirmak delta, Yeilirmak delta and Karagöl Marshes near Sinop) and in inner and south-west Anatolia (Eber Gölü, Karamik and Sultan Marshes). Commercial exploitation for the pharmaceutical industry and for other purposes takes place at only a few places and does not appear to affect the population seriously. However, many populations are threatened by the draining of their habitats.     

湿地生态系统服务功能及其价值核算——以福州市为例

湿地在生态保护和社会发展中占据重要地位,科学合理评估湿地生态系统价值,是湿地保护与合理开发、确保湿地资源可持续性利用的基础。如何科学有效、标准化地评估湿地生态系统生产总值(GEP)并使之纳入国民经济体系核算是科学界和政府部门关注的焦点。本研究构建了湿地生态系统生产总值核算框架体系,并以福州市为研究案例,以多源数据为基础,从功能量与价值量层面,开展了福州市湿地GEP核算研究。结果表明: 2015年,福州市湿地生态系统GEP为2392.33亿元,主要源于湿地的生态调节服务价值(1578.69亿元,占总价值的66.0%),约是产品供给服务价值和精神文化服务价值的2.2和15.6倍。湿地生态调节服务中,以水流动调节服务价值和气候调节服务价值最高,两者占生态调节服务价值的82.9%。福州市湿地单位面积生态调节价值为134.78万元·hm^-2,高于全国水平。福州市各区县中,闽清县湿地生态系统价值量最大,为888.31亿元,占福州市湿地生态系统产品供给和生态调节总价值量的40.1%。福州市滨海湿地的生态调节服务价值最大,约分别是河流湿地和人工湿地类型的2.5倍。福州市湿地生态系统GEP核算是“绿水青山就是金山银山”理念城市尺度的重要践行,为指导地方政府科学管理湿地生态系统提供了技术支撑。     

Perceived benefits of littoral wetlands in Uganda: a focus on the Nabugabo wetlands

Wetlands, commonly called swamps in Uganda, are estimated to cover about 13% of the total land surface area (about 30,000 km²) of the country and represent a considerable ecological, social and economic value. In 1989, the Ugandan government formerly recognised that wetlands need to be conserved and contribute considerably to the National economy and rural livelihood. The present analysis is focused on the Nabugabo wetland ecosystem. Located in Central Uganda, it is an important part of the extensive system of wetlands that surround Lake Victoria. The Nabugabo wetland is a source of important resources that are basic to the local economy, including fishing, water utilization, agriculture, livestock, wetland plants for construction and more recently, tourism. Investment in the area is low and a large percentage of the local community depends on the wetland resources for basic sustenance needs. After achieving Ramsar status, demarcation and conservation activities were initiated by the local and national leaders. However, these conservation efforts have provoked conflicts between the land owners and the policy makers, in particular to the demarcation of areas for conservation In the present analysis, we examine the benefits, perceived by local leaders and community members, of the wetland and its services, as well as views towards its conservation and management. The results show that differences between the community leaders and member exist regarding the perceived benefits of the wetlands. Tourism, while providing some opportunities for local persons is not always viewed positively. Conservation activities are viewed positively but some questions remain as to whether such efforts help or hinder the local population, in particular regarding access to basic resources.     

Use of vegetation classification and plant indicators to assess grazing abandonment in Estonian coastal wetlands

Question: What are the effects of grazing abandonment on the vegetation composition of Estonian coastal wetlands? Location: Vormsi Island and Silma Nature Reserve in western Estonia, Europe. Methods: Local knowledge and field reconnaissance were used to identify current and historical management levels of wetland sites within the west Estonian study area. Nine study sites, with varying management histories, were selected comprising an area of 287 ha. A total of 198 quadrats were taken from 43 distinct vegetation patches in five of the sites. TWINSPAN analysis was used to identify community type, and a phytosociological key was constructed for character taxa. This vegetation classification was then applied within a GIS‐based context to classify all the study sites, using a ground survey technique and 1:2000 scale air photos. Results: We identified 11 different brackish coastal wetland community types. Indicator species were defined with community characteristics for the seven main vegetation types readily recognisable in the field. Coastal wet grasslands were most extensive in grazed sites, or sites that had been more intensively grazed, while abandoned sites were largely composed of Phragmites australis stands, tall grassland, and scrub. Site variations based on vegetation composition were significantly correlated with past grazing intensity. Plant community types showed significant edaphic differences, with particularly low soil moisture and high conductivity and pH for open pioneer patches compared to other vegetation types. Conclusion: Abandonment of traditionally grazed coastal grasslands threatens their characteristic biodiversity. This study found that grazing abandonment reduced the extent of coastal wetland grasslands of particular conservation value. Nevertheless, plant species of conservation interest were found across the sequence of community types described. The study shows that grazing is an important factor influencing coastal wetland plant communities but suggests that vegetation distribution is affected by environmental variables, such as topography.     

