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The ecosystem services approach to conservation is becoming central to environmental policy decision making. While many negative biological invasion-driven impacts on ecosystem structure and functioning have been identified, much less was done to evaluate their ecosystem services. In this paper, we focus on the often-overlooked ecosystem services provided by three notable exotic ecosystem engineering bivalves, the zebra mussel, the quagga mussel, and the golden mussel. One of the most significant benefits of invasive bivalves is water filtration, which results in water purification and changes rates of nutrient cycling, thus mitigating the effects of eutrophication. Mussels are widely used as sentinel organisms for the assessment and biomonitoring of contaminants and pathogens and are consumed by many fishes and birds. Benefits of invasive bivalves are particularly relevant in human-modified ecosystems. We summarize the multiple ecosystem services provided by invasive bivalves and recommend including the economically quantifiable services in the assessments of their economic impacts. We also highlight important ecosystem disservices by exotic bivalves, identify data limitations, and future research directions. This assessment should not be interpreted as a rejection of the fact that invasive mussels have negative impacts, but as an attempt to provide additional information for scientists, managers, and policymakers. [ABSTRACT FROM AUTHOR]

Ecosystem macroscopic properties given by Ascendency theoretical framework were compared between two multispecies mass-balanced trophic models of the coastal benthic ecosystem along Mejillones Bay in northern Chile (SE Pacific). The models were constructed with a similar number of components representing system conditions for years 2006 and 2018 using Ecopath with Ecosim (EwE) software. The most relevant change was that the macroalgae (principally Rhodophyta group) increased notably over 12 years. In terms of Ascendency, the larger increase in Total System Throughput (TST) compared to the null increment in the Average Mutual Information would indicate that the benthic ecosystem of Mejillones Bay is moving towards eutrophic conditions. This is consistent with the reduction in the TST cycled, Finn's cycling index, and a two-fold increase in the flow of detritus. Likewise, the Keystone Species Complex seems to be sensitive to changes in the properties of ecosystems, reducing the number of components in cases of deteriorated ecosystem. Based on the results obtained, it is suggested the implementation of management strategies that allow reversing this trend towards eutrophication, such as, to strengthen environmental policies and monitoring programs in order to conserve the benthic communities of Mejillones Bay. [ABSTRACT FROM AUTHOR]

The spatially hierarchical stream hydrogeomorphology classification presented by Cox et al. ([3]), based on 42 Irish headwater streams, is simple to apply and may be applicable across northern and western Europe with similar climate - landscape conditions. It is clear from these papers and others presented at SEFS12 that the extensive length of the small stream network and high numbers of ponds poses challenges in terms of water quality and biodiversity monitoring. Small water bodies are increasingly recognised as important for biodiversity and in terms of their influence on downstream water quality and contributions to catchment ecosystem services (Riley et al., [12]). [Extracted from the article]

Oil pollution entering the marine environment has been an issue of concern for many decades. It can come from riverine or land-based sources, accidental and intentional discharges from ships, or as a by-product of offshore oil extraction. Growing awareness of the impact of oil pollution on the marine environment has led, since the late 1960s, to the introduction of measures to reduce or eliminate pollution from shipping and the offshore oil industry. A framework for environmental protection of the North Sea has developed over many decades through international agreements, regional cooperation, and national measures, while education has also played an important role with modern-day sailors being given due training to understand that dumping waste at sea is illegal in many areas, and is harmful to the marine environment. This paper presents data on trends in pollution from ships and oil installations. While significant reductions in oil pollution have been identified over more than two decades, there remain some areas where action is needed to reduce inputs still further, especially from oil and gas platforms. This paper illustrates that international cooperation can result in a reduction in marine pollution leading to a cleaner environment. [ABSTRACT FROM AUTHOR]

