Remnant tree decline in agricultural regions of South Australia.

Abstract

Agricultural landscapes in southern Australia were once dominated by temperate eucalypt woodlands of which only fragmented patches and scattered trees in paddocks remain. This study focuses on the decline of scattered trees in the Mount Lofty Ranges and South East agricultural regions of South Australia. A combination of digitized aerial photography and satellite imagery was used to extend a previous assessment of decline undertaken in the early 1980s and increase the period over which decline was assessed to 58–72 years. A total of 17 049 scattered trees were counted from the earliest time period assessed over 11 sites of which 6 185 trees were lost by 2008 — a 36 % decline. Recruitment of 2 179 trees during this period was evident. Imagery indicates that clearing for agricultural intensification is the primary cause of the decline. A range of management options and policy settings are required to reverse the decline notwithstanding the challenges of implementation at a landscape scale across privately owned land.