Abstract: Meadow steppe is a critical foundation for regional ecological security and husbandry development in Hinggan League. Under the combined influence of climate change and anthropogenic activities, these grasslands are experiencing notable alterations in community structure and biodiversity. The absence of systematic surveys and limited understanding of present conditions have constrained effective scientific conservation and management efforts. We established 15 plots across 3 counties in Hinggan League to survey communities belonging to four formations including Form. Cleistogenes festucacea, Form. Carex pediformis, Form. Setaria viridis and Form. Leymus chinensis. We used canonical correspondence analysis (CCA) to examine the relationship between environmental factors and species composition. The results showed that: (1) A total of 135 plant species belonging to 90 genera and 35 families were recorded. The dominant families were Asteraceae, Poaceae, Fabaceae, and Rosaceae. (2) Community α-diversity differed significantly among the four formations. In particular, the Cleistogenes festucacea and Carex pediformis formations exhibited strong adaptability to the habitats of Hinggan League. (3) Longitude, mean annual temperature, minimum temperature of the coldest month, altitude, and litter moisture content were key determinants shaping species composition. Meanwhile, altitude and precipitation were dominant drivers influencing α-diversity. These findings provide a scientific basis for the conservation and maintenance of regional biodiversity.

Key words: meadow steppe, species diversity, canonical correspondence analysis, environmental factor