Assessment of environmental conditions of Nan-Shih stream in Taiwan

Restoration is a complex endeavor requiring the understanding of the degrading environment before applying any improvement measure. Environmental and ecological data in Nan-Shih stream were investigated in this study to assess its stream condition. Based on the data collected, the Index of Biotic Integrity (IBI index) which takes fish species as the major target, the Family-level Biotic Index (FBI) aquatic insects Hilsenhoff index and the Genus Index (GI) of algae were thus analyzed to quantify Nan-Shih stream's ecological system. The indices above were then applied on Index of Stream Condition (ISC index) to describe the overall river condition. Modified sub-indices, including the hydrology, physical form, streamside zone, water quality, and aquatic life, were made and used to provide baseline assessment information. ISC value is 33.89 evaluated as marginal level, in which hydrology sub-index score was the lowest indicating impact of artificial structures affecting flow significantly. The recommendations of the river corridor restoration and the habitat improvement were thus proposed as a reference for river management.     

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.     

Fish and flow management in the Murray–Darling Basin: Directions for research

Effective natural resource management requires knowledge exchange between researchers and managers to support evidence‐based decision‐making. To achieve this, there is a need to align research with management and policy needs. This project aimed to identify the flow‐related ecological knowledge needs for freshwater fish to better inform environmental water management in the Murray–Darling Basin, south‐eastern Australia. Our major objective was to provide an up‐to‐date assessment of scientific research and integrate this with the knowledge requirements of relevant managers to guide future research. We reviewed the contemporary scientific literature and engaged managers specifically responsible for delivering flows for fish outcomes via a questionnaire and workshop. Research on fishes of the MDB has generally evolved from single locations and/or times to larger spatio‐temporal scales, including multiple sites, rivers and catchments. There has also been a trend from single life stage studies to incorporation of multiple life stages and population processes. There remain, however, significant deficiencies in knowledge for most native species, many of which are threatened. Four agreed key knowledge gaps were derived from the literature review and managers’ suggestions: (i) population dynamics, (ii) movement, dispersal and connectivity, (iii) survival and recruitment to adults and (iv) recruitment drivers. To inform policy and management, managers desired timely advice, based on robust research and monitoring. Fish species of most relevance to managers were those highly regarded by community stakeholders and whose life histories and population dynamics are potentially influenced by flow. Populations of these mostly large‐bodied, angling species (e.g. Murray Cod, Golden Perch and Silver Perch) have declined, often due to river regulation and, in conjunction with managers’ priorities, are relevant candidates for research to support the management of flow to rehabilitate fish populations in the MDB.     

Comparison of watershed disturbance predictive models for stream benthic macroinvertebrates for three distinct ecoregions in western US

The successful use of macroinvertebrates as indicators of stream condition in bioassessments has led to heightened interest throughout the scientific community in the prediction of stream condition. For example, predictive models are increasingly being developed that use measures of watershed disturbance, including urban and agricultural land-use, as explanatory variables to predict various metrics of biological condition such as richness, tolerance, percent predators, index of biotic integrity, functional species traits, or even ordination axes scores. Our primary intent was to determine if effective models could be developed using watershed characteristics of disturbance to predict macroinvertebrate metrics among disparate and widely separated ecoregions. We aggregated macroinvertebrate data from universities and state and federal agencies in order to assemble stream data sets of high enough density appropriate for modeling in three distinct ecoregions in Oregon and California. Extensive review and quality assurance of macroinvertebrate sampling protocols, laboratory subsample counts and taxonomic resolution was completed to assure data comparability. We used widely available digital coverages of land-use and land-cover data summarized at the watershed and riparian scale as explanatory variables to predict macroinvertebrate metrics commonly used by state resource managers to assess stream condition. The “best” multiple linear regression models from each region required only two or three explanatory variables to model macroinvertebrate metrics and explained 41–74% of the variation. In each region the best model contained some measure of urban and/or agricultural land-use, yet often the model was improved by including a natural explanatory variable such as mean annual precipitation or mean watershed slope. Two macroinvertebrate metrics were common among all three regions, the metric that summarizes the richness of tolerant macroinvertebrates (RICHTOL) and some form of EPT (Ephemeroptera, Plecoptera, and Trichoptera) richness. Best models were developed for the same two invertebrate metrics even though the geographic regions reflect distinct differences in precipitation, geology, elevation, slope, population density, and land-use. With further development, models like these can be used to elicit better causal linkages to stream biological attributes or condition and can be used by researchers or managers to predict biological indicators of stream condition at unsampled sites.     

