河岸无脊椎动物多样性维持机制研究进展

河岸是河流与陆地之间重要的生态界面,生物多样性丰富,但受到人为活动的严重威胁。无脊椎动物在河岸生物多样性中占有重要地位,发挥着非常重要的生态功能,也是水生生态系统和陆地生态系统之间物质和能量联系的重要纽带。尽管已有很多学者对河岸无脊椎动物群落进行了研究,但缺乏对河岸无脊椎动物多样性维持机制的总结。本文结合洪水和干旱、营养物质、微生境多样性、河岸植被、微气候梯度、食物资源以及河流空间梯度等影响因素,初步讨论和归纳了河岸无脊椎动物多样性的维持机制。周期性洪水和干旱引发了无脊椎动物的繁殖和迁移等行为,增加了河岸无脊椎动物群落周转率,为无脊椎动物创造了理想的条件。充足的营养物质使河岸具有较高的初级生产力,支撑了较高的无脊椎动物多样性。较高的微生境多样性为无脊椎动物提供了多样的生态位空间,孕育了特殊的河岸无脊椎动物种类。复杂的河岸植物群落不但是河岸无脊椎动物的食物来源之一,也为河岸无脊椎动物提供了多样的生态位空间和重要的避难场所。微气候环境的空间分异提供了复杂多样的生境条件,为水生无脊椎动物和陆生无脊椎动物种类在河岸共存创造了条件。跨越界面的资源补给增加了河岸无脊椎动物的食物可利用率,为河岸无脊椎动物提供了特殊的食物来源。这些因素在空间上呈现出明显的纵向梯度和侧向梯度,从更大尺度上为河岸无脊椎动物的多样化提供了条件。因此,探讨河岸无脊椎动物多样性的维持机制对于河岸生物多样性保护以及河流生态系统综合管理具有重要的指导意义。     

闽江流域生态安全格局及其生态保护修复措施

流域及其生态环境问题受到国内外的广泛关注,我国面临的流域生态环境问题突出亟待解决,体现流域生态系统完整性的山水林田湖草生命共同体理念对我国流域生态保护修复工作具有重要意义。以福建省山水林田湖草生态保护修复试点的工程区——闽江流域为例,在介绍其生态环境特征的基础上,通过梳理分析,根据区域生态功能的重要性构建“一江一带一区一屏”的闽江流域总体生态安全格局,面临的主要生态环境问题包括闽江水环境污染、流域岸带水土流失、矿区生态破坏、森林屏障和生物多样性退化等一系列威胁;分析提出了闽江水环境综合治理、干支流沿岸带水土流失防治、矿区废弃土地修复、武夷山地等重要生态屏障森林和生物多样性保护等主要任务及相应工程措施,体现了流域整体性、系统性的保护修复需求和内在逻辑;讨论了监测、评价等保障措施,为改善闽江流域生态系统和开展山水林田湖草生态保护修复工程提供科学依据和实践经验。     

LiDAR derived ecological integrity indicators for riparian zones: Application to the Houille river in Southern Belgium/Northern France

Riparian zones are central landscape features providing several ecosystem services and are exceptionally rich in biodiversity. Despite their relatively low area coverage, riparian zones consequently represent a major concern for land and water resource managers confirmed within several European directives. These directives involve effective multi-scale monitoring to assess their conditions and their ability to carry out their functions. The objective of this research was to develop automated tools to provide from a single aerial LiDAR dataset new mapping tools and keystone riparian zone attributes assessing the ecological integrity of the riparian zone at a network scale (24 km).Different metrics were extracted from the original LiDAR point cloud, notably the Digital Terrain Model and Canopy Height Model rasters, allowing the extraction of riparian zones attributes such as the wetted channel (0.89 m; mean residual) and floodplain extents (6.02 m; mean residual). Different riparian forest characteristics were directly extracted from these layers (patch extent, overhanging character, longitudinal continuity, relative water level, mean and relative standard deviation of tree height). Within the riparian forest, the coniferous stands were distinguished from deciduous and isolated trees, with high accuracy (87.3%, Kappa index).Going further the mapping of the indicators, our study proposed an original approach to study the riparian zone attributes within different buffer width, from local scale (50 m long channel axis reach) to a network scale (ca. 2 km long reaches), using a disaggregation/re-agraggation process. This novel approach, combined to graphical presentations of the results allow natural resource managers to visualise the variation of upstream–downstream attributes and to identify priority action areas.In the case study, results showed a general decrease of the riparian forests when the river crosses built-up areas. They also highlighted the lower flooding frequency of riparian forest patches in habitats areas.Those results showed that LiDAR data can be used to extract indicators of ecological integrity of riparian zones in temperate climate zone. They will enable the assessment of the ecological integrity of riparian zones to be undertaken at the regional scale (13,000 km, completely covered by an aerial LIDAR survey in 2014).     

