查看更多>>摘要：? 2021 Elsevier B.V.Establishing a suitable location for a fish collection system is crucial for luring and collecting fish and requires the swimming characteristics of fish to be considered. This study aimed to identify a suitable location to lure fish to the fish collecting system (or barge) on the Hong River. For this purpose, a 3D computational fluid dynamics model for the downstream of dam was verified using Acoustic Doppler current Profiler (ADCP) velocity data to simulate the flow field of river channel considering of seven typical operation scenarios. The swimming performance of five endemic fish (Bagarius rutilus, Cyprinus carpio rubrofuscus, Semilabeo obscures, Channa argus, and Opsariichthys bidens) were evaluated using three indexes, i.e., induced flow velocity, critical swimming speed, burst swimming speed, to determine their migration behavior zones by analyzing different flow velocities. By adapting the simulated flow fields in each operation scenario, potential fish migration aggregation zones were analyzed. The results suggested that the most optimal position for placing the FCP was in the left bank of river channel at X = 400–500 m in typical operation scenarios. This study provides a reference for designing FCP for fish pass facilities that combine fish swimming behavior and hydraulic variables of the river channel.
查看更多>>摘要：? 2021 Elsevier B.V.Coastal areas of India have a big potential for establishing renewable energy projects, which are generally regarded as green energy sources. However, such projects' construction work may cause a negative environmental impact on the surrounding waters. Aquaculture projects based on seaweed and fisheries, commonly referred to as integrated multitrophic aquaculture (IMTA), can help to mitigate these impacts. Although the purpose of any IMTA is to recirculate the waste products from cultivated species and not to mitigate the environmental impacts of energy projects, IMTA may serve as a complementary activity to compensate for the environmental impacts of marine energy projects. In return, marine energy projects can provide a few facilities to IMTA projects in their areas. IMTA projects are already practised in some parts of the world; however, rare examples are available with marine energy projects. This study aims to put an idea of potential IMTA projects in the areas of the proposed first offshore wind farm in India. This study also recommends the possible utilisation of the potential tidal energy plant in the estuary as a nursery for a few species in IMTA on the western coast of India. In addition, the current study discussed some major challenges, such as seasonal variations, ecological risks, selection of IMTA components, legal, economic and regulatory and social acceptance. Overcoming these challenges can promote further development of IMTA projects in Indian coastal waters.
查看更多>>摘要：? 2021 Elsevier B.V.The U.S. Clean Water Act requires that development projects causing negative impacts to wetlands must provide compensation for wetland losses through the wetland mitigation process. Compensation can be achieved through the purchase of credits from wetland mitigation banks, which are large wetland restoration projects constructed by third-party bank sponsors. To evaluate how effectively wetland mitigation banks have achieved the goal of “no net loss” of wetland resources, we compared mitigation banks to natural wetlands in the Chicago (Illinois, USA) region. We surveyed vegetation plots in 20 mitigation banks to compare vegetation metrics and composition between banks and 114 natural wetlands, representing a gradient of ecological quality, in northern Illinois. Based on metrics of species richness and floristic quality, mitigation banks possessed wetland plant communities of greater conservation value than the lowest quality, degraded, natural wetlands, but banks were not close to reaching equivalence with high-quality, reference, natural wetlands. Overall, the plant communities in banks were distinct from those of natural wetlands, a condition that appears to be driven by the abundance of the non-native species Typha angustifolia and Phragmites australis in mitigation banks. We found some evidence that dominance by native species may be lower in older banks, but otherwise did not find evidence for a relationship between vegetation metrics and bank age. These results will help those involved with wetland mitigation and similar offsetting programs assess whether compensation sites meet no-net-loss goals, informing goal setting, monitoring, and offsetting policies.
查看更多>>摘要：? 2021 Elsevier B.V.The Mekong River in Asia is one of the world's longest rivers. Although it has some of the highest levels of biodiversity and productivity in Asia, the water quality in the basin has recently deteriorated as a consequence of land use changes, dam reservoir construction, population growth, and climate change. For the first time, this study estimates the interannual and monthly variabilities of nutrient fluxes (nitrate - NO3?) and total phosphorus - TP) in the lower Mekong River and Tonle Sap River in Cambodia, and assesses the nutrient linkage between the them. Long-term monitoring data were obtained from Kratie station (in the upper reach of the Mekong River), Chroy Changva station (just upstream of the lower Mekong River–Tonle Sap River confluence), and Prek Kdam station (on the Tonle Sap River ~40 km upstream of the confluence and 70 km downstream of Tonle Sap Lake). From 1995 to 2017, the estimated interannual flux of NO3? was 364 ± 45 kt/y at Kratie and 557 ± 109 kt/y at Chroy Changva. From 2005 to 2017, the estimated interannual flux of TP was 100 ± 16 kt/y at Kratie and 73 ± 19 kt/y at Chroy Changva. Considerable seasonal differences were observed in both fluxes in the Mekong River, with 80–90% of the annual NO3? flux occurring from May to October. The results of the nutrient exchange budget indicated that the NO3? and TP fluxes from the Mekong River into Tonle Sap Lake were ~ 35.8 ± 12.5 kt/y and ~ 8.7 ± 3.3 kt/y, respectively, while these were 34.0 ± 13.8 kt/y and 6.6 ± 1.4 kt/y, respectively, from Tonle Sap Lake into the Mekong system. The results demonstrate that the Mekong River is a vital nutrient source, especially during the flood season, to Tonle Sap Lake and its floodplain.
