The Effect of Bedrock Differences on Plant Water Use Strategies in Typical Karst Areas of Southwest China

Moisture conditions are important ecological factors limiting plant growth in karst areas. In areas, because bedrock exposure and permeability significant soils dispersed—without spatial continuity—and shallow, the water storage required for uptake rock fissures as well shallow is very limited, therefore, an factor influencing growth. order to discover sources of used by plants zone ecosystem southwest China differences use under different lithological conditions, this study selected limestone dolomite test site Maocun, Guilin, Guangxi, comparison with clastic area. By measuring δD δ18O composition stem potential (soil water, groundwater precipitation) dominant species area, using IsoSource soil excess (SW-excess) models, we analyzed proportion utilization vegetation types conditions. The results showed that (1) slope intercept local rainfall line (LMWL) (SWL) area were smaller than those global (GMWL), also atmospheric precipitation Guilin (δD = 8.8δ18O + 17.96), indicating influenced evaporation formed nonequilibrium fractionation isotopes; (2) general, dolomite, limestone, areas dominated rainfall, groundwater, respectively; (3) fluctuation range SW-excess was significantly greater nonkarst xylem more depleted enriched there might be ecological–hydrological separation phenomenon i.e., “two worlds” hypothesis. provide scientific data hydrological regulation restoration