Biodiversity management and the Water Framework Directive under climate change

Future climate change needs to be considered when restoring freshwater ecosystems to good ecological status, as required by the Water Framework Directive (WFD). The diversity and population structure of aquatic organisms are affected both by climate through physico-chemical properties of their habitats and climate driven interactions within the biological part of the ecosystem. Further, climate change may result in abrupt regime shifts that may change future class boundaries for ecological status. In this project we have investigated how climate change influences management actions and assignment of ecological status of water bodies under WFD legislation. By utilizing existing and emerging large-scale databases on physico-chemical and biological quality elements covering major climatic and biogeographic gradients in Scandinavia, we link present day geographical variation in climatic conditions and physical and chemical properties of water bodies. Further, we combine these data with current information on fish communities and population structure of lakes, and this will serve as our mail tool and target to describe how climate affects ecological reference conditions, including non-linear threshold relationships between biological quality elements and pressures. The project did in its initial phases focused on collating datasets and databases on lake physiochemical characteristics as well as biological observations. This was used as input into model development for models linking catchment climate and vegetation, lake productivity, as well as lake physical characteristics. Advances includes augmenting the existing lake model MyLake to include processes for DOC photobleahing, floculation, and degradation by heterotrophic metabolism, as well as adding moduels for CO2 and O2 exchanges, and for the reactions of O, Al, Fe, P, Mn and S, and coupled the water column model to a sediment diagenetic module. We calibrated the model against high-frequency DO and water temperature data. Using the augmented MyLake model, we have explored how climate change and increase in DOC fluxes modulate ice phenology and dissolved oxygen concentrations. We have also integrate the new MyLake model with the BIWA gridded simulations of lake temperature over Scandinavia to predict the oxythermal habitat. Furthermore, the developed physical models have been linked to biotic parameters (ecological quality elements in WFR terminology) demonstrating that fish production follows a hump-shaped relationship with organic carbon input, and that this relationship is dependent upon fish community composition (i.e. historical biogeographical factors).

Measures to be taken in order to restore freshwater ecosystems to good ecological status, as required by the Water Framework Directive (WFD), need to consider future climate change. The diversity and population structure of aquatic organisms are affected by climate through physico-chemical properties of their habitats and climate driven interactions within the biological part of the ecosystem. Climate change may result in abrupt regime shifts that may change future class boundaries for ecological status. In this project we will investigate how climate change influences management actions and assignment of ecological status of water bodies under WFD legislation. By utilizing existing and emerging large-scale databases on physico-chemical and biological qua lity elements covering major climatic and biogeographic gradients in Scandinavia, we will link present day geographical variation in climatic conditions and physical and chemical properties of water bodies. We will further combine these data with current information on fish communities and population structure of lakes, and this will serve as our mail tool and target to describe how climate affects ecological reference conditions, including non-linear threshold relationships between biological quality ele ments and pressures. We will then subsequently test if climate change scenarios alter physical and chemical properties of water bodies to an extent where ecological class boundaries are likely to be crossed, and assess how management actions could mitigat e environmental impacts in order to meet good ecological status set by static reference conditions. We believe this could be directly applicable also to other systematic groups, notably invertebrates. The project will be carried out as a joint research ef fort between major Norwegian and Swedish institutional players on the subject, and benefit from synergies with initiated collaboration between NINAs and NIVAs Strategic Institute Initiatives on climate change.