Gibson: Flora and vegetation of Middle and South Ironcap, Digger Rock and Hatter Hill 
12 34 
Community types 
Figure 2. Dendrogram of 4 group level classification of 38 
quadrats established along the southern Forrestania greenstone 
belt between Middle Ironcap and Hatter Hill. 
Physical Correlates 
The climatic estimates and latitude and altitude 
showed significant intercorrelations, as did slope class 
and aspect (Table 2). Topographic position, slope, percent 
surface rock and percent litter showed significance 
differences between the mean values of the four 
community types (Table 3). No significance differences 
were found for latitude, altitude or the climatic estimates. 
Steeper slopes differentiated community types 1 and 
2, from 3 and 4, as did a higher percentage of surface 
rock and rock type (Table 3 & Fig 3). Surfical deposits of 
banded ironstone and laterite (often massive) occurred at 
most quadrats in community types 1 and 2 but 
uncommon in the other community types. Altitude and 
topographic position scores are somewhat misleading 
because topographical relief along the range was 
subdued except near Middle and South Ironcap. The 
broad intervening ridges where community type 3 was 
common had a similar topographic position score and 
altitude as community types 1 and 2 that were restricted 
to the more pronounced hill and ridge tops. The soil 
profiles on these broad ridges was much deeper than on 
the outcrops. 
The three dimensional ordination (stress = 0.17) of the 
38 quadrats showed clear separation between 
communities (1 and 2) found on the outcrops and the 
eucalypt woodlands of the broad ridges and colluvial 
deposits. The shrublands and mallee shrublands of 
community type 1 occur in the lower left quadrant, the 
mallee shrublands and thickets of community type 2 
occur in the centre and the woodlands of community 
type 3 and 4 in the upper right quadrant with segregation 
between these units (Fig 4). Good separation of the 
subtypes of community type 1 was found on the third 
axis (not shown). Of the site parameters only percentage 
surface rock was significantly correlated with the 
ordination, correlations could not be improved by 
standard data transformations, implying no simple non¬ 
linear response in the data. 
Discussion 
The southern Forrestania belt has a similar floral 
richness to the other goldfields ranges for which detailed 
information exists but is much richer in local endemics 
(Gibson et al. 1997; Gibson & Lyons 1998a,b; Gibson & 
Lyons 2001 a,b; Gibson unpublished data; Table 4). The 
reasons for this high level of local endemism is not clear; 
topographically and geologically the range between 
Middle Ironcap and Hatter Hill is no more diverse than 
other goldfields ranges nor is the current climatic 
gradients unusual. The range does form part of the 
western most greenstone belt, but so to do the Highclere 
Hills which have no local endemic taxa (Table 4). 
The significance of the flora of this area has long been 
recognized and it is one of the best collected ranges in 
the goldfields, yet the flora of the range is still poorly 
known as indicated by the number of taxa requiring 
further survey to an assessment of their threat status 
(Table 1) and that the current survey (that was restricted 
to the existing track network) located new populations of 
Table 2 
Matrix of Spearman rank correlation coefficients between site physical parameters and climate estimates. Correlation significant at P < 
0.01 shown in bold. See methods for parameter codes. 
Position 
Slope 
Aspect 
% rock 
% litter 
% bare 
Latitude 
Altitude 
Tann 
Trange 
Rann 
Rev 
Position 
1.00 
Slope 
0.25 
1.00 
Aspect 
0.22 
0.74 
1.00 
% rock 
0.06 
0.41 
0.17 
1.00 
% litter 
-0.14 
-0.11 
-0.03 
-0.40 
1.00 
% bare 
0.04 
0.01 
0.13 
-0.09 
-0.12 
1.00 
Latitude 
0.18 
0.15 
0.00 
0.28 
-0.19 
0.24 
1.00 
Altitude 
-0.08 
0.04 
-0.28 
0.36 
-0.03 
0.09 
0.68 
1.00 
Tann 
0.32 
0.11 
0.39 
-0.17 
0.05 
0.34 
0.44 
-0.26 
1.00 
Trange 
0.15 
0.14 
-0.02 
0.35 
-0.13 
0.25 
0.96 
0.75 
0.36 
1.00 
Rann 
0.17 
-0.01 
0.35 
-0.30 
-0.01 
-0.03 
-0.43 
-0.93 
0.50 
-0.51 
1.00 
Rev 
0.30 
0.17 
0.13 
0.21 
-0.13 
0.26 
0.89 
0.42 
0.69 
0.86 
-0.11 
1.00 
53 
