Dominant species remain stable and non-dominant species vary in alpine grassland
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Plant species diversity indices differ in growing season of alpine grassland
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Root to shoot ratio decreases to minimum in middle growing season of grassland
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Root to shoot ratio is larger in alpine grassland than temperate desert
Abstract
The relationships between vegetation and environmental factors have always been a core concern of ecologists. The dynamic characteristics of plant communities during the growing season can directly reflect these relationships, so we examined this issue for three typical ecosystems on the Tibetan Plateau. During the growing season, the dominant species remained stable while non-dominant species changed significantly in the alpine meadow and alpine steppe and a mono-dominant community was found in the temperate desert shrub. Due to the seasonal variations of temperature and soil water content, plant species diversity varied significantly during the growing season. Patrick richness, Pielou evenness and Simpson diversity indices differed significantly in the alpine meadow and alpine steppe. The total biomass of these three ecosystems was the largest during the middle growing season. Biomass was greater in the alpine meadow than the alpine steeps or temperature desert. The root-to-shoot ratio was the lowest during the middle growing season for the alpine meadow and alpine steppe and largest during the early growing season for temperate desert shrub. RDA showed the belowground and total biomass were greatly affected by soil physicochemical factors. Multiple linear stepwise regression showed the above ground biomass was greatly affected by relative atmospheric humidity and belowground and total biomass were greatly affected by soil organic carbon, total nitrogen at 0–20 cm soil depth and pH at 10–20 cm soil depth. These findings provide insights into understanding the relationships between vegetation and environmental factors and promote the sustainable utilization of local grasslands on the Tibetan Plateau.
