LONG-TERM VEGETATION CHANGE IN RELATION TO CATTLE GRAZING IN SUB-ALPINE GRASSLAND AND HEATHLAND ON THE BOGONG HIGH-PLAINS - AN ANALYSIS OF VEGETATION RECORDS FROM 1945 TO 1994

Changes in vegetation composition and structure are described for gras sland and heathland communities on the Bogong High Plains, in the Vict orian Alpine National Park. The data are based on long-term records co llected from permanent reference plots over the period 1945 to 1994 fr om plots established in 1945, 1946 and 1979. In the Pretty Valley gras sland plots, established in 1946, cattle grazing has prevented the lar ge-scale regeneration of a number of tall, palatable forbs and short, palatable shrubs, while in the absence of grazing, the cover of these Life forms increased substantially. The amount of bare ground and loos e litter was significantly greater on the grazed compared with the ung razed plot. Between 1979 and 1994, there was little or no identifiable trend in the cover of Vegetation or bare ground at either the Pretty Valley grazed site, or two additional grazed grassland sites establish ed nearby in 1979. The current condition of grazed grassland on the Bo gong High Plains is interpreted as stable, yet degraded. Improvement i n condition will occur in the absence of grazing. In the Rocky Valley open heathland plots, established in 1945, increases in shrub cover ov er the study period were due to growth of shrubs following the 1939 bu shfires that burnt much of the Bogong High Plains. From 1945-1979 shor ter-lived shrubs increased in cover; since 1979, these shrubs have sen esced, and are being replaced mainly by grasses. On the grazed plot lo nger lived, taller shrubs have continued to increase in cover and are not senescing. Between 1979 and 1989, total shrub cover declined on th e ungrazed plot, but increased on the grazed plot. There was no eviden ce that grazing has reduced shrub cover, and therefore potential fire risk, in open heathland. These findings have significant management im plications for the Alpine National Park and are consistent with those from other regions in the Australian alps.