Eurosiberian meadows at their southern edge: patterns and phytogeography in the NW Tien Shan

What are the community types, underlying gradients and phytogeographical affinities of montane meadows in the western Tien Shan? Aksu-Jabagly Nature Reserve, South Kazakhstan, Middle Asia. Species composition, structural and environmental variables were studied in 98 plots. Species composition was classified by cluster analysis and gradients explored using NMDS. Relationships between species richness, environmental and structural variables were investigated with regression analysis. Phytogeographic patterns were assessed by examining species distribution types. Seven community types were distinguished by cluster analysis. Three axes of the NMDS explained 77% of the variation, showing different overlap of communities with environmental and structural properties. Species richness showed linear relationships with pH, altitude, heat load, soil skeletal content and structural variables. Middle Asian and Eurosiberian species constituted the majority of the species pool and cover. The studied communities represent a unique mixture of Middle Asian and Eurosiberian species that exhibit structural and environmental similarities to Eurosiberian meadows. The Tien Shan mountain meadows can thus be considered an endemic-rich southern outlier of the broader Eurosiberian meadow formation. Shifts in land-use patterns pose a potential threat that deserves more attention from conservationists.