Restoration Of Lake Ecosystems Research Articles

Ecological risk assessment under the PSR framework and its application to shallow urban lakes.

Shallow urban lakes are naturally vulnerable to ecosystem degradation. Rapid urbanization in recent decades has led to a variety of aquatic problems such as eutrophication, algal blooms, and biodiversity loss, increasing the risk to lake-wide ecological sustainability. Instead of a simple binary assessment of ecological risk, holistic evaluation frameworks that consider multiple stressors and receptors can provide a more comprehensive assessment of overall ecological risk. In this study, we analyzed a combined dataset of government statistics, remote sensing images, and 1year of field measurements to develop an index system for urban lake ecological risk assessment based on the pressure-state-response (PSR) framework. We used the developed ecological safety index (ESI) system to evaluate the ecological risk for three urban lakes in Jiangsu Province, China: Lake Yangcheng-LYC, Lake Changdang-LCD, and Lake Tashan-LTS. LYC and LTS were classified as "mostly safe" and "generally recognized as safe," respectively, while LCD was assessed as having "potential ecological risk." Our data suggest that socioeconomic pressure and aquatic health are the two main factors affecting the ecological risk in both LYC and LCD. The ecological risk of LTS could be improved more effectively if regional management plans are well implemented. Our study highlights the pressure of external wastewater loading, low forest-grassland coverage, and lake shoreline damage on the three selected urban lakes. The findings of this study can inform watershed management for lake ecosystem restoration and environmental sustainability.

Environmental DNA for assessing impact and recovery of aquatic communities in an invaded mountain lake

Beaulieu J, Yates MC, Astorg L, Trépanier-Leroux D, Jeon H, Rudko SP, Humphries S, Fraser DJ, Cristescu ME, Derry AM. 2024. Environmental DNA for assessing impact and recovery of aquatic communities in an invaded mountain lake. Lake Reserv Manage. XX:XXX–XXX. The eradication of invasive species and associated side effects that influence the reestablishment of biological communities is a major challenge for conservation management of invaded ecosystems. We present a before-and-after-disturbance whole lake manipulation study from a high-elevation mountain lake in which we applied a 2-pronged approach to environmental DNA (eDNA) for assessing (1) impact and recovery of aquatic communities to the chemical eradication of invasive brook trout (Salvelinus fontinalis) and (2) the success of chemical eradication of the invasive fish. Using 18S and cytochrome oxidase I (COI) eDNA metabarcoding, we contribute to a paucity of literature that has comprehensively addressed nontarget effects of rotenone for invasive fish eradication on aquatic communities. We found that key trophic groups (phytoplankton, fungi, zooplankton, and macroinvertebrates) changed in community composition in response to rotenone applications. Fungi and macroinvertebrates, but not zooplankton and phytoplankton, reverted back toward pre-rotenone communities over the time scale of 2 yr. However, COI failed to detect several key species for food web reestablishment that were detected using physical specimen collection, likely due to low primer efficiency. We also found that quantitative polymerase chain reaction (qPCR), using species-specific primers, was effective for detecting brook trout presence/absence, although strong eDNA signals likely produced from carcasses in the ecosystem limited the utility of eDNA immediately following rotenone treatment. We provide specific recommendations for lake managers for the future application of eDNA approaches to monitor invasive fish eradication efforts and nontarget community effects for lake ecosystem restoration.

Sediment capping technology for eutrophication control and its potential for application in Indonesian lakes: a review

Eutrophication occurs when the lakes become enriched with nutrients. Some nitrogen and phosphorus fractions will settle in sediment, and others will be released back into the overlying water column. Excess nutrients in water bodies resulting in hypoxic to anoxic conditions that can cause a mass fish death. Hence, we need a sediment management strategy to minimize resuspension and transport of sediment back into the water column. Sediment capping is a containment technology to reduce the release of nutrients from sediment as a strategy for eutrophication control. This study aims to provide insight into sediment capping technology, including several considerations in capping design, as well as information on several active materials that have been applied as capping materials and their efficiencies. Capping materials such as calcite, zeolite, bentonite, activated carbon, sludge, biochar, and gypsum from previous studies showed the efficiency of 54–99 % nutrient reduction with capping duration of 10–300 days in some eutrophic lakes. Sediment capping technology has successfully promoted lake ecosystem restoration in other countries, and this technology has the potential to be applied in Indonesian eutrophic lakes as a strategy for eutrophication control and sustainable management of lake ecosystems by considering the selection of the most effective, efficient, easy, inexpensive, and eco-friendly capping materials.