湿地生态系统服务功能的价值评估

湿地生态系统服务功能的价值评估是目前生态学研究的热点领域之一。综述国内外湿地生态系统服务功能、价值相关研究成果,在此基础上,着重评述了湿地生态系统服务功能价值评估方法研究进程和价值评价2个方面的内容,给出了不同评估方法的特点,并对湿地生态系统服务功能价值评价涉及的价值排序、价值系数、价值动态各个侧面的研究分别予以评述,基于此对今后研究提出展望：明确主导服务功能价值、加强价值影响因素分析、开发价值动态模型、构建生态补偿机制、探讨人工湿地生态系统的服务功能价值流的变化。旨在加深对湿地生态系统服务功能价值的认知,为人类与湿地环境的可持续发展提供必要的理论支持。     

不同人为干扰下纳帕海湖滨湿地植被及土壤退化特征

以滇西北高原纳帕海湖滨退化湿地为研究对象,对比分析了人为隔断水源补给、牛羊过度放牧和家猪拱地三种人为干扰下湿地植被和土壤退化特征。结果表明：三种干扰方式下,纳帕海湖滨湿地植物群落类型多样性、物种丰富度、物种数、Shannon-Wiener指数、沼生植物重要值以及土壤有机质、全氮、速效氮、含水率、毛管孔隙度变化规律为：人为隔断水源补给＞牛羊过度放牧＞家猪拱地,而土壤容重和全钾含量变化规律完全相反。Pearson相关性分析表明,不同人为干扰下相同土壤指标之间相关性质和相关强度不同;CCA分析表明植物群落种类组成和分布与土壤含水率和全磷含量显著相关。以原生湿地样点为对照,人为隔断水源补给、牛羊过度放牧和家猪拱地样带土壤退化指数分别为-7.40%、-14.53%、-45.01%。认为纳帕海湖滨湿地退化是三种干扰协同作用结果,但作用程度不同,其顺序为家猪拱地＞牛羊过度放牧＞人为隔断水源补给。     

Nutrient and faecal contamination and retention in wetland enclosures (gei wais) in the Mai Po Marshes,Hong Kong

Nutrient and faecal contamination is an increasing problem to the shrimp productivity and wildlife conservation at the internationally important wetland ecosystems of the Mai Po Marshes (Hong Kong, P.R. China). The present study examined the nutrient status and faecal bacteria loading and potential retention capacity of contaminants of two wetland enclosures. Water in the wetland enclosures was eutrophicated with high concentrations of dissolved inorganic nitrogen (inorg–N_diss= 15.0 mg l^–1) and orthophosphate phosphorus (o-P = 1.89 mg l^–1) and was loaded with high levels of faecal coliforms (172 ×10³ cfu in 100 ml) and faecal streptococci (1.94 ×10³ cfu in 100 ml). The pattern of nutrient enrichment of two wetland enclosures is related to a north-to-south pollution gradient from the Shenzhen River to the wetlands. By retaining tidal water in the wetland for an 8-day period, water quality was greatly improved; NH₄–N was removed by 83%, o-P by 45% and faecal bacteria by 100%. This implies a self-purification capability of the wetland enclosures and a potentiality of using them as an alternative sewage treatment.     

Ku-ring-gai Flying-fox Reserve

Strong community support led to government protection of a bat colony in northern Sydney in 1985. Restoration of the roosting habitat of the Grey-headed Flying-fox ( Pteropus poliocephalus ) was implemented by a non-government organization in cooperation with the local government. The aims, methods, results and challenges of the project so far are outlined.     

Soil washing improves the recovery of total community DNA from polluted and high organic content sediments

Treatment of soil with surfactants and chelating agents is used in bioremediation studies to desorb and solubilize contaminants to increase their bioavalability to microorganisms. In the same way that pollutants are made more bioavailable to microorganisms, the procedure can be used to remove potential interfering materials from soil prior to cell lysis and extraction of DNA from indigenous microorganisms. The effect of soil washing was evaluated by extracting DNA from sediments of an intertidal freshwater wetland contaminated with hydrocarbons and from highly contaminated marine sediments from Sydney Harbour, Nova Scotia, Canada. Sediment samples had total organic carbon (TOC) contents that varied between 0.2% and 13%. The chemical lysis technique was also examined by comparison of an ammonium acetate precipitation of proteins and humic acids with a hexadecyltrimethylammonium bromide (CTAB) incubation and phenol:chloroform extraction. In this study, the incorporation of soil washing steps facilitated the desorption of contaminants from sediment surfaces and improved the recovery of DNA of amplifiable quality from both freshwater and marine sediments. CTAB contributed only slightly to the recovery of DNA of higher quality in the most contaminated sample from Sydney Harbour and was concomitant with a decrease in DNA yield in both sediment types. The incorporation of a soil washing step prior to the extraction of DNA from polluted environments may be important to solubilize and remove contaminants when high-quality DNA is required for subsequent analyses.     