Community structure is determined by a variety of ecological mechanisms, including environmental control, dispersal, and historical contingency. Recently, many studies have focused on the relative relevance of environment and dispersal in shaping metacommunities. Historical contingency (e.g., priority effects) rarely has been considered, although it could have a key role. In this context, the use of paleoecological methods could help assess the influence of past events on the present-day communities. In this survey, we compare living ostracod assemblages (i.e., biocoenoses) and subfossil assemblages (i.e., taphocoenoses) from 22 steppic shallow lakes and determine the relative contribution of environmental and spatial components on both assemblages. In addition, we estimate the role of putative priority effects of past assemblages on contemporary ones. Our results indicate a high concordance between both assemblages (Procrustes analysis; r = 0.877; P = 0.001). However, environment dominates over space in explaining the biocoenoses, whereas in taphocoenoses space dominates over environment. Furthermore, the contemporary metacommunity structure was related not only to pure environmental and spatial effects (suggesting species sorting and dispersal constraints) but also notably to pure historical effects, suggesting a significant major role of earlier habitat occupation in these ecosystems. [ABSTRACT FROM AUTHOR]

Climate change is likely to cause deleterious hydrological and ecological impacts in many of the world's major river basins. Using the Murray-Darling Basin, Australia, as a case study, we present an adaptation framework which addresses the hydrological impacts of climate change at three spatial scales: the high-conservation value asset, the water management unit and the entire basin. At each scale, the appropriate scientific, policy and operational tools differ, though should be applied in concert. At the scale of the asset, hydrodynamic modelling has improved the capacity of site managers to anticipate the effects of management interventions. These models have also contributed to improve hydrological modelling of the water management unit. When combined with ecosystem response models, hydrological models can compare ecological outcomes over a range of timescales, leading to improvements in the representation of environmental requirements in water sharing plans. At the scale of the basin, the Australian government has used a legislative mechanism to set overarching ecological and diversion objectives. In addition, the purchase of water-use entitlements has created a flexible mechanism to use the water market as a climate-change adaptation mechanism, responding to the changing water availability and conservation priorities that emerge over the coming decades. [ABSTRACT FROM AUTHOR]

There is both a fundamental and applied need to define expectations of changes in aquatic ecosystems due to global changes. It is clear that programs using biological indicators and reference-based comparisons as the foundation for assessments are likely to make increasingly erroneous decisions if the impacts of global change are ignored. Global changes influence all aspects of water resource management decisions based on comparisons to reference conditions with impacts making it increasingly problematic to find an 'undisturbed' water body to define acceptable conditions of ecological integrity. Using a more objective scale for characterizing reference conditions that is anchored in expectations for what would be attainable under undisturbed conditions, such as the Biological Condition Gradient (BCG) is one approach that maintains consistent definitions for ecosystem conditions. In addition, protection of reference stations and of unique or undisturbed aquatic resources is imperative, though the scope of protection options is limited. Projections indicate that encroaching land use will affect 36-48% of current reference surface waters by the year 2100. The interpretation of biological indicators is also at risk from global changes. Distinguishing taxonomic attributes based on temperature or hydrologic preferences can be used to enhance the ability to make inferences about global change effects compared to other stressors. Difficulties arise in categorizing unique indicators of global changes, because of similarities in some of the temperature and hydrologic effects resulting from climate change, land use changes, and water removal. In the quest for biological indicators that might be uniquely sensitive to one global stressor as an aid in recognizing probable causes of ecosystem damage, the potential similarities in indicator responses among global and landscape-scale changes needs to be recognized as a limiting factor. Many aspects of global changes are not tractable at the local to regional scales at which water quality regulations are typically managed. Our ability to implement water policies through bioassessment will require a shift in the scale of assessment, planning, and adaptations in order to fulfill our ultimate regulatory goals of preserving good water quality and ecological integrity. Providing clear expectations of effects due to global change for key species and communities in freshwater ecosystems will help water quality programs achieve their goals under changing environmental conditions. [ABSTRACT FROM AUTHOR]

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: . [ABSTRACT FROM AUTHOR]

