Philippe Usseglio-Polatera

Organic chemicals jeopardize the health of freshwater ecosystems on the continental scale

Significance Protection of freshwater ecosystems from organic pollutants is important to preserve biodiversity and the goods they provide to society, such as clean drinking water and recreation. Organic chemicals have been shown to adversely impact freshwater ecosystems in local and regional studies. Nevertheless, due to paucity of studies on larger spatial scales, it remains unknown how widespread the risk from organic chemicals is. For the first time, to our knowledge, we provide strong evidence that chemicals threaten the ecological integrity and consequently the biodiversity of almost half of the water bodies on a continental scale, based on the analysis of governmental monitoring data from 4,000 European sites. Due to limitations associated with the monitoring programs, our results are likely to underestimate the actual risks. Organic chemicals can contribute to local and regional losses of freshwater biodiversity and ecosystem services. However, their overall relevance regarding larger spatial scales remains unknown. Here, we present, to our knowledge, the first risk assessment of organic chemicals on the continental scale comprising 4,000 European monitoring sites. Organic chemicals were likely to exert acute lethal and chronic long-term effects on sensitive fish, invertebrate, or algae species in 14% and 42% of the sites, respectively. Of the 223 chemicals monitored, pesticides, tributyltin, polycyclic aromatic hydrocarbons, and brominated flame retardants were the major contributors to the chemical risk. Their presence was related to agricultural and urban areas in the upstream catchment. The risk of potential acute lethal and chronic long-term effects increased with the number of ecotoxicologically relevant chemicals analyzed at each site. As most monitoring programs considered in this study only included a subset of these chemicals, our assessment likely underestimates the actual risk. Increasing chemical risk was associated with deterioration in the quality status of fish and invertebrate communities. Our results clearly indicate that chemical pollution is a large-scale environmental problem and requires far-reaching, holistic mitigation measures to preserve and restore ecosystem health.

Perspectives for biomonitoring at large spatial scales: a unified measure for the functional composition of invertebrate communities in European running waters

