Understanding infiltration rates can greatly enhance predictions of hydrology and the effects of precipitation. Particularly in low elevation semiarid ecosystems, the pattern of infiltration has been shown to be a strong control on partitioning of the water budget and also on the composition and spatial organization of vegetation. Furthermore, soil below plant canopies has been shown to be an area of greater infiltration, creating a positive feedback. Whether higher elevation ecosystems in these arid and semiarid areas maintain these vegetation-infiltration relationships is not well understood. Here we compare patterns of infiltration along an elevational gradient that incorporates distinct ecosystems. We estimate infiltration rates using simple mini ring infiltrometers. Infiltration was measured in the cardinal directions at multiple distances from the stem of three random examples of the dominant plants in each ecosystem. Additionally, to assess canopy/intercanopy patterns, infiltration was measured every 50 cm along three 10 m transects in each ecosystem. To examine vegetation-infiltration relationships along this elevational gradient, we address three main hypotheses: (1) infiltration rates are highest nearest the plant stem regardless of ecosystem, (2) vegetation-infiltration relationships decrease with elevation; and (3) the difference between canopy and intercanopy infiltration rates is muddied in higher elevation ecosystems. We show on average that infiltration rates are higher next to a plant and decrease as distance from the plant increases. Even, in the higher elevation ecosystems, infiltration rates tend to be higher in canopy patches than in intercanopy patches. However, important variations in these vegetation-infiltration relationships emerge along the elevational gradient.
Lowry, F., Papuga, S.A. (2011): Vegetation-infiltration relationships along an elevational gradient in the semiarid southwestern United States. AGU Fall Meeting Presentations (Poster) Abstract H11E-1109..