Effects of land use on annual runoff and soil loss in Europe and the Mediterranean: A meta-analysis of plot data

The largest currently compiled database of plot runoff and soil loss data in Europe and the Mediterranean was analysed to investigate effects of land use on annual soil loss (SL), annual runoff (R) and annual runoff coefficient (RC). This database comprises 227 plot-measuring sites in Europe and the Mediterranean, with SL for 1056 plots (PL) representing 7024 plot-years (PY) and R for 804 PL representing 5327 PY. Despite large data variability, continental-wide trends are observed. Construction sites have the highest mean annual RC (57%) and SL (325 Mg.ha(-1).yr(-1)). Bare soil, vineyards and tree crops have high mean annual RC (5-10%) and SL (10-20 Mg.ha(-1).yr(-1)). Cropland and fallow show similar mean annual RC (8.0 and 7.3%), but lower SL (6.5 and 5.8 Mg.ha(-1).yr(-1)). Plots with (semi-)natural vegetation cover show lowest mean annual RC (<5%) and SL (<1 Mg.ha(-1).yr(-1)). Plot length and slope gradient correlations with R and SL depend on land-use type and are not concurrent for R and SL. Most land-use types show positive correlations between annual R and SL. Plots in cold climates have higher annual RC than plots in temperate and pan-Mediterranean climates. Annual SL in the pan-Mediterranean is less than in temperate zones, due to stony or clayey soils having a low erodibility. Annual RC in the pan-Mediterranean was higher than in temperate zones. Annual R increases strongly with increasing annual precipitation (P) above 500 mm.yr(-1), while annual SL was found to stabilize at P > 500 mm.yr(-1). For shrubland, annual SL was found to decrease for P > 250-500 mm.yr(-1), which is attributed to an accompanying increase in vegetation cover. However, no such trend was found for R. The results allow a rapid assessment of the impact of land-use changes on annual R, RC and SL, based on field-measured plot data.