DIVERSITY CHANGES AND PHYLOGENETIC STRUCTURE OF WOODY PLANTS IN DIFFERENT VERTICAL ZONES OF THE SYGERA MOUNTAINS

This study examines the woody plant community in the Sygera Mountains to reveal the diversity changes and phylogenetic structure of woody plants in different vertical zones. Three plots of 400 m(2) and two plots of 900 m(2) are set up in each zone. The line transect method is used to supplement the woody plant species list. Meteorological data are adopted to analyze the composition of woody plant flora, the characteristics of the phylogenetic structure, and their relationship with annual average temperature. Results showed that (1) temperate woody plants account for a large proportion (65.6%) in the woody plant community of the Sygera Mountains, and widespread woody genera account for a small proportion (12.6%). The composition of families and genera is rich in the mountainous warm temperate zone, and the species composition is rich in the mountainous temperate zone. (2) The Gleason index and phylogenetic diversity of the woody plant communities in the five vertical zones are significantly positively correlated with the annual average temperature (P < 0.01), whereas the net relatedness and nearest taxon indices are not correlated with the annual average temperature. (3) The woody plant communities in the alpine frigid and alpine desert zones of the Sygera Mountains exhibit phylogenetic clustering, which suggests that habitat filtering plays an important role in the construction of woody plant communities in these vertical zones. However, the other vertical zones show either phylogenetic clustering or phylogenetic overdispersion, indicating that the results might be the combined effects of habitat filtering and competitive exclusion. This study provides new insights into the diversity composition and construction mechanisms of woody plant communities in the Sygera Mountains.