河道生态系统特征及其自净化能力研究现状与发展

河道生态系统包括河道水体和河岸带两大部分,具有净化水体、降低污染物浓度的功能.研究河道生态系统的自净化能力对河道生态系统的健康评价及水环境管理具有重要的意义.目前该领域的研究主要侧重于两个方面:一方面是运用水质模型的方法模拟评价河道水体的自净化能力,另一方面则是研究河岸植被缓冲带对净化水体的作用.系统总结了目前研究的特点与不足,指出了今后应该重视的研究领域,主要包括:(1)应加强研究陆地生态系统空间异质性对河道自净化能力的影响研究;(2)需要系统解剖河道剖面形态结构与空间布局对河道水质自净化能力的影响;(3)重视面向外部复杂环境的参数获取方法的研究;(4)综合河岸生态系统与河道水体生态系统,系统研究非点源污染在陆-水迁移和水体运移中河道生态系统自净化能力的时空变化特征,从而为开展河道生态系统健康评价,河道生态系统管理提供科学的依据.     

Developing a vision for improved monitoring and reporting of riparian restoration projects

Representatives from agencies involved in natural resource management in the Murray‐Darling Basin gathered for a workshop in November 2010 to develop a vision for improved monitoring and reporting of riparian restoration projects. The resounding message from this workshop was that the effectiveness of riparian restoration depends on having sound, documented and agreed evidence on the ecological responses to restoration efforts. Improving our capacity to manage and restore riparian ecosystems is constrained by (i) a lack of ecological evidence on the effects of restoration efforts, and (ii) short‐termism in commitment to restoration efforts, in funding of monitoring and in expected time spans for ecosystem recovery. Restoration at the effective spatial scope will invariably require a long‐term commitment by researchers, funding agencies, management agencies and landholders. To address the knowledge gaps that constrain riparian restoration in the Basin, participants endorsed four major fields for future research: the importance of landscape context to restoration outcomes; spatio‐temporal scaling of restoration outcomes; functional effects of restoration efforts; and developing informative and effective indicators of restoration. To improve the monitoring and restoration of riparian zones throughout the Basin, participants advocated an integrated approach: a hierarchical adaptive management framework that incorporates long‐term ecological research.     

Evaluation of ecosystem health for the coastal wetlands at the Yangtze Estuary, Shanghai

Despite the growing awareness of the important ecological functions and values provided by coastal and estuarine wetlands, wetland degradation continues worldwide due to increasing anthropogenic disturbances. Chongming Dongtan wetlands, adjacent to Shanghai, the largest city and industrial and trading port in China in rapid urban expansion and socioeconomic development are currently threatened with biodiversity reduction, wetland loss, contamination, and invasion of exotic plant. Sustainable protection and management of Dongtan Nature Reserve necessitate research to develop diagnostic tools and indicators for a comprehensive and objective assessment of wetland ecosystem health condition. Based on the pressure-state-response framework and ecological and environmental surveys at the Dongtan wetlands, an indicator system was established for evaluating the coastal wetlands ecosystem health, using indicators detected from satellite imagery and current field surveys. Through the establishment of health assessment units and spatial quantification of the indicators, the spatial clustering analysis, integrated with remote sensing and geographic information system technique was applied to make an accurate diagnosis of ecosystem health for Chongming Dongtan wetlands and highlight the areas in subhealthy and unhealthy condition and urgent need of conservation and management. The results from this research indicated that the ecosystem health condition at the Dongtan wetlands showed spatial variation, to a certain extent, corresponding to the distributions of elevation and land cover types. More than 75 % of the total study area was at a relatively healthy level, with 34.19 km² for the very healthy zone and 41.08 km² for the healthy zone, while the subhealthy and unhealthy zones covered 18.23 and 4.76 km², respectively. This study demonstrated the potential for this integrated approach to give objective and effective evaluation of ecosystem health for the dynamic coastal and estuarine wetlands and provide up-to-date information to assist with early warning for ecological security and management decisions for Chongming Dongtan Nature Reserve.     