A review of the application of the macroinvertebrate-based multimetric indices (MMIs) for water quality monitoring in lakes.

The increasing stress on lake ecosystems is affecting their functioning such as providing goods and services to inhabiting organisms and riparian communities. Monitoring of water quality is important for sustainable management and restoration of lake ecosystems. However, the costs associated with traditional approaches have become prohibitive, while not giving reliable early warning signals on resource conditions. Thus, the current shift in the use of bioindicators and multimetric indices (MMIs) in the monitoring of water quality is currently gaining global recognition with more emphasis on its application in lotic ecosystems. Therefore, this paper provides an elaborated insight into the application of macroinvertebrate-based MMIs in lentic ecosystems and the successes achieved so far. The various metrics and indices, the development strategies, application challenges, the use of macroinvertebrates as bioindicators, and the future projection of enhancing MMI usage in lentic environment monitoring, particularly in developing countries, are extensively covered. The use of MMI as a rapid lake biomonitoring tool needs to be adopted for sustainable applications in lake ecosystem management and as an integrated approach to monitoring human-induced stress especially in developing countries where there is a paucity of information.

Phosphorus Recovery from Eutrophic Lake Water Using Al/Fe Micro-Electrolysis

Phosphorus (P) is a critical and nonrenewable resource. P crisis threatens future global food security, while P-induced eutrophication is damaging aquatic ecosystems. In eutrophic lakes, P is often heavily concentrated in algae-accumulated zones, creating “P reserves” for reuse. In this study, P was harvested from eutrophic lake water using Al/Fe micro-electrolysis and the stability of the harvested P was tested through anoxia incubation. The results showed that, compared with Fe micro-electrolysis, Al micro-electrolysis was more effective at co-harvesting dissolved and particulate P, and the yields were stable under anoxia conditions, making them suitable as slow-release P fertilizers. At 15 V, the P harvesting efficiency of Al micro-electrolysis was 2.68 times higher than that of Fe micro-electrolysis. This could be attributed to the powerful netting–bridging of amorphous Al hydroxides, which favor floatation separation and thereby P harvesting. Under anoxia, the transformation of Fe species caused P release from Fe micro-electrolysis yields, potentially enhancing P loss through leaching if the yields are used as soil P fertilizers. This study provides a promising strategy for P resource recycling from eutrophic lakes, which may be beneficial to the restoration of lake ecosystems and mitigation of the P crisis.

Restoration effects of submerged macrophytes on methane production and oxidation potential of lake sediments

The restoration of submerged macrophytes is an important step in lake ecosystem restoration, during which artificially assisted measures have been widely used for macrophyte recolonization. Compared with natural restoration, the impact of artificially assisted methods on methane (CH4) production and oxidation of lake sediments remains unclear. Therefore, after the restoration of submerged macrophytes in some parts of West Lake (Hangzhou, China), sediment samples from West Lake were collected according to restoration methods and plant coverage. The CH4 production potential, oxidation potential, and microbial community structure in the sediment were discussed through whole-lake sample analysis and resampling verification from typical lake areas. From the analysis of the whole lake, the average daily CH4 production potential (ADP) of artificially restored lake areas (0.12 μg g−1 d−1) was significantly lower than that of the naturally restored lake areas (0.52 μg g−1 d−1). From the resampling analysis of typical lake areas, the ADP of naturally restored lake areas was 1.8 times that of artificially restored lake areas (P < 0.01). Although there was no significant difference in the CH4 oxidation potential between the two restoration methods, the presence of submerged macrophytes significantly increased the abundance of the dominant methanotroph Methylocaldum in the sediment, and the rate of increase in the abundance of the dominant methanotroph Methylosinus was significantly higher in artificially assisted restoration than in natural restoration. This study revealed that the artificially assisted restoration of submerged macrophytes reduced the potential for CH4 production and increased the abundance of dominant methanotrophs in the lake sediment, which would be beneficial for the reduction of CH4 emissions during lake ecological restoration and environmental management.

