Ecohydrology Controls the Geomorphic Response to Climate Change

Erosion rate data worldwide show complex and contrasting dependencies to climate. Laboratory and numerical model experiments on abiotic landscapes suggest a positive response: Wetter (drier) shift in climate leads to an increase (decrease) in erosion rates with longer relaxation times under a drier climate. We performed eco-geomorphic landscape evolution model simulations driven by abrupt climate shift in a semiarid climate. With dynamic vegetation, the erosional response to climate shift was opposite to bare soil, variability of erosion rate lessened, and landscape relaxation time scales became insensitive to climate change direction. The spatial geomorphic response to a wetter climate was depositional in vegetated, incisional in barren landscapes, and got reversed with drier climate. A relationship between net erosion rate and mean landscape slope emerged, exhibiting a hysteresis loop. Our study offers insights to the interpretation of observed acceleration of erosion rates and increase mountain relief during Quaternary climate change.