查看更多>>摘要：? 2021 Elsevier B.V.Saltmarshes are increasingly recognised an important asset in coastal management as they dissipate wave energy and thus reduce the potential for coastal flooding. The frontal surface area (FSA) and the drag coefficient (Cd) are parameters commonly used in wave attenuation models to express the resistance of vegetation structure to incident waves. The FSA of vegetation represents the vertical surface area facing incoming waves which is calculated as the product of height, diameter and density whereas Cd is often used as tunable parameter that represents the vegetation-wave interactions that relies on both vegetation properties and wave conditions. Despite their importance in numerical modelling, substantial uncertainty remains in obtaining these parameters in the field due to the time-intensive and relatively expensive nature of data collection. An alternative structural vegetation parameter that can be included in wave attenuation models is the leaf area index (LAI). The primary advantage of the LAI is that it can be readily derived from satellite imagery, and thus provides a low-cost, fast alternative to field data collection. However, to date, its incorporation in widely-used coastal engineering models is lacking. The aim of this paper is to verify the use of remote-sensed LAI in numerical wave models as an alternative to FSA. Here, the widely used XBeach model for simulating storm impacts on a range of coastal systems is applied to two open coast sites with extensive saltmarsh; Chesapeake Bay, USA, and Brancaster, UK. To assess the performance of wave attenuation modelling using both methods, we compared the use of remote-sensed LAI from satellite imagery and field-based FSA as inputs into the model. The LAI-based model provides similar levels of accuracy as the FSA-based model. Likewise, higher uncertainties related to plant height, diameter, and density were found in the FSA-based model than in the LAI-based model. Therefore, the LAI-based model provides the advantage of a low-cost and fast method to accurately estimate and predict wave attenuation by vegetation using numerical models such as XBeach. Our practical application in the Brancaster site exemplifies an easy and fast approach to obtaining structural parameters of saltmarsh vegetation and estimating wave attenuation between natural and artificial saltmarshes as well as between seasons.
查看更多>>摘要：? 2022Marsh terracing is a coastal restoration technique that has been implemented in Louisiana and Texas for almost 30 years. Marsh terraces are segmented ridges of soil built in inland coastal ponds for the objectives of creating new marsh, disrupting fetch, and dissipating wind-driven wave energy, which causes marsh erosion. Despite widespread implementation, no numerical modeling studies have been conducted to understand the effect of terraces on wave climate in marsh environments. The objectives of this study were to: 1) simulate wave climates in marsh terrace fields using the Simulating WAves Nearshore (SWAN) model and evaluate the agreement between modeled and observed wave conditions and 2) assess the effectiveness of marsh terraces at reducing significant wave height by comparing wave climates in terraced sites with hypothetical unterraced sites. The SWAN model was used to simulate wind-waves at two terrace fields in coastal Louisiana. Model validation was performed using data collected with in situ wave instruments and wind data measured by NOAA stations located 25 km to the east and 62 km to the northeast of the study area. Results from this study modeled and measured small (0.03–0.14 m) and high–frequency waves (0.80–1.29 s) in the marsh terrace fields. Model validation revealed agreement between modeled and observed data, particularly for significant wave height and direction. Additionally, a comparison of wave climates in terraced and unterraced marsh environments indicated an average significant wave height reduction of 45% (min:18%, max: 84%) when terraces were present. Overall, the model was able to evaluate wave climates in marsh terrace fields and assess the effectiveness of this restoration technique in reducing significant wave height. The model's performance in this low energy and complex environment (shallow water, nonlinear shoreline, marsh fragmentated) is encouraging given the lack of research assessing wave parameters in marsh terrace environments.