Effects of aquaculture on the shallow lake aquatic ecological environment of Lake Datong, China

BackgroundThe restoration of lake ecosystems requires a good knowledge of the lake’s history and the driving mechanism of environmental changes. In this study, we used Lake Datong, the largest inland lake in Hunan Province China, as an example to study the effects of aquaculture, based on historical data of aquatic creature, diatom inferred-total phosphorous (DI-TP) data, and an Ecopath model. Lake Datong has undergone several stages of aquaculture from 1980, with a rapid increase in fish production and fish feed supplementation at each stage. Its water quality has deteriorated since the introduction of aquaculture and the lake has become moderate eutrophic status.ResultsAccording to the DI-TP data, before 1930, Lake Datong was in a mesotrophic status (50–60 μg/L DI-TP). Between 1930 and 1980, the number of nutrient-tolerant species increased slightly, which indicates a nutrient increase in the lake (66–83 μg/L DI-TP). From the 1980s to 2010 and especially since 2000, eutrophication increased rapidly, with eutrophic species dominating the diatom assemblage, such as Stephanodiscus hantzschii, S. minutulus, and a sudden decrease in Aulacoseira granulata (< 10%). The annual average DI-TP concentration was 202 μg/L. After 2010, DI-TP decreased to 127–152 μg/L. In 2019, consumer biomass in Lake Datong was very low because the large-scale aquaculture was restricted by local government. The biomass of submerged macrophytes was relatively high, indicating that excessive primary producers had not been used by consumers and therefore, had not entered the food web. This led to a reduction in the energy transfer efficiency (TE) of the ecosystem.ConclusionsThe succession of the water ecosystem of Lake Datong is reappeared by DI-TP analysis and historical reference data. Lake Datong has experienced four stages of eutrophication succession following the introduction of aquaculture activities, with dramatic changes in the composition and biomass of its aquatic creatures. After comprehensive management in 2017, the consumer biomass of Lake Datong was at a relatively lower level, and the biomass of submerged macrophytes was higher, meaning a large quantity of primary producers had not been used by consumers, thus had not entered the food web, which consequently reduces the energy TE of the ecosystem. Future management needs to pay attention to making a suitable macrophyte harvest plan, stocking herbivorous and omnivorous fish, and establishing rational fishing, which can not only enhance the energy flows and nutrient cycling of the ecosystem, but also improve the food web structure. Our results provide important reference values and theoretical support for decision-makers and stakeholders in the subsequent management of similar shallow lake-water ecosystems.

Multidimensional Assessment of Lake Water Ecosystem Services Using Remote Sensing

Freshwater is becoming scarce worldwide with the rapidly growing population, developing industries, burgeoning agriculture, and increasing consumption. Assessment of ecosystem services has been regarded as a promising way to reconcile the increasing demand and depleting natural resources. In this paper, we proposed a multidimensional assessment framework for evaluating water provisioning ecosystem services by integrating multi-source remote sensing products. We applied the multidimensional framework to assess lake water ecosystem services in the state of Minnesota, US. We found that: (1) the water provisioning ecosystem services degraded during 1998–2018 from three assessment perspectives; (2) the output, efficiency, and trend indices have stable distribution and various spatial clustering patterns from 1998 to 2018; (3) high-level efficiency depends on high-level output, and low-level output relates to low-level efficiency; (4) Western Minnesota, including Northwest, West Central, and Southwest, degraded more severely than other zones in water provisioning services; (5) human activities impact water provisioning services in Minnesota more than climate changes. These findings can benefit policymakers by identifying the priorities for better protection, conservation, and restoration of lake ecosystems. Our multidimensional assessment framework can be adapted to evaluate ecosystem services in other regions.

