Alteration in isotopic composition of gross rainfall as it is being partitioned into throughfall and stemflow by xerophytic shrub canopies within water-limited arid desert ecosystems

摘要: Abstract Isotopic composition of gross rainfall has been extensively used as a conservative tracer to track water movement and other hydrological processes in vegetated ecosystems. Recent studies from forest ecosystems, however, demonstrated that vegetation canopies can alter the isotopic rainwater during partitioning into throughfall stemflow, likely leading errors biases aforementioned studies. No known studies, date, had investigated this topic shrub-dominated arid semi-arid ecosystems where is typically driving factor ecological, biogeochemical processes. In study, event-based rainfall, stemflow induced by shrubs Caragana korshinskii were measured samples collected within water-limited desert ecosystem northern China, their stable isotopes (18O 2H) also analyzed laboratory. We mainly aimed investigate whether there an enrichment or depletion comparison evaluate possible underlying mechanisms. Our results indicated both while general more than which presumably affected combinative effects canopy evaporation, exchange, selective storage. Deuterium excess found be significantly higher (P