The use of Bayesian networks to guide investments in flow and catchment restoration for impaired river ecosystems

1.  The provision of environmental flows and the removal of barriers to water flow are high priorities for restoration where changes to flow regimes have caused degradation of riverine ecosystems. Nevertheless, flow regulation is often accompanied by changes in catchment and riparian land-use, which also can have major impacts on river health via local habitat degradation or modification of stream energy regimes.
2.  The challenges are determining the relative importance of flow, land-use and other impacts as well as deciding where to focus restoration effort. As a consequence, flow, catchment and riparian restoration efforts are often addressed in isolation. River managers need decision support tools to assess which flow and catchment interventions are most likely to succeed and, importantly, which are cost-effective.
3.  Bayesian networks (BNs) can be used as a decision support tool for considering the influence of multiple stressors on aquatic ecosystems and the relative benefits of various restoration options. We provide simple illustrative examples of how BNs can address specific river restoration goals and assist with the prioritisation of flow and catchment restoration options. This includes the use of cost and utility functions to assist decision makers in their choice of potential management interventions.
4.  A BN approach facilitates the development of conceptual models of likely cause and effect relationships between flow regime, land-use and river conditions and provides an interactive tool to explore the relative benefits of various restoration options. When combined with information on the costs and expected benefits of intervention, one can derive recommendations about the best restoration option to adopt given the network structure and the associated cost and utility functions.     

River networks as biodiversity hotlines

For several years, measures to insure healthy river functions and to protect biodiversity have focused on management at the scale of drainage basins. Indeed, rivers bear witness to the health of their drainage basins, which justifies integrated basin management. However, this vision should not mask two other aspects of the protection of aquatic and riparian biodiversity as well as services provided by rivers. First, although largely depending on the ecological properties of the surrounding terrestrial environment, rivers are ecological systems by themselves, characterized by their linearity: they are organized in connected networks, complex and ever changing, open to the sea. Second, the structure and functions of river networks respond to manipulations of their hydrology, and are particularly vulnerable to climatic variations. Whatever the scale considered, river networks represent "hotlines" for sharing water between ecological and societal systems, as well as for preserving both systems in the face of global change. River hotlines are characterized by spatial as well as temporal legacies: every human impact to a river network may be transmitted far downstream from its point of origin, and may produce effects only after a more or less prolonged latency period. Here, I review some of the current issues of river ecology in light of the linear character of river networks.     

北京市生态用地规划与管理对策

不合理土地开发加速了对自然生态系统的干扰和侵占,导致生态系统服务功能下降,危机区域生态安全,开展生态用地规划是构建区域生态安全格局的基础。合理规划和管理不同土地利用类型的数量和空间分布对区域可持续发展具有重要意义。目前我国广泛应用的土地利用分类体系主要以土地的社会经济属性为基础,忽视其生态属性,导致以提供生态系统服务为主、保障生态安全的土地缺乏保护机制,具有重要生态功能的土地得不到有效保护。以北京市为例,建立了北京市生态用地分类与规划的思路与程序,在明确北京市生态安全与生态系统服务功能的关系基础上分析了北京市生态系统服务功能重要性及其空间格局,并进行了北京市生态用地规划。研究规划了保障北京市生态安全的7类生态用地:地表水涵养与保护用地、地下水保护用地、生物多样性保护用地、水土保持用地、河流防护用地、公路防护用地和城市绿地,总面积5137.37km2,占北京市域面积的31.31%。最后从生态用地识别和划分、将生态用地融入土地利用分类体系、生态用地管理措施和对策3个方面探讨了生态用地规划和管理的方法与措施。研究结果为北京市土地利用规划和有效管理提供依据,也为其它地区的生态用地规划提供参考。     

Methodological and empirical considerations when assessing freshwater ecosystem service provision in a developing city context: Making the best of what we have

This study contributes to both the methodological and empirical literature by developing an integrative approach to assessing temporal and spatial change in riparian ecosystem service delivery by drawing on available and diverse data sets. These data sets act as multiple lines of evidence in supporting comparisons between data sets to test the validity of developed methods and the application of such methods. In order to synthesise these data as well as to determine the fluctuations in riparian ecosystem service provision a scoring system was developed. Methodologically, the scoring system proved informative across the majority of ecosystem services categories, showing close to 80% similarity in outcomes when comparing the scoring method to trends in long-term water quality measurements. Other benefits of the scoring system included its design simplicity, cost-effectiveness, and applicability and replicability across various urban settings. Empirically, the data sets used support the findings of the ecosystem services scoring exercise and suggests that fluctuations in ecosystem service delivery through time and across the river reaches are linked to land-use change and other human activities. Findings suggest that as water leaves an urban protected area and travels across transformed and impacted landscapes, the results are poor water quality and diminished ability of rivers to yield ecosystem services the further the river flows into the urban setting. Urbanisation and changes in land-uses in developing city contexts is therefore shown to affect potential ecosystem services benefits, necessitating increasing management interventions.     