Decline in nitrogen concentrations of eutrophic Lake Dianchi associated with policy interventions during 2002–2018

Excessive nutrient discharges have resulted in pervasive water pollution and aquatic eutrophication. China has made massive efforts to improve water quality since 2000. However, how long-term policy interventions govern external and internal fluxes as well as nitrogen (N) concentrations is not well known. Here we examined the historical N concentration change and its key drivers in eutrophic Lake Dianchi (southwest China) over the period 2002–2018, based on monthly observations of water quality and external N fluxes, local surveys of mitigation measures, and process-based model simulations of internal N fluxes. Our data indicated that N concentrations peaked at 3.0 mg L−1 in 2007–2010 but afterwards declined down to 1.2 mg L−1 in 2018. Compared with 2010, the decline in lake N concentrations was attributed to reduced riverine N inflow decreasing by 0.20 g N m−3 month−1 and the water-sediment exchange flux decreasing by 0.07 g N m−3 month−1 from 2010 to 2018. Adoptions of wastewater treatment, pollution interception, and transboundary water transfer dominated the changes in external and internal fluxes of N and thereby the decline of lake N concentrations. These findings underscore the priority of reducing external discharge for historical lake water quality improvement and the need of enhancing internal N removal for future lake ecosystem restoration.

Control and remediation methods for eutrophic lakes in the past 30 years.

Accelerated eutrophication, which is harmful and difficult to repair, is one of the most obvious and pervasive water pollution problems in the world. In the past three decades, the management of eutrophication has undergone a transformation from simple directed algal killing, reducing endogenous nutrient concentration to multiple technologies for the restoration of lake ecosystems. This article describes the development and revolution of three remediation methods in application, namely physical, chemical, and biological methods, and it outlines their possible improvements and future directions. Physical and chemical methods have obvious and quick effects to purify water in the short term and are more suitable for small-scale lakes. However, these two methods cannot fundamentally solve the eutrophic water phenomenon due to costly and incomplete removal results. Without a sound treatment system, the chemical method easily produces secondary pollution and residues and is usually used for emergency situations. The biological method is cost-effective and sustainable, but needs a long-term period. A combination of these three management techniques can be used to synthesize short-term and long-term management strategies that control current cyanobacterial blooms and restore the ecosystem. In addition, the development and application of new technologies, such as big data and machine learning, are promising approaches.

A Landscape Connectivity Approach for Determining Minimum Ecological Lake Level: Implications for Lake Restoration

We proposed a new approach to determine the minimum ecological lake level using a landscape connectivity approach. Using MIKE 21 and ArcGIS software, we simulated the water landscape and corresponding connectivity of Baiyangdian Lake on the North China Plain and analyzed the relationship between landscape connectivity and lake level. The minimum ecological lake level was defined as the breakpoint of the lake level-connectivity curve. Results suggested that the minimum ecological lake level of Baiyangdian Lake is 7.8–8.0 m, below which lake ecosystems become fragmented and potentially fragile. Alternatively, better connectivity at lower lake levels may be achieved by engineered modification of landscape patterns. Such approaches can mitigate the waste of water and economic resources due to excessive reliance on increasing water levels to meet minimum connectivity requirements. This approach provided a new perspective for lake ecosystem restoration of use in water-resource- and landscape management.

