Modeling rainfall interception loss by two xerophytic shrubs in the Loess Plateau

Abstract

Rainfall interception loss plays an important role in ecohydrological 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 2 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 2 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 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, whereas 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 leaf area index 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 2 shrub stands are mainly attributed to different canopy structures that 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.

Canopy transpiration and stand water balance between two contrasting hydrological years in three typical shrub communities on the semiarid Loess Plateau of China

“…The stemflow volume was measured using a graduated cylinder for each individual branch after each rainfall event. The experimental settings have been described in detail previously (Zhang et al, ). The Ic of the SP and HR were measured in 2015.…”

“…Although Ic has been evaluated in tropical and temperate forests (Peng et al, ; Toba & Ohta, ), relatively few researchers have studied it in water‐limited regions (Carlyle‐Moses, ). The Ic/P value shows significant variability and ranges from 3% to 37% in these areas (Zhang et al, ), suggesting Ic's importance in hydrological processes. Es may constitute a large fraction of ET attributable to considerable areas of exposed soil.…”

“…Extensive vegetation reestablishment practices have been implemented in this region in past decades to control soil erosion, and the total vegetation cover increased from 29.7% in 1998 to 42.2% in 2005 (Cao et al, ). Although many studies have focused on plant–water relations (Jiao, Lu, Sun, We, & Fu, ; Wang et al, ; Zhang et al, ), the hydrological effects of vegetation restorations, particularly the potential differences between native and introduced species, still remain unclear.…”

Surface water storage characteristics of main herbaceous species in semiarid Loess Plateau of China

“…Canopy interception accounts for 10-50% of gross rainfall and is an important and sometimes dominant water balance component in dryland ecosystems (Gerrits, Pfister, & Savenije, 2010;Li et al, 2016). It can smooth rainfall intensity, thereby decreasing surface runoff and soil erosion, and affect soil water infiltration, further influencing plant growth and vegetation dynamics during rainless period (Gerrit, 2010;Zhang et al, 2017). More broadly, interception is strongly linked to biogeochemical fluxes and energy conversion in the soil-plant-atmosphere continuum (Negi, Rikhari, & Garkoti, 1998;van Dijk et al, 2015).…”

“…Storage capacity is mainly controlled by rainfall characteristics, meteorological conditions, and canopy structure . Second, meteorological conditions such as net radiation, air temperature, relative humidity, and wind speed affect the rate of intercepted rainwater removed from canopy surface (Zhang et al, 2017). Second, meteorological conditions such as net radiation, air temperature, relative humidity, and wind speed affect the rate of intercepted rainwater removed from canopy surface (Zhang et al, 2017).…”