Classification of vegetation of the Barents Sea coast at the mouth of the Indiga River

Classification of coastal vegetation from the standpoint of the ecological-phytocoenotic approach at the estuary of the Indiga River, flowing into the southeastern part of the Barents Sea, is presented. On the base of 131 relevés of coastal vegetation, 23 associations in 18 formations were identified. The coastal vegetation in different biotopes differs in the structure and features of the phytocoenoses floristic composition. Based on the signs of vegetation cover, mesorelief, and hydrological features of the shores, the following biotopes were identified: saline and brackish marshes, beaches and dunes, tidal flats at the mouths of estuaries, saline and brackish lagoon lakes on marshes. The marches with 14 described associations have the highest phytocoenotic diversity. A phytocoenotic diversity of the beaches is noticeably less, 4 associations are described there. The vegetation background of the beaches is formed by the communities of the Leymeta arenarii formation, the vegetation background of the salty marshes is formed by the communities of the Cariceta subspathaceae, Cariceta glareosae, and Cariceta mackenziei formations. In saline lakes, large areas are occupied by communities of the Hippurideta tetraphyllae formation, and the communities of the Triglochineta maritimi and Plantagineta subpolaris formations are rare, the northern limit of their range runs approximately along the Indiga mouth. The vegetation of brackish marshes is mainly formed by the Cariceta salinae herbosum, Junceta gerardii, and Cariceta rariflorae communities. At the mouth of Indiga estuary, large areas are occupied by communities of the Magnocariceta formation. In the mouth of the Indiga, a little north of the range limit, communities of Eleocharis uniglumis, a rare species in the Nenets Autonomous Okrug, are described for the first time at the rank of association Eleocharitetum uniglumis. The aquatic vegetation of desalinated lagoon lakes is represented by the Myriophylleta sibirici formation. The halophyte vegetation of the Indiga River estuary is compared with the estuaries of the rivers of the Kanin Peninsula and the Pechora Bay. The ordination of geobotanical relevés shows a greater similarity of the coastal vegetation of the Indiga estuary with the estuaries of the rivers flowing on the Kanin Peninsula of the White and Barents Seas basins and with the vegetation of the rivers estuaries of the Pechora Bay coast. The article has an electronic appendix (https://journals.rcsi.science/0006-8136/issue/archive).