Hydrologic similarity to reference wetlands does not lead to similar plant communities in restored wetlands

Few wetland restoration projects include long‐term hydrologic and floristic data collection, limiting our understanding of community assembly over restored hydrologic gradients. Although reference sites are commonly used to evaluate outcomes, it remains unclear whether restoring similar water levels to reference sites also leads to similar plant communities. We evaluated long‐term datasets from reference and restored wetlands 15 years after restoration to test whether similar water levels in reference and restored sites led to vegetation similarity. We compared the hydrologic regimes for three different wetland types, tested whether restored wetland water levels were different from reference water levels, and whether hydrologic similarity between reference and restored wetlands led to similarity in plant species composition. We found restored wetlands had similar water levels to references 15 years after restoration, and that species richness was higher in reference than restored wetlands. Vegetation composition was similar across all wetland types and was weakly correlated to wetland water levels overall. Contrary to our hypothesis, water table depth similarity between restored and reference wetlands did not lead to similar plant species composition. Our results highlight the importance of the initial planting following restoration and the importance of hydrologic monitoring. When the restoration goal is to create a specific wetland type, plant community composition may not be a suitable indicator of restoration progress in all wetland types.     

Possible use of wetlands in ecological restoration of surface mined lands

Surface mining for coal has dramatically altered millions of hectares throughout the Appalachian region of eastern North America. Flat benches and vertical high walls have replaced well-drained slopes, and wetlands have developed accidentally on abandoned benches. Surface mining is continuing in this region, but new regulations do not include specifications for wetland construction in the reclamation process. Recent research has suggested that many ecosystem services appropriate for the Appalachian landscape could be performed by constructed wetlands. Inclusion of wetland construction in a reclamation plan could lead to a net increase in wetland acreage locally, as well as offset the loss of natural and/or accidental wetlands. By studying accidentally-formed wetlands, we hope to determine what species can be established in wetlands that are constructed to enhance nontreatment goals in reclamation. Study sites included 14 emergent wetlands in Wise County, Virginia. Sampling in June and August detected a total of 94 species in 36 vascular plant families. Obligate wetlands species, species that occur in wetlands over 99 percent of the time, were found in all 14 sites and included 26 species. The presence of so many wetland species without intentional management efforts suggests that wetland establishment could become a common component of mine reclamation.     

水深对塘堰湿地水力性能的影响

塘堰湿地因其良好的生态性能而被广泛用于水稻灌区的排水净化,由于湿地的水力性能及净化效果受到诸多因素影响,客观认识这些因素的作用机理有助于提高湿地设计和运行管理的质量.本文通过示踪剂试验探讨了不同水深（20、40、60 cm）对塘堰湿地水力特性的影响.结果表明： 随着湿地水深的减小,湿地的有效容积率从0.421增加到0.844,水力效率从0.281增加到0.604;在水深较小时（20和40 cm）,湿地前半部分的有效容积率达到0.9以上,明显优于湿地整体情况,湿地前半部分的水流混合情况高,接近于完全混合流.通过对原始示踪曲线的标准化分析发现,矩分析参数与水力参数有较好的数值一致性,水力参数与不受尾部截断误差影响的矩指数之间具有良好的一致性.塘堰湿地水深较小时有利于提高湿地的水力性能,试验结果可为今后塘堰湿地的优化设计提供参考.     

一种新型的人工湿地生态工程设计--以山东省南四湖为例

本文采用了一种新的人工湿地设计理念 ,将两种类型的人工湿地有机地 ,动态地结合起来 ,设计出一套具有生态恢复和生态净化功能的工程体系。依据对湖区现状调查结果 ,按照生态学和生态经济学的基本原理 ,以保证湿地生态系统结构与功能的完整性为主要目标 ,在对湖区进行重点规划的基础上 ,提出了重点地段生态工程建设的设计方案 ,并对方案的预期目标进行了讨论     

