THE SOIL SEED BANK OF A LONG-GRAZED THEMEDA TRIANDRA 
GRASSLAND IN VICTORIA 
Ian D. Lunt 
Department of Botany, La Trobe University, Bundoora, Victoria 3083 
Present address: Flora and Fauna Survey Group, Department of Conservation, Forests and Lands Victoria, 
378 Cotham Road, Kew, Victoria 3101 
Lunt, I. D., 1990:05:31. The soil seed bank of a long-grazed Themeda triandra grassland in 
Victoria. Proceedings of the Royal Society of Victoria 102(1): 53-57. ISSN 0035- 
9211. 
The soil seed bank of a remnant Themeda triandra grassland was described using the 
seedling emergence technique. The grassland had been grazed by stock for over 70 years until 
managed for nature conservation in 1985. Seventeen native species and 24 exotics were 
recorded in the seed bank, which was dominated by exotics, Vulpia hromoides accounted for 
6 l%of germinants and V hromoides, Romulea rosea and Air a cupaniana together accounted 
for 81%. The seed bank contained one native species, Crassula decumbens , that was not 
otherwise known from the reserve and three additional exotics, Cerastium glomeratum. 
Saginaprocumbens and a Vicia species. Species-poor and species-rich T. triandra grasslands 
within the reserve had very similar seed banks, and few of the extra species in the vegetation 
of the former were present in the soil seed bank. It is suggested that the soil seed banks of 
long-grazed remnants of T. triandra grasslands may contain few native species that are not 
present in the standing vegetation. In long-grazed T. triandra grassland, disturbances that 
are necessary to maintain the diversity of native species, such as burning, are likely to pro¬ 
mote exotic species as much as, if not more than, natives. 
TEMPERATE grasslands dominated by 
Themeda triandra are poorly represented in con¬ 
servation reserves in Australia (Specht 1981) 
and the best remnants in Victoria are typically 
small and fragmented on rail and road ease¬ 
ments (Stuwe & Parsons 1977, Stuwe 1986). 
Effective conservation of grassland ecosystems 
requires the reservation of large areas. However, 
suitable sites invariably have been grazed by 
stock for considerable periods of time and, 
consequently, have relatively low diversities of 
native species, and many exotics (Stuwe 1986). 
Many sites from which grazing has recently been 
removed support dense T. triandra (over 90% 
cover) with few individuals of other species 
(Stuwe 1986, McDougall 1987). 
Typically, the standing vegetation at a par¬ 
ticular site is only part of the total flora, and 
propagules of additional species are stored in the 
soil, often for periods far longer than the lifespan 
of established plants. Species present in the soil 
seed bank may often be promoted by soil or veg¬ 
etation disturbances such as ploughing or burn¬ 
ing (Major & Pyott 1966, Roberts 1981, Fenner 
1985, Chancellor 1986). Soil seed banks thus 
provide the potential for vegetation change. 
The 154 ha Derrimut Grassland Reserve, the 
largest grassland reserve on the basalt plains of 
western Victoria, was grazed by sheep and cattle 
for over 70 years until managed for nature con¬ 
servation in 1985. It was studied in order to: (a) 
provide a general description of the soil seed 
bank of a previously grazed T. triandra grassland 
now managed for nature conservation; and (b) 
determine whether native species in the stand¬ 
ing vegetation of small patches of species-rich 
grassland within the reserve were represented in 
the seed bank of larger areas of species-poor 
grassland. 
METHODS 
The Derrimut Grassland Reserve (37°48'30"S, 
144°47'40"E) is 14 km west of Melbourne, Vic¬ 
toria. Site characteristics, land use history and a 
floristic classification of the vegetation are given 
by Lunt (1990a). Although the reserve contains a 
number of native grassland and wetland veg¬ 
etation types, the seed bank study included only 
grasslands dominated by T triandra. One spe¬ 
cies-rich site, floristically related to T. triandra 
grassland but classified as Vulpia hromoides 
grassland due to a low cover of T. triandra (Lunt 
1990a), is referred to T. triandra grassland 
throughout this paper. 
In January 1987, soil samples 40 mm deep 
and 0.25 m 2 in area were taken next to four of the 
richest and four of the poorest vegetation 
quadrats. The mean species richness of the 
former was 35 species per 15 m 2 quadrat and of 
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