Australian Journal of Ecology (1981) 6,

Soils and vegetation of central Australian sandridgesII. Sandridge vegetation in the Uluru National Park Area,Northern Territory, Australia

R. BUCKLEYDept. of Biogeography and Geomorphology,Research School of Pacific Studies, AustralianNational University, Canberra, Australia 2600

Abstract

Belt transects taken over the main sandridges inUluru National Park, Northern Territory, show aconsistent fioristic zonation from swale todunecrest.

On the larger ridges five or six zones aredistinguishable and the crest assemblage is largelydisjunct; on the lower dunes the pattern istruncated.

The Uluru dunefields are representative of theNorthern Territory and central WesternAustralia, though the fioristic assemblage differsregionally.

Introduction

Uluru National Park lies near the centre of themain anticlockwise swirl of Australian longi-tudinal sandridges described by Jennings &Mabbutt (1967) and Bowler (1976) and its ridgesare reticulate, chained or confused. Meanannual rainfall was 303 mm between 1964 and1974, but the long-term mean is probably closerto 180 mm (Gaffney 1977). Rains were heavybefore and during fieldwork (1975-6); 372 mmfell in 1973, 936 mm in 1974, 378 mm in 1975 and109 mm in 1976. Mean monthly maximum andminimum temperatures range from 19°C and 4°Crespectively in July to 35°C and 2 r c in Januaryand February. Humidity is low except immedi-ately after rain, and evaporation high. Climate is

discussed more fully by Slatyer (1962) andBuckley (1979a, b; 1981).

Soils range from red earths and red clayeysands in the swales to deep homogeneous redQuaternary aeolian siliceous sands on theridgecrests (Litchfield 1962). They are describedin more detail by Buckley (1979a, b; 1981). Thepark lies in the Simpson Land System of Perry etal. (1962); sandplain and dunefield bearinghummock grassland dominated by the spinifexesTriodia pungens, T. basedowii and Plectrachneschinzii. Hooper et al. (1973) divided the parkinto 15 land units, the dunefield units beingseparated on the basis of pattern, height anddominant Triodia species. This study con-centrates on the higher dunes, most repre-sentative of the main arid central Australianlongitudinal dunefields, and in particular on thefloristic gradient between crest and swale. Suchdunes lie in land units 5dl and 5d2 of Hooper etal. (1973). The latter occurs in two regions in thePark; one 10 km northwest of Ayers Rock,and the other north of the Olgas. These arereferred to subsequently as 5d2-AR and 5d2-OL. The fullest development of the vegetationzonation is shown on the higher dunes of units5d2-AR and 5dl, which were therefore investi-gated most intensively.

Previous studies in the area include Jessup(1951) in northwestern South Australia, Perry &Lazarides (1962) and Chippendale (1963) in thesouthern and southwestern Northern Territory,and Beard (1974) in the Gibson Desert, WesternAustralia. These were reviewed by Buckley(1979a, b; 1981); essentially they recognizedeither swales and ridges or swales, flanks andridges.

Aerial views of the Ayers Rock sandridgesshow narrow red crests, bordered by twin green

0307-692X/81/12OO-O391 $02.00 © 1981 Blackwell Scientific Publications

392 R, Buckley

lines of bushes on the upper slopes, cuttingthrough the spinifex cover of flanks and swales.Subjectively, one may recognize up to sixvisually distinct topographic-floristic belts on thehigher dunes:

(1) Crest—level, gently rounded, or undulating;sand loose and sparsely vegetated on higherdomes, firmer and more densely vegetated onlower bowls or saddles.(2) Upperslope—steep loose sand with smallunstable slipfaces in some dunes. Characterisedby 2-3 trunked shrubs including Gyrostemonramulosus and particular Eremophila andAcacia species.(3) Midslope—firm but uncrusted sand sloping at5-10° and bearing small rounded woody shrubs(especially Myrtaceae and Chloanthaceae) lessthan 1 m high, associated in land unit 5d2-ARwith Plectrachne schinzii,(4) Lowerslope—gently sloping compacted andoften crusted sand, with dense spinifex cover.(5) Outer swale—very gently sloping compactedclayey sand bearing tussock grasses such asEragrostis eriopoda (woody woollybutt) andMonachather paradoxa (bandicoot grass), andisolated shrubs.(6) Central swale—hard level clayey sand or red

earth bearing mulga scrub or witchetty bush{Acacia aneura. A, kempeana).

