Rain shadow effects of individual shrub related to crown shape in arid desert

Abstract

AbstractRain shadow effects of individual shrubs (RSEISs) during wind‐influenced rain events influence the redistribution of net rainfall, which is especially important in water‐limited ecosystems. Two shrub species, Caragana korshinskii, which has an inverted conical shape and large crown size, and Artemisia ordosica, which has a hemispheroidal shape and small crown size, were selected for study in the southeast edge of the Tengger Desert of Northern China. Throughfall was measured at 12 different positions around each shrub (four distances from the trunk in each of three directions) during each of the 210 rain events occurring over a 10‐year period; wind speed during each rain event and various crown properties of the shrubs were also measured. RSEISs were quantified using coefficient of variation of throughfall. Thoughfall was most variable for C. korshinskii near the trunk and under the crown, and for A. ordosica, at the edge of the crown and within the space between plants. The coefficient of variation in thoughfall at each distance from the trunk (CVDistance) for C. korshinskii positively related to plant height and the plant area index (PAI; p < 0.05), whereas the CVDistance for A. ordosica was positively related to height, PAI, crown area, and volume (p < 0.01). RSEISs were structured by interspecific crown shape rather than crown size and branch density of a given plant. In conclusion, RSEIS lead to different local hydrologic budgets, which may have relevant implications in maintenance of the patchy pattern of vegetation in water‐limited ecosystems.