The Restoration Dynamics of Fallow Vegetation in the Steppe Zone of the Khakassia Republic Based on Terrain and Satellite Data

Resumo

The dynamics and specific features of the restoration of forbs–grass–wormwood and wormwood–grass phytocoenoses on fallow lands in the Altai region, the Republic of Khakassia, were determined on the basis of terrain and satellite data. The species composition, structure, and phytomass of the phytocoenoses were revealed. A gradual formation of structural elements of steppe communities in the studied areas was determined. This work showed the usefulness of time series of satellite data on the NDVI (Normalized Difference Vegetation Index) obtained with the use of MODIS (Moderate Resolution Imaging Spectroradiometer) for the study of specific features of restored fallows. In general the biological parameters, projective cover, and phytomass determine the value of the NDVI. Interannual NDVI variability reflects the rate and time period of fallow restoration. From a certain point, the parameters increased and became close to the steppe (control variant). It has been revealed that not only abiotic factors (climate and soils), but also biotic parameters (grazing and recreational load) affect the NDVI. In this connection, the duration of restoration stages does not always correspond to the published data. They vary under different conditions. Climatic data of the Abakan meteorological station (index 29862 in the network of the World Meteorological Organization) for the period from 2000 to 2017 were statistically treated. The long-term annual average norms of temperatures and precipitation amounts (year and month) for the World Meteorological Organization base period of 1961–1990 were calculated. The dynamics of the temperature and precipitation, using long-term series of data, has been analyzed.