Assessing ecosystem function of restoration plantings in south-eastern Australia

We used the Landscape Function Analysis (LFA) (sensu Tongway and Hindley, 2004) to assess the development of ecosystem function in revegetation, particularly in relation to the basic ecological functions of soil stability, water infiltration and nutrient cycling. We compared these three LFA indices between two types of revegetation plantings, remnants, and cleared agricultural land (paddocks), in an agricultural landscape in south-eastern Australia. We differentiated between 'woodlot plantings' (planted with overstorey eucalypts only) and 'ecological plantings' (planted with many indigenous species of trees and shrubs). Remnant and paddock sites indicated the goal and starting point of restoration, respectively. Sites in remnant vegetation scored highest for all three functional attributes, whereas paddocks had high scores for soil stability, but low scores for water infiltration and nutrient cycling. Contrary to our expectations, soil stability, water infiltration and nutrient cycling did not differ between ecological plantings and woodlot plantings, and increased with age of planting (2-26. years) only for the nutrient cycling index. Although LFA provided an overview of some key functional differences between site types, it may be too coarse as a tool to measure restoration success. Specifically, the three functions considered by the LFA were strongly influenced by a single variable relating to perennial vegetation cover, but were essentially unaffected by more subtle differences between site types, such as quantity of leaf litter or cover of grasses. We also caution that Landscape Function Analysis derives surrogates of very basic functional attributes which may not be sufficiently sensitive to accurately reflect more complex ecological functions such as habitat provision for wildlife.