Abstract: To understand the niche characteristics of plants along soil nutrient resource axis in the karst peak-cluster depression, we analyzed the niche characteristics of dominant plant species in forests around the Five-hundred-meter Aperture Spherical radio Telescope (FAST) on soil nutrient resource axis using canonical correspondence analysis, Levins niche breadth, and Pianka niche overlap index. The results showed that total soil phosphorus, available nitrogen, and organic carbon had significant effects on the distribution of dominant species (P<0.05). The niche breadths of Quercus acutissima, Ficus tikoua, and Rhus chinensis on the soil nutrient resource axis were higher and more suitable for the habitat of the study area. Quercus fabri, Inula cappa, and Litsea coreana had lower niche breadth on the soil nutrient resource axis, with lower resource utilization efficiency. The niche breadth was influenced by the species’ importance value, in that species with higher niche breadth had higher importance values. The species with higher niche overlap index did not occupy higher niche breadth but were in the middle and lower values. The species with niche overlap greater than 0.5 accounted for 50% of the total species number when considering the soil nutrient resource axis. In conclusion, vegetation around FAST was relatively stable, and total phosphorus, available nitrogen, and organic carbon were important soil nutrient factors affecting the distribution of dominant species around FAST.

Key words: karst, peak-cluster depression, niche breadth, niche overlap index, soil nutrient resource axis, FAST.