Shallower swales bear spinifex throughout andlack Acacia woodland: lower dunes havevegetated crests and lack mobile crest domes andupperslope slipfaces.

Aims and methods

Central Australian sandridge vegetation wasexamined with reference to the followingquestions.

(1) Is the overall flodstic compositionhomogeneous, or is there regional variation?(2) Do the subjectively recognized vegetationbelts on the sandridges represent a consistenttopographic zonation in flodstic composition?(3) If so, is the floristic vadation continuous fromcrest to swale or are there distinct zones, partiallydisjunct from each other floristically?(4) Which species are topographically restrictedand which occur over a wide topographic range?How much variation is there between species?(5) Do species behave similarly throughout theirgeographic range? Are they stenotopic in onearea and eurytopic in another? If stenotopic, are

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Sandridge vegetation of Uluru N. P. area 393

they restricted to the same topographic zonethroughout?(6) Are the same fioristic groups recognizablethroughout? If so, do they occupy the sametopographic range? That is, how much regionalvariation is there in topographic pattern?

Vegetation patterns were analysed as follows.Belt transects of contiguous quadrats were laidout perpendicular to the sandridges fromrandom points on the dune axes at a number ofsites (Figs 1 and 2). Transects were generallytaken in pairs. Two comprised 1130 1 m x 1 mquadrats scored for cover of bare ground, litter,and each spinifex species; total aerial cover; anddensities of all other species. These proved toosmall, being approximately the same size asindividual shrubs, spinifex hummocks, or inter-hummock spaces. Five metre-square quadratsscored for presence or absence of each specieswere used therefore in all remaining transects.These were large enough to ensure that all butlarge trees and the most scattered ephemerals inthe assemblage sampled would occur in almost

every quadrat in that assemblage, but smallenough to enable precise location of zoneboundaries. The raw transect data demonstratedfulfilment of the first criterion in that therecorded distributions of almost all species arecontinuous or nearly so throughout their overallranges. The degree of zone overlap in manycases showed that zone boundaries were rarelysharp enough to fall within a single quadrat.

Following initial subjective rearrangement ofthe species-quadrat matrices by species to showthe different topographic ranges of each speciesand the general floristic gradient from swale tocrest, sample transects were subjected to a rangeof ordination and classification techniquesincluding four monothetic divisive and ninepolythetic agglomerative unconstrained hier-archical algorithms, the Gordon-Birks con-strained clustering algorithm (Gordon & Birks1972), and Wishart's mode analysis (Wishart1969). Clustering algorithms were comparedusing a variety of similarity measures. Of these,unconstrained hierarchical polythetic agglomer-

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394 R, Buckley

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Sandridge vegetation of Uluru N. P. area 395

ation using euclidean distance and the error sumof squares, and followed by relocation wasselected to divide each transect into overlappingzones. Binary frequency ratios (b.f.r.) werecalculated for each species in each cluster of eachtransect. These are defined as the ratio of theproportion of cluster quadrats containing thespecies to the corresponding proportion over thewhole transect. Further detail was given byBuckley (1979a; 21-29).

Results

Site locations and transect numbers are shown inFig. 1 and Table t, and reordered species-quad-rat matrices for each transect were presented byBuckley (t979a; Appendix 3. t): an example, therelatively short transect W4, is shown in Fig. 3,and copies ofthe others are available on request.They show a gradual floristic change from swaleto dunecrest, the crest assemblage being largelydisjunct on many dunes. Some species, such asAristida browniana, grow on all parts of thedune-swale complex, whereas others have topo-graphically restricted distributions: for example.Acacia aneura in the central swales andCrotalaria cunninghamii on the crests.

