Analysis of the dynamics of condition forest plant communities in the “Makarovsky” nature sanctuary (Sakhalin Island) by remote sensing data

Abstract

The results of the analysis of changes in the state of forest plant communities in the “Makarovsky” Nature Sanctuary in the period from 1980 to 2020 are presented in the article. In the process of our work there was created a model of the vegetation cover of the “Makarovsky” Sanctuary, which made it possible to determine the difference between plant communities and their condition. The data for the construction of the cartographic model were formalized spectral characteristics of the surface of plant communities recorded on Landsat-1–7 and Sentinel-2 images. In a specially protected natural area, 7 classes of objects have been identified when conducting uncontrolled classification using ArcGIS according by their spectral characteristics. The division of dark coniferous and deciduous forests, the identification of the boundaries of plots with different species composition of forest stands and the allocation of felling sites was performed on the basis of the normalized vegetation index (NDVI). The accuracy of determining the composition of forest stands based on the results of interpretation was checked by data of geobotanical research data on the territory of the “Makarovsky” Nature Sanctuary. As part of the vegetation cover of the “Makarovsky” Nature Sanctuary, 8 forest communities were identified—spruce-fir, stone-birch forests, cedar elfin formation, valley deciduous, birch, birch-spruce forests, woodlands, sometimes larch forests, and 2 non-forest communities—Kuril bamboo formation and meadow vegetation. Forest communities occupy 95 % of the territory of the “Makarovsky” Sanctuary. The landscape and climatic conditions of the area are optimal for the growth of spruce-fir forests, which cover 44 % of the total area of the “Makarovsky” Nature Sanctuary. Birch and stone-birch forests (39 %) are widespread on logged land in Sanctuary. There is a wide distribution of secondary succession in the territory of the “Makarovsky” Nature Sanctuary. The composition of forest stands in Sanctuary has changed significantly over the research period in favor of young coniferous trees. Vegetation in the “Makarovsky” Nature Sanctuary has preserved its natural pristine appearance and reflects both altitude differentiation and landscape-zonal features of the middle taiga subzone of Sakhalin. The use of satellite images of medium spatial resolution made it possible to accurately analyze the state of forests of the “Makarovsky” Sanctuary. More detailed researches require the use of unmanned aerial vehicles.