Summary Environmental policies increasingly focus on the enhancement of ecological functions across large geographical areas and thus call for biomonitoring tools that assess these functions at large spatial scales. A potential answer to this call would be to use general biological traits of organisms that indicate ecological functions, as such traits will be comparable among communities even across biogeographic regions that differ in their taxonomic composition. Here, we used benthic invertebrates and European running waters as example to illustrate how multiple biological traits could provide a measure for the large-scale biomonitoring of the functional composition of communities. Our measure considered the relative abundance of 63 categories of 11 biological traits (such as size, reproductive and dispersal potential, food and feeding habits) that indicate various ecological functions. Comparing this measure for 10 most natural French reference regions with 37 other most natural regions/stream types scattered across Europe demonstrated an extremely high spatial and temporal stability of the functional composition of natural invertebrate communities at the European scale. Thus, our functional measure corresponds to a fundamental standard for a large-scale biomonitoring tool, which is the stable and reliable indication of the natural reference state across ecoregions that differ more or less in their taxonomic composition. Applying our functional measure to regulated stream sites below dams (in England, Finland and Spain) and to streams receiving sewage inputs (in Wales, Poland and Sardinia) demonstrated highly significant (p −6 ) differences in the functional composition between the human-impacted and the natural reference communities. In addition, some of the trait categories responded in a consistently contrasting way to each of the two types (regulation, sewage) of human impact. Consequently, our measure for the functional composition of invertebrate communities provides a first unified European baseline for future stream and river management: it was stable in the most natural but otherwise very different running water types across Europe, it safely indicated human impact, and it could potentially discriminate specific types of human disturbances. As all living organisms have multiple biological traits, our approach could serve to generate, for other types of communities and ecosystems, a set of large-scale biomonitoring tools that use similar and perhaps even comparable measures for the functional community composition. Umweltpolitik konzentriert sich zunehmend auf die grosraumige Verbesserung okologischer Funktionen und fordert deshalb Bioindikatorsysteme, die diese Funktionen grosraumig bewerten. Eine potentielle Antwort auf diese Forderung konnte die Benutzung funktioneller, allgemein biologischer Merkmale von Organismen sein, da solche Merkmale zwischen Lebensgemeinschaften verschiedener biogeographischer Regionen vergleichbar sind, selbst wenn sich die Regionen in ihrer taxonomischen Zusammensetzung unterscheiden. Am Beispiel benthischer Wirbelloser und europaischer Fliesgewasser zeigen wir, wie eine Vielzahl von biologischen Merkmalen als Mas fur eine grosraumige Bioindikation der funktionellen Zusammensetzung von Lebensgemeinschaften dienen kann. Unser Mas basiert auf der relativen Haufigkeit von 63 Kategorien in 11 biologischen Merkmalen (z.B. Korpergrose, Reproduktions- und Dispersionspotential, Nahrung und Ernahrungsweise), die verschiedene okologische Funktionen indizieren. Ein Vergleich dieses Mases von 10 besonders naturnahen franzosischen Referenzregionen und 37 anderen, uber ganz Europa verteilten, besonders naturnahen Regionen/Flieswassertypen zeigte eine extrem hohe raumliche und zeitliche Stabilitat der funktionellen Zusammensetzung naturlicher Wirbellosengemeinschaften im gesamten europaischen Raum. Somit entspricht unser funktionelles Mas einer Grundanforderung an ein grosraumiges Bioindikatorsystem: die stabile und zuverlassige Indikation des naturlichen Referenzzustandes fur verschiedene Okoregionen, die sich mehr oder minder in der taxonomischen Zusammensetzung unterscheiden. Die Anwendung unseres funktionellen Mases auf regulierte Flieswasserabschnitte unterhalb von Staudammen (in England, Finnland und Spanien) sowie auf abwasserempfangende Fliesgewasser (in Wales, Polen und auf Sardinien) zeigte hochsignifikante (p −6 ) Abweichungen in der funktionellen Zusammensetzung zwischen durch den Menschen beeinflusten und naturlichen Lebensgemeinschaften. Zusatzlich veranderten sich einige Kategorien der biologischen Merkmale ubereinstimmend gegensatzlich fur jeden der beiden Typen (Regulation, Abwasser) menschlicher Einflusse. Unser Mas der funktionellen Zusammensetzung von Wirbellosengemeinschaften schafft folglich eine erste einheitliche Basis fur ein zukunftiges Flieswassermanagement in Europa: es war stabil in besonders naturnahen aber ansonsten sehr verschiedenen Flieswassertypen des gesamten europaischen Raumes, es indizierte verlaslich menschliche Einflusse und es konnte auf verschiedene spezifische menschliche Storungen unterschiedlich reagieren. Da alle lebenden Organismen eine Vielzahl biologischer Merkmale aufweisen, sollte unser Ansatz auf andere Typen von Lebensgemeinschaften und Okosystemen ubertragbar sein. Er konnte fur diese verschiedenen Typen eine Serie von grosraumigen Bioindikatorsystemen schaffen, die ahnliche und vielleicht sogar vergleichbare Mase fur die funktionelle Zusammensetzung von Lebensgemeinschaften benutzen.

Stream community structure in relation to spatial variation: the influence of mesohabitat characteristics

Community structure of benthic macroinvertebrates was studied in six first- through fourth-order streams in northeast France, to elucidate changes in richness, abundance, diversity and evenness of mesohabitat assemblages as a function of environmental conditions. Patch samples were subjected to multivariate analyses to determine: (i) relationships among seven indices describing community structure (structure parameters); (ii) relationships among seven environmental variables; (iii) the relationship between community structure and environmental characteristics of patches. Faunal data showed that indices measuring the distribution of individuals among taxa (evenness, dominance) and richness are prominent in describing the structure of macroinvertebrate communities of mesohabitats. The analysis of environmental data demonstrated a major differentiating ability of current velocity and strong inter-relations among in-stream hydraulic-dependent parameters in structuring the mesohabitat environment. The co-structure (= relationship) between community organization and environmental variables indicated that substrate may be a primary determinant of community structure. Current velocity and water depth emerged as secondary factors. Trends in community structure were closely related to the spatial variability of mesohabitats. Species richness increased with habitat heterogeneity. Total abundance increased with trophic potentialities of patches. Equitability and diversity seemed to increase with patch stability.

