查看更多>>摘要：Unreasonable utilization of water resources cause serious water shortage and associated pollution problems. Improving water use efficiency (WUE) is helpful for alleviating water scarcity and mitigating water pollution. However, due to the conflict between water saving and economic development as well as uncertain parameter information, it is challenging to improve WUE. To address these problems, a water-footprint-based interval fuzzy robust fractional programming (WF-IFRFP) model was developed through integrating water footprint (WF), interval parameter programming (IPP) and fuzzy robust optimization (FRP) into a fractional programming (FP) framework. The developed WF-IFRFP model improved upon traditional methods by being able to tackle interval numbers and fuzzy sets under different system-violation risks. The developed model was applied to a water management case in the northwest of Inner Mongolia, China. The results of WF assessment showed that the water consumption of crop growth increased, water, whereas that used for reducing total nitrogen concentration decreased from 2012 to 2016. Then, specific benefit- and risk-explicit plans for cropping pattern adjustments were generated. The results showed that the water supply-demand ratio from WF-IFRFP would be [5.1,10.7] % higher than that in the benchmark year of 2016. To assess its performance and merits, the optimal results from the WF-IFRFP model were compared to four alternative models. These comparisons reveal that the WF-IFRFP model is beneficial for improving irrigation WUE.
查看更多>>摘要：We present an applied model that helps restoration practitioners select an ideal mix of species to plant in order to meet their restoration objectives. The model generates virtual plant communities designed to optimize the delivery of multiple ecosystem functions. We used an optimization approach to find the most cost-effective combinations of species to plant to optimize the delivery of four ecosystem functions: rapid establishment of vegetation coyer, soil building, biological soil health and resistance to invasion. We used trait-function relationships to characterize species' effects on ecosystem functions. This model accounts for key operational constraints selected by the user, including budget, the number of species to plant, and which functions to consider. The user can also decide whether or not to maximize the functional diversity of the species mix to increase its resilience to global environmental change. To demonstrate the practicality of this approach, we derived optimal species mixtures for the restoration of forests damaged by Cu-Ni smelters in the City of Greater Sudbury (Ontario, Canada). The species mixtures generated by the model varied according to which functions and operational constraints were selected. Results show that the species mixtures that were the most effective at delivering multiple functions were also cost-effective, but were less functionally diverse. This tool provides restoration practitioners with cost-effective restoration strategies for managing the recovery of multi-faceted socio-economic and environmental values in disturbed landscapes.
查看更多>>摘要：With little consideration of both natural and social disturbance in previous studies on Ecological security patterns (ESPs), the identification of conservation priority areas is not accurate enough to enhance the structure and quality of the ecosystem for regional ecological security. To address this gap, this study developed a novel framework of "importance-connectivity-disturbance" to identify ESPs, selecting the Pearl River Delta (PRD) as the study area. Ecological sources were identified by combing ecological importance and landscape connectivity. A more integrated ecological resistance was developed to represent natural and social disturbance, and applied to obtain levels of regional ecological security. Ecological corridors were then extracted and classified using the minimum cumulative resistance (MCR) model and gravity model. The results showed that 9645.77 km~2 of ecological sources and 72 potential ecological corridors were determined, and the region with the higher security grade accounted for 19.18% of the entire area. The optimized ESPs of "one ring, two cores, three zones, and four axes" was developed based on key components of ESPs and local socioeconomic conditions. This study provides a novel perspective on the methodology of identifying ESPs and an essential reference for ecological protection and regional development planning in urban agglomerations.
查看更多>>摘要：Forestland vegetation restoration changes the state of soil water storage and consumption, leading to changes in soil water content. Many scholars have conducted research on the soil water content of restored forestland vegetation in different climatic regions. However, due to the uniqueness of the karst environment, the research findings from other humid regions may not be indicative of the impacts of forestland vegetation restoration on the soil water content in humid karst regions. In this work, the soil water content of four sample plots with different restoration durations in a karst region was examined. The results showed that the soil water contents of the sample plots with different restoration durations differed significantly. As the restoration process of the forestland vegetation progressed, the soil water content decreased, but the range of reduction was small. There was a significant negative correlation between forestland vegetation restoration duration and soil water content (P < 0.01), and the Spearman correlation coefficient between the two was -0.621. At different soil depths and in different seasons, the soil moisture content also decreased with increased restoration duration. Compared with humid non-karst regions, the karst environment bedrock possessed thin soil layers and strong water permeability, which further amplified the effect of vegetation restoration on the reduction of soil moisture content.
