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Aims: In this paper we propose the first syntaxonomic classification for the mesophilous scrub vegetation in Tajikistan with some remarks on their environmental variability. Methods: Altogether 120 relevés were sampled using the standard, seven-degree cover-abundance scale of Braun-Blanquet, in 2015–2021. They were classified by the modified TWINSPAN method using the four step interval scale with cutoff levels of 0%, 2%, 5% and 10% and total inertia as a measure of cluster heterogeneity. Diagnostic species were identified using the phi coefficient as a fidelity measure. Detrended Correspondence Analysis (DCA) was used to determine the relationship between the sampled plots, vegetation units and major gradients in species composition. Results: Plant communities known so far as šhiblyak and including xeric and mesophilic shrublands seral or marginal to broad-leaved forests in the nemoral zone of the Irano-Turanian region are described herein. Numerical analyses of vegetation data allowed distinguishing five associations representing the Ranunculo tenuilobi-Cotoneasterion hissarici alliance. The new associations include: Eremuro comosi-Rhuidetum coriariae, Calophacetum grandiflorae, Fraxinetum raibocarpae, Pruno sogdianae-Crataegetum turkestanicae, Aflatunio ulmifoliae-Caraganetum turkestanicae. For the latter association, two habitat variants (with Ferula clematidifolia and Malus sieversii) are proposed. The main factors determining the species composition of the studied vegetation include: elevation, mean annual temperature and sum of annual precipitation. Conclusions: The research results herein presented fill the gap in knowledge about the shrubland vegetation of Tajikistan. Studies in neighbouring countries and a focus on subalpine scrubs in dry habitats are needed to complete the classification of shrubland vegetation of Middle Asia. |