TABLE 1, Sites and transects (See Fig. 1)

Site

ARBGARASARHKARVIARDRARSOARCS

Landunit

5d25d25d25d25d25d25c2

Subunit

ARARARAROLOL

—

Transects

W1-W4W5-W6W15-W16W21W7-WI2W13-W14W27

The complete fusion dendrograms for eachtransect were given by Buckley (1979a) and areavailable on request. Similarity levels for clusterseparation were chosen to define a sandridgezonation, if present, with as many consistentlyrecognizable and separable zones as possible.This number was found to depend on duneheight. In general, transects were divided into 3,4,5 or 6 clusters. This provided a useful zonationtallying well with field observations, withacceptably low overlap between zones and withfloristic groups consistent between transects.

TABLE 2. Species with b.f.r. > L5 in zonesof transect W3.

Crest: Sida sp. D, Euphorbia wheeleri, Eucalyptusterminalis, Triodia pungens. Calotis erinacea. Grevilleastenobotrva. Crotalaria cunninghamii. Dampiera cinerea.Acacia ligulata, Pomax umbellata. Crotalaria strehlowii,Helichrysum ambiguum, Trichodesma zeylanicum

Upperslope: Corynotheca lateriflora. Crotalaria strehlowii.Pomax umbellata, Trichodesma zeylanicum. Grevilleastenobotrya, Crotalaria cunninghamii, Plectrachne schinzii.Helichrysum ambiguum. Stackhousia megaloptera. Calotiserinacea

Midslope: Ptychosema anomalum. Baeckea polystemona,Plectrachne schinzii. Thryptomene maisonneuvii. Brunoniaaustralis. Scaevola parvifolia, Acacia ligulata. Stackhousiamegaloptera. Lobelia heterophvlla. Grevillea eriostachva.Duboisia hopwoodii. Dampiera cinerea

Lowerslope: Alvogyne pinonianus. Podolepis canescens.Eremophila willsii. Eragrostic eriopoda

Swale: Dicrastylis sp.. Helipterum stipitatum. Newcastliaspodiotricha, Dicrastylis beveridgei. Monachather paradoxae.Codonocarpus cotinifolius. Amphipogon caricinus

TABLE3 . Species with b.f.r. > 1.5 in zones of Transect W4

Crest: Crotalaria cunninghamii. Euphorbia wheeleri. Sidasp. D. Triodia pungens, Calotis erinacea. Acacia ligulata,Eremophila gibsonii, Trichodesma zeylanicum. Dampieracinerea

Upperslope: Corynotheca lateriflora, Pomax umbellata.Ptychosema anomalum, Eremophila gibsonii. Grevilleastenobotrya. Acacia dictyophleba. Calotis erinacea. Sidasp. D,Triodia pungens, Helichrysum ambiguum, Trichodesmazeylanicum, Stackhousia megaloptera. Euphorbia wheeleri.Dampiera cinerea. Thryptomene maisonneuvii

Midslope: Sida sp. B. Alvogvne pinonianus. Thrvptomenemaisonneuvii, Plectrachne schinzii. Grevillea stenobotrva,Grevitlea eriostachya. Acacia ligulata, Eragrostis eriopoda,Scaevola parvifolia. Baeckea polystemona. Acacia dictyo-phleba, Trichodesma zeylanicum. Lechenaultia striata.Helichrysum ambiguum. Stackhousia megaloptera, Brunoniaaustralis, Eremophila willsii. Dampiera cinerea. Amphipogoncaricinus

Lowerslope: Duboisia hopwoodii. Euphorbia wheeleri.Monachather paradoxa, Codonocarpus cotinifolius, Rulingialoxophvlla, Calvtrix longiflora, Grevillea eriostachva.Podolepis canescens

Swale: Lobelia heterophvlla. Eremophila willsii (mostlyempty quadrats)

