The Danube River Basin is the most international river basin in the world shared by more than 80 million people from 19 countries, all contracting parties of the International Commission for the Protection of the Danube River, which coordinates the conservation, improvement and rational use of the waters. The Danube connects with 27 large and over 300 small tributaries on its way from the Black Forest to the Black Sea with a catchment size of approximately 800,000km². The construction of hydropower dams represents one of the most severe pressures affecting river ecosystem integrity, as it involves the modification of riverine habitats, transformation of a river section into reservoir stretches, modifications of the hydrological regime, of water temperature, turbidity, sediment load, and the interruption of river continuity, causing large-scale effects for the river.
The AQUACROSS Case Study explores trade-offs and synergies of biodiversity and ecosystem services related to hydro-morphological alterations of the River Danube and its tributary rivers. It focusses on alterations in longitudinal and lateral connectivity, and on the consequences of these, in addition to eutrophication.
Potential measures aiming to support Ecosystem Based Management include several alternatives of hydro-morphological restoration and remediation measures for river sections and their floodplains. Restoration of the main channel and re-connection of floodplains and wetlands aim to increase hydro-morphic dynamics and resilience as well as ensure biodiversity or flood protection. Morphological restoration of rivers as well as protection, conservation and restoration of wetlands/floodplains are defined as measures of basin-wide importance to conserve biodiversity (EC, 2011, Target 2), ensure the good status in the river stretch, flood protection, pollution reduction and climate adaptation by 2021. Due to the strong linkage between Danube Delta and Danube River policymakers should exploit at local and regional level actions that can increase the institutional cooperation that is needed to mitigate the effect of cyanobacteria blooms and its potential toxic effect on aquatic diversity. Those actions must be address to reducing eutrophication all over the Danube Basin.
The effects of multiple human activities on aquatic biodiversity and ecosystem services are evaluated for the Danube River. Thereby the AQUACROSS linkage framework is used to explore linkages between various human activities, pressures, ecosystem components, ecosystem functions and ecosystem services at basin scale. A policy analysis supports the identification of challenges in implementation of existing policies and the identification of appropriate Ecosystem Based Management responses. A quantitative approach specifically focuses on the navigable main stem of the Danube River, where the interactions of several human activities and pressures related to hydro-morphological alteration on biodiversity and ecosystem services are quantified.
This project is a Case Study under the Horizon 2020 project AQUACROSS, which builds on work undertaken in the previous pillars to develop concepts, practices and tools for better implementation of Ecosystem Based Management. This includes identifying and understanding the linkages between aquatic ecosystems and human well-being and identifying innovative management responses for aquatic ecosystems.
As part of the Horizon 2020 AQUACROSS project, this Case Study seeks to advance the application of Ecosystem Based Management for aquatic ecosystems. AQUACROSS aims to develop and test an assessment framework, which considers the full array of interactions, including human activities, within aquatic ecosystems.