Improving biological indicators to better assess the condition of streams

Biological indicators of stream condition are in use by water resource managers worldwide. The State of Maryland and many other organizations that use Indices of Biotic Integrity (IBIs) must determine when and how to refine their IBIs so that better stream condition information is provided. With completion of the second statewide round in 2004, the Maryland Biological Stream Survey (MBSS) had collected data from 2500 stream sites, more than doubling the number of sites that were available for the original IBI development. This larger dataset provided an opportunity for the MBSS to address the following shortcomings in the original IBIs: (1) substantial disturbance apparent in some reference sites, (2) fish IBIs could not be applied to very small streams, (3) natural variability within IBIs (based on regions) resulted in some stream types (e.g., coldwater and blackwater streams) receiving lower IBI scores and (4) one IBI was not able to discriminate degradation as desired (i.e., Coastal Plain fish IBI). Therefore, development of new fish and benthic macroinvertebrate IBIs was undertaken to achieve the goals of: (1) increased confidence that the reference conditions are minimally disturbed, (2) including more natural variation (such as stream size) across the geographic regions and stream types of Maryland and (3) increased sensitivity of IBIs by using more classes (strata) and different metric combinations. New fish IBIs were developed for four geographical and stream type strata: Coastal Plain, Eastern Piedmont, warmwater Highlands and coldwater Highlands streams; new benthic macroinvertebrate IBIs were developed for three geographical strata: Coastal Plain, Eastern Piedmont and Highlands streams. The addition of one new fish IBI and one new benthic macroinvertebrate IBI partitioned natural variability into more homogeneous strata. At the same time, smaller streams (i.e., those draining catchments <300 ac), which constituted a greater proportion of streams (25%) sampled in Round Two (2000–2004) than Round One (1995–1997), because of the finer map scale, were included in the reference conditions used to develop the new IBIs. The resulting new IBIs have high classification efficiencies of 83–96% and are well balanced between Type I and Type II errors. By scoring coldwater streams, smaller streams and to some extent blackwater streams higher, the new IBIs improve on the original IBIs. Overall, the new IBIs provide better assessments of stream condition to support sound management decisions, without requiring substantial changes by cooperating stream assessment programs.     

Modifying the Bank Erosion Hazard Index (BEHI) Protocol for Rapid Assessment of Streambank Erosion in Northeastern Ohio

Understanding the source of pollution in a stream is vital to preserving, restoring, and maintaining the stream’s function and habitat it provides. Sediments from highly eroding streambanks are a major source of pollution in a stream system and have the potential to jeopardize habitat, infrastructure, and stream function. Watershed management practices throughout the Cleveland Metroparks attempt to locate and inventory the source and rate the risk of potential streambank erosion to assist in formulating effect stream, riparian, and habitat management recommendations. The Bank Erosion Hazard Index (BEHI), developed by David Rosgen of Wildland Hydrology is a fluvial geomorphic assessment procedure used to evaluate the susceptibility of potential streambank erosion based on a combination of several variables that are sensitive to various processes of erosion. This protocol can be time consuming, difficult for non-professionals, and confined to specific geomorphic regions. To address these constraints and assist in maintaining consistency and reducing user bias, modifications to this protocol include a “Pre-Screening Questionnaire”, elimination of the Study Bank-Height Ratio metric including the bankfull determination, and an adjusted scoring system. This modified protocol was used to assess several high priority streams within the Cleveland Metroparks. The original BEHI protocol was also used to confirm the results of the modified BEHI protocol. After using the modified assessment in the field, and comparing it to the original BEHI method, the two were found to produce comparable BEHI ratings of the streambanks, while significantly reducing the amount of time and resources needed to complete the modified protocol.     

