Conservation



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Conservation

 Science W. Aust. 7 (1) : 73–88 (2008)

Flora and vegetation of banded iron formations of the

Yilgarn Craton: Koolanooka and Perenjori Hills

RACHEL MEISSNER AND YVETTE CARUSO

Science Division, Department of Environment and Conservation, PO Box 51,

Wanneroo, Western Australia, 6946. Email: Rachel.Meissner@dec.wa.gov.au



ABSTRACT

A study of the flora and plant communities of Koolanooka and Perenjori Hills, east of Morawa, recorded 238 taxa,

with 217 native and 21 weeds. Nine priority taxa were found and five new species were identified and are considered

endemic to the hills. Fifty quadrats were established to cover the major geographical, geomorphologic and floristic

variation across the hills. Data from 48 of these quadrats were used to define five community types, with two

subtypes in one community. Differences in communities were strongly correlated with landform and soil fertility.

Patterns of high plant endemicity and restricted communities are similar to those found on other ranges within the

Yilgarn Craton. None of the plant communities found on the Koolanooka and Perenjori Hills is reserved in the

conservation estate.

INTRODUCTION

Banded iron formation ranges within the Yilgarn Craton

are highly prospective for iron ore exploration and mining.

Previous studies on greenstone and banded ironstone

ranges in the Goldfields have found high plant endemicity

and restricted vegetation types (Gibson et al. 1997; Gibson

& Lyons 1998a,b; Gibson & Lyons 2001a,b; Gibson

2004a,b). It is hypothesised that similar patterns would

also be found on the ironstone ranges in the Yilgarn

Craton. The current knowledge of the vegetation and flora

that occur on these ranges is poor and based on Beard’s

pioneering vegetation mapping (Beard 1976).

The Koolanooka Hills, Aboriginal for hill of wild

turkeys (Rogers 1996), is located approximately 20 km

east of Morawa. Perenjori Hills is located 10 km southeast

of Koolanooka and 12 km to the northeast of Perenjori

(Figure 1). Both hills are located near the boundary of

the agricultural and pastoral zones in Western Australia,

which roughly correlates with the boundary of the

Eremaean and Southwest IBRA provences (Figure1).

The Koolanooka and Perenjori Hills are part of the

Koolanooka synform, one of several Archaen belts within

the Yilgarn Craton. The hills strike NNW–SSE and N–S

respectively. The banded iron formation within the

Koolanooka synform is part of the middle sedimentary

association. The association contains siltstones, sandstones,

conglomerates interbedded with banded iron formation and

shale. This in turn is intruded by granitoids and bounded

by upper and lower volcanic associations (Baxter & Lipple

1985). Historically, iron ore was mined in the northern

part of Koolanooka Hills between 1966 and 1975 (Baxter

& Lipple 1985). Currently, there is interest in further

exploiting the iron ore resources of Koolanooka Hills.

The climate of the region is dry warm mediterranean

(Beard 1990) with a mild wet winters and hot dry

summers. Mean annual rainfall recorded at Morawa is

333.8 mm, but not as variable in more arid regions (227.8

mm 1


st

 decile; 453.7 mm 9

th

 decile; recorded 1911 to



2004). Rain primarily falls in winter, derived mainly from

cold fronts moving in an easterly direction over the Indian

Ocean. Summer rains are unpredictable and tend to occur

later in the season. Summer rains originate from troughs

and depressions and sometimes tropical cyclones off the

northwest coast of Western Australia (Rogers 1996).

The highest maximum temperatures occur during

summer, with the January as hottest month (mean

maximum temperature 36.7 °C with mean of 7.4 days above

40 °C). Winters are mild with lowest mean maximum

temperatures recorded for July of 18.1 °C. Temperatures

rarely fall below 0 °C in winter (a mean of 0.2 days below

0 °C), with a mean minimum of 6.2 °C in July.

The Koolanooka and Perenjori Hills were described

by Beard (1976) as a single vegetation system, the

Koolanooka system, consisting of Allocasuarina



huegelianaEucalyptus ebbanoensisAcacia acuminata,

Dodonaea inaequifolia interspersed with communities of

Allocasuarina campestrisAcacia acuminataGrevillea

paradoxaMelaleuca cordataMelaleuca nematophylla and

Melaleuca radula. The footslopes grade into Eucalyptus

loxophleba woodlands interspersed with the thickets.

