Trends in Vegetation at Kosciusko. 1. Grazing Trials in the Subalpine Zone, 1957-1971
Authors: Wimbush DJ , Costin AB 
Published: December 2005

This paper examines vegetation changes in the absence of fires at Kosciusko during the 14 years following the
general withdrawal of livestock grazing at Kosciusko in 1958 on two pairs of plots on subalpine grassland at
Dainers Gap (elev. 1700 m) and in the Hotel Kosciusko Water Reserve (elev. 1660 m). One plot in each pair
was experimentally grazed. and the other plot was ungrazed. The vegetation of the Kosciusko Reserve was in
a relatively natural condition, characterized by continuous forb-rich snowgrass associated with regenerating
snowgum woodland. At Dainers Gap the snowgrass was less continuous, and there was no snowgum
regeneration.
In the Kosciusko Reserve the main effect of grazing was to reduce the cover of the large palatable forbs.
This change appeared to be largely reversible within 6 years after the 8 years of grazing treatment was
discontinued.
At Dainers Gap the tussocks spread laterally in the absence of fire. on both the grazed and ungrazed
plots. Under grazing (5 sheepjha/season), small grazing-adapted herbs maintained themselves on the
intertussock spaces, but in the absence of grazing they were largely replaced by taller-growing species, many
of which appeared only after this treatment had ceased. Shrubs, although uncommon, increased rapidly in
size, especially on the grazed plot where competition from herbaceous species was reduced. On the grazed
plot the area of bare soil did not decrease appreciably but on the ungrazed plot it decreased on all but the
largest bare patches where the lateral spread of tussocks and shrubs was not sufficient to cover them. Under
grazing the standing crop on the intertussock spaces at Dainers Gap remained at low levels of about
0.3 kg/m2. but when not grazed for 10 years it increased to about 1 kg/m2, with a resultant increase in
surface soil organic matter and decrease in bulk density.
During the one season when sheep were weighed at monthly intervals. they gained weight at both sites at
the start of the grazing season until the supply of the relatively palatable and nutritious herbs and grass
inflorescences was exhausted, then lost weight as mature snowgrass leaves became the main part of their diet.
Seasonal weight losses of sheep increased over the 15 years of the experiment as most of the major forbs were
eliminated by grazing from the Kosciusko Water Reserve plot, and the area of minor herbs was reduced at
Dainers Gap by the encroachment of snowgrass tussocks onto the intertussock spaces.
At Dainers Gap in the absence of grazing and fires; water catchment and nature conservation values
improved but. without fire, unpalatable snowgrasses and shrubs increased and the value of the area for
grazing was reduced. With grazing, the previously unsatisfactory conditions for water catchment and nature
conservation were maintained. At the Kosciusko Water Reserve nature conservation and grazing values
were reduced by grazing.
Introduction
Transhumant grazing increasingly became a major issue in the use and management
of the Snowy Mountains, following completion of the Hume Dam in the early 1920s
and the report by Byles (1932) documenting the deterioration of parts of the Hume