Assessing hydrogeochemical heterogeneity in natural and constructed wetlands

While water quality function is cited as animportant wetland function to design for and preserve,we demonstrate that the scale at which hydrochemicalsamples are collected can significantly influenceinterpretations of biogeochemical processes inwetlands. Subsurface, chemical profiles for bothnutrients and major ions were determined at a site insouthwestern Wisconsin that contained areas of bothnatural and constructed wetlands. Sampling wasconducted on three different scales: (1) a large scale(3 m between sampling points), (2) an intermediatescale (0.15 m between sampling points), and (3) a smallscale (1.5 cm between sampling points). In mostcases, significant vertical heterogeneity was observedat the 0.15 m scale, which was much larger thanpreviously reported for freshwater wetlands and notdetected by sampling water table wells screened overthe same interval. However, profiles of ammonia andtotal phosphorus showed tenfold changes in the upper0.2 meters of the saturated zone when sampled at thesmall (1.5 cm) scale, that was not depicted bysampling at the intermediate scale. At theintermediate scale of observation, one constructedwetland site differed geochemically from the naturalwetlands and the other constructed wetland site due toapplication of off-site salvaged marsh surface anddownward infiltration of rain. While importantdifferences in dissolved inorganic phosphorus anddissolved inorganic carbon concentrations existedbetween the constructed wetland and the naturalwetlands, we also observed substantial differencesbetween the natural wetland sites for theseconstituents. A median-polishing analysis of our datashowed that temporal variations in constituentconcentrations within profiles, although extensivelyrecognized in the literature, were not as important asspatial variability.     

盐沼湿地大规模恢复的概念生态模型——以盐城为例

大规模湿地生态恢复是一项耗资巨大、复杂的系统工程,需要以整个区域湿地结构和功能恢复作为基本目标,将时间和空间上分散的研究成果进行系统梳理,形成对区域湿地生态变化及其驱动因素的规律性认识。本研究以盐城盐沼湿地为案例,以1987年作为未干扰或干扰较少的状态,从结构-过程-功能耦合作用角度,确定区域湿地恢复的关键生态特征,包括:健康与动态潮间带湿地系统、碱蓬生态系统生产力与弹性、复杂景观镶嵌与相互作用、潮间带底栖动物丰富与鸟类觅食基地,以及濒危与关键水鸟种群保护。在此基础上,将围垦与土地利用、水管理、全球变化与海平面上升作为驱动区域湿地生态变化的三大外部因素;海岸侵蚀与沉积、区域水格局变化、地形地貌变化、湿地空间变化与连通性丧失,以及互花米草入侵等是影响湿地生态系统变化的内在压力因子;基于这些压力因子与湿地生态系统变化之间复杂作用关系分析,形成了外部驱动力-内在压力源-生态影响-生态特征之间联合作用下的区域湿地恢复概念生态模型。此模型以复杂因果关系研究为基础,直观展示了湿地恢复需要去除或减缓各种压力因子的一般路径,有利于指导大规模盐沼湿地恢复规划与实践。     

我国湿地生态状况评价研究进展

从湿地生态状况评价定义、国际重要湿地和全国重点湿地生态状况和主要评价方法等方面研究综述了我国湿地生态状况评价。对全国1413处湿地生态状况的研究显示,国际重要湿地生态状况总体较好,重点湿地生态状况较差,生态状况差有341处,占24.85%,并系统分析了各类湿地生态状况评价的方法、内容和结果。认为湿地生态状况评价是满足湿地保护管理需求的一项基本技术研究工作,开展湿地生态状况评价可以从不同空间、时间尺度反映湿地生态变化趋势,满足湿地生态系统保护修复的管理要求,并揭示各生态因子的内在关系,是提高湿地的保护、管理和合理开发的重要技术手段。最后分析了当前湿地生态状况评价所面临的难点,并提出了相关对策建议。     

A comparison of vascular vegetation and protozoan communities in some freshwater wetlands of Northern Lower Michigan

Vascular vegetation and protozoan communities were sampled in seven wetland sites — two bogs, two fens, two marshes, and one swamp — in summer 1977. Two similarity indices were used to compare vascular vegetation and Protozoa from each site with all the other sites. Bog sites were the most distinct from other wetland types with respect to chemical and physical characteristics, dominant vascular vegetation, and protozoan species composition. The swamp site had the highest similarity to all other sites with respect to both dominant vascular vegetation and protozoan species. Protozoan communities from different wetland types were much more similar than dominant vascular species; however, the pattern of similarity between wetland sites was very similar for both groups (Pearson product-moment correlation coefficient = 0.76).Protozoan communities were also compared with those from several nearby lakes with respect to colonization rate onto polyurethane foam artificial substrates. The structure and dynamics of protozoan communities of wetlands were broadly different from those of other freshwaters, and somewhat unique to the other wetland types. Evidence for a high degree of eutrophy in certain bog lakes is presented.     

