Vegetation-infiltration relationships across climatic and soil type gradients

The enhancement of infiltration capacity in the presence of vegetation is well documented in arid ecosystems where it can significantly impact the water balance and vegetation spatial organization. To begin progress toward developing a theory of vegetation-infiltration interactions across a wide spectrum of climate regimes, three key questions are addressed: (1) Does vegetation also enhance infiltration capacity in mesic to hydric climates, and if so, what processes contribute to this enhancement? (2) Is there a canonical relationship between vegetation biomass and infiltration rate? and (3) How does the vegetation-infiltration feedback evolve across climatic gradients? To address these three questions, new field data examining biomass-infiltration relationships in different vegetation types in a humid climate and on loamy soils are combined with a meta-analysis of biomass-infiltration relationships from nearly 50 vegetation communities spanning a climatic gradient from hyperarid deserts to the humid tropics and representing a full spectrum of soil types. Infiltration capacity increased as a power law function of aboveground biomass in water-limited ecosystems, but vegetation biomass was not significantly correlated to infiltration capacity in humid climates. Across a climatic gradient from xeric to hydric, the slope of the power law relationship between aboveground biomass and infiltration capacity decreased.