Effects of Sand-Drift Dynamics on the Conservation and Restoration of Grey Dunes

Since 2012, within the framework of DPWE, research has been ongoing on the restoration and management issues of dry dune grasslands (habitat Grey dunes). The research is a mix of observations of what is ‘happening’ in the field and an exploration of the underlying processes.

The objective of the research is a more precise interpretation of the data that were collected in 2014 and 2015 in and around eight blowouts, so as to determine: (i) the effects of aeolian activity on the quality of the soil and vegetation of dune grasslands, and (ii) the permanence of these effects.

In 2016 we are addressing the following questions:

  • How much sand has disappeared from the deflation zone and how much deposited around the blowout?
  • How is this related to the dimensions, morphology and landscape position of the blowout?
  • How does the sand transport affect the displacement of lime, that is, the acid buffer capacity, and other important materials such as iron and phosphate?
  • How does the transport of calcium carbonate affect the quality of vegetation and on what spatial scale?
  • How does the transport of calcium carbonate affect the permanence of well-developed dune grasslands in the deposition zone?

How long do well-developed dune grasslands that appear in the deflation zone following stabilisation last?

Soil research in a blowout area. In the two soil profiles one can see a light-coloured deposition layer over an old humus profile.

Soil research in a blowout area. In the two soil profiles one can see a light-coloured deposition layer over an old humus profile.

Sand balance, quantification acid buffer capacity, spatial pattern soil chemistry and vegetation/plant species, permanence buffered conditions

The activities involved are the following:

  • Calculation of the sand balance (sand disappeared from the deflation zone, sand transported to the deposition zone, missing residual) of separate blowouts, based on surveys of topography and interpretation of soil profile descriptions. The margins of uncertainty are also taken into consideration. For four blowouts, levelling of the deflation zone is also necessary. Quantification of the transported acid buffer capacity in the deposition zone around the blowouts, on the basis of the sand balances and available soil chemistry data. Other chemical compounds are also examined, including iron and phosphorus, since such elements play an important role in phosphate availability.
  • Closer analysis of the spatial pattern of soil chemistry and vegetation/plant species.
  • Calculation of the permanence of well buffered conditions in deposition zones and in deflation zones once aeolian activity stops. A high acid buffer capacity is important for the ecological quality of dune grasslands. These calculations are done using a new version of DUVELCHEM (Stuyfzand 2010), with the input of carefully screened soil quality data and recent data on bulk atmospheric deposition (from a 4.5-year monitoring in the neighbouring NW core of the Kennemer dunes; Stuyfzand & Arens 2015).

DPWE report and workshop

The project concludes with a DPWE report containing the analysis results. A workshop with ecologists, managers of the DPWE companies, and other nature managers, will also be organised in collaboration with the Dutch OBN Knowledge Network for Nature Restoration and Management.