A FLORISTIC SURVEY OF THE DERRIMUT GRASSLAND RESERVE, 
MELBOURNE, 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, 
378 Gotham Road, Kew, Victoria 3101 
Lunt, I. D., 1990:05:31. A floristic survey of the Derrimut Grassland Reserve, Melbourne, 
Victoria. Proceedings of the Royal Society of Victoria 102(1): 41-52. ISSN 0035- 
9211. 
The 154 ha Derrimut Grassland Reserve contains the largest Themeda grassland on 
public land on the basalt plains of western Victoria. It includes three types of wetland and 
two of grassland. Wetland vegetations appear to be dependent upon the duration of seasonal 
flooding, and grassland vegetations on previous land use, particularly ploughing. A total of 
102 species of native plants and 78 exotics are listed; three native species are rare or vul¬ 
nerable in Victoria. 
ONE of the most important issues for nature 
conservation in temperate Australia is the pres¬ 
ervation of native grasslands and grassy wood¬ 
lands. Grasslands of Themeda, Stipa, Danthonia 
and Poa once dominated extensive areas of tem¬ 
perate New South Wales, Victoria, Tasmania 
and south-eastern South Australia but were 
rapidly destroyed by agriculture. Today only 
small patches remain, few of them protected in 
conservation reserves (Groves 1979, Specht 
1981a, Davies 1982, Frood & Calder 1987, 
Kirkpatrick et al. 1988). 
The original Themeda grasslands were domi¬ 
nated by T. triandra with sub-dominant 
Danthonia and Stipa species. The grasses 
formed discrete tussocks rather than a closed 
turf, and a variety of herbs, particularly compo¬ 
sites, grew on the bare earth in the inter-tussock 
spaces (Patton 1935, Willis 1964). 
Many of the most diverse remnants of 
Themeda grassland in Victoria are on railway 
reserves that have been burnt regularly and 
grazed infrequently over the past 100 years 
(Stuwe & Parsons 1977, Stuwe 1986). If grass¬ 
lands are to be effectively protected, then the 
narrow and typically small remnants of railway 
reserves must be supplemented by larger rem¬ 
nants; invariably these have been grazed and are 
oflower diversity than rail-line remnants (Stuwe 
& Parsons 1977). 
The Keilor basalt plains, immediately west of 
Melbourne, encompass many of the best, large 
remnants of Themeda grassland in western 
Victoria (Stuwe 1986) plus two of the largest 
reserves for Themeda grassland in the State: the 
Laverton North and Derrimut Grassland Re¬ 
serves, of 40 ha and 154 ha respectively. This 
paper presents the results of a floristic survey of 
the Derrimut Grassland Reserve. 
SITE DESCRIPTION 
The Derrimut Grassland Reserve occupies 154 
ha on the north-eastern corner of Boundary and 
Fitzgerald Roads in the City of Sunshine, 14 km 
west of Melbourne. The mean annual rainfall at 
Laverton, 7 km SSW of the reserve, is 568 mm 
(Bureau of Meteorology, unpublished data) and 
is evenly distributed throughout the year. The 
maximum monthly mean temperature is 26°C in 
January and the mean minimum is 5°C in July. 
The reserve is situated on the Keilor basalt 
plains, the underlying rock being olivine basalt 
belonging to the Newer Volcanics, of Early 
Pleistocene age (Mines Department, undated; 
Douglas 1982). Surface rock is locally abundant 
in the reserve and the topography is gently 
undulating (Fig. 1). Most soils are duplex but 
gradational soils occur in some areas of low 
elevation and poor drainage. Topsoils are of silty 
clay, silty clay loam and clay loam, and generally 
are neutral to slightly basic, with pH ranging 
from 6.0 to 7.5. Hummocks about 1 m in dia¬ 
meter and depressions (“gilgai” topography) in 
the north-east of the reserve reflect small-scale 
variations in the soil profile (Lunt 1987). A 
semi-permanent lake called Lake Stanley or 
Andersons Marsh occupies an area of about 15 
ha in the southern part of the reserve (Fig. 1). A 
major drainage line flows intermittently into 
Lake Stanley from the north-west, and a minor 
drainage line flows from the north-east. 
41 
