Sandstränder vid Vänern – en hotad strandtyp?

Abstract

The essay is based on the well-documented overgrowth along the shoreline of Lake Vanern. Previous researches show that overgrowing beaches has been going on for a long time and that it has accelerated in recent years. Those studies have examined all of the lake's shores in general, but this paper has chosen study only the sandy beaches of Lake Vanern. The paper seek to answer questions about how much open sand there was 50 years ago and how much there is today. By comparing these two results this paper aims to clarify the threat against the values that can be found in the sandy beaches in Lake Vanern. Investigation has been carried out and found that for 50 years ago was 94 acres of open sandy beach and today remains 33 acres. The negative trend in the last 50 years has been 64% in loss of open sand. The main reason for the change is that vegetation has been established on the sandy beach. As part of the paper, a method for surveying the beaches previous open sandy area has been developed. The method is based on field surveys. The results show that the method can be used for inventory of the sandy beach. Mature trees grow on or above the older shoreline formed by the previous high tide and storm surge. The older shoreline (that was flooded before the regulation of the see) separates older vegetation from younger. A further aim was to clarify the threat against the values that can be linked to the sandy beach. It has been noted that there are high values, not just social and recreational, but also a rich biodiversity. The results show that the decline of open sand is great and several red-listed species dependent on open sunlit sand and are in danger of disappearing if the trend of overgrowing continues.