We synthesized information on selected contaminants in the Upper Mississippi River, summarized regulatory measures enacted to reduce pollution, and described biotic and ecosystem responses to regulatory actions. Contamination of the river with mercury and lead rapidly followed settlement of the basin by European immigrants in the mid-1800s. Metal contamination peaked in the 1960s and has since decreased substantially. DDT, its degradation product DDE, and PCBs biomagnified to concentrations that adversely affected wildlife in upper trophic levels. National (U.S.A.) environmental regulations enacted from 1972 to 1991 reduced discharges of wastes from point sources, improved wastewater treatment, and reduced or banned the production or usage of certain chemicals, such as DDT, PCBs, and lead. Responses to these regulatory measures include reductions in ecosystem contamination, reductions in biotic exposure, and recovery of affected wildlife populations. Recovery from pollution has been slow, however, and we conclude that proactive approaches focusing on prevention are highly preferable to reactive approaches in management of toxic substances. Past successes in reducing point-source pollution, which is greatest near urban areas, do not extend to nonpoint-source pollution, given that the existing regulatory framework does not adequately address nonpoint sources. The river continues to receive hundreds of recently synthesized chemicals, and the behavior and effects of most of these compounds in aquatic ecosystems are largely unknown. Emerging contaminants and recently discovered mechanisms of adverse biological effects, such as endocrine disruption, pose continuing challenges to scientists and environmental managers concerned with the ecological health of this riverine ecosystem. [ABSTRACT FROM AUTHOR]

Lake Balaton, one of the largest lakes in Europe, is an important centre for summer tourism in Hungary. The appearance of the water is, however, influenced by a number of physical and biological factors such as the frequency of storms, the hydrological balance, the water level and the growth of algae. Here we report the results of a survey designed to test the reaction of the local population to these seasonal and inter-annual variations. This survey was based on a questionnaire completed by 960 permanent inhabitants of the shoreline villages and was designed to explore their awareness of the local and regional factors responsible for the changes. About one-quarter of the respondents considered that the drying effects of global climate change had already had an effect on the Lake Balaton area. Although younger (16–26) and middle-aged (27–50) respondents benefit most from good water quality, those in the oldest age group (51–92) were more concerned about the quality of the water and broader issues such as biodiversity and the conservation of the landscape. Considering that the future of the lake depends on the youngest generation, this suggests that their environmental education could be improved to strengthen their understanding of environmental issues. [ABSTRACT FROM AUTHOR]

The European Water Framework Directive offers an unprecedented opportunity for improvement of ecological quality of both freshwater and marine systems. It has implications for every aspect of how catchments are used by human societies and could potentially mean a step change in how waters and catchments are managed. It must be implemented, however, by official bodies, which seem likely to apply ecologically outdated approaches, used in the past simply to manage water quality, to tackle the very different problem of improving ecological quality. Ecological quality can be characterised by parsimony of available nutrients, characteristic physical and biological structure, strong connectivity among systems and mechanisms of resilience to cope with normal, natural change. The implications of these are that high quality systems in a given location do not have unique lists of species and single formulae for how the biodiversity is constituted. They have considerable inherent variability whilst preserving their fundamental functional characteristics. This appears not to have been recognised by official bodies that seek simple taxonomic indices as measures of quality. To some extent this is a function of the way the Directive has been written, but a slavish adherence to this approach may undermine the spirit of the Directive and result in a failure to bring about the fundamental reform that is needed. [ABSTRACT FROM AUTHOR]

Results from recent studies report increases in mercury in the environment and increased bioaccumulation in aquatic food webs. The Canadian Wildlife Service (CWS) and the Canadian National Park Service initiated this study to determine whether common loons ( Gavia immer) are exposed to sufficiently high mercury concentrations in prey fish to impair their reproduction and survival. Monitoring of loon reproduction, measurement of lake physicochemistry, and fish sampling for mercury analysis were conducted in various regions in Québec, Canada, during summers from 1997 to 2002. Reproductive success was assessed and loons were captured at night and banded. Blood and feathers were collected to measure mercury. Mean blood and feather Hg concentrations in males (2.6 μg/g w.w and 17.6 μg/g d.w.) and females (1.8 μg/g w.w and 8.9 μg/g d.w.) were within the normal range of samples from north-eastern North America. However, one third (33%) of the loons sampled had mercury levels in blood or feathers exceeding the high risk levels for health and reproduction. Loons from western Québec showed significantly lower Hg levels than those from eastern Québec, both in blood and feathers. This study will help to determine the potential effects of mercury on the Québec and North-American loon population and provide information to assist in decisions on pollution abatement policies. [ABSTRACT FROM AUTHOR]

