REHABILITATION OF SEMIARID LANDSCAPES IN AUSTRALIA .2. RESTORING VEGETATION PATCHES

This paper describes a practical technique, tested experimentally, for rehabilitating degraded semiarid landscapes in Australia. This rehabi litation technique is based on the ecological principle that semiarid landscapes are spatially organized as patchy, source-sink systems; thi s patchy organization functions to conserve limited water and nutrient s within the system. The aim was to rebuild vegetation patchiness, los t through decades of utilization of these landscapes as rangelands, Pa tches were reconstructed from large tree branches and shrubs obtained locally and placed in elongated piles along contours. These piles of b ranches were very effective in recreating productive soil patches with in the landscape, as described in part I of this study. These new patc hy habitats promoted the establishment and growth of perennial grasses . Although the foliage cover of these grasses declined into a drought, which started before the end of the experiment, plant survivorship re mained high. This suggests that patches also function as refugia for o rganisms during droughts. The patches of branches remained robust and functional, even under grazing impacts, although plant growth and surv ival were significantly higher within an ungrazed paddock than in a gr azed paddock.