In many semiarid regions, runoff and erosion differ according to vegetation
patch type. These differences, although hypothesized to fundamentally affe
ct ecological processes, have been poorly quantified. In a semiarid pinon-j
uniper woodland [Pinus edulis Engelm, and Juniperus monosperma (Engelm.) Sa
rg.] in northern New Mexico, He measured runoff and erosion from the three
patch types that compose these woodlands: Canopy patches (those beneath woo
dy plants), vegetated patches in intercanopy areas, and bare patches in int
ercanopy areas. The bare intercanopy patches exhibited the highest rates, f
ollowed by vegetated intercanopy patches and then by canopy patches. Large
convective summer storms, though relatively infrequent, generated much of t
he runoff and most of the sediment; prolonged frontal storms were capable o
f generating considerable runoff but little sediment. A portion of the runo
ff and most of the sediment generated from bare intercanopy patches was red
istributed down-slope, probably to adjacent vegetated intercanopy patches,
demonstrating connectivity between these two patch types. Our results indic
ate that there are significant and important differences in runoff and sedi
ment production from the three patch types; that bare intercanopy patches a
ct as sources of both water and sediment for the vegetated intercanopy patc
hes; and that the transfer of water and sediment at small scales is both fr
equent enough and substantial enough to be considered ecologically signific
ant.