Historisk markanvändning på Färsna gårds inägor och utmarker
Semi-natural grasslands are threatened biotopes in the landscape and without conservation measures high values of nature will be lost. Meanwhile, the biological values associated with cultural values of the traditional agricultural landscape in Sweden. Studies of land use history may help to understand how today biological diversity has evolved and how it can be preserved. Färsna farm in Norrtälje has left some of the old heritage of biological diversity in the form of nature - forest and grassland, which hosts an unusual herb-rich flora. Through the study of historic maps and från1673/1767/1801/1901 1952 and orthophoto of the area has a picture of how land use has changed over time emerged. TUVAInventory of Swedish Board of Agriculture and Forest Agency's survey were used as input to verify the natural values in the area. After the analysis in ArcGIS 9.3.1. were areas with long continuity in land use encirclement. With good planning and the right management of Färsna farm it may be possible to maintain the biological diversity and the entire area would be valuable refuges for many more threatened species.