Pieter Hendrik Nienhuis: Aquatic Ecologist and Environmental Scientist

Prof. Dr. Pieter Hendrik (Piet) Nienhuis worked for almost 40 years in all aspects of aquatic ecology and environmental science and retired on 31 October 2003. He can be characterised as a distinguished scientist, shaped in an applied estuarine and aquatic research ambience of the former Delta Institute for Hydrobiological Research (DIHO) in Yerseke in the Netherlands. His appointment as a full professor at the Radboud University Nijmegen offered him a challenging step from monodisciplinarity in ecology, via multidisciplinarity in the application of ecological knowledge in river science to interdisciplinarity in environmental science and management. This paper describes his education, teaching activities, research, scientific publications, science management, and significance for various scientific disciplines. He made important contributions to biosystematics of angiosperms and algae, the ecology of seagrasses, nutrient cycling and eutrophication in estuarine ecosystems, and the integrated modelling of the ecological functioning of estuaries. Subsequently, he paid much attention to environmental problems in river basins, ecological rehabilitation and sustainable development. His work influenced the view of ecologists, aquatic scientists and water managers in the Netherlands as well as abroad, in particular regarding the drawbacks of compartmentalization of the estuaries and the importance of connectivity and morphodynamics in river systems. In hindsight, it appears as a logical line that he gradually moved from estuarine ecological research that became increasingly driven by societal and environmental problems to the field of environmental science and management.     

The big ecological questions inhibiting effective environmental management in Australia

The need to improve environmental management in Australia is urgent because human health, well‐being and social stability all depend ultimately on maintenance of life‐supporting ecological processes. Ecological science can inform this effort, but when issues are socially and economically complex the inclination is to wait for science to provide answers before acting. Increasingly, managers and policy‐makers will be called on to use the present state of scientific knowledge to supply reasonable inferences for action based on imperfect knowledge. Hence, one challenge is to use existing ecological knowledge more effectively; a second is to tackle the critical unanswered ecological questions. This paper identifies areas of environmental management that are profoundly hindered by an inability of science to answer basic questions, in contrast to those areas where knowledge is not the major barrier to policy development and management. Of the 22 big questions identified herein, more than half are directly related to climate change. Several of the questions concern our limited understanding of the dynamics of marine systems. There is enough information already available to develop effective policy and management to address several significant ecological issues. We urge ecologists to make better use of existing knowledge in dialogue with policy‐makers and land managers. Because the challenges are enormous, ecologists will increasingly be engaging a wide range of other disciplines to help identify pathways towards a sustainable future.     

Landscape scale assessment of stream channel and riparian habitat restoration needs

Human modifications of streams and rivers have caused extensive stream channel and riparian degradation. Cost-effective, rapid assessment tools can be used to better manage such areas by identifying the status of habitats for restoration planning and protection. We used a spatially explicit, reach-scale geographic information system modeling strategy to examine stream channel and riparian condition and prioritize restoration actions. The stream channel condition index uses information on land use, road and railroad density, and sinuosity. The riparian condition index uses calculations of percent forest, patch density, and convexity based on land cover in the floodplain. Reaches were classified into restoration categories based on stream channel and riparian condition model results, land ownership, slope, position in the subwatershed, and adjacency to high-quality habitat. We compared modeled restoration priority rankings with those in the management plan for the East Credit subwatershed in Ontario, Canada. Predicted stream channel restoration priority rankings matched field-based classifications for 86% of the reaches in the East Credit subwatershed. Predicted riparian restoration priority rankings matched field-based classifications for 81% of the reaches. Our methods replicate with fairly good accuracy the results obtained using intensive field surveys and stakeholder input. Managers can use these cost-effective strategy development tools to identify candidate reaches for further study and prioritize stream channel and riparian restoration actions over large regions.     

