A class is the highest rank in the vegetation hierarchy (according to the Braun-Blanquet method). For example, meadows, xerothermic grasslands or deciduous forests can be treated as a class. Describing a class requires a particularly accurate and thorough analysis of the structure, diversity and habitat and climatic conditions of the occurrence of plant communities. Most often, well-defined plant communities, associations and orders need to be presented beforehand. A vegetation class should be characterized by a unique and repeatable structure, many endemic species included in its communities, similar habitat and climate characteristics in which phytocenoses develop.

Studies in Southwest Asia (Tajikistan, Kyrgyzstan, Iran) made it possible to distinguish, on the basis of 1,276 phytosociological images, a group of vegetation patches that are characterized by the loose compactness of the uppermost layer (about 30-70%), high species richness (up to 60 species in a patch), the presence of many endemics, a common natural history and a very characteristic composition of animal communities, including the historical presence of antelope. It is the antelopes and the characteristic gnawing of the tree crowns from underneath that causes the unique physiognomy of the community, which looks like a savannah with pistachio trees with umbrella-shaped crowns. They are the main component of this vegetation (Pistacia vera i P. khinjuk). Both pistachio species are among the oldest in the genus, having jointly evolved in Central Asia. Our research has shown that loose pistachio groves are a distinct vegetation typical of the Irano-Turanian region, and due to their specific ecology, phytogeography and unique species composition, they should be considered as a class of vegetation Pistacietea verae. This vegetation needs further study and comparison with similar vegetation in the western Irano-Turkish and Hindu Kush regions.

Article available:
https://vcs.pensoft.net/article/104841/

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2024-08-26 13:57:52