The Importance of Landscape Age in Influencing Landscape Health

Ancient landscapes dominate many parts of the world and are common in Australia—do they have a future for continued agricultural production and the supply of ecological goods and services? The hypothesis is that old, weathered landscapes respond differently from young landscapes when subjected to intensive landuse. The major difference in response is that system function regresses or fails in old landscapes. The aging phenomenon is illustrated using data from a podzol chronosequence on coastal sand dunes at Cooloola, Queensland, Australia. The old systems here are shown to regress naturally from forest systems to health systems as access to nutrients decreases. Responses to landuse disturbances in old landscapes other than sand dunes, show analogous regressive trends to the dune landscapes, but the biophysical nature of the responses can vary. How can such trends in landscape health be measured to better link land capability with landuse? The concept of sustainability may not be appropriate for old landscapes and a different framework based on a health paradigm is suggested. Starting from an equilibrium perspective, we move to a conditional stability concept and then to a conditional health paradigm. Health and ill-health are deemed to be definable within predetermined limits, that is a compliance measure, similar to the diagnostic approach in human medicine.