Koolanooka vegetation system was endorsed by the

Minister for Environment as a Threatened Ecological

Community (TEC) in 2001. The TEC, plant assemblages

of the Koolanooka system, is based upon Beard’s (1976)

vegetation system described above, covering the entire

extent of both hills, approximately 4500ha. It is currently

ranked vulnerable following English and Blythe (1999).



74

R. Meissner & Y. Caruso



Figure 1. Location of survey and distribution of quadrats (

ᮡ) on Koolanooka and Perenjori Hills. The 340 m contour is shown,



with remnant vegetation represented by shaded areas represent, dashed lines represent roads. In the inset, the grey line represents

the zone between the Southwest and Eremaean provinces.

The aim of the present work was to undertake a

detailed floristic survey of the Koolanooka and Perenjori

Hills and to identify the plant communities that occur on

the ranges. This was achieved by detailed flora lists, and

description of plant communities based on a series of

permanently established quadrats. Ultimately, the aim is

to place these communities in a regional context with other

banded ironstone ranges throughout the Yilgarn Craton.

METHODS

Fifty 20 x 20 m quadrats were established on the crests,

slopes and foot slopes of Koolanooka and Perenjori Hills

in October 2005 (Figure 1). These quadrats were

established to cover the major geographical,

geomorphologic and floristic variation found in the study

area. Each quadrat was permanently marked with four steel

fence droppers and their positions determined using a GPS

unit. All vascular plants within the quadrat were recorded

and collected for later identification at the Western

Australian Herbarium.

Data on topographical position, disturbance,

abundance, size and shape of coarse fragments on the

surface, the amount of exposed bedrock, cover of leaf litter

and bare ground were recorded following McDonald et

al. (1990). Additionally, growth form, height and cover

were recorded for dominant taxa in each stratum (tallest,

mid- and lower).

Twenty soil samples were collected from the upper 10

cm of the soil profile within each quadrat. The soil was

bulked and the 2 mm fraction analysed for B, Ca, Cd, Co,

Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, S and Zn using

the Mehlich No. 3 procedure (Mehlich 1984). The

extracted samples were then analysed using Inductively

Coupled Plasma – Atomic Emission Spectrometer (ICP-


Flora and vegetation of Koolanooka & Perenjori Hills

75

AES). This procedure is an effective and cost efficient

alternative to traditional methods for evaluating soil

fertility and has been calibrated for Western Australian

soils (Walton & Allen 2004). pH was measured in 0.01M

CaCl


2

 at soil to solution ratio of 1:5. Effective cation

exchange capacity (eCEC) was calculated from the sum

of exchangeable Ca, Mg, Na and K (Rengasamy &

Churchman 1999). Exchangeable Ca, Mg, Na and K were

obtained by multiplying the values of Ca, Mg, Na and K

obtained from ICP-AES by a standard constant.

Quadrats were classified on the basis of similarity in

species composition on perennial species only, to be

consistent with other analyses of banded ironstone ranges

(Gibson 2004 a, b). Perennials were also more consistent

across season and amount of pre-survey rainfall. Life form

followed Paczknowska and Chapman (2000), where

perennial is defined as a plant whose life span extends over

2 or more growing seasons. The quadrat and species

classifications were undertaken using the Bray and Curtis

coefficient and Flexible UPGMA (Unweighted pair-group

mean average; â = -0.1; Belbin 1989). Indicator species

and species assemblages characterising each community

were determined following Dufrene and Legendre (1997)

using the INDVAL routine in PC-ORD (McCune &

Mefford 1999). Quadrats were ordinated using SSH

(semi-strong hybrid multidimensional scaling),

correlations of environmental variables were determined

using the PCC (Principal Component Correlation) routine

and significance determined by the MCAO (monte-carlo

attributes in ordination) permutation test in PATN (Belbin

1989).


Statistical relationships between quadrat groups were

tested using Kruskall-Wallis non parametric analysis of

variance (Siegel 1956), followed by non-parametric

comparison (Zar 1999). Correlations between

environmental parameters were analysed using Spearman

Rank correlation coefficient.

Nomenclature generally follows Paczkowska and

Chapman (2000).