The clusters are plotted in Figs. 4 and 5. Eachsquare represents a quadrat, with those on thesame horizontal level belonging to the samecluster, and clusters ranked downwards fromcrest to swale. Species with binary frequencyratio (b.f.r.) greater than 1.5 in each zone aregiven in Tables 2, 3 and 5 to 18, with zonesnamed and listed in the same order as in Figs 4and 5. It should be emphasized that these tablesdo not merely represent partitions of the overall

396 R. Buckley

TABLE 4. Distribution of species in short crest transects

Species

Brachysfome ciliaris

Eragrostis eriopodaDicrastylis beveridgeiAmphipogon carkinusCodonocarpus cotinifoliusRulingia loxophyllaLobelia heterophyllaGrevillea eriostachyaEremophila willsiiTriodia basedowiiCatosperma goodeniaceaBrunonia australlsCalytrix longifloraScaevola parvifoliaAcacia dictyophlebaCalandrinia remotaAlyogyne pinonianusHelichrysum ambiguumPlectrachne schinziiCorynetheca laterifloraThryptomene maisonneuvei

Lechenaultia striataEucatvptus terminalis

u

8137

1059

11129

109

11273856524

42

b

121212343445142769

115

112

0

c

00000000000000000000011

Species

Gyrostemon ramulosus

Stackhousia megalopteraDampiera cinereaAcacia ligulataDuboisia hopwoodiiTriodia pungensDodonaea attenuataSalsola kaliPtychosema anomalumPomax umbellataDaviesia arthropodaAristida brownianaEriachne aristidea

Cassia pleurocarpaTrichodesma zeylanicumGrevillea stenobotryaEremophila gibsonii

Calotis erinaceaSida sp. DPtilotus latifoliusCrotalaria strehlowiiCrotalaria cunninghamii

u

2

322511121100

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00000

b

9

10972

1142571

165

1131311

54111

c

1

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1936

10

Figures indicate number of transects where: u, species occurs only in upperslope cluster; b, species is in both slope and crestclusters; c, species occurs only in crest cluster. (The thirteen species never found in crest clusters have been omitted from the table).

TABLE 5. Species with b.f.r. > 1.5 in zones of Transect W5

Crest: Pomax umbellata, Corynotheca lateriflora, Crotalariacunninghamii, Euphorbia wheeleri, Dampiera cinerea,Grevillea stenobotrya, Crotalaria strehlowii, Calotis erinacea.Lobelia heterophylla, Alyogyne pinonianus, Sida sp. D,Trichodesma zeylanicum

Upperslope: Duboisia hopwoodii, Gyrostemon ramulosus,Sida sp. B. Stachhousia megaloptera, Triodia pungens,Plectrachne schinzii, Sida sp. D, Grevillea eriostachya,Thryptomene maisonneuvii. Acacia ligulata, Crotalariastrehlowii, Grevillea stenobotryaMidslope: Helipterum pterochaetum. Acacia dictyophleba,Eragrostis eriopoda. Cassia pleurocarpa. Helichrysumbracteatum, Eremophila willsii, Brachyscome ciliaris,Alyogyne pinonianus, Helichrysum ambiguum, Rulingialoxophylla

Lowerslope: Podolepis canescens, Calytrix longiflora,Codonocarpus cotinifolius, Brunonia australis, Baeckeapolystemona, Helipterum stipitatum, Triodia basedowii

TABLE 6. Species with b.f r. > 1.5 in zones of Transect W6

Crest: Crotalaria cunninghamii. Acacia dictyophleba,Triodia pungens, Sida sp. D, Crotalaria strehlowii. Euphorbiawheeleri, Pomax umbellata. Calotis erinacea. Trichodesmazevlanicum, Corynotheca lateriflora, Helichrysum ambiguum

Upperslope: Dampiera cinerea. Sida sp. B. Grevilleastenobotrya, Alyogyne pinonianus, Gyrostemon ramulosus,Stackhousia megaloptera. Eremophila gibsonii. Acacialigulata, Helichrysum ambiguum

