VEGETATION OF DERRIMUT GRASSLAND RESERVE 
43 
RESULTS AND DISCUSSION 
Plant species 
One hundred and eighty species of vascular 
plants were recorded from the reserve (see 
Appendix), including 102 natives (57% of spe¬ 
cies) and 78 exotics (43%). All but six species 
were herbs and many of the most widespread 
species in the reserve were exotic (Table 1). 
Three of the native species recorded are rare or 
vulnerable in Victoria: Comesperma polyga- 
loides, Stipagibbosa and Stipa setacea (Gullan et 
al., in prep.). The reserve included 26% of the 
391 species of native plants that occur on the 
Keilor basalt plains (Willis 1964). Although 
Asteraceae, Poaceae and Cyperaceae were the 
largest families in the reserve and on the plains 
in general, many large families on the plains 
were absent from or poorly represented at 
Derrimut; for example, the reserve included 
only one of 15 orchid species, two of 13 native 
legumes and none of the 14 native chenopods 
recorded from the Keilor basalt plains. 
Vegetation types 
Two major vegetation groups, wetland veg¬ 
etation and grassland vegetation, were identi¬ 
fied from the floristic table (Table 2). They were 
divided into five minor groups, comprising 
three wetland vegetations [Amphibromus- 
Agrostis grassland, Eleocharis sedgeland and 
mixed-species herbland) and two grassland 
vegetations ( Themeda grassland and Vulpia 
grassland). 
The five minor groups were differentiated by 
floristic and structural features, and their names 
refer to the dominant species and vegetation 
structure (after Specht 1981b): mixed-species 
herbland was co-dominated by a number of spe¬ 
cies. In the following discussion, “grasslands” 
refer to Themeda and Vulpia grasslands and do 
not include the minor wetland group, Amphibro- 
mus-Agrostis grassland, unless otherwise noted. 
The term “species richness” denotes the mean 
number of species in each quadrat. 
Wetland vegetation 
“Wetland vegetation” is a convenient name to 
encompass three minor groups of diverse struc¬ 
ture and composition but similar habitat. They 
occurred in areas that were seasonally or almost 
permanently inundated: the margins of Lake 
Stanley and small depressions along drainage 
lines and within grasslands. The eastern 
drainage line did not carry surface water for 
sufficiently long periods to support wetland 
vegetation. 
Amphibromus-Agrostis grassland was co-dom¬ 
inated by Amphibromus nenmus and Agrostis 
avenacea (Fig. 2). It was restricted to a narrow 
band on the edge of Lake Stanley (Fig. 1) which 
was inundated for almost the entire period of 
observation (November 1986 to January 1988). 
Species richness was very low: on average, only 
12 species occurred per quadrat (Fig. 3). 
Eleocharis sedgeland, dominated by Eleo¬ 
charis acuta , occurred in small depressions 
throughout the reserve (Figs 1, 4) and was most 
common in the numerous depressions along the 
western drainage line. It was inundated season¬ 
ally, but surface water evaporated in summer 
causing the silty clay soils to crack deeply. Spe¬ 
cies richness was very low: viz. 11 species per 
quadrat (Fig. 3). Eleocharis sedgeland was floris- 
tically related to Amphibromus-Agrostis grass- 
Species 
% 
Species 
% 
*Romulea rosea 
92 
*Leontodon taraxacoides 
39 
* Vulpia bromoides 
92 
Schoenus apogon 
39 
*Lolium rigidum 
74 
Eryngium ovinum 
38 
Themeda triandra 
74 
Juncus bufonius 
38 
Convolvulus erubescens 
67 
*Plantago corn nopus 
38 
*Briza minor 
66 
Acaena echinata 
36 
*Bromus hordeaceus 
59 
Danthonia setacea 
36 
Oxalis perennans 
59 
*Briza maxima 
34 
*Aira cupaniana 
56 
*Cyperns tenellus 
34 
Stipa bigeniculata 
56 
*Cicendia quadrangular is 
33 
Danthonia duttoniana 
41 
* Trifolium striatum 
33 
*Hypochoeris radicata 
41 
*Trifolium subterraneum 
33 
Table 1. Species recorded from 33% or more of quadrats and percentage of quadrats in 
which each occurred. Asterisks show exotic species. 