查看更多>>摘要：Ecosystem stability is the interaction result of species diversity, environmental conditions and external disturbances, the research on diversity and stability of plant community and their relationship with environmental factors is the prerequisite of establishing a self-organized ecosystem with adaptability and resilience. Taking Nangqian County in the source region of Lancang River as study area, this paper empirically analyzed the influence and mechanism of plant diversity and environmental factors on community stability through Spearman correlation test, regression analysis and redundancy analysis (RDA), so as to provide scientific basis for ecological restoration and construction of stable plant community. The results showed that the descending order of community stability was N8 > N3 > N5 > N4 > N2 > N9 > N6 > N7 > N1 (N1-N9 respectively represent the nine sampling sites selected in this study). Community stability index (S) tended to decrease first and then increase with the increase of Species richness index (R) and Pielou evenness index (J), but had no significant correlation with Simpson dominance index (D) and Shannon-Wiener diversity index (H). Plant diversity mainly affected stability through mechanism channels such as improving performance effect, species evenness and interspecific competition. Topsoil organic carbon (T_OC), pH (T_PH) and sodicity (T_ESP) had important influence on community stability. Temperature (TEMP) and precipitation (PRCP) influenced the distribution pattern of plant communities, while topographic factors including elevation (ELEV), slope (SLOPE) and aspect (ASPECT) affected mean value of species abundance (μ) and Species richness index (R) through solar radiation intensity, temperature, precipitation and soil conditions. In the source regions of Lancang River and other similar areas, ecological restoration should pay attention to the adaptation of species to moisture, heat and soil conditions, give full play to the important role of dominant species in maintaining stability, take into account species evenness and weaken intensity of interspecific competition while increasing diversity.
查看更多>>摘要：Determination of reclamation status of secondary forests is particularly urgent in human impacted landscapes for conservation of biodiversity and other ecosystem services. However, there is a lack of a quantitative method to estimate the recovery status of secondary forest globally. In the present work, the authors have attempted to estimate the recovery status of a dry secondary forest of Similipal Biosphere Reserve (SBR), India quantitatively witii a nearby primary forest. We have formulated an equation (measure of climax stage) to estimate the secondary forest for its possible climax stage (early climax stage/mid climax stage/stable climax stage/non climax stage) based on species richness. For this study, the value of ''measure of climax stage'' between 0 and 0.2 is considered as stable climax stage, 0.2-0.6 as mid climax stage and 0.6-1 as early climax stage. On the other hand, the value >1 was considered as a non-climax stage of the forest. Accordingly, the studied secondary forest was estimated as to be in mid climax stage (measure of climax stage = 0.4230) even after c. 25 years of successional stage. We have also estimated the recovery stage of a secondary dry forest in SBR by fitting it with a suitable equation and found that the time frame for the stable climax stage is more than 50 years. ANOVA analysis indicates that there is no significant difference observed in the case of soil nutrient contents (except Electrical Conductivity) between primary and secondary forest sites. This developed equation may be implicated in the evaluation of reclamation status of secondary and degraded forest lands globally. Further, in-depth study is encouraged for the development of a modern climax concept to understand the ecological restoration process in a better way.
查看更多>>摘要：Bivalve shellfish are common in coastal ecosystems where their aggregate structure attenuates wave energy and provides habitat, while delivering water quality benefits through their feeding activity. These factors make them appropriate candidates for inclusion in living shorelines to facilitate positive ecological outcomes. In 2014, a 61 m shellfish-based living shoreline was constructed along a salt marsh at the DuPont Nature Center in Milford, Delaware with the goal to maximize shellfish populations for water quality benefits. Monitoring was conducted to assess oyster and ribbed mussel population development and evaluate their relative contribution to cumulative filtration at three positions— on structures near mean low water (low), along the marsh edge (high), and on the untreated mudflat between (mid). Oyster and ribbed mussel counts and size demographics were converted to population and biomass densities to calculate filtration capacity in each position through 2020. Cumulatively, shellfish on the Mispillion living shoreline filtered 6763 kg of seston, but population and biomass development varied spatiotemporally between species. Between 2018 and 2020, oyster population and biomass densities declined at the low, but increased at the high positons, while ribbed mussel densities increased at both. Despite differences among species and position, the annual summed filtration of the low and high positions continually increased. These results indicate that a multi-species approach, across a variety of appropriate spatial niches, can help maintain or enhance overall filtration capacity through either complementary species contributions at a single positon, or spatial compensation by a single species across positons.