Pollution effects on fisheries — potential management activities

Management of ocean pollution must be based on the best available scientific information, with adequate consideration of economic, social, and political realities. Unfortunately, the best available scientific information about pollution effects on fisheries is often fragmentary, and often conjectural; therefore a primary concern of management should be a critical review and assessment of available factual information about effects of pollutants on fish and shellfish stocks. A major problem in any such review and assessment is the separation of pollutant effects from the effects of all the other environmental factors that influence survival and well-being of marine animals. Data from long-term monitoring of resource abundance, and from monitoring of all determinant environmental variables, will be required for analyses that lead to resolution of the problem. Information must also be acquired about fluxes of contaminants through resource-related ecosystems, and about contaminant effects on resource species as demonstrated in field and laboratory experiments. Other possible management activities include: (1) encouragement of continued efforts to document clearly the localized and general effects of pollution on living resources; (2) continued pressure to identify and use reliable biological indicators of environmental degradation (indicators of choice at present are: unusually high levels of genetic and other anomalies in the earliest life history stages; presence of pollution-associated disease signs, particularly fin erosion and ulcers, in fish; and biochemical/physiological changes); and (3) major efforts to reduce inputs of pollutants clearly demonstrated to be harmful to living resources, from point sources as well as ocean dumping. Such pollution management activities, based on continuous efforts in stock assessment, environmental assessment, and experimental studies, can help to insure that rational decisions will be made about uses and abuses of coastal/estuarine waters.     

The Importance of Ecoregion Versus Drainage Area on Fish Distributions in the St. Croix River and its Wisconsin Tributaries

Aquatic ecoregions, based on regional landscape features, have been proposed as a model for aquatic resource management. The model assumes the existence of a typical biota associated with a given ecoregion and serves as the basis for biological assessment, reference site designation, and determination of stream potential, based on this biotic assemblage. Contrasting models for predicting stream ecosystem structure focus on the importance of local site conditions, including the regular and predictable changes that occur as a function of area draining to a site. In this study, a classification of 429 stream sites over an area of approximately 20000km² in the St. Croix River basin delineated three major species groups: redhorse/spotfin shiner; brook charr/sculpin; and mixed species. Numerical analyses revealed no relationship between the species communities and ecoregions. In contrast, there was a strong association between the species communities and the area draining to the site. Our study highlights the importance of accommodating the inherent structure associated with site drainage area when imposing a regionally-based ecological classification upon stream ecosystems. This structure is expressed in the systematic changes to the physical habitat that occur with increasing drainage area and are reflected by the species community at the site. Management models that currently incorporate ecoregions in the classification or prediction of stream ecosystem structure would benefit from the inclusion of specific components that incorporate drainage area measurements.now at Environment Protection Authority     

Diagnostic PCR to identify five rare species of Cypriniformes in China

The major problem that fisheries managers face when trying to enforce the law is identifying fish species. This problem is even worse when it comes to identifying eggs, larvae, bloodstains, scales, mucous stains, and mixtures of these in markets, restaurants and fishing areas. To assist in the acquisition of urgently needed conservation and management data on rare and endangered fish catch and sale, we have developed and tested a highly streamlined molecular genetic approach to identify Cypriniformes fish species. We used species-specific primers and species-specific ladders in a seven-primer multiplex polymerase chain reaction format based on DNA sequence differences among species in the nuclear ribosomal second internal transcribed spacer (ITS2) to discriminate simultaneously among five rare and endangered Cypriniformes species in China. This technique distinguished samples with 100% accuracy. This genetic approach will be useful for the assessment, management and conservation of fish.     