Lagoon of Islands,Tasmania: Ecosystem response to dam wall removal

Lagoon of Islands was a rare wetland of high conservation value, supporting floating islands of vegetation before it was dammed to supply water for consumptive use downstream. After damming, water quality declined to such an extent that in 2013, the dam wall was removed and a wetland restoration project was commenced, resulting in immediate improvements in water quality and, within five years, regeneration of a plant community largely composed of dominant species of the original wetland.     

广州市湿地公园植物调查与分析

为更好地提高湿地公园的生态服务能力、加强湿地公园的物种保育功能并促进湿地公园建设和发展质量,对广州地区20个湿地公园植物进行了实地调查。结果表明,调查区域共有205种湿地植物;对其物种组成、生活型、生态习性、优势科属及应用频度等的分析表明,湿地公园的植物群落结构比较简单,主要植物种类同质化现象很严重,保护和珍稀植物种类应用较少等。基于此,推荐了55种本土植物作为广州市湿地公园进行生态改造和景观配置的候选物种,同时还提出了对未来湿地公园的建设和管理的若干建议。     

滇西北高原典型退化湿地纳帕海植物群落景观多样性

采用时空替代法,运用3S技术,结合植物群落实地调查,研究了云南西北高原典型退化湿地纳帕海的植物群落景观多样性格局。结果表明:人为干扰加速了纳帕海原生沼泽、沼泽化草甸植物群落景观向草甸、垦后湿地植物群落景观演替,湿地环境不断丧失,湿地功能逐渐退化;不同演替阶段沼泽植物群落景观多样性在空间上呈现出不同的格局是对湿地环境变化的响应,体现了湿地环境变化与功能现状,并在一定程度上反映了人为干扰的类型与强度。     

莽山浪畔湖国家重要湿地植物多样性及环境解释

研究莽山高山湖泊湿地植物多样性对环境因子的响应分析,不仅有助于深入了解湿地植物对环境变化下的适应策略,同时对保护当地湿地珍稀濒危物种具有重要价值。采用系统聚类分析、典范对应分析(CCA)和Pearson相关性分析等方法,对研究区30个植物群落样方进行分析,研究植物多样性与环境因子(土壤、水)之间的相互关系。研究结果表明:浪畔湖国家重要湿地植物群落可分为蕨状苔草+宽叶泽苔草群丛、雪白睡莲+莼菜群丛、水毛花+宽叶泽苔草群丛、莼菜+宽叶泽苔草群丛等4类。雪白睡莲+莼菜群丛Patrick丰富度指数和Pielou均匀度指数最低,Simpson多样性指数最高,水毛花+宽叶泽苔草群丛与之相反。浪畔湖国家重要湿地植物多样性与土壤速效钾和水深呈极显著相关性,与水质氨氮呈显著相关性,水深和土壤速效钾是影响湿地植物群落分布格局的主要因子。群落物种多样性指数与环境因子之间存在显著相关性,群落物种丰富度指数随水深增加呈先增后降的趋势,群落物种均匀度指数与水质氨氮浓度之间呈负相关关系。本研究旨在揭示浪畔湖国家重要湿地植物多样性与环境因子之间的生态关系,为保护湿地珍稀物种及维持湿地生态系统稳定提供理论依据。     

Ecological impacts of dams,water diversions and river management on floodplain wetlands in Australia

