ИСТИНА

In the territory of Central Forest State Nature Biosphere Reserve (Tver` Province, NW Russia, Lat.: 56°26´–56°39´N, Long.: 32°29´–33°01´E) grassland mostly exist as small patches in the place of abandoned settlements surrounded by old-growth forests. These peculiar herb communities still remain poorly studied, while their area is declining due to forest expansion. The aim of the study is to survey herbaceous vegetation (meadows and ruderal communities) remaining after several decades of protection and compare them with currently managed local herbaceous vegetation in terms of species richness, species diversity, site conditions as well as functional and coenotic structure of floristic composition. We analyzed 209 relevés made in 2013–2014. Classification procedure was carried out by using cluster analysis and indicator species analysis. For ordination we ran Detrended Correspondence Analysis (DCA). Landolt’s and Ramensky’s scales were used to evaluate ecological conditions. The presence of four herbaceous community types was revealed: managed mesic meadows, abandoned mesic meadows, tall-herb meadowsweet communities, and ruderal tall-herb communities, which jointly account for 40% of the Reserve flora, including 4 red-list species (mainly confined to abandoned mesic meadows) and 16 alien species. These four types differ in present-day and past management patterns, floristic composition and ecological conditions as well as in coenotic and functional group shares (including participation of forbs, graminoids and woody species). Of special interest are the abandoned mesic meadows, which still look like grasslands and retain a high share of meadow species. Their coenotic and functional spectra are different from those of managed meadows and more similar to other abandoned grassland types. Despite some successional changes after 25 years without management, the studied mesic meadows seem relatively stable, retaining all the key meadow features, although their area has shrunk, and the spread of woody and forest species increased. The facts suggest that meadows under protection regime have a natural ability to withstand expansion of woody vegetation and invasion of alien plant species. Nevertheless, they require special activities to maintain them, otherwise they may eventually disappear, which means a significant loss of biodiversity of the entire protected area.