The functional traits of dominant species exerts strong effects on the biomass of ephemeral plant communities under snow experiment in the arid area, Northwest China.

Abstract

In the mid-latitudes, snow is an important component of seasonal precipitation and one of the most important abiotic factors affecting the ecosystem. Winter snow cover may affect plant growth and community function by changing moisture, temperature, nutrient ions and soil micro-environment. Community biomass is an important index reflecting community function, but the way snow cover affects biomass is not clear. We conducted a manipulative experiment with four levels of snow depths in Gurbantunggut Desert in Central Asia, i.e. snow removal (- S), natural snow depth (CK), doubling of snow depth (+ 2S_double) and tripling of snow depth (+ 3S_triple). We found significantly increased plant community biomass with increasing level of snow depth as a result of increased height of the dominant species Erodium oxyrhinchum. Increases in the snow depth significantly increased the community species richness, but had no significant effect on diversity indexes. The effects of snow cover on the plant community biomass were mainly resulted from soil water of snow melting. With the increase of snow cover depth, the increase of community biomass was mainly affected by the functional traits of the dominant species. This result is consistent with the "mass ratio hypothesis". The results indicate that the increase of snow cover will promote the increase of short-lived plant productivity in arid areas, and the response of productivity to snow cover is mainly realized through the change of functional traits of dominant species.