Ophioglossum vulgatum (Polypodiopsida, Ophioglossaceae) in the Vologda region, Russia

In 2015, Ophioglossum vulgatum L. ( Ophioglossaceae ) was included in the Red Data Book of the Vologda Region, with a 3/LC status, due to the emerging negative trend of decrease of localities and populations numbers. In the region, from 1826 to 2020, this species was reported in 90 localities in 22 (out of 26) administrative districts. Localities of adder's-tongue fall within the boundaries of 38 squares of grid mapping adopted by Atlas Florae Europaeae (46,9% of their total number in the region), while in 14 of them, the species was not found in the last two decades, and within certain squares, disappeared or sharply reduced its abundance in communities in several localities. Ophioglossum vulgatum usually prefers meadow and edge-meadow biotopes, but some cases of its occurrence in disturbed natural and modified habitats have been recorded as well. In communities, mosses and vascular plants (over 200 species recorded) adjoin adder’s-tongue. The most constancy show 37 species of herbaceous and 8 species of woody plants, but not one of them shows 100% constancy to O. vulgatum . The decrease in the agricultural load on meadow biotopes and the subsequent natural transformation of communities are the main threats to the existence of O. vulgatum in the taiga zone. Adder’s-tongue was recorded on the territory of eight protected areas. Necessary protection measures include (1) organization of regional "meadow" protected areas ("zakazniks" or natural monuments) in places where the largest O. vulgatum populations are found, the protection regime of which implies moderate agricultural loads in the form of cattle grazing and haying, as well as (2) monitoring of known populations dynamics and search for new adder’s-tongue populations. We assume that the emerging negative trends in the existence of O. vulgatum in the region will continue.