A hierarchical view of the interactions of runoff and infiltration with vegetation and microtopography in semiarid shrublands

Measurements of runoff and infiltration were made at five spatial scales, t erracette (< 1 m), hummock (10-20 m(2)), part-slope (1000-2000 m(2)), slope (1 ha) and catchment (50 ha), on a shrubland and an open forest site. The study was aimed at understanding the relationships between runoff productio n, vegetation patterns and microtopography at different spatial scales with in a sparsely vegetated, semiarid area. The results of runoff monitoring an d rainfall simulation experiments showed that runoff did not occur at the s lope scale. It was buffered at the terracette level by nonuniform infiltrat ion at the rims of terracettes and at the hummock scale by rapid infiltrati on under oak shrubs and trees. Slope and catchment runoff were not connecte d to runoff at these fine scales. The field evidence is discussed within th e context of hierarchy theory, and the implications for management of these shrublands are related to maintaining both the vegetation mosaic and runof f on these slopes. (C) 1998 Elsevier Science B.V. All rights reserved.