Midslope: Dicrastylis beveridgei, Thryptomenemaisonneuvii, Baeckea polystemona. Rulingia loxophylla.Plectrachne schinzii. Calytrix longiflora, Ptychosemaanomalum, Amphipogon caricinus

Lowerslope: Pimelea trichostachya, Salsola kali. Cassiapleurocarpa, Monachather paradoxa, Triodia basedowii,Enchylaena tomentosa, Casuarina decaisneana, Dicrastylis sp..Acacia murrayana, Brunonia australls, Eremophila willsii,Calandrinia remota, Solanum centrale. Lobelia heterophylla,Amphipogon caricinus

floristic list for each transect. The only speciesnoted are those characteristic of each clustergroup. Since many transects were compared,these are tabulated rather than being discussedin the text. In general, each cluster groupcomprises an unbroken or nearly unbrokensequence of quadrats occupying a restricted

topographical range, and thus constitutes adefinable topographical-floristic zone charac-terized by these species.

Vegetation patterns at each site will bedescribed first, followed by a summary of generalpatterns.

Sandridge vegetation of Uluru N. P. area 397

TABLE 7. Species with b.f.r. > 1.5 in zones of Transect W15 TABLE 10. Species with b.f.r. > 1.5 in zones of Transect W7

Crest: Grevillea stenobotrva. Gvrostemon ramulosus.Crotalaria cunninghamii, Dodonaea attenuata. Acacia ligulata

Upperslope: Trichodesma zeylanicum. Eremophila gibsonii.Euphorbia wheeleri, Dampiera cinerea. Acacia ligulata.Dodonaea attenuata, Plectrachne schinzii. Thryptomenemaisonneuvii, Aristida browniana

Midslope: Ptychosema anomalum. Grevillea eriostachva.Plectrachne schinzii. Thryptomene maisonneuvii, Dampieracinerea, Brunonia australis. Rulingia loxophylla. Amphipogoncaricinus

Lowerslope: Helipterum stipitatum. Dicrastylis sp.. Salsolakali. Triodia basedowii, Amphipogon caricinus. Rulingialoxophylla. Aristida browniana. Brunonia australis

Swale: Acacia aneura, Triodia pungens. Eremophilalatrobei, Thyridolepis multiculmis. Acacia murravana.Eragrostis eriopoda

TABLE 8. Species with b.f.r. > L5 in zones of Transect W16

Crest: Crotalaria cunninghamii. Gvrostemon ramulosus.Eremophila gibsonii. Acacia ligulata, Grevillea stenobotrya.Sida sp. B. Trichodesma zeylanicum

Upperslope: Alyogyne pinonianus, Dampiera cinerea,Solanum centrale. Sida sp. B. Acacia ligulata. Grevilleastenobotrya, Trichodesma zeylanicum. Eremophila gibsonii,Plectrachne schinzii. Brunonia australis. Thryptomenemaisonneuvii. Gyrostemon ramulosus. Grevillea eriostachya

Midslope: Acacia dictyophleba. Eremophila willsii.Grevillea eriostachva. Thryptomene maisonneuvii, Plectrachneschinzii. Amphipogon caricinus, Eragrostis eriopoda

Lowerslope: Rulingia loxophylla, Exocarpus sparteus,Helipterum stipitatum. Eragrostis eriopoda. Acacia murrayana.Amphipogon caricinus. Triodia basedowii

Swale: Triodia pungens. Enchylaena tomentosa,Thyridolepis multiculmis, Eremophila latrobei. Cassiapleurocarpa. Acacia aneura, Sida platycalyx. Monachatherparadoxa, Salsola kali

TABLE9. Species with b.f.r. > 1.5 ion zones of Transect W21

Crest: Ptilotus latifolius. Calotis erinacea. Crotalariastrehlowii. Solanum coactitiferum. Euphorbia wheeleri. Acacialigulata. Grevillea stenobotrya, Dodonaea attenuata, Triodiapungens, Salsola kali. Lobelia heterophylla. Acacia kempeana.Alyogyne pinonianus. Sida sp. B.

