GIS ANALYSIS OF CHANGE IN AN AGRICULTURAL LANDSCAPE IN CENTRAL FINLAND

Changes in landscape over a period of 50 years were analysed in a rura l area of 324 ha in Central Finland. The data were digitized from aeri al photographs of the National Land Survey taken in 1944, 1959, 1979 a nd 1991, and analysed with the IDRISI (TM) geographic information syst em (GIS). The average proportion of land in agricultural use in the sa mple area was 17.4%. The arable area declined from the maximum of 62.3 ha (1959) to 47.6 ha. The total length of linear landscape elements, predominantly ditch bank habitats, halved, from 876 m/ha of field (194 4) to 449 m/ha by the end of the period. The average rate of loss of f ield boundary habitat was 9.1 m/ha/ year. At the same time, the Shanno n-Weaver index of diversity of agricultural landscape elements dropped from 0.37 to 0.24. The number of field parcels declined by 29%, and t he mean parcel size increased by 45%, from 1.2 ha to 1.7 ha. The index value of the fractal dimension measuring the complexity of parcel sha pes also fell, from 1.88 (1959) to 1.86 (1991). The change in spatial structure reflects the intensification of farming in Finland. Biodiver sity at ecosystem level has clearly declined. However, the implication s for the agroecosystem and its sustainability are still unknown.