Factors Affecting Wetland Use by Spring Migrating Ducks in the Southern Prairie Pothole Region

There is increasing recognition of the importance of wetlands in the prairie pothole region (PPR) of the northern United States for stopover habitat for spring-migrating waterfowl. The quality and quantity of stopover habitat found near breeding areas can affect speed and success of migration and subsequent breeding events. Conservation and management of wetlands in the region has traditionally focused narrowly on reproductive phases of the life cycle, and little to no research has examined how ducks use a diversity of available wetlands in the region during migration. We conducted weekly surveys on 1,061 wetlands during spring 2018 and 2019 to examine factors affecting duck use of wetlands in the intensively modified southern PPR landscape of Iowa, USA, for wetland restoration and conservation strategies. We compared wetland types, which included farmed, seasonal, and semi-permanent wetlands, and lakes. The highest duck use per unit area occurred on semi-permanent wetlands, followed by seasonal, and then farmed wetlands, and lakes. Ducks were highly clustered in our study, with 75% of all use-days occurring on only 37 wetlands comprising 41% of all wetland area surveyed. We used hurdle models to examine how local and landscape factors measured within and around wetlands influenced duck use during spring migration. Multiple factors related to duck use at local and landscape scales, such as wetland area, vegetation abundance, and number of wetlands in the surrounding landscape. Among semi-permanent wetlands, local factors within wetlands were more important than landscape factors in determining duck use. Collectively, our findings suggest semi-permanent wetlands within the PPR play a key role in transitioning birds from wintering areas to breeding areas and that management of semi-permanent wetlands should promote interspersion of emergent vegetation and open water and growth of submersed aquatic plants to improve their function for migrants. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.     

Prairie Wolf Slough Wetlands Demonstration Project: A Case Study Illustrating the Need for Incorporating Soil and Water Quality Assessment in Wetland Restoration Planning,Design and Monitoring

In northeastern Illinois, restored wetlands are used to improve water quality in streams degraded by agriculture and urban development. Using freshwater wetlands to reduce nitrogen loading to lakes and rivers is well documented; however, there are fewer studies addressing their use to remove phosphorous. In 1998, a systematic water quality monitoring project was begun at Prairie Wolf Slough Wetland Demonstration Project, a restored palustrine emergent marsh wetland located on an abandoned farm field north of Chicago. The wetland drains 98 ha of mixed land uses into the Chicago River. Our objectives were to assess spatial and temporal variations in total suspended solids, soluble reactive and total phosphorous concentrations, and mass loadings and compute a mass balance and retention efficiency for these constituents. Water sampling was conducted from 1998 to 2003. In 2004, soil samples were collected from the marsh and an adjacent abandoned farm site and analyzed for soil test (Bray) phosphorus. The marsh effectively traps suspended solids but acts as a source of soluble reactive and total phosphorous to the river both during the growing and nongrowing seasons. Net export of phosphorous from the wetland was likely due to mobilization of orthophosphate as a result of anoxic conditions produced during inundation events. Often little consideration is given to the link between soil and water quality when locating restoration sites. Our study adds to a growing body of literature that clearly demonstrates the need for both soil and water quality assessments in wetland restoration planning, design, and monitoring.     