Upperslope (1): Helichrysum ambiguum. Acacia murray-ana, Enchylaena tomentosa, Ptychosema anamalum, Cato-sperma goodeniacea. Eragrostis eriopoda, Triodia pungens.Solanum coactiliferum. Satsola kali. Euphorbia wheeleri

Upperslope (2): Pomax umbellata. Podolepis canescens.Grevillea eriostachya, Alyogyne pinonianus. Bassia johnsonii,Dodonaea attenuata. Stackhousia megaloptera, Helipterumstipitatum, Scaevola parvifolia. Lobelia heterophylla. Acacialigulata, Brunonia australis

Midslope: Codonocarpus cotinifolius. Acacia dictyophleba.Brachyscome ciliaris, Eremophila willsii. Helipterumstipitatum. Brunonia australis. Grevillea eriostachya

Lowerslope: Cassia pleurocarpa, Scaevola depauperata.Calytrix longiflora. Triodia basedowii, Rulingia loxophytla.Stackhousia megaloptera, Monachather paradoxa

Crest-upperslope: Eremophila gibsonii. Calotis erinacea.Ca.isia nemophila var. platypoda. Dicrastylis beveridgei.Grevillea stenobotrva. Acacia ligulata. Helichrysumambiguum. Dampiera cinerea. Alvogyne pinoniamis.Crotalaria strehiowii. Acacia dictyophbleba. Solanumcoactiliferum, Scaevola parvifolia

Upper midslope: Solanum coactiliferum. Grevilleaeriostachya. Brunonia australis. Acacia dictyophleba.Brachysema chambersii. Lobelia heterophvlla. Catospermagoodeniacea, Crotalaria strehlowii. Alvogvne pinonianus.Solanum centrale

Lower midslope-bare ground: Rulingia loxophylla,Monachather paradoxa

Lowerslope-swale 1: Thyridolepis multiculmis, Rhagodiaspinescens. Enchylaena tomentosa, Eremophila latrobei.Catosperma goodeniacea. Amphipogon caricinus. Acaciapruinocarpa. Solanum centrale. Monachather paradoxa,Brachysema chambersii

Lowerslope-swale 2: Acacia aneura. Brachyscome ciliaris.Dicrastylis sp.. Calandrinia remota, Bonamia rosea.Eremophita willsii. Brachysema chambersii

TABLE 11. Species with b.f.r. > 1.5 in zonesof Transect W8

Crest: Dampiera cinerea. Sida sp. D. Grevillea stenobotrva.Trichodesma zeylanicum, Crotalaria cunninghamii. Crotalariastrehlowii. Eriachne aristidea, Calotis erinacea. Cassianemophila. Eremophila gibsonii. Helichrysum ambiguum

Upperslope: Dodonaea attenuata. Eremophila gibsonii.Cassia nemophila, Alyogyne pinonianus. Helichrysumambiguum. Acacia ligulata. Calotis erinacea. Thryptomenemaisonneuvii

Midslope: Keraudrenia integrifolia. Bonamia rosea. Acacialigulata. Solanum coactiliferum. Lobelia heterophylla.Greviltea eriostachya, Thryptomene maisonneuvii

Lowerslope-swale 1: Ptilotus obovatus. Thyridolepismulticulmis. CalytrLx longiflora, Grevillea eriostachva. Acaciaaneura. Acacia maitlandii. Eremophila willsii. Solanumcoactitiferum. Enchylaena tomentosa, Brachyscome ciliaris

Lowerslope-swale 2: Vittadinia sp.. Salsola kali,Amphipogon caricinus. Helichrysum bracteatum. Casuarinadecaisneana. Santalum lanceolatum, Hetipterum stipitatum,Dicrastylis sp.. Calandrinia remota, Brachyscome ciliaris.Enchylaena tomentosa, Scaevola parvifolia. Rulingia loxo-phylla, Solanum centrale, Brunonia australis. Eremophitawillsii

