Relationship between coastline changes and dynamics of coastal ecosystems of Tahkuna Peninsula, Estonia

The coastal zone as a boundary between sea and mainland is characterized by different landscape types with high biodiversity. Global climate change is one of the most significant factors that is causing changes on coastal area. The climate warming during the last decades has been evident in the Baltic Sea region. The effects of climate change on seacoast can be seen in the changes of sea level, coastal hydrodynamics and ice conditions as well as in human actions. On regional and local level the change of coastal landscape generally depends on shoreline stability. Most vulnerable to erosion are densely populated coastal areas with cities. The coastal erosion is an increasing problem, it also causes reducing and damaging coastal communities including habitats of NATURA 2000. During the last decades, the coastline and morphology of sandy beaches have noticeably changed at Tahkuna Peninsula. Different methods have been used for landscape investigation. Landscape changes were studied by using maps of different periods and analysed with computer programs. Method of landscape complex profile was used as a basis for research. The aim of the study was to find relationships between coastline changes and dynamics of coastal ecosystems. Due to the intensive erosion the study area with habitats of sandy beaches (1210, 1640), embryonic, white, grey dunes (2110, 2120, 2130) has decreased. Repeated surveys in the eastern part of peninsula (Tõrvanina) show the disappearance of a 45-m-wide strip of land during 1976-1998. The eroded deposits are partly transported to the south where the sandy spit is rapidly elongating, there takes place development of new plant communities. Changes along the coast are result of combination of natural processes and human influence (Lehtma harbour). The study area has a high nature conservation and recreational value. Therefore it is essential to continue monitoring and to improve the planning processes in these vulnerable areas.