Distribution, ecology and conservation status of Dionysia involucrata Zaprjag., an endangered endemic of Hissar Mts (Tajikistan, Middle Asia)

Abstract

Dionysia involucrata Zaprjag. (Primulaceae) is known as critically endangered endemic species of Hissar Mountains in Tajikistan. It is reported from few localities mainly in Varzob River valley and its tributaries. The species inhabits steep or overhanging faces of granite rocks in narrow river gorges. During the research all known populations of D. involucrata were examined in respect of the habitat conditions and species composition of vegetation plots. We analyzed the population extent of the species in its range in Tajikistan and the main threats in order to assess its conservation status. The detrended correspondence analysis was performed on a matrix of 65 relevés and 49 species (vascular plants and mosses), to classify the phytocoenosis with domination of D. involucrata according to their floristic composition in relation to other petrophytic vegetation units. Using our field data regarding present extent of occurrence and area of occupancy we conclude that the threat category of D. involucrata should be reassessed from critically endangered to endangered. The species shows decline tendency in extent of occurrence, area of occupancy as well as in number of locations. The vegetation plots with domination of D. involucrata have relatively high level of separateness due to different species composition. We define the new association -Dionysietum involucratae -representing chasmophytic vegetation of submontane and montane zone in Middle Asia (ca. 1000-1600 m a.s.l.). The plots of Dionysietum involucratae were found mainly on granite rocks, on very steep or overhanging faces, on southwestern or southern exposition. The association is rather poor in species with inconsiderable contribution of mosses. Despite the diagnostic species, Campanula incanescens, Carex koshewnikowii and Scutellaria hissarica were the most abundant and frequent taxa within the researched patches of vegetation.

Vegetation of rock crevices of the montane and colline zones in the Pamir-Alai and Tian Shan Mts in Tajikistan (Middle Asia)

“…Dionysia involucrata is an endemic species from the central section of the Hissar Range, known mainly from several locations in Varzob River valley (Nowak et al 2014a). The plots of Dionysietum involucratae were found in five locations of the main diagnostic species in the valleys of the Varzob and Takob rivers.…”

Dwarf shrub vegetation of rock ledges and clefts in the Pamir Alai Mountains (Middle Asia: Tajikistan)

“…Hydrogen ion concentrations were measured in aqueous rock solution using the ELMETRON CP-105 pH meter. During fi eld surveys, 488 phytosociological relevés documenting patches representing the Asperulo-Poion (Nobis et al 2013, Caricion koshevnikovii Nowak et al 2014) as well as fern associations on rock clefts and crevices and the association of Dionysietum involucratae Nowak et al 2014(Nowak et al 2014d were taken. Additionally ca.…”

Phylogeny and morphology of Anthracoidea pamiroalaica sp. nov. infecting the endemic sedge Carex koshewnikowii in the Pamir Alai Mts (Tajikistan)

“…Carex koshewnikowii occurs there mainly in the association of Dionysietum involucratae A. Nowak, M. Nobis, S. Nowak & A. Nobis (Nowak et al 2014a). It grows on granite rocks of a relatively low cohesion index and acidity (pH 6.0 to 6.5) on rock faces, mainly on SW-S-SE-E aspects with almost vertical, or even overhanging, inclinations, the approximate mean being 100° (Fig.…”