TABLE 12. Species with b.f.r. > 1.5 in zones of Transect W9

Crest: Acacia dictyophleba. Crotalaria cunninghamii,Calotis erinacea, Triodia pungens

Upperslope: Acacia murrayana, Crotalaria strehlowii,Calotis erinacea

Midslope: Scaevola parvifolia. Trichodesma zevlanicum.Eremophila gibsonii, Triodia pungens. Grevillea .ftenobotrya.Thryptomene maisonneuvii. Keraudrenia integrifolia.Grevillea eriostachya, Dicrastylis beveridgei. Helichrysumambiguum

Lowerslope: Triodia basedowii. Calandrinia remota.Catosperma goodenicea. Brunonia australis. Halgania cyanea,Eremophila willsii. Vittadinia sp.. Eragrostis eriopoda, Calvtrixlongiflora, Rulingia loxophylla. Lobelia heterophytla,Eremophila gibsonii, Codonocarpus cotinifolius

398 R. Buckley

TABLE 13. Species with b.f.r. > 1.5 in zones ofTransectWlO

Crest: Sida sp. D, Euphorbia wheeleri. Eucalyptusterminalis. Eremophila ginsonii, Triodia pungens, Caiotiserinacea. Grevillea stenobotrya, Crotalaria cunninghamii,Dampiera cinerea. Acacia ligulata. Pomax umbellata, Crota-laria strehlowii, Helichrvsum ambiguum, Trichodesmazeylaniciim

Upperslope: Corynotheca laterifiora, Crotalaria strehlowii,Pomax umbellata, Triehodesma zeylanicum, Grevillea steno-botrya, Crotalaria cunninghamii, Hetichrysum ambigttum,Stackhousia megaloptera, Caiotis erinacea

Midslope: Ptychosema anomalum, Baeckea polystemona,Plectrachne schinzii, Thrvptomene maisonneuvii, Brunonlaatistralis, Scaevola pan'ifolia. Acacia ligulata, Stackhousiamegaloptera. Lobelia heterophylla, Grevillea eriostachya.Duboisia hopwoodii. Dampiera cinerea

Lowerslope: Podolepis canescens, Eremophila willsii,Grevillea eriostachya, Dicrastvlis sp.. Helipterum stipitatum,Alyogyne pinonianus, Newcastlia spodiotricha, Dicrastylisbeveridgei, Monachather paradoxa, Codonocarpus cotini-fotius. Amphipogon cariciniis

TABLE 14. Species with b.t.r. > 1.5 in zones of Transect Wtl

Crest: Eucalyptus terminalis, Crotalaria cunninghamii,Crotalaria strehlowii, Caiotis erinacea, Triodia pungens,Helichrvsum ambiguum

tjpperslope: Daviesia arthropoda, Alyogvne pinonianus,Enchylaena tomentosa, Dicrastylis beveridgei. Acacia ligulata,Helichrysum ambigutim, Triodia pungens, Trichodesmazevlanicum. Brachvscome ciliaris, Rulingia loxophylla. Lobeliaheterophylla

Lowerslope: Exocarpus sparteus, Calandrinia remota,Dicrastylis sp., Calytrix longifiora, Alvogvne pinonianus,Scaevola parvifolia. Catosperma goodeniacea, Ptilotusobovatus, Pimelea trichostachya, Brunonia australis

Mound: Thyridolepis multiculmis. Vittadinia sp.. Ptiiotuspolystachyus, Enneapogon polvphyllus, Salsola kali,Casuarina decaisneana, Brachyscome ciliaris, Solanumcentrale

Site ARBG

Four main dune chains trend approximately NE-SW between the Olgas and Sedimentaries roads(Fig. 2) and the fourth was designated as siteARBG. The dune chains are about 1 km apartwhere best defined, but in some places isolatedintermediate dunes blur the distinction betweenchains. Each chain consists of short linear,crescentic or annular ridges, often linked bysaddles. Main swales between chains containoval patches of mulga some 300 m across by500-1500 m long. Nowhere are these joined in acontinuous swale mulga band, though mulga

