Combined effects of climate change and nitrogen deposition

Insight into combined effects

It is very probable that climate change has an impact on the presence and the quality of scanty grasslands in the coastal dunes as well as inland. It therefore plays an important role in the realisation of nature objectives. How these ecosystems will react to climate change depends in part on the level of the nitrogen deposition. In dry ecosystems, the availability of nitrogen and water often both constitute constraints to the productivity of the vegetation. This is why it is important to understand and quantify the combined effects of climate change and nitrogen deposition. Based on this knowledge, management and policy can be adapted in a timely manner to the possible future effects. Moreover, climate change and nitrogen deposition also have an influence on the aeolian dynamics in dune ecosystems (Aggenbach et al., 2018) and thereby also impact the biodiversity.

Schematic representation of the possible effects of the climate and nitrogen deposition on the productivity of scanty grasslands. Wales involves low and NL high nitrogen deposition.

Focus on grasslands in dry dunes and inland

To predict how scanty grassland vegetations in the Netherlands react to the combined effects of climate change and nitrogen deposition, we will make use in this project of already existing data along a gradient with different climatological conditions and nitrogen deposition levels from other European countries. To this end, we will be collaborating with various research groups in North-West Europe.

For scanty dune grasslands on the coast, a new central dataset is being compiled from different European dune areas. In addition, we are making partial use of existing datasets for inland grasslands.

Scenario analyses for nitrogen accumulation in the soil using the dynamic soil-vegetation model PROBE, of the influence of nitrogen deposition and its feedback on biological nitrogen fixation. LD = area with low nitrogen deposition and NB = area with high nitrogen deposition.

Quantitative knowledge for better management and policy

The project should produce quantitative knowledge about the combined effects of (trends in) climate change and nitrogen deposition on scanty grasslands in the Dutch dune areas and in the inland. This insight is essential for the development of climate adaptive measures and as input for policy on nitrogen deposition. Moreover, on the basis of this knowledge, the KWR-developed vegetation prediction model PROBE can be further improved, enabling it to assess scenarios for climate change and nitrogen deposition.

Species-rich dune grassland in NW Wales with a low nitrogen deposition.

Measurement of productivity of enclosures in dune grassland