ECOLOGICAL ANALYSIS OF THE SPECIES OF PLOCAMA VASSILZENKOI (LINCZ.) M. BACKLUND & THULIN BY SOIL SUBSTRATE TYPES AND ALTITUDE ZONES

Abstract

This study presents a quantitative ecological analysis of the endemic taxon Plocama vassilczenkoi (Lincz.) M. Backlund & Thulin, belonging to the tribe Putorieae of the family Rubiaceae, with respect to soil substrate types and altitudinal zones. A total of 36 occurrence records were analyzed based on catalogues of the TASH and FRU herbarium collections, published floristic syntheses, and systematic field expeditions conducted during 2020–2025; 33 of these records contained precise altitude data. The species occurs across an altitudinal range of 406–1521 m (M = 790 m; SD = 277 m). According to Q.Z. Zokirov’s classification of altitudinal zonation [13], the ecological optimum of the species is concentrated in the lower part of the adyr zone, at 500–800 m, accounting for 45.5% of the 33 records with available altitude data (χ²(3) = 10.52; p = 0.015). Substrate analysis showed that adyr and open-adyr habitats (36.1%), foothill–slope substrates (19.4%), gravelly substrates (13.9%), and rocky steep slopes (11.1%) constitute the principal habitats of the species (χ²(6) = 18.06; p = 0.006). The distribution pattern of the species was characterized across three floristic regions: Western Tian Shan (33%), Fergana–Alay (53%), and Kohistan (14%). The findings quantitatively confirm the species’ specialized xerophytic–petrophytic ecology and provide a scientific basis for habitat-centered conservation measures.