Success of lake restoration depends on spatial aspects of nutrient loading and hydrology

Many aquatic ecosystems have deteriorated due to human activities and their restoration is often troublesome. It is proposed here that the restoration success of deteriorated lakes critically depends on hitherto largely neglected spatial heterogeneity in nutrient loading and hydrology. A modelling approach is used to study this hypothesis by considering four lake types with contrasting nutrient loading (point versus diffuse) and hydrology (seepage versus drainage). By comparing the longterm effect of common restoration measures (nutrient load reduction, lake flushing or biomanipulation) in these four lake types, we found that restoration through reduction of nutrient loading is effective in all cases. In contrast, biomanipulation only works in seepage lakes with diffuse nutrient inputs, while lake flushing will even be counterproductive in lakes with nutrient point sources. The main conclusion of the presented analysis is that a priori assessment of spatial heterogeneity caused by nutrient loading and hydrology is essential for successful restoration of lake ecosystems.

Economic and ecosystem costs and benefits of alternative land use and management scenarios in the Lake Rotorua, New Zealand, catchment

Abstract A significant challenge in resource management is addressed: the perceived trade-off between economic growth and ecosystem restoration and conservation. Traditional approaches to management regard restoration as a potential cost to economic productivity. In this study we show that by considering a broader range of economic values, including ecosystem services values, an argument can be made that restoration of lake ecosystems also leads to favourable economic outcomes when commonly disregarded values are considered. Our case study analyses the ecological outcomes of different catchment mitigation and land use scenarios in terms of water quality results in a lake, assessing changes in land use values based on opportunity costs, and ecosystem services values. We show that when considering the value of ecosystem services, intensive agricultural land use is not necessarily the most economically valuable form of land use within a lake catchment. Indeed, a shift towards alternative land uses within a catchment can lead to both ongoing economic benefits and improvements in water quality. In this context, land-use change offers an option for water quality improvement that minimises lake and land mitigation costs, while adding value to catchment land use. An argument is made supporting land use change towards indigenous forest types, which can sustain alternative sources of income such as a range of recreational values, while supporting important ecosystem functions for the region.

淡水湖泊生态系统退化驱动因子及修复技术研究进展

PDF HTML阅读 XML下载 导出引用 引用提醒 淡水湖泊生态系统退化驱动因子及修复技术研究进展 DOI: 10.5846/stxb201606281269 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家科技支撑计划项目（2012BAD14B14）；江西省教育厅青年基金项目（JJ1412） Research progress on the driving factors of freshwater lake ecosystem degradation and associated restoration techniques Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:目前我国多数淡水湖泊污染、退化问题非常严重，诸多修复技术也已初见成效。影响淡水湖泊生态系统退化的驱动因子众多，既有生物因素也有非生物因素，它们之间相互联系，相互作用，且作用机理错综复杂。首先介绍了淡水湖泊生态系统退化的含义及形式；其次，分析、总结了淡水湖泊生态系统退化的驱动因子，从退化的生态学完整性意义和退化修复的技术手段上看，淡水湖泊生态系统主要受物理、化学和生物三大驱动因子影响，且基本遵循"环境变化-驱动力-压力（阈值）-状态-响应"原理；再次，在厘清湖泊生态系统退化驱动原理的基础上，从淡水湖泊生态系统功能模块和湖泊生态系统修复实践经验总结的角度出发，构建了淡水湖泊生态系统修复模块技术体系，并就湖泊富营养化和湖滨湿地生态系统退化修复的技术进行了讨论和对比；最后，对淡水湖泊生态系统修复的环境变化驱动因子的作用机制、作用途径和修复技术的长效机制等方面进行了展望。 Abstract:At present, most freshwater lakes in China are severely polluted and degraded. In this regard, we have achieved considerable initial success using a number of restoration techniques. There are many factors that affect the degradation of freshwater lake ecosystems, including both biotic and abiotic factors. These factors are interrelated and interact with each other, and thus causal mechanisms are complicated. In this paper, we initially introduce the meaning and degenerate forms of freshwater lake ecosystem degradation. We then summarize the factors driving the degradation of freshwater lake ecosystems. From the perspectives of ecological integrity and degradation restoration techniques, freshwater lake ecosystems are mainly affected by three types of driving factors (physical, chemical, and biological), which essentially follow the "environmental change-driving force-pressure (threshold)-state-response" principle. We then construct a technical system for a freshwater lake ecosystem restoration module, based on functional modules of freshwater lake ecological systems and practical experience of lake ecosystem restoration, to clarify the driving principle of lake ecosystem degradation, and subsequently discuss and compare degenerate restoration techniques in water eutrophication and freshwater lakeside wetland ecosystems. Finally, we present an outlook of the long-effect mechanism of remediation technology, and the future mechanisms of action and pathways of the driving factors of environmental change in freshwater lake ecological restoration. 参考文献 相似文献 引证文献

