THE RATE OF BOG GEOSYSTEMS ADVANCING ON THE LICHEN PINE FOREST (A CASE STUDY OF THE BOLSHOYE KAMSKOYE BOG, CIS-URALS)

Abstract

The dynamics of raised bogs in the north of the Kama region were studied using multi-temporal Landsat satellite images with stable snow cover. The use of winter images was determined by the need to exclude the factor of the underlying surface (soil cover, grass and subshrub vegetation) from the spectral image and to fix changes only in the tree layer of pine forests. Manual (expert) classification of the multitemporal composite was carried out according to spectral features. The displacement of the boundaries of bog phytocenoses deep into the first terrace is observed at an average distance of 75–85 m, which corresponds to the rate of displacement of critical conditions for pine life (formation of dead wood) – about 2 m/year. In the course of field works on test sites, the extent of tree vegetation inhibition and the intensity of the bog’s advance on adjacent geosystems were recorded. In the summer season of 2022, there was conducted a study of the composition of phytocenoses in the lower layer of vegetation in the border zone of the southern ‘shore’ of the Bolshoye Kamskoye Bog. The change of pine-cotton grass-subshrub-sphagnum phytocenosis to pine-subshrub-moss phytocenosis was recorded at a distance of 135–165 m when the bog invaded the forest geosystems. The main changes were recorded in the lower tier of vegetation. It is assumed that the change in the lower tier in time overtakes the process of the forest stand degradation, but in terms of the rate of boundaries displacement in space, it shows almost the same values – about 2 m/year.