MOUNTAIN WETLAND VEGETATION CHANGES FOR THIRTEEN YEARS IN VITOSHA MOUNTAIN (BULGARIA)

This study presents a sample of the high-mountain wetland vegetation changes over a 13-year period in Vitosha Nature Park. We re-survey the vegetation at the same locations, that were ensured by a 10 m buffer delimited around each 2006 coordinates and within this buffer sampling plots were relocated in 2019. We re-confirm all the previous high-mountain wetland vegetation plots, but detected changes of vegetation composition as: 1) an increase in both cover and diversity of vascular plants accompanied by decreasing of bryophytes mainly at the expense of Sphagnum species for the sub-alpine mires of Scheuchzerio-Caricetea fuscae; and 2) a reverse tendency towards an increase in the cover and diversity of bryophytes in the lower mountain belts for the wet meadows of class Molinio-Arrhenatheretea. According to the observed plant species composition changes for this 13-year period in Vitosha Mtn., the sub- alpine mire vegetation "tend to get dryer", while lower wet meadow grasslands have become closer to mire vegetation. The high-mountain wetlands preservation is important for both the biodiversity conservation and for the long-term monitoring on vegetation and climate perspectives.