The STAR project: context, objectives and approaches

STAR is a European Commission Framework V project (EVK1-CT-2001-00089). The project aim is to provide practical advice and solutions with regard to many of the issues associated with the Water Framework Directive. This paper provides a context for the STAR research programme through a review of the requirements of the directive and the Common Implementation Strategy responsible for guiding its implementation. The scientific and strategic objectives of STAR are set out in the form of a series of research questions and the reader is referred to the papers in this volume that address those objectives, which include: (a) Which methods or biological quality elements are best able to indicate certain stressors? (b) Which method can be used on which scale? (c) Which method is suited for early and late warnings? (d) How are different assessment methods affected by errors and uncertainty? (e) How can data from different assessment methods be intercalibrated? (f) How can the cost-effectiveness of field and laboratory protocols be optimised? (g) How can boundaries of the five classes of Ecological Status be best set? (h) What contribution can STAR make to the development of European standards? The methodological approaches adopted to meet these objectives are described. These include the selection of the 22 stream-types and 263 sites sampled in 11 countries, the sampling protocols used to sample and survey phytobenthos, macrophytes, macroinvertebrates, fish and hydromorphology, the quality control and uncertainty analyses that were applied, including training, replicate sampling and audit of performance, the development of bespoke software and the project outputs. This paper provides the detailed background information to be referred to in conjunction with most of the other papers in this volume. These papers are divided into seven sections: (1) typology, (2) organism groups, (3) macrophytes and diatoms, (4) hydromorphology, (5) tools for assessing European streams with macroinvertebrates, (6) intercalibration and comparison and (7) errors and uncertainty. The principal findings of the papers in each section and their relevance to the Water Framework Directive are synthesised in short summary papers at the beginning of each section. Additional outputs, including all sampling and laboratory protocols and project deliverables, together with a range of freely downloadable software are available from the project website at www.eu_star.at.

The spatial heterogeneity of a river bottom: a key factor determining macroinvertebrate communities

We examined the relationships between mesohabitat heterogeneity and benthic macroinvertebrate assemblages in a fourth-order stream (Mortagne, North-Eastern France). The heterogeneity of the mesohabitat mosaic was described around each sampling point for eight different surfaces from 0.5 to 4 m radius. Environmental descriptors integrated both the composition and configuration heterogeneity of the substrate mosaic. Faunal data were analysed in terms of biocenotic indices and taxonomic composition. The maximum number of significant Spearman correlations was obtained for a mosaic with a diameter of 2 m around the sampling point and significant correlations were both the highest and the most numerous for this surface. Relationships were established between community structure and substrate heterogeneity. The faunal richness was higher in a heterogeneous environment composed of numerous substrates, an elevated patchiness and with high perimeters. Such a mosaic potentially offers a great number of niches for invertebrates. A reduced distance between two types of substrate favours exchange of species. At the opposite, a very homogeneous mosaic offers a low variety of niches and shelters fewer taxa. Furthermore, in a homogeneous environment we observed that one or two particular taxa dominated the community, probably because competition with taxa coming from neighbouring patches was reduced. The community composition mainly depended on the characteristics of the mesohabitat sampled. Our results showed that the neighbouring environment around such mesohabitats also had a significant influence. Further research must be conducted to specify the influence of the mosaic heterogeneity on biological and ecological traits of invertebrates.

Biomonitoring through biological traits of benthic macroinvertebrates: how to use species trait databases?

The aim of this paper was to investigate the potential use of biological and ecological traits of macroinvertebrates as indicator systems of quality conditions in freshwater ecosystems. To provide a framework for the trait analysis, a data base was developed; it stored biological information about 472 benthic macroinvertebrate taxa. Twenty-two variables describing biological and ecological traits were resolved into a number of simple attributes. A fuzzy coding procedure was used to describe the link between taxa and variables. Three strategies, using simple descriptive statistics or multivariate ordination techniques, were examined in their abilities to demonstrate some of the characteristics of the environment and to bring out clear information on the rate of changes in habitats. We used the Loire River, France, as a specific example. Like faunal analyses, trait analyses showed that a major change occurred in the community in the upper reaches of the river, but transition zones that were not detected with faunal data alone, were discriminated. They corresponded to differences in combinations of biological and ecological traits of communities and were linked to tributary influences (e.g. the Allier–Loire confluence) or anthropogenic disturbances: dams (Grangent, Villerest) or urban zones (Le Puy, Tours). We concluded that the species trait approach had the potential to evaluate the actual state of ecosystems, to discriminate among different types of human impact, and to develop monitoring tools considering the functional diversity of communities.

Assessment of functional integrity of eutrophic streams using litter breakdown and benthic macroinvertebrates