Assessing deer densities and impacts at the appropriate level for management: a review of methodologies for use beyond the site scale

• 1 Population density alone is unlikely to be a good predictor of the impacts of deer on their environment. The assessment of management requirements should therefore be based on assessment of deer impacts, alongside estimates of density.
• 2 Both density and impacts need to be monitored at a landscape scale, and there is a need to develop appropriate methodologies that allow managers to consider the current and likely future impact of deer.
• 3 The relevant scale for assessment (and management) varies both with deer species and context of impact, but should always encompass at least the estimated biological range of the population of deer present in an area. Some impacts (e.g. deer–vehicle collisions, and risks of disease transmission) may need to be assessed at a wider regional level.
• 4 In this review we consider various approaches available for assessing: absolute or relative animal abundance; impacts of ungulates on agriculture, forestry, amenity woodlands and other conservation sites; impacts on public safety (e.g. through road traffic accidents) and on humans or livestock through potential spread of disease.
• 5 In each case the advantages and disadvantages of a variety of methods are considered, before recommendations are made for methodologies which are sufficiently accurate, sufficiently robust and sufficiently practical to be favoured in a management context.
• 6 To address impacts at the landscape scale requires management policies that integrate information on both positive and negative impacts of deer in order to ensure appropriate and holistic management. We present a decision‐support framework suitable for use within the UK, using inputs from a variety of possible impact types to assist managers and forewarn of situations where current management may need to be modified.

     

Modelling of Nutrient Emissions in River Systems – MONERIS – Methods and Background

MONERIS is a semi‐empirical, conceptual model, which has gained international acceptance as a robust meso‐ to macro scale model for nutrient emissions. MONERIS is used to calculate nitrogen (N) and phosphorus (P) emissions into surface waters, in‐stream retention, and resulting loads, on a river catchment scale. This paper provides the first (i) comprehensive overview of the model structure (both the original elements and the new additions), (ii) depiction of the algorithms used for all pathways, and for retention in surface waters, and (iii) illustration of the monthly disaggregation of emissions and the implementation of measures. The model can be used for different climatic conditions, long term historical studies, and for future development scenarios. The minimum validated spatial resolution is 50 km², with a temporal resolution of yearly or monthly time steps. The model considers seven emission pathways (atmospheric deposition on surface waters, overland flow, erosion, tile drainage, groundwater, emissions from sealed urban areas, and point sources), and six emission sources (natural background, fertilizer application, nitrogen atmospheric deposition on arable land and other areas, urban sources, and point sources); and these are calculated separately for different land‐uses. The pathway and source‐related approach is a prerequisite for the implementation of measures to reduce non‐point and point‐source emissions. Therefore, we have modified MONERIS by the addition of a “management alternative” tool which can identify the potential effectiveness of nutrient reduction measures. MONERIS is an appropriate tool for addressing the scientific and political aspects of river basin management in support of a good surface water quality. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

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.     

The development of an assessment system to evaluate the ecological status of rivers in the Hindu Kush-Himalayan region: introduction to the special feature