Environmental evolution of Lake Liangzi and its driving factors over the past 100 years, Hubei Province

湖泊生态系统的修复必须建立在历史生态环境演化过程与驱动机制认识的基础之上.针对草型湖泊演化历史研究相对不足的现状,以长江中游典型草型湖泊梁子湖为研究对象,结合²¹⁰Pb和¹³⁷Cs年代测试,通过对沉积柱高分辨率的多指标分析(硅藻、元素地球化学和粒度)以及流域历史资料重建近百年来梁子湖生态环境的演化过程,并在此基础上利用冗余分析定量区分影响该湖泊生态环境演化的关键驱动因子.结果显示,沉积物总磷和重金属元素Cu是影响该湖泊生态环境演化的2个显著变量,它们分别单独解释硅藻组合的12.7%和8.5%变率.这表明近百年来人类活动引起的营养输入对梁子湖生态环境演化起关键性作用,而重金属污染也是影响梁子湖环境演变的重要因子.本研究结果可以为梁子湖及长江中下游其他类似湖泊的环境治理提供科学依据.;The restoration of lake ecosystems requires a good knowledge on the history in the lakes and the driving mechanism of environmental changes. Aimed at current situation of limited study on past environmental changes of macrophyte-dominated lake, Lake Liangzi, located in the middle reach of the Yangtze River, was selected for historical environment study. High-resolution multi-proxy(i.e. diatom, geochemistry and grain size), ²¹⁰Pb/¹³⁷Cs dating of a sediment core collected from this lake and documentary data(i.e. population and air temperature) were analyzed to investigate environmental changes during the past one-hundred years. Furthermore, effects of key driver on the evolution of ecological environment were estimated quantitatively using the redundancy analysis. Results showed that total phosphorus and heavy metal element Cu from the sediments were two significant variables, explaining solely 12.7% and 8.5% of the variances in diatom data, respectively. Therefore, anthropogenic nutrient input was the most important factor on the environmental evolution of Lake Liangzi. Meanwhile, heavy metal pollution also imposed an important effect on this lake. The results of this study can provide a baseline of scientific information for environment restoration in the present lake and other similar lakes in the Yangtze floodplain.

