Vegetation composition and distribution on the northern slope of Karlik Mountain to Naomaohu basin, East Tianshan Mountains

Abstract

This paper reports the characteristics of plant flora in the region of the northern slope of Karlik Mountain to Naomaohu basin, based on field investigation of the vegetation and referring to relevant lit- erature. The results show that the flora of the study area mainly consists of communities of single species or a limited number of species, genera and families. The flora composition is marked by the phenomenon of dominant families and genera; the temperate element occupies a dominant position, while in terms of the genera the Tethys element is an important component. Areal-types of the species are dominated by the floral element of Asian Central-part with xerophytic characteristic, and the life-forms of plants are mainly perennial and herbaceous. These characteristics reflect that the compositions of the species in this region possess both ancient and young elements. Analysis of the relationship between the species composition, plant community diversity and altitude gradient, we found that the structure of the vegetation has an obvi- ous vertical distribution. The lower and higher altitude areas, where the climate conditions are relative in- clement, are mainly occupied by the plant communities with simple structure and single dominant popula- tion, while the species richness in the mid-altitude area increases with favorable temperature and precipi- tation. Consequently, the species diversity and evenness indices show single-peak distribution with in- creasing elevation (about 2500 m.