Achievement Of Good Ecological Status Research Articles

Ecotoxicological tools in support of the aims of the European Water Framework Directive: A step towards a more holistic ecosystem-based approach

The Water Framework Directive (WFD) aims to attain ‘good quality’ status for all European water bodies through the achievement of good ecological status. To this purpose, the WFD advocates the creation of cost-effective monitoring tools to deliver appropriate data that help to create links between chemical and ecological indicators, as those from ecotoxicological research. Here, it was evaluated whether the integration of ecotoxicological tools, as bioassays and biomarkers, did (or did not) strengthen the robustness of the assessment of the ecological status obtained through well stablished biotic indices in two Atlantic estuaries. For that, a battery of in-situ bioassays, including five macroinvertebrate species (the crab Carcinus maenas, the amphipod Echinogammarus marinus, the isopod Cyathura carinata, the snail Peringia ulvae and the polychaete Hediste diversicolor, each one providing complementary information regarding key ecological functions) and a set of biomarkers, was used. In addition, the concentrations of heavy metals in sediments, and in macroalgae (Fucus), were determined, along with sediment granulometric, water physicochemical and nutrients characterization. We show that by interpreting the values of all indicators together, along with environmental components, it is possible to perform a more holistic description of the quality status of a waterbody – and, to begin to allude to factors limiting that quality. Ecotoxicological tools (in situ bioassays and biomarkers) appear to provide an added value of useful information for monitoring programmes regarding the true state - within which, both known and unknown contaminants are potentially present at concentrations sufficient to cause biological effects. Our results support the use of in situ bioassays and biomarkers within protocols aimed at fulfilling the goals of the WFD. In doing so, more complete and informative assessments of the ecological quality status of water bodies can take place.

Estimating river nutrient concentrations consistent with good ecological condition: More stringent nutrient thresholds needed

Nutrient pollution remains one of the leading causes of river degradation, making it important to set thresholds that support good ecological condition, which is the main objective of managing Europe's aquatic environment. A wide range of methods has been used by European member states to set river nutrient thresholds in the past, and these vary greatly among countries, even for similar river types. In some countries, thresholds have been set using expert judgement or the statistical distribution of nutrient concentrations. Application of such thresholds creates problems for planning strategies to achieve good ecological status and for managing transboundary river basins. An alternative approach is to examine the statistical relationship between nutrient concentration and one, or more, biological variables. Such relationships can then be used to inform decisions by water managers. We use such 'ecology-based' approaches (univariate regression and mismatch analyses) to derive nutrient thresholds for several river types in Central Europe. Our analysis focused on soluble reactive phosphorus (SRP) and total nitrogen (TN), two variables which were responsible for significant variation (40–55%) in river benthic floras. In this study, for the first time, river nutrient thresholds are estimated using both macrophytes and phytobenthos (EQRs) separately and in combination, calculated as the minimum and the average of the EQRs of the two sub-elements. The resulting thresholds supporting good ecological status range from 21 to 42 µg/L SRP and 0.9–3.5 mg/L TN for the low alkalinity lowland river type, and 32–90 µg/L SRP and 1.0–2.5 mg/L TN for the low alkalinity mid-altitude river type. These targets are compared to the values set by member states. We demonstrate that some national nutrient thresholds fall within the range of predicted values if uncertainty is taken into consideration; however, several threshold values considerably exceed this range. Adopting ecology-based nutrient targets should improve sustainable river management where nutrients are the major pressure preventing the achievement of good ecological status.

Agua y medio ambiente en España: diagnóstico y perspectivas de algunas líneas de acción

Teniendo como referente el trascendente papel de las aguas continentales en el medio ambiente, se analiza el cambio de perspectiva que la aplicación de la Directiva Marco Europea del Agua supone en esta relación agua-medioambiente. En este contexto, se abordan algunos de los principales problemas que actualmente afectan al agua y, a través de las masas de agua y los ecosistemas hídricos, al medio ambiente. Finalmente, se plantean diversas iniciativas de gestión y restauración encaminadas a conseguir el buen estado ecológico de las masas de agua continentales. En el artículo queda patente la estrecha interrelación agua-medioambiente, la existencia actualmente en nuestro país de un marco legal que posibilita más que nunca la gestión del agua desde una perspectiva de conservación y mejora del medio ambiente, y la necesidad de que la aplicación de las diferentes normativas conduzca, en la práctica, a la obtención del buen estado ecológico de las masas de agua continental mediante la resolución de diferentes problemas a través de medidas de protección y restauración.