Mathias Scholz

Long-term reactions of plants and macroinvertebrates to extreme floods in floodplain grasslands.

Extreme summertime flood events are expected to become more frequent in European rivers due to climate change. In temperate areas, where winter floods are common, extreme floods occurring in summer, a period of high physiological activity, may seriously impact floodplain ecosystems. Here we report on the effects of the 2002 extreme summer flood on flora and fauna of the riverine grasslands of the Middle Elbe (Germany), comparing pre- and post-flooding data collected by identical methods. Plants, mollusks, and carabid beetles differed considerably in their response in terms of abundance and diversity. Plants and mollusks, displaying morphological and behavioral adaptations to flooding, showed higher survival rates than the carabid beetles, the adaptation strategies of which were mainly linked to life history. Our results illustrate the complexity of responses of floodplain organisms to extreme flood events. They demonstrate that the efficiency of resistance and resilience strategies is widely dependent on the mode of adaptation.

Mapping water quality-related ecosystem services: concepts and applications for nitrogen retention and pesticide risk reduction

One of the challenges of using the ecosystem service (ES) framework in the context of planning and decision support is the question of how to map these services in an appropriate way. For water quality-related ESs, this implies a movement from the display of classical water quality indicators towards the mapping of the service itself. We explore the potential of mapping such water quality-related ESs based on three case studies focusing on different aspects of these services: (1) a European case study on pesticides, (2) a multi-scale German case study on nitrogen retention and (3) a more local case study on nitrogen retention in the Elbe floodplain (Lödderitzer Forst). All these studies show a high spatial variation of the results that can be depicted in maps of ES supply. This allows an identification of areas in which nitrogen retention is highest or which areas face the highest ecological risk due to pesticides. The multi-scale case study shows how the level of detail of the results varies with model resolution – a hierarchical approach to environmental and river basin management seems useful, because it allows the planners to determine scale-specific environmental problems and implement specific measures for the different planning levels.

Dyke-slotting initiated rapid recovery of habitat specialists in floodplain mollusc assemblages of the Elbe River, Germany

Dyke openings are regarded as suitable measures for restoring biodiversity and ecosystem functioning in degraded floodplains. Nevertheless, only few studies evaluate the effects and success of such measures on biodiversity. The present work analyses the influence of one of the first dyke-slotting projects carried out along the Middle Elbe River (Germany) on floodplain mollusc assemblages. By applying a before-after-reference-control-impact-monitoring design, we specifically tested how species diversity and composition responded to the restoration measure. Floodplain reconnection led to a considerable increase in mollusc diversity. However, the overall community turnover was rather small only present among species with high soil humidity preferences. They mainly profited from the frequent floodings shifting species composition to be more hygrophilous and floodplain characteristic. Moderately hygrophilous and desiccation tolerant species were almost not affected by the dyke-slotting. Presumably, this can be explained by the already similar species composition of the active reference and the reactivated floodplain due to a high seepage water influence. So far, this indicates a successfully initiated recovery process. All in all, our results emphasize the crucial need of long-term monitoring to reveal the full ecological effects of restoration measures and the consideration of diversity-, community-, and species-level responses to evaluate restoration success.

Ökosystembasierte Klimapolitik für Deutschland

Die Leistungen der Natur konnen zur Losung des Klimaproblems beitragen, indem sie gezielt fur den Klimaschutz und die Anpassung an den Klimawandel genutzt werden. Hierdurch lassen sich einerseits kostengunstiger Klimaschutz und andererseits Synergien zwischen Klimapolitik und Naturschutz- und Biodiversitatspolitik erzielen. Im vorliegenden Beitrag werden zunachst die Wirkungen der deutschen Energie- und Klimapolitik auf die Biodiversitat und die Okosysteme in Deutschland aufgezeigt. Im Anschluss daran erfolgt eine Untersuchung der Okosystemleistungen naturnaher Landnutzungen fur Klimaschutz und Klimaanpassung. Es zeigt sich, dass im Agrarsektor erhebliche Minderungspotenziale fur Klimaschutz vor allem durch den verringerten Ausstos von Lachgas sowie die Erhaltung von Grunland bestehen. Moore und andere kohlenstoffreiche Boden konnen durch Erhaltung und Wiederherstellung als Kohlenstoffsenken dienen. Auenflachen leisten insbesondere einen Beitrag zum Hochwasserschutz und damit zur Anpassung an den Klimawandel. Die Klimawirkungen in den einzelnen Bereichen werden okonomisch bewertet und Handlungsempfehlungen fur eine okosystembasierte Klimapolitik formuliert.