Natural risks and vulnerabilities of dynamic coastal dune landscapes

Résumé 0

Set in the Habitats Directive as priority habitat, fixed dunes with herbaceous vegetation (grey dunes) occur around the coasts of Europe. As a part of many coastal dune systems these habitats are especially complex and low resilience and need special attention from the conservation and management perspectives. Nearly a decade we have studied representative examples of fixed dunes in Estonia. Due to growing anthropogenic pressure and ongoing global changes it is vital to distinguish the changes and analyse general trends of development of grey dunes. The selected sites Keibu (located on the NW coast of mainland Estonia) and Ruhnu (located on the eastern coast of Ruhnu Island) are representative examples in Estonia, with a coverage of a geographical range and ecological variation. Both sites are part of conservation and monitoring areas. In each site, we have compiled a landscape profile to visualize the topography, vegetation and soils. he study was carried out on perpendicular to shoreline landscape profiles in order to express the full spectrum of coastal dune plant communities and surface deposits from shores towards inland. Both, natural and human impacts have been considered in the assessment of changes in the structure and functioning of the grey dunes in Estonia. The results show that changes in dune landscapes can be rapid, especially on sandy beaches due to stronger storm surges in recent decades. The inland areas are more affected by human activity and the changes there are well reflected. The gradual loss of open sandy habitats on the sites is evident during the last 100 years and show the overall development trends of dynamic coastal dune landscapes. This study has proven that these areas need permanent observation to assess the level of changes. It is vital to contribute to the decision making processes concerning their optimal use and conservation needs to maintain their resilience.