Effect of different land-use on occurrence and morphological traits of Carex buxbaumii (study from Biebrza National Park, Poland)

Carex buxbaumii is rare sedge of moist to wet meadows, marshes and fens. The population trends and detailed habitat requirements of this species remain unknown. In Poland, C. buxbaumii belongs to EN category of IUCN, while is even more endangered in other European countries. The knowledge on this species is limited, but probably it needs active protection for its maintenance. It is also known that plants respond morphologically to changes in the site conditions which may help to determine the ways of effective method of their conservation. Therefore, we examined the frequency and morphology of Carex buxbaumii growing in a sward of fen-grasslands i) abandoned for 15 years, ii) mowed, or iii) grazed by Konik horses. The description of the occurrence and of the morphological reaction to the differentiation in land–use type of C. buxbaumii is presented against the background of changes in vegetation cover that occurred in 2010–2016 in the examined fen-grassland.