查看更多>>摘要：Hydrodynamic forces from ships operating in sheltered, confined fairways can result in increased wave impact and sediment transport leading to loss of land and habitats. Nature-based solutions (NBS) offer the potential to mitigate ship-induced erosion and increase biodiversity and ecosystem services. The aim of this study is to evaluate the performance of NBS in a sheltered, confined fairway located in a cold, temperate region. The case study presents the results of a 2.5-year study of the morphologic response at two sites where NBS was implemented to mitigate bluff erosion and at one site where NBS was implemented to mitigate the retreat of a reed belt. Moreover, a qualitative assessment was made of the vegetation development at the sites. The results showed that fine sediments with planted vegetation could not withstand the hydrodynamic forces induced by the ships. However, by adding sills as stabilizing structures, the forces were sufficiently attenuated for the vegetation to establish. The vegetation, which reduced the ship-generated waves and currents, was especially important during high water-level events when the energy dissipation by the sill decreased. Moreover, a small-scale nourishment was successfully applied to mitigate bluff erosion without negatively affecting sediment supply to an adjacent sandy beach. This study demonstrates tiiat NBS can be implemented to retain erodible sediment and favour vegetation growth in fairways experiencing primary and secondary waves produced by large, ocean-going ships.
查看更多>>摘要：This study analyzed the correlations between the meteorological/substrate-moisture variables and the evapotranspiration (ET) to improve the understanding of the factors influencing the thermal performance of green roofs, including cooling the surface and interior temperature of the building, in a subtropical climate. Daily ET of the green roof had been estimated using the FAO Penman-Monteith method to increase the number of ET data and the Nash-Sutcliffe coefficient is 0.51-0.62 compared to the observed daily ET from data of green roof ex- i periments in Taipei during December 2012 and September 2013. Based on correlation analysis, this study then suggests that ET may have a higher influence on T_(diff), i.e. the difference in surface temperatures of green and original roofs, than the meteorological variables or substrate water content (SWC), although the radiative heating is sometimes more influential to T_(diff) than the cooling caused by ET of the green roof in thin substrate condition. This study also found that under wet and dry substrates, daily ET is highly correlated with weather-related variables and with SWC, respectively. Furthermore, because of the low insulation of wet substrate, more downward fluxes are sometimes found under high than low SWC conditions. On the contrary, under the dry substrate, increasing SWC helps reduce the downward fluxes. This study, therefore, indicates that an optimal range of substrate moisture appears to maximize the function of a green roof in reducing the surface temperature and the downward substrate-bottom flux. Considering that a counterbalance exists between SWC and ET as well as irrigation can be applied to control SWC, future studies could be aimed at the optimal range of SWC to execute informed irrigation concerning the thermal performance, water-saving irrigation, and storm-water-retention function of the green roofs either in dry period or before storm events.
查看更多>>摘要：With population growth, demand for agricultural products has increased, which affects agriculture, fertiliser use and land management. Due to nutrient inputs from arable areas, the water quality of rivers and lakes near agricultural lands has deteriorated. Constructed wetlands (CWs) are one of the measures used to improve water quality through natural water treatment processes. We studied phosphorus removal in relation to environmental characteristics in five in-stream free surface flow CWs in Finland, Estonia and Latvia. Wetland/catchment area ratios varied from 0.1% to 5%. Three CWs were covered in dense vegetation. On average, the Vanda CW and Hovi CW TP removal efficiency throughout the study period were highest (32.1 ± 3.6% and 34.9 ± 4.4%, respectively) among all studied CWs. Nummela Gateway CW, Rantamo-Seitteli CW and Mezaciruli CW showed lower TP removal efficiency and on many occasions the outflow concentration exceeded the inflow concentration in Rantamo-Seitteli and Mezaciruli CW. Vegetation cover emerged as the most important factor in the treatment efficiency of in-stream CWs, reducing flow rate, increasing water retention time and decreasing probability of the CW becoming a source of phosphorus during flood events.
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