DIVERSITY AND DISTRIBUTION OF RUSH COMMUNITIES FROM THE PHRAGMITO-MAGNO-CARICETEA CLASS IN PAMIR ALAI MOUNTAINS (MIDDLE ASIA: TAJIKISTAN)

Abstract

The study presents results of geobotanical investigations conducted in rush vegetation from the Phragmito-MagnoCaricetea class in the central Pamir-Alai Mts (Tajikistan, Middle Asia). Studies were carried out mainly within the SyrDaria, Pyandzh, Zeravshan, Kafirnighan, Khanaka and Surkhandaria river valleys in the years 2008‒2012. The research was focused on the classification of rush plant communities developing within this poorly-investigated area. Habitat conditions were checked for all vegetation plots, including pH reaction, water depth, inclination and altitude. Altogether 231 phytosociological relevés using the Braun-Blanquet method were sampled. The analyses classified the vegetation into 28 plant communities, including 26 associations. Eight new plant associations were proposed: Scirpetum hippolytii, Mentho asiaticae-Nasturtietum microphyllae, Juncetum brachytepali, Sparganietum stoloniferi, Eleocharitetum argyrolepis, Eleocharitetum mitracarpae, Caricetum songoricae and Rorippo palustris-Alismatetum graminei. The main discrimination factor for the data set is the floristic structure of the associations. Rush vegetation from the PhragmitoMagno-Caricetea class is spread throughout all river valleys of the research areas in montane and subalpine as well as in alpine zones. The vegetation patches occur mainly along the shores of water bodies and in ditches. Only sporadically have rush communities been noted within rice fields, where communities of the class Oryzetea sativae prevail. The study shows that riverside habitats with rush vegetation can harbour a relatively rich flora. Almost 200 species were found in vegetation plots, including some which are rare and have not been recorded until now in this part of Middle Asia.