RESULTS

Flora

A total of 237 taxa from 53 families were recorded from

the 50 established quadrats and adjacent areas. Of these

237 taxa, 216 were native and 21 weeds. The dominant

families in order were Asteraceae (39 species, 3 weeds),

Myrtaceae (21), Poaceae (21 species, 11 weeds),

Mimosaceae (19) and Chenopodiaceae (11).

Rare and Priority Flora

Nine priority taxa (designated P1, P2, P3) were found

during the survey of Koolanooka and Perenjori Hills.

• Acacia acanthoclada subsp. glaucescens (P3) is an

intricately branched shrub to 2 m with pungent

branchlets and glaucous phyllodes. It was found

growing in open forests and mallee woodlands and

of E. ebbanoensis or E. loxophleba subsp. supralaevis.

It has been previously found on Koolanooka Hills.

• Baeckea sp. Perenjori (J.W. Green 1516) (P2) is a

small myrtaceous shrub to 1.5 m with pink flowers.

This taxon is restricted to the Morawa and Perenjori

region. In this survey, it was found growing on the

crests and slopes of Perenjori and Koolanooka Hills.

• Gunniopsis rubra (P3) is a small succulent herb to

10 cm growing on water gaining sites in sandy loam.

A single collection was made of this taxon from a

colluvial outwash site, growing under mallee

woodlands of Eucalyptus subangusta subsp. pusilla and

Eucalyptus ebbanoensis subsp. ebbanoensis.

• Melaleuca barlowii (P1) is a myrtaceous shrub to

1.8 m known mainly from the Mullewa and Morawa

area growing on roadside reserves. It has been

collected previously from Koolanooka Hills. In this

survey, it was collected from two sites on Koolanooka

Hills, growing in shrublands of Allocasuarina

acutivalvis on a lower and mid slope.

• Millotia dimorpha (P1) is a small yellow flowered

daisy characteristically with two rows of glandular

involucral bracts. This species is poorly collected, and

originally known only from Koolanooka Hills and

Kadji Kadji Station. It has recently been found

growing on the slopes of Mount Karara, east of Kadji

Kadji (Markey and Dillon, 2008).

• Mribelia sp. Helena and Aurora (B.J. Lepschi 2003)

(P3) is a perennial, leaf less but pungent shrub to

3m. Originally found only on the Helena and Aurora

Ranges in the western Goldfields, it was found

growing on the mid to upper slopes of Koolanooka

Hills with A. acutivalvis and E. ebbanoensis. This is a

new record for Koolanooka Hills and a range

extension of over 400km for the species.

• Persoonia pentasticha (P2) is a proteaceous shrub to

2 m with pungent five ribbed leaves. In this survey,

it was found at two sites on crests of Koolanooka

Hills, growing in open forests of A. acutivalvis and



E. ebbanoensis.

• Rhodanthe collina (P1) is an annual daisy with small

delicate flowers. It is known mainly from the pastoral

stations near Paynes Find on flats and water gaining

sites. A single specimen was found on Koolanooka

Hills on a rocky midslope. This is a new record, range

extension and population for the area.

• Stenanthemum poicilum (P2) is small shrub to 50 cm

that was found growing on the crests and upper slopes

of Koolanooka Hills in open mallee forests and

woodlands of E. ebbanoensis and A. acutivalvis. It has

been previously collected from rocky sites in the

Morawa area. This a new record for Koolanooka

Hills.


New Species

During the survey, six new species were identified. These

taxa are apparently endemic to the Koolanooka and


76

R. Meissner & Y. Caruso

Perenjori Hills. Further surveys are required to determine

the distribution and population size of each taxon. Further

taxonomic work is also required to determine taxonomic

rank of several of the taxa.

• Acacia muriculata is a shrub to 2 m found growing

only on the slopes and crests of Koolanooka Hills in

open mallee forests and woodlands of E.  ebbanoensis

and  A. acutivalvis. It characterised by hair y

verruculose-ribbed branchlets and falcate phyllodes

with solitary globular flowers (Maslin & Buscomb

2007). It has recently been listed as Priority One

species and is known only from Koolanooka Hills.

• Acacia graciliformis is an openly branched shrub to

2 m with slender stems and short pungent phyllodes.

It was found at four sites growing in Eucalyptus

woodlands crests and slopes of Koolanooka Hills.

This species is closely allied to Acacia mackeyana and

A. dissona which differ significantly from the species

in their phyllode nervature (Maslin & Buscomb

2007). It has been listed as a Priority One species

due to its restricted habitat and location.

