Aerial photographic interpretation of vegetation changes on the Bogong High Plains, Victoria, between 1936 and 1980

Abstract

The vegetation of two areas on the Bogong High Plains in 1936 was compared with that in 1980 by using a point sampling technique on aerial photographs. Between 1936 and 1980, the cover of closed heathland, wetland and trees (Eucalyptus pauciflora) increased but the cover of grassland decreased. No change was detected overall in the cover of open heathland. The increase in closed heathland was not due to direct conversion of grassland areas. Most change was from grassland to open heathland and from open heathland to closed heathland vegetation. The increase in wetland vegetation may have been a response to the reduction in grazing pressure since the 1930s. The greater cover of trees in 1980 was due to expansion of existing patches rather than the establishment of new patches. This may have been attributable in part to regeneration following bushfires in 1926 and 1939. The possible role of higher mean temperatures associated with global warming in the increased tree and shrub cover is worthy of further investigation.