Contrasting responses of two typical plant communities to precipitation variability in horqin sandy land, northeast China

Abstract

The ongoing modification of precipitation regime highlights the necessity to further investigate underlying vegetation processes. To figure out the key precipitation characteristics that largely affected the biomass and species richness of different plant functional groups in the semiarid sandy land, we compared the 15-year (from 2005 to 2019) variation in the aboveground biomass (AGB), precipitation use efficiency (PUE) and species richness of two typical biotopes (fixed dune and sandy grassland) in Horqin Sandy Land, a semiarid sandy land in northeast China. Results showed that the sandy grassland had higher AGB and PUE, lower species richness than the fixed dune; the annuals contributed 60.16% of the AGB and 60.32% of the species richness in sandy grassland, while contributed 53.40% and 75.77% in fixed dune, respectively; the AGB and species richness in the fixed dune had medium positive correlation with annual precipitation, while that in the sandy grassland had medium positive correlation with the total amount of specific rainfall events in the growing season (e.g. cumulative precipitation of 10–40 mm rain events and number of ≥ 10 mm rain event). There was no significant correlations were detected between PUE and annual precipitation, and weakly positive correlations were detected between PUE and amount and number of medium rainfall events in growing season. Our results suggested that the biomes dominated by annual plants were more responsive to the variability of growing season rainfall pattern rather than annual precipitation. In semiarid sandy grassland communities, the frequent medium rainfall events (5–50 mm) have significant role on the biomass, and the high species richness is likely to depend on the number of larger ones (≥ 10 mm). The AGB and species richness of grassland communities in semi-arid sandy land was the result of the combined effect of amount size, number and interval of rain event.

Keywords

• aboveground biomass
• species richness
• precipitation regime
• fixed dune
• sandy grassland