长江中下游四大淡水湖生态系统完整性评价

PDF HTML阅读 XML下载 导出引用 引用提醒 长江中下游四大淡水湖生态系统完整性评价 DOI: 10.5846/stxb201410101992 作者: 作者单位: 中国科学院南京地理与湖泊研究所,中国科学院南京地理与湖泊研究所,中国科学院南京地理与湖泊研究所,中国科学院南京地理与湖泊研究所,中国科学院南京地理与湖泊研究所,中国科学院南京地理与湖泊研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点基础研究发展计划(2012CB417006);国家水污染治理重大专项(2012ZX07501002-008,2012ZX07506-001,2012ZX07103003-04-01,2012ZX07501-001-03);江西省水利厅科技项目(KT201406);鄱阳湖湿地与流域研究教育部重点实验室(江西师范大学)开放基金(PK2015007) Aquatic ecological integrity assessment of four large lakes in the middle-to-lower reaches of the Yangtze River, China Author: Affiliation: Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences,Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences,Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences,Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences,Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences,Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:长江中下游地区是我国淡水湖泊集中分布区域,研究该区域湖泊生态系统完整性对于湖泊生态系统保护和恢复具有重要意义。物理、化学和生物完整性指标已经广泛应用于河湖生态系统健康评价,但是缺少物理、化学和生物完整性的综合评价方法。以历史调查状况为主要参照系统,构建了基于物理、化学和生物完整性的多参数湖泊完整性综合评价指标体系,结合近年来长江中下游四大淡水湖(洞庭湖、鄱阳湖、巢湖、太湖)生态系统调查数据,对四大淡水湖生态系统完整性进行了评价。结果表明,洞庭湖、鄱阳湖、巢湖和太湖的综合得分分别为66、71、57和57。根据评价等级划分标准,洞庭湖和鄱阳湖生态系统完整性状况都达到"好"的等级,而巢湖和太湖则处于"一般"等级;结果显示,该指标能够表征人类活动对于湖泊生态系统完整性不同方面的干扰,且能够反映四大淡水湖生态系统完整性历史变化状况。因此,该方法可以作为长江中下游淡水湖泊生态系统完整性综合评价的工具并能够为湖泊生态系统的保护和恢复提供科学支撑。 Abstract:Many freshwater lakes are distributed in the middle-lower reaches of the Yangtze River basin; they are of great importance as water supply resources and for aquatic eco-system maintenance. The evaluation of lake health and its variation is useful for environmental management of lake ecosystems. Numerous indices related to physical, chemical, and biological integrity are widely applied to assess the health of lake ecosystems. However, few studies have assessed the ecological integrity of lakes using a combination of physical, chemical, and biological integrity metrics in China, especially at a regional scale. Based on a review of previous research, a lake ecological integrity index (LEII) including physical, chemical, and biological (algae, macroinvertebrates, and fish) integrity metrics was developed to evaluate four large lakes in the middle-lower reaches of the Yangtze Basin. Reference conditions were defined mainly based on historical data collected in the 1950s and 1960s, when the status of lake ecological integrity was acknowledged as "good." The final score for the lake ecosystems integrity index was calculated by combining the scores for physical, chemical, and biological integrity metrics. Additionally, the scores were divided into five categories, i.e., excellent, good, fair, poor, and very poor. The LEIIs of Lake Dongting, Poyang, Chaohu, and Taihu were 66, 71, 57, and 57, respectively. Based on the LEII scores, Lake Dongting and Lake Poyang were rated "good" and Lake Chaohu and Lake Taihu were "fair." However, the individual indices showed different status for the four large lakes. For instance, the physical integrity index was higher than 80 for all lakes except Chaohu Lake (71), suggesting an "excellent" status. The highest score for the chemical integrity index was observed in Lake Poyang (71) and the lowest score in Lake Taihu (56). Three were rated as "good." The biological integrity index ranged from 46 in Lake Taihu to 65 in Lake Poyang, two were rated as "fair." The four large lakes suffered from various degrees of damage in physical, chemical, and biological integrity, and these differences demonstrated the effects of human activity on the ecological integrity of the four large lakes over the past 50 years. Consequently, the LEII can be used as a tool to assess the ecological integrity of the four large lakes along the Yangtze River, and the results provide a scientific basis for lake ecosystem restoration and protection. 参考文献 相似文献 引证文献

An Area Growth Model of Eichhornia Crassipes with Application to Lake Ecosystem Restoration

The aim of this study was to investigate the use of a model to determine growth properties of Eichhornia crassipes in lake ecosystem restoration, in particular Eichhornia crassipes area. A logistic model was constructed to eatimate the area of Eichhornia crassipes and tested in Eichhornia crassipes samples. The area of Eichhornia crassipes was measured nine times in experiment period using GPS and satellite remote sensing images. The measurements were shown to lead to a determination of the parameters of accurate logistic model with an overall Goodness of Fit Index of 0.9753. This indicates that there is a possibility of obtaining accurate Eichhornia crassipes area from the logistic model and suggests that it is possible to implement lake ecosystem restoration with harvesting Eichhornia crassipes to remove the nutrient in lake.

