Introduction

The tendency of water to infiltrate (infiltrability) determines the productivity of rangelands. However, how patterns of infiltrability change in response to gradients of disturbance remains largely unexplored. To address this, we examined changes in the pattern of infiltrability across a disturbance gradient in a semi–arid Australian woodland. We measured the spatial distribution of infiltrability in relation to distance from the canopy of trees and shrubs at long ungrazed sites to ploughed and grazed sites. Infiltrability on long ungrazed sites was relatively homogenous throughout the landscape and up to distances of four metres from plant canopies. In contrast, at either grazed or grazed and ploughed sites, infiltrablilty was demonstrated a heterogeneous pattern across the plot. Infiltrability was also greatest only around vegetated patches but very low at distance of more than 2 m from woody plant canopies. Factors such as increased bulk density and removal of cryptogamic soil crusts as a result of livestock trampling are probably responsible for the heterogeneous patterns of infiltrability. Our results highlight the importance of maintaining woody plants for maximising infiltration of water in the semi–arid woodland. Removal of woody shrubs by ploughing with and without grazing appears to have a deleterious effect on infiltrability.