Trends in the Massachusetts cranberry industry create opportunities for the restoration of cultivated riparian wetlands

Many ecosystem services provided by wetlands decline if they are managed for agricultural use. Ecological restoration of retired agricultural lands can restore these ecosystem services, yet practitioners require information on where restoration is possible and most likely to succeed. We report trends in the Massachusetts cranberry industry which suggest that cranberry farms located in riparian fens are well suited for ecological restoration that enhance their characteristics and functions as wetlands. We created a classification scheme for cranberry farms based on their: (1) crop status; (2) renovation status; (3) cultivar type; and (4) hydrologic type for the Wareham River watershed in southeastern Massachusetts. We ranked farms for their priority for restoration and extrapolated our results to the total cranberry acreage of Massachusetts. The occurrence of low‐yielding native cranberry cultivars in all riparian farms (i.e. those with a direct hydrological connection to an adjacent river or stream), combined with our finding that 100% of the area of the highest‐yielding new cultivars were planted in newly renovated but non‐riparian farms suggest that riparian farms are not targets for investment but instead have a high likelihood of retirement. We found that 20% of farm area in this watershed had riparian hydrology, a proportion suggesting the existence of over 1,000 ha of high‐priority farms for restoration statewide. Restoration of these stream‐adjacent riparian farms can provide an exit strategy for some cranberry growers, ease economic pressures on remaining growers, and develop wetlands able to provide ecosystem services such as habitat provision, nitrogen removal, and recreation.     

Do riparian reserves support dung beetle biodiversity and ecosystem services in oil palm-dominated tropical landscapes?

Agricultural expansion and intensification are major threats to global biodiversity, ecological functions, and ecosystem services. The rapid expansion of oil palm in forested tropical landscapes is of particular concern given their high biodiversity. Identifying management approaches that maintain native species and associated ecological processes within oil palm plantations is therefore a priority. Riparian reserves are strips of forest retained alongside rivers in cultivated areas, primarily for their positive hydrological impact. However, they can also support a range of forest‐dependent species or ecosystem services. We surveyed communities of dung beetles and measured dung removal activity in an oil palm‐dominated landscape in Sabah, Malaysian Borneo. The species richness, diversity, and functional group richness of dung beetles in riparian reserves were significantly higher than in oil palm, but lower than in adjacent logged forests. The community composition of the riparian reserves was more similar to logged forest than oil palm. Despite the pronounced differences in biodiversity, we did not find significant differences in dung removal rates among land uses. We also found no evidence that riparian reserves enhance dung removal rates within surrounding oil palm. These results contrast previous studies showing positive relationships between dung beetle species richness and dung removal in tropical forests. We found weak but significant positive relationships between riparian reserve width and dung beetle diversity, and between reserve vegetation complexity and dung beetle abundance, suggesting that these features may increase the conservation value of riparian reserves. Synthesis and applications: The similarity between riparian reserves and logged forest demonstrates that retaining riparian reserves increases biodiversity within oil palm landscapes. However, the lack of correlation between dung beetle community characteristics and dung removal highlights the need for further research into spatial variation in biodiversity–ecosystem function relationships and how the results of such studies are affected by methodological choices.     

Plant invasions in the rivers of the Iberian Peninsula,south-western Europe: A review

Aquatic and riparian ecosystems are known to be highly vulnerable to invasive alien species (IAS), especially when subjected to human-induced disturbances. In the last three decades, we have witnessed a growing increase in plant invasions in Portugal and Spain (Iberian Peninsula, south-western Europe), with very detrimental economic, social and ecological effects. Some of these species, such as the giant reed (Arundo donax L.) and the water hyacinth (Eichhornia crassipes (Mart.) Solms-Laub.), number among the world's worst weeds. We present an appraisal of this invasive alien river flora and the most problematic aquatic weeds. We review various aspects of invasion ecology, including spatial and temporal patterns of invasion, species invasiveness, species traits of invasive weeds, and relationships between human disturbance in rivers and surrounding areas and invasibility, and contextualize them in overall state-of-the-art terms. We also acknowledge the use of IAS as bioindicators of the ecological quality of rivers, wetlands and riparian zones. Remote-sensing tools and Geographic Information Systems for detecting and monitoring IAS in Iberian rivers are presented.     

