Inter- and intra-event rainfall partitioning dynamics of two typical xerophytic shrubs in the Loess Plateau of China

Abstract

Abstract. Rainfall is known as the main water replenishment in dryland ecosystems, and rainfall partitioning by vegetation reshapes the spatial and temporal distribution patterns of rainwater entry into the soil. The dynamics of rainfall partitioning have been extensively studied at the inter-event scale, yet very few studies have explored its finer intra-event dynamics and the relating driving factors for shrubs. Here, we conducted a concurrent in-depth investigation of all rainfall partitioning components at inter- and intra-event scales for two typical xerophytic shrubs (Caragana korshinskii and Salix psammophila) in the Liudaogou catchment of the Loess Plateau, China. The event throughfall (TF), stemflow (SF), and interception loss (IC), and their temporal variations within the rainfall event, as well as the meteorological factors and vegetation characteristics, were systematically measured during the 2014–2015 rainy seasons. Our results showed that C. korshinskii had significantly higher SF percentage (9.2 %) and lower IC percentage (21.4 %) compared to S. psammophila (3.8 % and 29.5 %, respectively), but their TF percentages were not significantly different (69.4 % vs. 66.7 %). At the intra-event scale, TF and SF of S. psammophila were initiated (0.1 vs. 0.3 h and 0.7 vs. 0.8 h) and peaked (1.8 vs. 2.0 h and 2.1 vs. 2.2 h) more quickly, and TF of S. psammophila lasted longer (5.2 vs. 4.8 h) and delivered more intensely (4.3 vs. 3.8 mm h−1), whereas SF of C. korshinskii lasted longer (4.6 vs. 4.1 h) and delivered more intensely (753.8 vs. 471.2 mm h−1). For both shrubs, rainfall amount was the most significant factor influencing inter-event rainfall partitioning, and rainfall intensity and duration controlled the intra-event TF and SF variables. The C. korshinskii with larger branch angle, more small branches, and smaller canopy area, has an advantage over S. psammophila to produce SF more efficiently. The S. psammophila has lower canopy water storage capacity to generate and peak TF and SF earlier, and it has larger aboveground biomass and total canopy water storage of individual plants to produce higher IC compared to C. korshinskii. These findings contribute to the fine characterization of shrub-dominated ecohydrological processes, and improve the accuracy of water balance estimation in dryland ecosystems.

Influence of intra-event rainfall variation on surface–subsurface flow generation and soil loss under different surface covers by long-term field observations

“…In addition to inter-event rainfall variation, the intra-event variation significantly alters rainfall infiltration, runoff generation and erosion processes (Dunkerley, 2021;An et al, 2022).…”

“…For example, serious soil disturbance induced by large scale mechanical excavation resulted in enormous regions of bare soil during agricultural land use (Niu et al, 2021). The inter-and intra-event variations were important consequences of rainfall changes with global warming (Dunkerley, 2021b;An et al, 2022). The increase in extreme rainfall frequency and intensity was the most typical form of expression, and finally water erosion risk was aggravated (Nie et al, 2020;Shenoy et al, 2022).…”

“…Fang et al, 2012). These rainfall parameters, however, do not account for intra-event variability characteristics in natural rainfall features, such as the temporal distributions of intensity peaks in rainfall profiles (Flanagan et al, 1988), which have important impacts on water erosion and related landsurface processes (Dunkerley, 2012;An et al, 2022;Liu et al, 2022). For example, rainfall events with the same features (e.g., RA, RD, I, and I30) create significantly different runoff rates and soil losses, and these phenomena may be caused by intra-fluctuations in rainfall characteristics (Todisco, 2014;Mohamadi and Kavian, 2015;Almeida et al, 2021).…”

Quantity or Efficiency: Strategies of Self‐Organized Xerophytic Shrubs to Harvest Rain

“…We measured the representative plant traits at the leaf, branch, and shrub scales, which were verified to significantly affect rainfall redistribution of multi-stemmed shrubs, based on our own in situ measurements (An et al, 2022;Yuan et al, 2016Yuan et al, , 2017Yuan et al, , 2019) and other peer-reviewed studies conducted at similar sites on the Loess Plateau of China (Yang et al, 2019;Zhang et al, 2017). Canopy area and height were measured for the clumped shrubs and all 31 scattered shrubs of V. negundo.…”

Variability in Water Capacity of Small-Leaved Linden Associated with Both the Presence of Honeydew and Various Sources of Pollution

“…Factors that may affect interception also include the amount of pollution, dust, or the hairs on the leaf surface [4]. The problem of interception has been the focus of hydrologists' attention for many years [5][6][7][8], but recently it has been addressed to a greater extent in the context of global climate change and increasing air pollution, as well as the response of plants to these factors [9].…”