Analysis of the physical impacts of human activities on the aquatic environment

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Work Package 1: Analysis of the physical impacts of human activities on the aquatic environment

Task 1.1: Review of hydro- morphological pressures and impacts

The aquatic environment is subject to broad range of pressures. Many of the threats to freshwater fish and fisheries focus on gross changes to the habitat or community structure, as a result of pollution, flow regulation, loss or change of aquatic habitat, over-exploitation and introduction of exotic species. These have all contributed towards the critical situation facing freshwater biota. Of these, hydro-morphological pressures and impacts have often been considered of secondary importance relative to water quality (because pollution effects often hide hydro-morphological impacts). However, morphological alterations are known to be linked to biodiversity loss and aquatic community changes. Furthermore, hydro-ecologists are frequently asked to define the degree to which a river’s flow regime can be altered whilst maintaining good ecological status, such as required to implement the EU Water Framework Directive or to derive criteria for abstraction of flow in rivers. It is therefore imperative that the impacts of hydro-morphological pressures are assessed to underpin operations to ameliorate the issues.

Task 1.2: Water body status and responses of biota to hydro-morphological change

This task will review the water body status and responses of biota to hydro-morphological changes and attempt to categorise the scale of impacts and losses of functionality related to different pressures. This review will concentrate on pressures that affect longitudinal and lateral connectivity, habitat heterogeneity and ecosystem processes and functionality. It will seek to establish how modifications of various characteristics of the water body morphology and hydrological regimes regulate ecosystem functions relevant to fish population and community structures in different river types and to define thresholds of hydrological change that trigger alterations to key functions.

In this context it is important to recognise the diversity and scale of impacts in different water body types of different pressures, and how these affect recovery processes. Hence there is a need to structure the review to account for the different water typologies that exist based on national derogations. This will be linked to the river typologies based on fisheries derived by the EU FAME ( project. The aim is to define generic the responses of biota to changes in different scenarios so expertise at the local level is transferable, to identify gaps in knowledge of responses of biota to hydro-morphological changes; and to assess adaptation strategies of relevant biotic components to human pressures.

Task 1.3: Ecological potential of heavily modified and artificial water bodies

Finally, little to no expertise has been exchanged to define the ecological potential of heavily modified and artificial water bodies. The ecological potential is the direct link between hydromorphology and ecology, since water quality cannot be an argument in this respect. Since impact is strongly dependent on the water body type and their environmental settings and the scale of modification, there is a need for a European wide classification of HMWB similar to the river typologies. This will be developed based on national classifications, inter-calibration results and scientific findings. Such a classification will allow transferability of local information and processes on impacts to the national and European level and act as a platform for defining good ecological potential for the various water bodies.