Trait-based sediment retention and runoff control by herbaceous vegetation in agricultural catchments: A review

Abstract

Soil degradation by concentrated runoff and soil erosion induces major environmental and economic damages, notably in agricultural areas under temperate climates. The use of herbaceous vegetation aims to increase the hydraulic resistance and thus reduce runoff and soil erosion while retaining sediments on site. However, the identification of the most suitable species to mitigate runoff is often specific to a phytogeographical territory and hampered by the intraspecific variability, which reduces the transposition of a solution to other territories and the ability to quantify the effects of the vegetation. Using a plant trait-based approach allows understanding and characterising the direct effects of the vegetation on runoff and soil erosion mitigation as well as on the sediment retention increase. Here, we review the influence of plant aboveground functional types and traits of herbaceous vegetation on the hydraulic resistance and sediment retention and the contentious effects of the functional diversity on the hydraulic resistance and sediment retention, within agricultural catchments. Using this knowledge, we propose applications of the trait-based approach to design and manage herbaceous hedges for sediment retention and soil erosion control. This review synthesises recent advances regarding the effects of the functional traits on runoff and sediment retention and defines a trait-based selection method of the plant species for runoff and soil erosion control.