Efficacy of restoration measures in grey dunes

Abstract

Grey dune ecosystems in Europe show a decrease in area and quality. Lacks of natural dynamics and increased eutrophication have led to grass encroachment and increased shrub cover. Policy to improve the quality of these dry dune systems has been developed but the efficacy of measures for ecological restoration is not always clear. In this research the efficacy of sod cutting and increased aeolian sand dynamics as restoration measures to improve the quality and increase the area of grey dune is researched. To this purpose articles in international scientific literature and management reports from the Netherlands are reviewed.

The restoration measures are not often discussed in scientific literature and restoration measures are often not sufficiently monitored. Much of the literature on the effects of increased aeolian sand activity is mainly geomorphological. Scientific knowledge on the long term effects of restoration measures in grey dunes or comparable systems is scarce. However from the reviewed studies a few general trends became obvious. Sod cutting and the increase of aeolian sand dynamics can be an effective way to increase both the quality and the area of grey dune ecosystems. Dependent on how the measures are performed both measures can have a beneficial effect on pioneer stages as well as species rich dune grasslands. Points of interest are the effect on SOM, the soil seed bank, sand deposition and pH, as well as the scale of the measures. These factors are crucial in the establishment of target communities.

Future research should focus on the effects of recovery measures on soil processes, soil biota and on the effects on the longer term. Effects of the restoration measures on species rich grey dune grasslands on the longer term are uncertain. Recovery in lime-rich sites seems to be slower while in acid dunes the grass encroachment is a bigger problem. Ecosystem managers should monitor recovery measures and report the results of these monitoring studies to improve the knowledge on ecosystem restoration and improve future management.