Effects of changes in growing season precipitation regimes on plant community structure,function and aboveground biomass in typical habitats in the Horqin Sandy Land
To explore change rule of plant community structure,function and aboveground biomass within arid and semi-arid grasslands in China,particularly under changing precipitation regimes during the growing season,field simulation control experiments were conducted in fixed sand dunes and sandy grasslands in 2022.The exper-imental treatments included:a reduction of water by 60％from May to September(P60-),an increase of water by 60％during the same period(P60+),a 100％water reduction from May to June(P100-)and a 100％water increase in the same two months(P100+).This study analyzed changes in plant community characteristics(species diversi-ty,vegetation coverage,plant density,and aboveground biomass),plant community functional traits(height,leaf thickness,specific leaf area,leaf dry matter content,and leaf carbon and nitrogen content),and soil physi-cal and chemical properties(soil water content,pH,conductivity,mechanical composition,and carbon and ni-trogen content).The correlations with aboveground biomass were also examined.The results indicated that drought conditions(P60-and P100-)increased the prominence of annual C4 plants such as Chloris virgate and Tribu-lus terrestris(P＜0.05),while diminishing the role of perennial plants like Cleistogenes squarrosa(P＜0.05).In fixed dunes,extreme early-season drought(P100-)led to an increase in the Simpson dominance index(P＜0.05)and a decrease in the Shannon-Wiener diversity index(P＜0.05).Conversely,drought throughout the growing season(P60.)increased aboveground biomass(P＜0.05).In sandy grasslands,drought(P60.and P100.)reduced veg-etation cover and plant density(P＜0.05).The increase in aboveground biomass under drought conditions was pri-marily due to the increased dominance of species with larger biomass.Moreover,differences in soil water con-tent and fine sand content between the fixed sand dunes and sandy grasslands could negatively or positively im-pact aboveground biomass.This effect is mediated through influences on the Shannon-Wiener diversity index and plant community height.Therefore,shifts in precipitation regimes during the growing season altered species com-position,vegetation characteristics,and soil physicochemical properties in the grassland communities of the Horqin Sandy Land.These changes affected aboveground biomass and consequently transformed the structure and function of the grassland ecosystem in this region.
precipitation regimevegetation characteristicfunctional traitsoil physicochemical propertyHorqin Sandy Land
NETL
NSTL
万方数据