• Caesia sp. Koolanooka Hills (R.Meissner & Y.Caruso

78) is a geophyte to 30 cm with pale yellow flowers

growing on crests and slopes of Koolanooka and

Perenjori Hills. The species is closely related to Caesia

sp. Wongan (K.F. Kenneally 8820) but with smaller,

pallid flowers and spreading anthers. It may belong

to a sub-group of the genus that is endemic to

ironstone ranges, including such species as Caesia

sp. Ennuin (N.Gibson & M.N.L yons 2737)

(G. Keighery

1

, pers. comm.). The occurrence on the



ranges is unusual as most Caesia spp. grow in deep

clay soils on flats and plains.

• Dodonaea scurra is a dioecious shrub to 1 m with

verticillate leaves and solitary flowers. It is closely

allied to Dodonaea caespitosa but is distinguished by

relatively more clustered leaves per node and distinctly

rounded capsules with simple scattered hairs

(Shepherd et al. 2007). It was found only on the

slopes and crests of Koolanooka Hills in several

different communities. There was one previous

collection in the Western Australian Herbarium of

this taxon, which was misidentified, from the

Koolanooka Hills. It is has recently been listed as

Priority One due to its limited distribution to

Koolanooka Hills.

• Drummondita rubroviridis is a spindly shrub to 1.5 m

with glandular clavate leaves, held recurved to

horizontal, and subsessile, solitary flowers that possess

red petals with green tips (Meissner & Markey 2007).

It is closely related to D. wilsonii and D. ericoides,

both taxa with restricted distributions (Mollemans

1993). This species was only found on the slopes

and crests of Koolanooka Hills, growing mainly in

open mallee forests and woodlands of E. ebbanoensis

and A. acutivalvis.

• Lepidosperma sp. Koolanooka (K. Newbey 9336)

is a sedge to 50 cm found growing on the slopes

of Koolanooka and Perenjori Hills in open forests

and shrublands of A. acutivalvis or A. campestris.

Although previously collected from Koolanooka,

it was not recognised as a new species until the

current survey collected sufficient material for the

status to be determined with confidence. It is

closely related to another newly discovered granite

endemic,  Lepidosperma sp. Karara (H.Pringle

3865) found growing on granite outcrops on

Karara Station.

Flora of taxonomic interest

• Hibbertia aff. exasperata belongs to a complex,

including Hibbertia rostellataHibbertia nutans and

Hibber tia uncinata, of unresolved taxonomy

(Wheeler 2004). Fur ther work needs to be

undertaken to elucidate the taxonomic relationships

within this complex. The species was collected only

from the slopes and crests of Koolanooka Hills,

mainly from mallee woodlands of E. ebbanoensis and



A. acutivalvis.

• Eucalyptus ebbanoensis subsp. glauciramula is a mallee

to 3 to 6m and was collected from both ranges. It

was commonly the dominant Eucalyptus and was

found across the landscape, from crests to lower

slopes and plains. It has previously been collected

from the range. The nearest populations are nearly

400 km to the east in the Goldfields.

• Labichea lanceolata subsp. brevifolia is a shrub to 3m.

It was found growing at single site on a midlsope of

Koolanooka Hills, in an open forest of A. acutivalvis.

The taxon is found in three discreet areas; around

Esperance, York and an outlying nor thern

population. The specimen collected in this survey

belongs to the northern variant of the taxon, found

in scattered populations between Geraldton and

Morawa. These collections have narrow leaves and

look superficially more like Labichea eremaea than



L. lanceolata, but differ from the former as they have

4 rather than 5 sepals. Revision of this taxon is

required.

• Tetraria aff. capillaris is a sedge with curly leaves

growing to 50 cm. It was found growing at a single

site on Koolanooka Hills in Allocasuarina acutivalvis

subsp.  acutivalvis woodland with M. nematophylla,

H. aff. exasperata and L. sp. Koolanooka (K.Newbey

9336). It is closely allied to Tetraria capillaris and

this complex is in need of taxonomic revision

(R. Barrett

2

, pers. comm.).