Australian floodplain wetlands are sites of high biodiversity that depend on flows from rivers. Dams, diversions and river management have reduced flooding to these wetlands, altering their ecology, and causing the death or poor health of aquatic biota. Four floodplain wetlands (Barmah‐Millewa Forest and Moira Marshes, Chowilla floodplain, Macquarie Marshes, Gwydir wetlands) illustrate these effects with successional changes in aquatic vegetation, reduced vegetation health, declining numbers of water‐birds and nesting, and declining native fish and invertebrate populations. These effects are likely to be widespread as Australia has at least 446 large dams (>10 m crest height) storing 8.8 × 10⁷ ML (10⁶ L) of water, much of which is diverted upstream of floodplain wetlands. More than 50% of floodplain wetlands on developed rivers may no longer flood. Of all of the river basins in Australia, the Murray‐Darling Basin is most affected with dams which can store 103% of annual runoff and 87% of divertible water extracted (1983–84 data). Some floodplain wetlands are now permanent storages. This has changed their biota from one tolerant of a variable flooding regime, to one that withstands permanent flooding. Plans exist to build dams to divert water from many rivers, mainly for irrigation. These plans seldom adequately model subsequent ecological and hydrological impacts to floodplain wetlands. To avoid further loss of wetlands, an improved understanding of the interaction between river flows and floodplain ecology, and investigations into ecological impacts of management practices, is essential.     

Macroinvertebrate community convergence between natural,rehabilitated, and created wetlands

Wetland restoration practices can include rehabilitating degraded wetlands or creating new wetlands. Empirical evidence is needed to determine if both rehabilitated and created wetlands can support the same macroinvertebrate communities as their natural counterparts. We measured long‐term macroinvertebrate community change in seasonal wetlands known as Delmarva Bays in Maryland, U.S.A. We compared a rehabilitated, a created, and a natural Delmarva Bay. We hypothesized that the created and rehabilitated wetlands would develop different macroinvertebrate communities. We also hypothesized that the community composition of the rehabilitated wetland would become more similar to that of the natural wetland than to that of the created wetland over 9 years encompassed by this study. We monitored the macroinvertebrates, including both predators and primary consumers, and environmental conditions in the three wetlands from March to August in 2005, 2006, 2007, and 2012. Cluster analysis indicated that from 2005 to 2007, the macroinvertebrate community of the rehabilitated wetland and the created wetland were more similar to each other than to the natural wetland. In 2012, the rehabilitated wetland was more similar to the natural wetland than to the created wetland. This similarity was driven principally by changes in the composition of primary consumer taxa. Our results suggest that rehabilitated Delmarva Bays are more likely to support a natural macroinvertebrate community than are created wetlands. Restoration practices that rehabilitate existing wetlands may be preferred over practices that create new wetlands when restoration project goals include developing natural macroinvertebrate communities in a short period of time.     

Status of water environment pollution in the Xixi Wetland and its ecological treatment countermeasures

In this paper,the water quality of the Xixi Wetland was evaluated and the characteristics of water pollution were described according to the survey data.Based on the status of water quality and its functional requirements as an urban wetland,biological-ecological countermeasures were suggested.The experimental use of ecological technologies,such as artificial wetlands,ecological aquiculture and artificial floating island,were done in several fish ponds in the Xixi Wetland.Water monitoring results show that the quality of the treated water has improved significantly and the measures to purify the eutrophic water in the wetland have been effective.     

Status of water environment pollution in the Xixi Wetland and its ecological treatment countermeasures

In this paper, the water quality of the Xixi Wetland was evaluated and the characteristics of water pollution were described according to the survey data. Based on the status of water quality and its functional requirements as an urban wetland, biological-ecological countermeasures were suggested. The experimental use of ecological technologies, such as artificial wetlands, ecological aquiculture and artificial floating island, were done in several fish ponds in the Xixi Wetland. Water monitoring results show that the quality of the treated water has improved significantly and the measures to purify the eutrophic water in the wetland have been effective.     

Evaluating the ecological performance of wetland restoration in the Yellow River Delta,China

Long-term monitoring is essential to evaluate the effects of wetland restoration projects. A monitoring program before and after restoration has been carried out in the study area located in the Yellow River Delta since 2001. Water quality, soil salinity, soil organic matter, plant community, and bird species were chosen as indicators in this program. During the past seven years, the restored wetland showed increasing efficiency in reducing water pollution levels. Soil quality was constantly improved through salinity reduction and soil organic matter accumulation. The vegetation community quickly re-established after the restoration was initiated in 2002. The restored vegetation communities provide favorable habitat conditions for birds and thirty-seven bird species were observed in October 2007. Based on Canonical Correspondence Analysis (CCA), plant species and vegetation community are mainly influenced by soil salinity and water depth. These indicate that conducting freshwater to the project area is an efficient measure for vegetation restoration. While monitoring results show that the restoration project had positive effects on the wetland ecosystem over the past seven years, two issues remain for future study: (1) the contribution of harvesting vegetation to stabilizing nutrient removal rate and the accumulation of soil organic matter in the soil; and (2) the effects of excessive propagation of Phragmites australis on spatial heterogeneity and plant diversity.