Kangaroo Island (Environmental Region 3.1)
This region consists of eight environmental associations. The island is characterized by an undulating upland plain with an extensive laterite cover which gives rise to mottled-yellow duplex soils. The plain rises to an average height of 100-150 m and is bounded by a densely dissected scarp falling steeply to the cliffed coastline. Along the southern coastline some dunes are developed but otherwise these are rare. A characteristic feature of the eastern. somewhat lower-lying part of the island is the occurrence of numerous rounded salt lakes and depressions which may be due to solution processes in the calcrete cover. Shallow red sands occur on the intervening plains. In the eastern part of the island mallee was the dominant native vegetation. The endemic Kangaroo Island narrowleaf mallee (E. cneorifolia) was a widespread component of this formation, but exploitation for eucalyptus oil has led to depletion of its numbers. Other common species of this mallee are cup gum (E. cosmophylla), white mallee (E. oleosa and E. foecunda). Due to extensive clearing in areas suitable for agriculture most of the mallee has disappeared, and the large remnants in Gantheaume association occur on soils unsuitable for agricultural development. On deeper soils in the wetter in the wetter, western part of the island, the mallee is replaced by low open forest, or in sheltered positions, by open forest. Brown stringybark (E. baxteri), cup gum and pink gum (E. fasciculosa) are common species in the low open forest, and in open forest messmate stringybark (E. obliqua) is an important component. Scattered stands of these forest occur as uncleared blocks in the central section of the island, but in the west large tracts remain in nature reserves and on uncommitted Crown land. The landscape of Kangaroo Island is characterized by contrasts between open paddocks with roadside trees and large tracts of native forest and scrub. The coastline also has many attractive features including sandy beaches, varied rock formations and sheer cliffs. The scenic resources of the island are detailed in the landscape descriptions of the environmental associations. Kangaroo Island has a cool climate with a winter rainfall maximum. Mean annual rainfall increases from 500 mm in the east to 800 mm in the west, with most of the rain occurring between April and October. Mean annual evaporation ranges from 1600 mm in the west to almost 1700 mm at the eastern end of the island. While mean monthly evaporation is high in summer, it falls below the median monthly rainfall during winter. Temperatures are cool to cold in winter and cool to mild in summer, and diurnal variation is relatively low.