查看更多>>摘要：? 2021Urban air quality can be improved through a variety of strategies, one of which is to increase the amount of urban vegetation. In cities where there is insufficient ground space for increased vegetation, roof space can be utilised to establish green roofs that help to mitigate harmful gas content in air. This study uses the closed static chamber method to determine the scale of greenhouse gas (GHG) fluxes from three green roof types: Sedum mat roofs (three sites), lightweight clay aggregate (LECA)-based roofs (four sites), and Gramineae sod roofs (six sites). GHG fluxes from these sites were also compared with those from a flat roof lawn garden and a natural control area. Our results highlight the importance of soil-based archaea in affecting all GHGs from green roofs. Mat and LECA roofs had similar carbon dioxide (CO2) fluxes, but CO2 flux from sod roofs was strongly affected by substrate composition. Furthermore, CO2 flux had a similar seasonal variation across all study sites, with the lowest fluxes in May and September, and the highest fluxes in June, July and August. The main process involving methane (CH4) on green roofs was oxidation, with sod roofs having stronger oxidation levels than either mat or LECA roofs. This was further confirmed by microbial data on methanogens and methanotrophs. There was no significant nitrous oxide (N2O) flux from any of the study sites. According to the results, we conclude that non-fertilised green roofs are not significant sources of GHGs and will rather help to mitigate GHG levels in urban areas, like Gramineae-based roofs may be used effectively for CH4 consumption.
查看更多>>摘要：? 2021 Elsevier B.V.Heathlands are threatened habitats throughout the whole Europe, which have initiated numerous restoration programmes aimed mostly at plant community reconstruction; however, little is known about soil fauna restoration. Here we have studied newly established wet and dry heathlands in the Netherlands after topsoil removal of previously agricultural land, where we manipulated the soil pH (acidification by Sulphur or liming by Ca ions as Dolokal) and introduced plant or soil material to speed up the restoration process. We sampled experimental plots and nearby mature heathlands (used as local reference habitat) over five years (2013–2017) for nematodes, mesofauna (mainly springtails and mites) and macrofauna. Although soil inoculation proved to be a substantive step in target plant community development and also helped to shift soil faunal assemblages towards the target, the latter were still far from reference heathland after five years. Only macrofaunal densities showed similar densities in 2017 as in local reference spots. The succession dynamics of all studied groups and trophic composition of macrofauna and nematodes differed in wet and dry heathlands. Soil amendments improved the initial colonisation as well as liming at the wet sites, which probably created suitable microhabitats for soil fauna development.
查看更多>>摘要：? 2022 Elsevier B.V.Ecological programs (EPs) can reverse the degradation of ecosystems and promote the achievement of the sustainable development goals (SDGs). The public understanding of the role of EPs in the context of SDGs can influence people's participation and decision-making. However, there is a lack of insights into the systematic patterns of cognitive associations between the programs and SDGs. Here we identify the public perception of EPs using mental maps that illustrate how people relate nine EPs to SDGs linked to nature, human well-being, and economic productivity. Based on information collected from stakeholders, it was found that “Soil and Water Loss Control”, “Sand Prevention and Control”, “Shelterbelt Construction”, and “Wetland Conservation” were indicated as the key programs for the achievement of SDGs in Linzhi. The mental map of the majority of the people identified trade-offs between the environmental/social and economic sustainability elements supported by EPs. Some people related multiple EPs to social and economic sustainability elements, while others primarily saw multiple EPs as targeting the environmental and economic sustainability elements. The dominant mental map here identified could serve as a model for engaging in, and communicating, ecological programs. We suggest a direction for addressing SDG trade-offs through ecological program-based management, which is based on three aspects: priority adjustment, integrated portfolio, and stakeholder engagement.
查看更多>>摘要：? 2022 Elsevier B.V.Fly ash dump has been noticed as one of the hazardous dumpsites on the earth, which pollutes our environment. Therefore, an affordable and effective approach for the restoration of fly ash dumps is urgently required worldwide. In this direction, to find out potential plant species through the assessment of naturally colonized vegetation is a basic criterion of ecological restoration. With the above vision, the present study was performed to identify potential colonizer plants of fly ash dumps for ecological restoration. The intensive field studies were made during 2019–2020 to gather naturally occurring plants from fly ash disposal area of Koradi Thermal Power Plant, Nagpur, Maharashtra, India. Therefore, naturally colonizing plants were assessed on the basis of their dominance, ability of improving the rhizospheric FA, and ecological significance for their ecorestoration potential. Acacia nilotica L., Acmella oleracea L., Bacopa monnieri L., Cynodon dactylon (L.) Pers., Cyperus rotundus L., Dactyloctenium aegyptium L., Digitaria sanguinalis L., Trianthema portulacastrum L., Typha latifolia L. and Portulaca oleracea L. were recognized as potential plants for ecological restoration of FA dumps. Hence, the characteristics of above identified potential plant species can be used in ecological restoration of newly FA disposal areas.
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