Plant morphology and distribution control runoff and erosion in semi-arid environments

Abstract

Understanding of the effects of vegetation patches and their distribution on soil erosion is important for ecological restoration in semi-arid environments. In this study, six multidimensional morphology metrics and expectations were applied to analyze the effects of plant morphology and distribution on runoff and sediment in two dominant plant species, Artemisia sacrorum Ledeb (AS) and Spiraea pubescensTurcz (SP), at micro-plots (60 cm × 60 cm plots) and field-plots (3 m × 10 m field-plots) in the Loess Plateau of China. The results indicated that, at micro-plot scale, the morphological heterogeneity of the two isolated shrubs (AS and SP) could be identified by spherical cap surface area of canopy and plant volume, which also lead to the isolated SP to have stronger ability to control runoff and erosion than the isolated AS. At field-plot scale, spherical cap surface area of canopy expectation (32.01 ± 1.99 m2) and plant volume expectation (4.06 ± 0.38 m3) of SP field-plots was significantly larger than those of the AS field-plots (15.85 ± 2.46 m2 and 1.10 ± 0.21 m3 respectively) in the potential contributing runoff area (2 m area form the field outlet). These differences result in SP field-plot to have more effective ability to retain runoff and to trap sediment than AS field-plot. The high-dimensional morphology metrics and expectations could determine the role of plant hydrological functions in controlling runoff and sediment at multiple spatial scales. This knowledge improves our understanding of the roles that plant morphology and distribution have on the runoff and erosion from different vegetated plots, and offers a new route to explaining plant morphology and distribution as controls on soil erosion in water-limited ecosystem.