Publication Date:
2017-03-01
Description:
Rainfall interception loss plays an important role in eco-hydrological processes in dryland shrub ecosystems, but its drivers still remain poorly understood. In this study, a statistical model was developed to simulate interception loss based on the mass balance measurements arising from the partitioning of rainfall in two dominant xerophytic shrub ( Hippophae rhamnoides and Spiraea pubescens ) communities in the Loess Plateau. We measured throughfall and stemflow in the field under natural rainfall, calculated the canopy storage capacity in the laboratory, and identified key factors controlling these components for the two shrubs. We quantified and scaled-up the stemflow and the canopy storage capacity measurements from the branches and/or leaves to stand level. The average interception loss, throughfall, and stemflow fluxes account for 24.9%, 72.2%, and 2.9% of the gross rainfall for H. rhamnoides , and 19.2%, 70.7%, and 10.1% for S. pubescens , respectively. Throughfall increased with increasing rainfall for both shrubs, however, it was only correlated with the leaf area index (LAI) for S. pubescens . For stemflow measured from individual branches, we found that the rainfall amount and basal diameter are the best predictors for H. rhamnoides , while rainfall amount and branch biomass appear to be the best predictors for S. pubescens . At the stand level, stemflow production is affected by the rainfall amount for H. rhamnoides , and it is affected by both the rainfall amount and the LAI for S. pubescens . The canopy storage capacity of H. rhamnoides (1.07–1.28 mm) was larger than S. pubescens (0.88–1.07 mm), and it is mainly determined by the branches and stems of H. rhamnoides , and the leaves of S. pubescens . The differences in interception loss between the two shrub stands are mainly attributed to different canopy structures induced differences in stemflow production and canopy storage. We evaluated the effects of canopy structure on rainfall interception loss, and our developed model provides a better understanding of the effects of the canopy structure on the water cycles in dryland shrub ecosystems.
Print ISSN:
0885-6087
Electronic ISSN:
1099-1085
Topics:
Architecture, Civil Engineering, Surveying
,
Geography
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