Backfilling canals to restore wetlands: empirical results in coastal Louisiana

Wetland restoration is largely a developing science and engineering enterprise. Analyses of results are too few and constrained to observations over a few years. We report here on the effectiveness of one restoration technique used sparsely in coastal Louisiana for several decades. Canals have been dredged in coastal Louisiana wetlands since 1938 for oil and gas exploration and extraction. These canals are typically dredged to 2.5 m depth and are 20 to 40 m wide. Canal lengths vary from 100 m to several 1000s m in the case of outer continental shelf pipeline canals that cross the wetlands.Today, thousands of miles of canals crisscross these wetlands. Studies have linked dredged canals to a number of undesirable effects on the wetland environment including alterations in salinity, flooding and drainage patterns, direct loss of marsh by convention to open water, and increases in marsh erosion rates. These effects have led state and federal agencies charged with managing the wetland resource to look for methods of mitigating canal impacts. One possible method of managing spoil banks after the abandonment of a drilling site is to return spoil material from the spoil banks to the canal with the hope that marsh vegetation will be reestablished on the old spoil banks and in the canal. The movement of former spoil bank material back into the canal is referred to as backfilling.The purpose of this study was to (1) examine how backfilled canals changed over 10 years, (2) examine factors influencing success with multiple regression statistical models, and, (3) compare costs of backfilling with other Louisiana marsh restoartion projects. We examined the sites to document and interpret changes occurring since 1983/4 and to statistically model the combined data derived from these new and previous analyses. Specifically, we wanted to determine the recovery rates of vegetation, water depth, and soils in backfilled canals, restored spoil banks, and in nearby marshes, and to quantify the influence of plugging canals on these rates.The major factors determining backfilling restoration success are the depth of the canal, soil type, canal dimensions, locale, dredge operator skill, and permitting conditions. Plugging the canal has no apparent effect on water depth or vegetation cover, with the exception that submerged aquatic vegetation may be more frequently observed behind backfilled canals with plugs than in backfilled canals without plugs. Canal age, soil organic matter content, and whether restoration was done as mitigation on-site or off-site were the most important predictors of final canal depth. Canal length and percentage of spoil returned (+) had the greatest effect on the restoration of vegetation cover. Backfilled canals were shallower if they were older, in soils lower in organic matter, and backfilled off-site. Backfilling the canal restores wetlands at a cost of $1,200 to $3,400/ha, which compares very favorably with planned restoration projects in south Louisiana.Corresponding Editor: Anonumous     

A test of vegetation-related indicators of wetland quality in the prairie pothole region

This study was part of an effort by the U.S. Environmental Protection Agency to quantitatively assess the environmental quality or health of wetland resources on regional and national scales. During a two-year pilot study, we tested selected indicators of wetland quality in the U.S. portion of the prairie pothole region (PPR). We assumed that the amount of cropland versus non-cropland (mostly grassland) in the plots containing these basins was a proxy for their quality. We then tested indicators by their ability to discriminate between wetlands at the extremes of that proxy. Amounts of standing dead vegetation were greater in zones of greater water permanence. Depth of litter was greater in zones of greater water permanence and in zones of basins in poor-quality watersheds. Amounts of unvegetated bottom were greater in basins in poor-quality watersheds; lesser amounts occurred in all wetlands during a wetter year. Greater amounts of open water occurred during a wetter year and in zones of greater water permanence. When unadjusted for areas (ha) of communities, plant taxon richness was higher in wet-meadow and shallow-marsh zones in good-quality watersheds than in similar zones in poor-quality watersheds. Wet-meadow zones in good-quality watersheds had greater numbers of native perennials than those in poor-quality watersheds. This relation held when we eliminated all communities in good-quality watersheds larger than the largest commnities in poor-quality watersheds from the data set. We conclude that although amounts of unvegetated bottom and plant taxon richness in wet-meadow zones were useful indicators of wetland quality during our study, the search for additional such indicators should continue. The value of these indicators may change with the notoriously unstable hydrological conditions in the PPR. Most valuable would be indicators that could be photographed or otherwise remotely sensed and would remain relatively stable under various hydrological conditions. An ideal set of indicators could detect the absence of stressors, as well as the presence of structures or functions, of known value to major groups of organisms.     