Development of an Assessment System to Evaluate the Ecological Status of Rivers in the Hindu Kush-Himalayan Region (ASSESS-HKH) was a 3-year research project funded by the European Union (Contract number: INCO-CT-2005-003659). This article provides an overview of this research project by summarising the objectives, the approaches and the main achievements. The main objective was to develop and apply a biological assessment system to evaluate the river’s ecological quality and to provide a scientific basis for the identification of sustainable water policy options and management strategies. The assessment tools were jointly developed by European partners, who provided their experience from recent research activities (STAR, AQEM) and Asian partners, who provided the knowledge about Asian river catchments and management necessities. The project was organised into eight work packages defining the time line for all phases, such as establishment of a stream typology and definition of reference conditions and stages of impairment classes for the rivers in the Asian countries, including a review of existing policies for water management. A specific part of the project was dedicated to increasing the overall poor knowledge of benthic invertebrates in the region and their value to the classification of the river’s ecological quality. All activities were accompanied by information events for local residents, universities and water managers. A total of 396 multi-habitat samples, from 115 rivers in five different ecoregions, were taken in two different seasons and accompanied by information on 95 parameters describing river and catchment characteristics. The benthic invertebrates in the samples were taxonomically identified based on keys generated within the project. Taxalists, with abundances per site, and field protocol information were entered into a specifically developed software tool. This dataset was the basis for developing ecological river assessment methods, called HKHscreening (Rapid Field Assessment), HKHbios (HKH Biotic Score) and HKHindex (Multimetric Index). Furthermore, a software tool (ECODAT) for using these methods was developed. The monitoring tools will serve citizens and scientists of the Hindu Kush-Himalayan region and will provide a scientific basis for policy recommendations, mitigation strategies, transnational water resource planning and sustainable ecosystem management. Additional outputs, including all sampling and laboratory protocols and project deliverables, together with the freely downloadable software, are available at the following website: http://www.assess-hkh.at.     

Restoring streams in an urbanizing world

1. The world's population is increasingly urban, and streams and rivers, as the low lying points of the landscape, are especially sensitive to and profoundly impacted by the changes associated with urbanization and suburbanization of catchments. 2. River restoration is an increasingly popular management strategy for improving the physical and ecological conditions of degraded urban streams. In urban catchments, management activities as diverse as stormwater management, bank stabilisation, channel reconfiguration and riparian replanting may be described as river restoration projects. 3. Restoration in urban streams is both more expensive and more difficult than restoration in less densely populated catchments. High property values and finely subdivided land and dense human infrastructure (e.g. roads, sewer lines) limit the spatial extent of urban river restoration options, while stormwaters and the associated sediment and pollutant loads may limit the potential for restoration projects to reverse degradation. 4. To be effective, urban stream restoration efforts must be integrated within broader catchment management strategies. A key scientific and management challenge is to establish criteria for determining when the design options for urban river restoration are so constrained that a return towards reference or pre‐urbanization conditions is not realistic or feasible and when river restoration presents a viable and effective strategy for improving the ecological condition of these degraded ecosystems.     

两类水质综合评价方法的特点及其在河流水环境管理中的作用

河流水质恶化已成为严峻的环境问题,针对河流开展水质综合评价对河流水环境管理具有重要意义。依据不同的评价目标,选择合理的综合评价的评估标准成为河流水质评价中重要的问题之一。通过基于期望值和阈值的水质健康综合评估法(ETI)和水质质量指数(WQI)两种水质综合评价方法对"引滦入津"工程重要水源地伊逊河水质进行评价,结果显示:1)伊逊河水质ETI评估结果为良好等级,WQI评估结果为一般等级;2)伊逊河采样点水质在ETI评价中分布于4个等级,WQI仅分布于2个等级;3)伊逊河自上游至下游水质显著降低,特别是ETI评估中由优秀等级转变为差等级;4)ETI和WQI评估结果显示极显著相关性(R=0.951,P0.01);5)通过逐步多元回归,ETI评估结果的主导因子是DO、EC、SS、BOD_5和TP(P0.05),WQI评估结果的主导因子是DO、SS、BOD_5、TP、TN和NH_3-N(P0.05)。进一步分析表明伊逊河水质恶化与其流域内土地利用情况密切相关。在河流水环境管理中,ETI作为一种水质相对值评估方法,能更好体现流域内水质差异的区分度,便于管理者迅速定位流域内亟需治理的河流或河段,同时能够根据河流自身特征制定管理目标,可作为河流管理绩效评估的有效手段;而WQI作为一种水质绝对值评估方法,更适用于河流水质时间变化评估,对河流经长期治理后的管理效果评价起到重要作用。