Dynamics of Reed Vegetation Area in the Sivash Gulf (Sea of Azov) according to Satellite Data

Abstract

The paper analyzes peculiarities of formation of the Sivash Gulf coastal area, which manifest at the moment as a combination of abrasive and accumulation processes. The paper gives more details about vegetation coasts (a special coast type related to a specific sedimentation type) defined by reed vegetation development, which is prevalent near clough entries in apexes of ingressive gulfs and “secondary” lagoons. Using data of digital multizonal satellites Landsat 5 and 7 as well as Sentinel-2 L1C, the paper considers dynamics (2014–2020) of reed coast areas in the East and South Sivash after damming the North Crimean Canal in 2014 as a consequence thereof and related increase of salinity in the gulf water area. For comparison, the paper analyzes dynamics of vegetation coast spread as a result of the canal functioning, also reed vegetation area growth up to the 1990s is considered. The ecological role of reed vegetation as a distinctive biotope is shown. It is emphasized that damming of the North Crimean Canal not only led to changes of the gulf salinity regime but also affected its entire ecosystem, including the reed coast, formation of which was promoted by increase of fresh water volume in the gulf water balance. Impact of the North Crimean Canal and its damming in 2014 on change of the reed vegetation area in the East and South Sivash was estimated using satellite data. At the studied zone of Prisivashie, flood plain areas shrank most of all in the Knyazevsky and Balaganovsky Gulfs as well as near the Alekseevskaya extinct lake in the South Sivash. In the Rogachinsky Gulf, despite discontinued drainage, influence of waste waters remains significant. Therefore, reed communities have preserved here best. It is shown that for some water areas shrinkage of areas populated by reed vegetation can considerably slow down provided there are local p ermanent or periodic fresh water sources, e. g. waste waters coming from settlements.