Phytoplankton Abundance Constrains Planktonic Energy Subsidy to Benthic Food Web

Linkages across habitats between habitats are fundamental components of ecological processes. As a major characteristic of within-lake food webs, linkage of benthic and planktonic food webs has received a great deal of attention in recent aquatic studies. However, planktonic energy subsidy to benthic consumers has been infrequently tested in experiment. In a field experiment manipulating nutrients and phytoplankton abundance, we ask how changes in phytoplankton abundance affect planktonic energy subsidy to benthic primary consumers across nutrient levels. Our results suggest that the planktonic subsidy to benthic primary consumers depends on the phytoplankton abundance. Furthermore, highly taxon-specific planktonic energy subsidy to benthic primary consumers suggests that the benthic community composition partially determines the degree of the planktonic-benthic linkage. Because shallow and eutrophic lakes distribute worldwide, and many ecological functions are mediated by planktonic-benthic linkage, it will be important to consider these findings to protection and restoration of lake ecosystems.

Temporal variations of NDVI and correlations between NDVI and hydro-climatological variables at Lake Baiyangdian, China

In this paper, correlations between vegetation dynamics (represented by the normalized difference vegetation index (NDVI)) and hydro-climatological factors were systematically studied in Lake Baiyangdian during the period from April 1998 to July 2008. Six hydro-climatological variables including lake volume, water level, air temperature, precipitation, evaporation, and sunshine duration were used, as well as extracted NDVI series data representing vegetation dynamics. Mann-Kendall tests were used to detect trends in NDVI and hydro-climatological variation, and a Bayesian information criterion method was used to detect their abrupt changes. A redundancy analysis (RDA) was used to determine the major hydro-climatological factors contributing to NDVI variation at monthly, seasonal, and yearly scales. The results were as follows: (1) the trend analysis revealed that only sunshine duration significantly increased over the study period, with an inter-annual increase of 3.6 h/year (p < 0.01), whereas inter-annual NDVI trends were negligible; (2) the abrupt change detection showed that a major hydro-climatological change occurred in 2004, when abrupt changes occurred in lake volume, water level, and sunlight duration; and (3) the RDA showed that evaporation and temperature were highly correlated with monthly changes in NDVI. At larger time scales, however, water level and lake volume gradually became more important than evaporation and precipitation in terms of their influence on NDVI. These results suggest that water availability is the most important factor in vegetation restoration. In this paper, we recommend a practical strategy for lake ecosystem restoration that takes into account changes in NDVI.

Long-term Water Quality Variations and Chlorophyll a Simulation with an Emphasis on Different Hydrological Periods in Lake Baiyangdian, Northern China

Eutrophication and water quality degradation comprise one of the most important environmental problems associated with protecting freshwater. Here, systematical analyses of trends, qualitative and quantitative analyses of water quality variables, and simulations of eutrophication were conducted to evaluate biochemical oxygen demand (BOD), total phosphorus (TP), total nitrogen (TN), dissolved oxygen (DO), chlorophyll a (Chl a), and Secchi disk data (SD) based on separate hydrological periods to enhance our understanding of lake ecosystem restoration. Long-term trends were identified using seasonal-trend decomposition with local error sum of squares, while non-supervised artificial neural networks were used to identify qualitative characteristics, and quantitative characteristics were measured using statistical analyses. Numerical simulation of Chl a by the hybrid evolutionary algorithm provided a theoretical solution for ecological warnings. The results were as follows: (1) declining trends in BOD, TP, TN, DO and Chl a were observed during long-term seasonal decomposition after December 2006, but SD increased after June 2003; (2) partitioned K-means maps revealed quantitative characteristics with heterogeneous changes during three hydrological periods, with BOD, TN, SD and Chl a showing the highest clustering quality; (3) BOD and DO showed clear relative hierarchies when compared with other parameters based on quantitative analysis; (4) Chl a simulation revealed heterogeneous changes in the three hydrological periods, and sensitivity analyses indicated that BOD was highly sensitive to Chl a, but TP was not. The sensitivities of other parameters changed during different hydrological periods. The methods described here can be used as preliminary management tools for degraded lakes.