Modeling the effects of vegetation-erosion coupling on landscape evolution

From rainfall interception at the canopy to added soil cohesion within the root zone, plants play a significant role in directing local geomorphic dynamics, and vice versa. The consequences at the regional scale, however, are known in less quantitative terms. In light of this, the numerical Channel-Hillslope Integrated Landscape Development model is equipped with coupled vegetation-erosion dynamics, allowing for sensitivity analysis on the various aspects of vegetation behavior. The processes considered are plant growth, plant death, and the additional resistance imparted by plants against erosion. With each process is associated a single parameter, whose effects on the spatiotemporal nature of a 1 km(2) basin is studied. Through their inhibition of erosion, plants steepened the topography and reduced drainage density, yet, in doing so, made erosive events more extreme. Plants more susceptible to erosion act to decouple neighboring cells and cause extensive and perennial network and channel adjustments.