Change of regulating ecosystem services in the Danube floodplain over the past 150 years induced by land use change and human infrastructure

Ecosystem services in floodplains are manifold. The regulating services regarding hydrological issues (e.g. flood protection, water purification) are of particular importance along rivers, and depend strongly on size and land use of the floodplain. In this paper, we transfer the commonly known land use changes in floodplains over the last 150 years into significant changes of the amount of different regulating ecosystem services. We investigated a floodplain stretch of 17 km along the Danube in Germany (approx. 90 km²). Thus, we mapped the spatial expansion of the active floodplain and the land use distribution for three different times: the earliest (not the pristine) state of 1869 on the basis of a historical map, 1963 after river regulation and 2013 as navigation channel with a hydropower dam on the basis of aerial photographs. The land use types woodland, grassland, arable land, settlements, and water bodies were distinguished. On the basis of land use as a proxy, we calculated the potential of four ecosystem services (flood retention, nitrogen and phosphorous retention, habitat provision) according to the method of Scholz et al. (2012a). The spatial extension of the active floodplain was continuously reduced from 56 km² (1869) to 18 km² (1963) to 11 km² (2013). The amount of grassland and arable land was reduced significantly in the active floodplain, whereas woodland increased. This entails a decrease of f lood retention (-80%), and nutrient retention (nitrogen: -60%, phosphor: -76%). Likewise, habitat provision was significantly reduced. In total, the potential benefits for humans have been negatively affected over the time by land use change and, above all, by the construction of embankments. Therefore, ecosystem services should be regarded by future floodplain management

Assessing land use and flood management impacts on ecosystem services in a river landscape (Upper Danube, Germany)

Rivers and floodplains provide many regulating, provisioning and cultural ecosystem services (ES) such as flood risk regulation, crop production or recreation. Intensive use of resources such as hydropower production, construction of detention basins and intensive agriculture substantially change ecosystems and may affect their capacity to provide ES. Legal frameworks such as the European Water Framework Directive, Bird and Habitats Directive and Floods Directive already address various uses and interests. However, management is still sectoral and often potential synergies or trade‐offs between sectors are not considered. The ES concept could support a joint and holistic evaluation of impacts and proactively suggest advantageous options. The river ecosystem service index (RESI) method evaluates the capacity of floodplains to provide ES by using a standardized five‐point scale for 1 km‐floodplain segments based on available spatial data. This scaling allows consistent scoring of all ES and their integration into a single index. The aim of this article is to assess ES impacts of different flood prevention scenarios on a 75 km section of the Danube river corridor in Germany. The RESI method was applied to evaluate scenario effects on 13 ES with the standardized five‐point scale. Synergies and trade‐offs were identified as well as ES bundles and dependencies on land use and connectivity. The ratio of actual and former floodplain has the strongest influence on the total ES provision: the higher the percentage and area of an active floodplain, the higher the sum of ES. The RESI method proved useful to support decision‐making in regional planning.BMBF, 033W024A, ReWaM - Verbundprojekt RESI: River Ecosystem Service Index, Teilprojekt

Der River Ecosystem Service Index in der Modellregion "Donauauen zwischen Neu-Ulm und Donauwörth" - Berücksichtigung vielfältiger Ökosystemleistungen bei der Planung von Hochwasserschutzmaßnahmen

Geplante Hochwasserrückhalteräume an der Donau in Bayern bilden das Grundgerüst für Szenarien, in denen Öko-systemleistungen für einen Alternativenvergleich herangezogen wurden. Der Vergleich wurde mit Hilfe des River Eco-system Services Index RESI erstellt, der im Auenmagazin 16 vorgestellt wurde. Der RESI ergänzt die klassischen mo-netären Bewertungsverfahren wie etwa die Kosten-Nutzen-Analyse durch eine fünfstufig skalierte Bewertung von 27 Ökosystemleistungen, basierend auf einer quantitativen und räumlich expliziten Erfassung (Puschetal. 2019). Für das Fallbeispiel Donau zeigt er klar die Vor- und Nachteile verschiedener Planungszustände für unterschiedliche Sek-toren auf und ermöglicht so eine integrative Entscheidungsfindung

Restoration of ecosystem functions and efficiency control: case study of the Danube floodplain between Neuburg and Ingolstadt (Bavaria/Germany)

The Danube floodplain is disconnected from its river, and natural water dynamic is inhibited by regulation and hydropower generation. Notwithstanding the hydropower dams, this restoration project aims to bring back natural water dynamics to the floodplain by a new floodplain stream, by ecological flooding and by temporary groundwater drawdown during summer months. Due to the new floodplain stream, former fluctuating water zones which are habitat for the target species Oenanthe aquatica changed to aquatic habitats which are also required. The measure groundwater drawdown aims to enhance the abiotic conditions for this pioneer species of muddy streambanks. The scientific efficiency control compares the situation before restoration implementation with the effects of three different types of groundwater drawdown. For these three types, the hydrological situation was investigated, and the effects on the potential area and on the occurrence of O. aquatica were mapped. The outcome is that one type can enhance germination of O. aquatica, but is detrimental for aquatic organisms. The other type is able to provide the same suitable conditions for O. aquatica, without severely harming the aquatic habitats. The third type cannot reach the needed low water levels and is therefore not a comparable option. The results show that an interdisciplinary monitoring is able to develop a measure suitable for both competing habitat types

Change of regulating ecosystem services in the Danube floodplain over the past 150 years induced by land use change and human infrastructure

Ecosystem services in floodplains are manifold. The regulating services regarding hydrological issues (e.g.flood protection, water purification) are of particular importance along rivers, and depend strongly on size and land use of the floodplain. In this paper, we transfer the commonly known land use changes in floodplains over the last 150 years into significant changes of the amount of different regulating ecosystem services. We investigated a floodplain stretch of 17 km along the Danube in Germany (approx. 90 km2). Thus, we mapped the spatial expansion of the active floodplain and the land use distribution for three different times: the earliest (not the pristine) state of 1869 on the basis of a historical map, 1963 after river regulation and 2013 as navigation channel with a hydropower dam on the basis of aerial photographs. The land use types woodland, grassland, arable land, settlements, and water bodies were distinguished. On the basis of land use as a proxy, we calculated the potential of four ecosystem services (flood retention, nitrogen and phosphorous retention, habitat provision) according to the method of Scholz et al. (2012a). The spatial extension of the active floodplain was continuously reduced from 56 km2 (1869) to 18 km2 (1963) to 11 km2 (2013). The amount of grassland and arable land was reduced significantly in the active floodplain, whereas woodland increased. This entails a decrease of flood retention (-80%), and nutrient retention (nitrogen: -60%, phosphor: -76%). Likewise, habitat provision was significantly reduced. In total, the potential benefits for humans have been negatively affected over the time by land use change and, above all, by the construction of embankments. Therefore, ecosystem services should be regarded by future floodplain management