This paper presents the results of a phytosociological study of the vegetation of the loose juniper forests of Pamiro-Alaya in Tajikistan. On the basis of 119 phytosociological images, we identified two main types of this vegetation with Zeravshan juniper and Pseudosabin juniper. It turned out that these two types of juniper forests represent two distinct vegetation classes, the first associated with the warm Irano-Turanian area, the second with the terrain of continental Central Asia. The previous view that the main factor differentiating these communities is mainly altitude has been refuted. Zeravshan juniper canes are found mainly in southwest Asia, and Pseudo-Sabian juniper in Central Asia, and in Central Asia their ranges overlap giving a false impression of their distribution.

Abstract

The paper presents the first syntaxonomic classification for juniper wood communities in Tajikistan with some remarks on their environmental gradients. A total of 119 relevés were sampled between 2015 and 2021 using the seven-degree Braun-Blanquet cover-abundance scale. They were classified by a modified TWINSPAN method. Diagnostic species were identified using phi coefficient as a fidelity measure. Detrended Correspondence Analysis (DCA) was used to determine relationships between samples, vegetation units and major gradients in species composition. Plant communities have been divided into two main groups. The first one is a west Irano-Turanian wood of Juniperus polycarpos var. seravschanica of the Pamir-Alai mountane belt. It occurs in two variants depending mainly on the aspect and precipitation. The second juniper wood type in Tajikistan is a stand of Juniperus pseudosabina. It prefers the northern slopes and north-eastern ranges of the Pamir-Alai and slightly lower elevations. Both juniper wood types are highly distinct in terms of species composition, especially in the moss layer, and have therefore been assigned to different classes: Pino-Juniperetea (Juniperetum seravschanicae) and Juniperetea pseudosabinae (Carici turkestanicae–Juniperetum pseudosabinae). The main factors determining the species composition of the studied associations are latitude, growing season precipitation, annual range of air temperature and precipitation of coldest quarter. Our study has shown that there are two very distinct vegetation types of the juniper wood groves in Tajikistan, which reflect the main phytogeographical division between the provinces of Turkestan and Central Asia.

Nowak A., Nobis M., Nowak S., Kotowski M., Swierszcz S. 2022, Phytosociological survey of juniper wood vegetation in Tajikistan (Middle Asia). Dendrobiology 88, 16-36 doi.org/10.12657/denbio.088.002

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2023-09-20 06:34:51