Prairie wetland communities recover at different rates following hydrological restoration

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Testing a Passive Revegetation Approach for Restoring Coastal Plain Depression Wetlands

Restoration of coastal plain depressions, a biologically significant and threatened wetland type of the southeastern United States, has received little systematic research. Within the context of an experimental project designed to evaluate several restoration approaches, we tested whether successful revegetation can be achieved by passive methods (recruitment from seed banks or seed dispersal) that allow for wetland "self-design" in response to hydrologic recovery. For 16 forested depressions that historically had been drained and altered, drainage ditches were plugged to reestablish natural ponding regimes, and the successional forest was harvested to open the sites and promote establishment of emergent wetland vegetation. We sampled seed bank and vegetation composition 1 year before restoration and monitored vegetation response for 3 years after. Following forest removal and ditch plugging, the restored wetlands quickly developed a dense cover of herbaceous plant species, of which roughly half were wetland species. Seed banks were a major source of wetland species for early revegetation. However, hydrologic recovery was slowed by a prolonged drought, which allowed nonwetland plant species to establish from seed banks and dispersal or to regrow after site harvest. Some nonwetland species were later suppressed by ponded conditions in the third year, but resprouting woody plants persisted and could alter the future trajectory of revegetation. Some characteristic wetland species were largely absent in the restored sites, indicating that passive methods may not fully replicate the composition of reference systems. Passive revegetation was partially successful, but regional droughts present inherent challenges to restoring depressional wetlands whose hydrologic regimes are strongly controlled by rainfall variability.     

退耕还湿后土壤细菌群落结构和生物量变化过程

土壤细菌对湿地生态系统功能和健康维持起着重要作用。以菜子湖原始湿地、不同退耕年限湿地(3a、7a、11a和21a)和仍耕作油菜地土壤为研究对象,应用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)、高通量测序和磷脂脂肪酸(PLFAs)方法分析土壤细菌群落组成和生物量,探讨它们在退耕还湿后的变化过程及其影响因素。结果表明,退耕还湿后土壤变形菌门(α-变形菌纲、β-变形菌纲和δ-变形菌纲)、酸杆菌门(酸杆菌纲和全噬菌纲)、Nitrospinae(Nitrospinia纲)和硝化螺旋菌门(硝化螺旋菌纲)相对丰度先增高后降低;这些参与氮循环的土壤细菌对退耕后湿地生态恢复过程中土壤氮素提升起着重要作用。与农业生产活动密切关联的厚壁菌门(芽孢杆菌纲和梭菌纲)和放线菌门(放线菌纲)相对丰度逐渐降低。湿地土壤细菌多样性在退耕初期(3—7a)上升达到最大,退耕中后期逐渐降低。表层土壤各类群细菌生物量逐渐升高,亚表层土壤各类群细菌生物量则先降后升再降。水分条件和容重是与研究区土壤细菌群落结构和多样性密切相关的土壤因子,而全氮是与土壤细菌生物量密切相关的土壤因子。研究从生态过程视角解析了土壤细菌群落较详...     

Working with land and sea rangers to tackle tropical wetland restoration and conservation on the north-western islands,Torres Straits,Australia

Importance of community stakeholder participation in coastal freshwater and tidal wetland monitoring and restoration has become increasingly recognised. In Australia, Land and Sea Rangers (LSR) are appointed land and sea custodians from local indigenous communities and under guidance of experts learn a range of scientifically relevant and rigorous sampling techniques to protect and conserve Country. Scientific training to build LSR confidence to tackle restoration and conservation of sensitive and culturally important wetlands is shown here. Between May 2014 and May 2015 three training campaigns were completed where LSR on Boigu and Saibai Islands (the most northern islands in the Torres Straits, Australia), completed water quality and wetland flora/fauna surveys across both islands. Forty wetland fauna species were documented (with a similar wetland assemblage on each ANOSIM P?>?0.4) comprising 35 fish species (including the invasive freshwater climbing perch, Anabas testudineus), two crustaceans, a freshwater turtle (Chelodina oblonga) (a relic freshwater species after the last sea level rise approximately 6,000 years ago in the region), and two mangrove snakes (Myron richardsoni and Fordonia leucobalia) (both snake records represent a range extension). This data was presented at community workshops with the purpose to build LSR confidence, and with the community, develop a plan to conserve wetland cultural and environmental values. Five thematic wetland conservation themes were identified which resulted in agreeing to management actions necessary on both islands. Since the inception of this program in 2014, additional LSR restoration and monitoring programs have extended to wetlands on other islands in the Torres Straits. We advocate the need for more remote area wetland monitoring and management programs facilitated through LSR programs.     

