Plant canopy interception of rainfall and its significance in a banded landscape, arid western New South Wales, Australia

Abstract

The canopy interception storage capacity of three plants in an arid, banded (runoff‐runon) landscape was determined in the field from weight gain under artificial rain. The plants, two shrubs and a grass, were the bladder saltbush Atriplex vesicaria (Heward ex Benth.), the pearl bluebush Maireana sedifolia (F. Muell.) P. G. Wilson, and perennial Mitchell grass Astrebla lappacea (Lindl.) Domin. For saltbush and Mitchell grass, canopy water storage capacity (1.3 mm) correlated strongly with projected canopy area, while for the dense canopy of the bluebush (2.0 mm capacity), plant weight was a better predictor. In view of canopy cover amounts in each plant community, and the mean rain day rainfall of 5.7 mm, estimated annual water losses amount to 32% for Mitchell grass communities, 5% for saltbush communities, and <1% for bluebush communities. Canopy interception loss is shown to be a significant influence on the water redistribution that supports banded landscapes in the arid Broken Hill area.