Assessment of vegetation in the ravines of Khortytsia Island (Zaporizhzhya) using Landsat satellite data

This work highlights the issues of prompt detection of changes in vegetation density of small forests in steppe ravines, which belong to the recreational zone of Zaporizhzhya city, using Landsat 8 satellite multispectral images in the time range. The results of changes in the density of woody and herbaceous plants using the normalized difference vegetation index (NDVI) are presented. The main advantage of NDVI is the reliability and ease of data acquisition, as well as a wide range of tasks that can be solved using it. A series of thematic maps was obtained for the years 2000, 2010, 2020, 2024. Based on the values of the NDVI index, several classes of dense, moderate and sparse vegetation were distinguished within each ravine forest. Forest ravines also feature some areas with exposed soil. The dynamics of vegetation changes over the years of research have been examined.Temporal changes of the relative area occupied by woody vegetation and the state of this type of vegetation were also assessed. The multidirectional nature of their changes has been established both within a particular ravine and when compared to the parameters of various other ravines over the course of our research. This is due to the influence of many exo- and endodynamic environmental factors. The coastal part of Khortytsia Island has undergone drainage due to the destruction of the dam of the Kakhovka HPP, which led to an increase in the length of the coastline and the area of the mouth of the ravines under study. As was established via the satellite images in 2024 that, compared to 2020, the area of the coastal zone of the analyzed ravines increased by at least a factor of 1.75 (Heneralka) and at most 3.4 (Shyroka) respectively. The magnitude of this indicator for the remaining ravines falls within the aforementioned range of values.It is recommended to continuously monitor changes in the coast of Khortytsia Island in terms of its succession processes and the state of hydrobionts.