Because of climate change and the need for sustainable water systems, water management has changed considerably in recent years, from river management to basin management. This change is illustrated for both the main Dutch river system and a small, representative regional water system in the Netherlands. This change results in four major challenges, (1) creating an effective regional administration which functions as a network authority, (2) increasing collaboration with other water managers, (3) increasing efficiency and achieving goals at minimum cost, and (4) communicating in an open manner with stakeholders. The article outlines the way in which water managers try to address these challenges. Special attention is given to the need for increased coordination between environmental policies and water policies. [ABSTRACT FROM AUTHOR]

Meteorological and climatic processes in mountain regions play a key role in many environmental systems, in particular the quantity and quality of water that influences both aquatic ecosystems and economic systems often far beyond the boundaries of the mountains themselves. This paper will provide a general overview of some of the particular characteristics of mountain weather and climate, to highlight some of the unique atmospheric features that are associated with regions of complex topography. The second part of the paper will focus upon characteristics of climate and climatic change in the European Alps, a region with a wealth of high quality data that allows an assessment on how climate and dependent environmental systems have evolved in the course of the 20th century and how alpine climate may undergo further changes to “global warming” in the 21st century, as the atmosphere responds to increasing levels of greenhouse gases that are expected in coming decades. [ABSTRACT FROM AUTHOR]

Temporal trends in macrobenthic communities of the Valli di Comacchio, the largest lagoonal ecosystem in the Po River deltaic area, were examined at four sampling sites located along a putative stress gradient and characterized by different levels of disturbance. Trends of parameters characterizing macrobenthic community structure were analyzed using data collected quarterly from 1996 to 2002. The positive slopes in trends of proportion of abundance of opportunistic species observed at all the four study sites indicated the persistence of stressful conditions. Conversely, temporal trends of species richness and diversity showed a positive slope at three out of four sites, thus indicating an increase of community structural complexity. It is suggested that the increase in abundance of detritivorous opportunistic species, as well as the increase in diversity and species richness, is probably driven by the frequency of physical disturbance that resets the ‘successional clock’ of the benthic communities of the Valli. Redundancy was assessed through multivariate analyses and a ‘forward selection backward elimination’ algorithm. At the ecosystem level (i.e., merging counts from the four sites), two response units (a response unit is the smallest subset of species for which the Spearman rank correlation with sample similarities for the full species set exceeds a predetermined value) were obtained. Each of the response units encompassed quite a large taxonomic and functional spread, since all guilds were well represented. Conversely, at the local level, only one response unit was obtained. Species number and function is essential to long-term maintenance of community and ecosystem processes over a complete cycle of common disturbance events. Since redundancy reflects the resistance to change of community functioning, we hypothesize that the macrobenthic communities of the Valli di Comacchio are quite resistant to environmental changes, despite disturbances that generate fluctuations in species abundance and complement at the local level. [ABSTRACT FROM AUTHOR]

From 2000 to 2002, sediment contamination by Cd, Cu, Hg, Pb and Zn was analysed in the Pialassa Baiona salt marsh, which receives petrochemical wastewaters from the industrial district of Ravenna (Italy). The recent contamination levels were compared with data of previous studies carried out in 1982, in order to assess whether environmental policies and remedial measures reduced sediment pollution. Sedimentary profiles of Cu and Pb were homogeneous along the uppermost 0–10 cm horizon, which corresponded to the sedimentation in the last 30 years. Concentrations of Zn attained a peak (up to 800 mg kg−1 dry weight) in the 0–4 cm sediment horizon, which was assumed to correspond to the last 10–15 years. A wide-spread contamination by Hg was detected in the salt marsh as well as in the main channel with peaks up to 20–40 mg kg−1 dry weight. Nonetheless, recent sediments resulted less contaminated, since Hg discharge from industrial plants ceased about 20 years ago. Contamination levels by Hg values were two orders of magnitude higher than the international sediment quality standards. Cadmium, which was analysed for the first time in 2000–2002, attained a peak in the surface layers (1–2.5 mg kg−1 d.w.), with a progressive decline along the sediment column. Through comparison with pre-industrial values detected in the deeper sediment horizons (before 1920), Hg showed the highest enrichment factor, up to 300 times. Cd and Zn concentrations in recent sediments were from 2 to 10 times higher than background values. In terms of possible adverse effects, Hg posed the highest risk, and Cd and Zn were frequently above the recommended thresholds. [ABSTRACT FROM AUTHOR]