Primary evaluation of carbon sequestration potential of wetlands in China

As one of the important ecosystem services of wetlands, carbon sequestration potential of lakes and swamps in China were investigated. Significant differences were found among the carbon sequestration potential of various lakes, determined by natural conditions and human disturbance. In this study, swamps had a carbon sequestration potential of 4.90 TgC, much higher than lakes in China. Mangrove and coastal marsh have the highest carbon sediment rate among swamps. Carbon sequestration potential in returning farms to lakes and swamps was 30.26 and 0.22 GgC. … a^?1, respectively. Under the ongoing national wetland conservation action plan in China, the carbon sequestration potential of wetland restoration was 6.57 GgC. … a^?1. Protection and restoration measurements can improve carbon sequestration potential of wetlands.     

A hydrologic assessment of the Everglades Nutrient Removal Project, a subtropical constructed wetland in South Florida (USA)

The Everglades Nutrient Removal Project (ENRP), a 1544-ha constructed wetland in south Florida, was intensively monitored throughout its five-year operational history. Water budgets for the ENRP and each of its interior treatment cells were dominated by surface flows (≥85% of inflows; ≥68% of outflows) with smaller contributions from precipitation, evapotranspiration, groundwater flux, and change in storage. The mean water depth, hydraulic loading rate for surface water, and nominal hydraulic retention time for the entire wetland were 0.6 m, 3.1 cm d⁻¹ and 17.7 d, respectively, and were comparable to values anticipated in design. The east flow-way was slightly shallower (0.2 m) and received proportionately more flow (61%) than the west flow-way. The hydrology of other treatment wetlands is often driven by surface flows. All treatment cells in the ENRP were to some extent hydraulically short-circuited. There was net groundwater inflow to the ENRP from Water Conservation Area 1 (WCA-1) resulting from significant head differences between these wetlands. Groundwater outflow to the adjacent farmlands was greatest in Cell 2 and substantially exceeded groundwater inflow. All hydrologic parameters exhibited seasonality to some extent; fluctuation in water depth and groundwater inflows corresponded with the seasonal change in stage in WCA-1. Errors in the ENRP and individual cell water budgets were generally less than 10% and within the range of errors for water budgets from other wetlands.     

基于植物多样性特征的武汉市城市湖泊湿地植被分类保护和恢复

湿地植被多样性特征及其影响因素的调查分析是湿地植被保护与恢复策略制定的基础。借鉴生物多样性热点分析原理,在武汉市城市湖泊湿地植物多样性调查的基础上,研究了湖泊湿地的植被多样性特征,探讨了城市湖泊湿地植被分类保护与恢复对策。结果表明,武汉市湿地维管束植物的物种丰富度、植物多样性、优势度和均匀度指数在各湖泊间的变化趋势较为一致,但在空间变化幅度上存在一定差异。按照物种丰富度、多样性、优势度、均匀度、湿地植被群丛数目,以及典型湿地植物的物种所占比例、丰富度和优势度的差异,可将调查涉及的26个典型湖泊湿地分为原生植被湖泊、次生植被湖泊、人工植被湖泊和退化植被湖泊4类。原生植被湖泊应建立相对严格的湿地保护区,优先保护原有湿地植被。次生植被湖泊最多,城市发展区内的次生植被湖泊应建立30-100m的植被缓冲带,促进植被自然恢复和发育;而农业区的次生植被湖泊应引导和规范湖泊周围的农业生产模式,以减少人类活动干扰。人工植被湖泊应通过建立城市湿地公园,人工促进植被的近自然恢复。而退化植被湖泊则应尽快采用生态工程法促进湿地植被生境改善,并积极开展近自然湿地植被重建与恢复。