The desertification of a Bass Strait Island and a plan for its recovety: the case of East Kangaroo Island, Furneaux Group

Abstract

East Kangaroo Island is a low, mostly calcarenite-covered granitic island in the Furneaux Group which was observed in 1828 to have been fertile and well-wooded by Allocasuarina verticillata. Over 160 years of grazing and a succession of drought years have contributed to the decline of the native vegetation in biomass, ground cover and native species diversity. In the summer of 1999/2000, bare ground comprised 80% of the island, and the sparse vegetation mostly consisted of heavily browsed exotic grasses and herbs. The meagre flora of 91 taxa comprises 45% introduced species. The increased exposure from lack of vegetative cover has assisted the salt-wind-tolerant Austrostipa stipoides to spread inland, particularly from the west coast. An evaluation of the biomass puts the island within the range of that recorded for semi-arid deserts. Stock were removed in early 2000, and methods to restore the vegetation are proposed.