Currently, interest is growing in evaluating stream functional integrity while river assessment schemes are still exclusively based on structural indicators determined from various aquatic communities. Although some approaches relying on macroinvertebrate functional groups and combinations of traits have been advocated as means to assess ecosystem function, there has been no attempt to test the reliability of these methods with any direct functional indicator even though litter breakdown has been recently proposed as a functional indicator of stream impairment. The purpose of this study was to compare nine benthic macroinvertebrate-based structural metrics with functional metrics based on leaf litter breakdown in coarse and fine mesh bags in nine streams distributed along a eutrophication gradient. In coarse mesh bags, a 10-fold drop in breakdown rate of alder litter indicated a high sensitivity of this functional indicator to the deleterious effects of ammonium and its associated products, ammonia and nitrite. In contrast, microbial breakdown measured in fine mesh bags did not vary substantially along the gradient. Taxonomic and functional structures of macroinvertebrate assemblages were altered in the most eutrophic streams, as shown by drops in IBGN (French biotic index), BMWP (Britain biotic index) and EPTC (Ephemeroptera, Plecoptera, Trichoptera and Coleoptera) richness. Shredder richness and an ecological diversity index calculated from functional groups defined from multiple trait combinations exhibited the highest correlation with litter breakdown rate. Our results indicate that indirect assessment of stream functional integrity by structural indicators is realistic but requires specific metrics not necessarily based on traits or functional groups. Leaf litter breakdown is confirmed as a reliable indicator for direct assessment of streams impacted by eutrophication.

Assessing the ecological status in the context of the European Water Framework Directive: Where do we go now?

The Water Framework Directive (WFD) is now well established as the key management imperative in river basins across Europe. However, there remain significant concerns with the way WFD is implemented and there is now a need for water managers and scientists to communicate better in order to find solutions to these concerns. To address this, a Science-Policy Interface (SPI) activity was launched in 2010 led by Directorate-General for Research and Innovation and Onema (the French national agency for water and aquatic ecosystems), which provided an interactive forum to connect scientists and WFD end-users. One major aim of the SPI activity was to establish a list of the most crucial research and development needs for enhancing WFD implementation. This paper synthesises the recommendations from this event highlighting 10 priority issues relating to ecological status. For lakes, temporary streams and transitional and coastal waters, WFD implementation still suffers from a lack of WFD-compliant bioassessment methods. For rivers, special attention is required to assess the ecological impacts of hydromorphological alterations on biological communities, notably those affecting river continuity and riparian covering. Spatial extrapolation tools are needed in order to evaluate ecological status for water bodies for which no data are available. The need for more functional bioassessment tools as complements to usual WFD-compliant tools, and to connect clearly good ecological state, biodiversity and ecosystem services when implementing WFD were also identified as crucial issues.

Towards a renewed research agenda in ecotoxicology

New concerns about biodiversity, ecosystem services and human health triggered several new regulations increasing the need for sound ecotoxicological risk assessment. The PEER network aims to share its view on the research issues that this challenges. PEER scientists call for an improved biologically relevant exposure assessment. They promote comprehensive effect assessment at several biological levels. Biological traits should be used for Environmental risk assessment (ERA) as promising tools to better understand relationships between structure and functioning of ecosystems. The use of modern high throughput methods could also enhance the amount of data for a better risk assessment. Improved models coping with multiple stressors or biological levels are necessary to answer for a more scientifically based risk assessment. Those methods must be embedded within life cycle analysis or economical models for efficient regulations. Joint research programmes involving humanities with ecological sciences should be developed for a sound risk management.

Global climate change in large European rivers: long-term effects on macroinvertebrate communities and potential local confounding factors

Aquatic species living in running waters are widely acknowledged to be vulnerable to climate-induced, thermal and hydrological fluctuations. Climate changes can interact with other environmental changes to determine structural and functional attributes of communities. Although such complex interactions are most likely to occur in a multiple-stressor context as frequently encountered in large rivers, they have received little attention in such ecosystems. In this study, we aimed at specifically addressing the issue of relative long-term effects of global and local changes on benthic macroinvertebrate communities in multistressed large rivers. We assessed effects of hydroclimatic vs. water quality factors on invertebrate community structure and composition over 30 years (1979-2008) in the Middle Loire River, France. As observed in other large European rivers, water warming over the three decades (+0.9 °C between 1979-1988 and 1999-2008) and to a lesser extent discharge reduction (-80 m(3) s(-1) ) were significantly involved in the disappearance or decrease in taxa typical from fast running, cold waters (e.g. Chloroperlidae and Potamanthidae). They explained also a major part of the appearance and increase of taxa typical from slow flowing or standing waters and warmer temperatures, including invasive species (e.g. Corbicula sp. and Atyaephyra desmarestii). However, this shift towards a generalist and pollution tolerant assemblage was partially confounded by local improvement in water quality (i.e. phosphate input reduction by about two thirds and eutrophication limitation by almost one half), explaining a significant part of the settlement of new pollution-sensitive taxa (e.g. the caddisfly Brachycentridae and Philopotamidae families) during the last years of the study period. The regain in such taxa allowed maintaining a certain level of specialization in the invertebrate community despite climate change effects.