1

 Science Division, Department of Environment and Conservation, Western Australia

2

 Science Directorate, Botanic Gardens & Parks Authority, Kings Park and Botanic Garden, Western Australia



Flora and vegetation of Koolanooka & Perenjori Hills

77

Plant Communities

Initial analysis of the data with all species excluding

singletons (species which occurred in only one plot)

compared to an analysis of data with only perennial species

revealed little difference in the groupings and ordination.

Ninety eight perennial taxa were included in the final

analysis. Subspecies of E. ebbanoensis and A. acutivalvis

were reduced to species level for the analysis, due to the

difficulty in differentiating between subspecies without

sufficient flowering or fruiting material.

Forty eight quadrats out of the fifty established on the

ranges were used in the final analysis. In the initial analysis,

two quadrats were outliers and subsequent removal

improved the ordination stress. Quadrat KOOL26 was a

species poor Eucalyptus salmonophloia woodland occurring

over limestone and KOOL36 was an open shrubland of



Acacia tetragonophylla and Calycopeplus paucifolius and

had a high percentage of weeds present, probably due to

high levels of disturbance. Both sites had high levels of

calcium, magnesium and high pH.

Community groups were separated into 5 groups,

based upon clear pattern in the final dendrogram. This

pattern was also the first division separates the

Allocasuarina shrublands and thickets (Communities 1-4)

from the more fertile woodland sites (Community 5;

Figure 2). The second division separates communities

restricted mainly to the crests, upper and mid slopes of

Koolanooka Hills (Communities 1 and 2) from

communities common between Perenjori and Koolanooka

Hills (Community 3) and communities found on the lower

slopes of Koolanooka (Community 4). These divisions

can also be clearly seen in the sorted two-way table of the

sites and species classification (Table 1).

In total, five community types, one with two subtypes,

were recognised.

Community 1 – Woodlands, mallee shrublands and

shr ublands of A. acutivalvisE. ebbanoensis over

shrublands of Acacia spp. and Myrtaceae spp. The

community occurs only on crests and slopes of Koolanooka

Hills and can be further divided into 2 subtypes.

Community type 1a – This community is found only on

Koolanooka Hills on all landforms except colluvial

outwashes. It is described as mallee shrublands, shrublands

and woodlands of A. acutivalvisE. ebbanoensis and

Melaleuca spp. over shrublands with Micromyrtus

racemosaG. paradoxa and M. sp. Helena and Aurora (B.J.

Lepschi 2003) present. The community had the lowest

mean species richness ( annuals and perennials) of all

communities (mean 32.3 ± 0.6 species per quadrat). The

best indicator species are Acacia neurophylla subsp.

neurophyllaCheiranthera filifolia var. simplicifolia,

D. rubroviridisE. ebbanoensisG. paradoxaMicromyrtus

racemosa subsp. racemosaMelaleuca atroviridisM. sp.

Helena and Aurora (B.J. Lepschi 2003) and Thysanotus



manglesianus (Table 1).

Community type 1b – This community is only found on

the slopes of Koolanooka Hills. It is best described as

woodlands and shrublands of A. acutivalvis with an

understorey of L. sp. Koolanooka (K.Newbey 9336),

Pimelea avonensis, and Acacia nigripilosa subsp.

nigripilosa. Mean species richness was 34.0 ± 0.5 species

per quadrat. Indicator species were A. nigripilosa subsp.



nigripilosa,  Austrostipa hemipogonC. sp. Koolanooka

Hills (R.Meissner & Y.Caruso 78), L. sp. Koolanooka (K.

Newbey 9336), M. nematophylla, P. avonensis and

Tricoryne elatior. This community is characterised by taxa

from Species groups D and G (Table 1).

Community type 2 – This community occurs only on

Koolanooka Hills, mainly on crests and upper slopes and

contains taxa from Species group A (Table 1). It can be

described as mallee woodlands and shrublands of



E. ebbanoensis and A. acutivalvis. This community had the

second highest species richness with a mean of 38.6 ± 1.3

species per quadrat. Indicator species were S. poicilum,

H. aff. exasperataA. acutivalvis and Ptilotus obovatus

subsp. obovatus.

Community type 3 – This community occurs on midslopes

and crests of Koolanooka and Perenjori Hills. It can be

described as open woodlands, shrublands and open

shrublands of Allocasuarina spp., M. nematophylla, and



Figure 2. Dendrogram of 6 group level classification of 48

quadrats established at Koolanooka and Perenjori Hills.


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