Development of a reference-based method for identifying and scoring indicators of condition for coastal plain riparian reaches

Indicators of riparian ecosystem condition for headwater coastal plain streams were identified from data obtained from a reference population of reaches ranging widely in ecological condition. Each indicator was associated with some facet of hydrologic, biogeochemical, and/or habitat functioning and to channel condition, riparian zone condition, or both. Variation in the condition of the indicators among reference reaches provided a framework for developing narratives that could be used to partition and score the condition of the indicators from 0 (severely altered) to 100 (relatively unaltered). The developed narratives were the basis for creating a scoring approach for assessing stream condition at the reach scale (100-m long × 60-m wide segment). This approach was designed to be a rapid, field-based assessment method (<1 h/site) that could be applied by resource professionals with several days of training in the method. Although most alterations to riparian reaches usually affect both channels and riparian zones together, the ability to score channel and riparian zone condition separately is useful for diagnosing problems and suggesting viable restoration options at the reach scale. The assessment method is also useful for comparing the condition of reaches relative to one another, thus offering guidance for prioritizing restoration efforts at a watershed scale.     

Challenges in applying scientific evidence to width recommendations for riparian management in agricultural Australia

Intact riparian zones maintain aquatic–terrestrial ecosystem function and ultimately, waterway health. Effective riparian management is a major step towards improving the condition of waterways and usually involves the creation of a ‘buffer’ by fencing off the stream and planting vegetation. Determination of buffer widths often reflects logistical constraints (e.g. private land ownership, existing infrastructure) of riparian and adjacent areas, rather than relying on rigorous science. We used published information to support riparian width recommendations for waterways in agricultural Victoria, Australia. We focused on different ecological management objectives (e.g. nutrient reduction or erosion control) and scrutinised the applicability of data across different environmental contexts (e.g. adjacent land use or geomorphology). Not surprisingly, the evidence supported variable ‘effective’ riparian widths, depending on the objective and environmental context. We used this information to develop a framework for determining riparian buffer widths to meet a variety of ecological objectives in south‐east Australia. Widths for reducing nutrient inputs to waterways were most strongly supported with quantitative evidence and varied between 20 and 38 m depending on environmental context. The environmental context was inconsistently reported, making it difficult to recommend appropriate widths, under different land‐use and physiographic scenarios. The evidence to guide width determination generally had high levels of uncertainty. Despite the considerable amount of published riparian research, there was insufficient evidence to demonstrate that implemented widths achieved ecological objectives. We emphasise the need for managers to clearly articulate the objectives of proposed riparian management and carefully consider the environmental context. Monitoring ecological responses associated with different riparian buffer widths is essential to support future management decisions.     

黄河上游甘蒙柽柳生长对极端旱涝的响应

青藏高原黄河上游河岸带是典型的生态脆弱区, 然而近年来气候变暖加剧了该地极端旱涝事件的频繁发生, 高原河岸带生态脆弱区植被是否能够应对极端旱涝事件的干扰成为流域生态环境管理工作所关注的重点问题。为了研究黄河上游河岸林中主要树种对极端旱涝的响应, 该研究选取青海省同德县和兴海县3处河岸林中的47株甘蒙柽柳(Tamarix austromongolica), 分别从树干面向邻近山体一侧及与之垂直的一侧分别获取1根树轮样本, 分析其历史生长。通过对比两个方向上的生长速率判断甘蒙柽柳是否受到地质灾害影响从而将其划分为受伤组和对照组, 分析两组甘蒙柽柳在过去63年中径流极值年的抵抗力状况及两个方向的生长差异。研究发现, 甘蒙柽柳对干旱和洪涝均有着很强的抵抗力, 河岸带多样化的水分来源有助于甘蒙柽柳在极端干旱环境中较好地生长; 但洪涝伴随泥石流等地质灾害的频发使甘蒙柽柳面向山体侧面受到严重的生长抑制, 表现出显著的方向性差异, 从而影响甘蒙柽柳的形态。较长的创伤恢复期带来的遗留效应可能造成甘蒙柽柳对外界干扰的较高敏感性。研究黄河上游甘蒙柽柳生长对极端旱涝的响应, 将有助于评估生态脆弱区生态弹性过程, 同时为高原河岸带生态建设和恢复提供科学依据。     

生态系统综合评价的内容与方法

生态系统综合评价是系统分析生态系统的生产及服务能力,对生态系统进行健康诊断,做出综合的生态分析和经济分析,评价其当前状态,并预测生态系统今后的发展趋势,为生态系统管理提供科学依据。从总体上讲,综合评价更强调生态系统一系列产品与服务功能之间的权衡,具有很强的实践意义。许多学者对不同的生态系统服务功能进行了经济价值评估,但缺乏对生态系统的产品、服务、健康与管理之间关系的进一步探讨。对生态系统服务功能评价、健康评价的生态管理与预测进行了系统论述,目的是提出生态系统综合评价的框架,指导生态系统评价行动及生态系统管理。     

Stream invertebrate diversity reduces with invasion of river banks by non‐native plants

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