TABLE 15. Species with b.f.r. > 1.5 in zones of Transect W12

Crest-upperslope: Crotalaria cunninghamii, Santalumlanceolatum, Caiotis erinacea, Grevillea stenobotrya. Eriachnearistidea, Eucalypttis terminalis, Triodia pungens, Tricho-desma zeylanicum, Crotalaria strehlowii

Upper-midslope: Helichrysum ambiguum. Acacia ligulata,Helipterum stipitatum, Casuarina decaisneana. Dampieracinerea, Dodonea attenuata, Alyogyne pinoniantis, Eremo-phila willsii, Thryptomene maisonneuvii. Lobelia heterophylla,Grevillea eriostachya, Crotalaria strehlowii. Stackhousiamegaloptera, Trichodesma zeylanicum. Acacia dictyophleba,Brunonia australis. Eucalyptus terminalis

Lowerslope: Pimelea trichostachya, Helipterum ptero-chaetum, Goodenia mueckeana. Euphorbia drummondii.Solanum coactiliferum, Rulingia loxophylla. Calandriniaremota, Scaevola parvifolia, Catosperma goodeniacea

Outer swale: Cassia pleurocarpa, Sida sp. B, Ptilotusobovatus, Helichrysum bracteatum, Monachather paradoxa.Eragrostis eriopoda. Enchylaena tomentosa, Eremophila gilesii

Central swale: Codonocarpus cotinifolius. Acacia aneura,Grevillea juncifolia, Eremophila latrobei, Eremophila gilesii,Brachyscome ciliaris. Vittadinia sp., Enchylaena tomentosa,Eragrostis eriopoda, Monachather paradoxa, Helichrysumbracteatum. Ptilotus obovatus. Solanum centrale, Keraudreniaintegrifolia

TABLE 16. Species with b.f.r. > 1.5 in zons of Transect W13

Crest: Caiotis erinacea, Grevillea stenobotrya. Crotalariacunninghamii, Eriachne aristidea, Trichodesma zeylanicum

Upperslope: Lobelia heterophylla, Triodia pungens,Solanum coactiliferum. Acacia kempeana, Ptilotuspolystachyus, Rulingia loxophylla, Thryptomene maison-neuvii, Grevillea eriostachya. Alyogyne pinonianus,Calandrinia remota

Midslope: Grevillea juncifolia, Salsola kali, Calandriniaremote, Monachather paradoxa, Solanum centrale, Grevilleaeriostachya. Alyogyne pinonianus

Lowerslope: Euphorbia drummondii. Dicrastylis sp.,Indigofera sp., Ptilotus obovatus, Grevillea eriostachya,Triodia basedowii, Solanum centrale, Brachyscome ciliaris,Scaevola parvifolia. Salsola kali, Monachather paradoxa,Cassia artemisiodes, Helichrysum bracteatum

Swale: Vittadinia sp.. Spartothamnella teucriiflora.Eremophila latrobei. Cassia nemophila. Acacia aneura.Aristida contorta, Sida platycalyx, Thyridolepis multiculmis,Enchylaena tomentosa, Rhagodia spinescens

Treebase: Acacia ligulata. Eucalyptus terminalis. Abutilonfraseri, Helichyrsum bracteatum. Rhagodia spinescens. Cassiaartemisiodes, Enchylaena tomentosa, Thyridolepis multiculmis

woodland is continuous in neighbouring sand-plains. Central-swale mulga patches generally liebetween the higher portions of the dune chains,and are surrounded by an outer-swale zone ofEremophila species over Triodia basedowii,transitional to the main spinifex zone. Centres ofannular ridges are at lowerslope rather than

Sandridge vegetation of Uluru N.P. area 399

TABLE 17. Species with b.f.r. > 1.5inzonesofTransectW14

Crest-upperslope: Grevillea stenobotrya. Acacia ligulata,Crotalaria cunninghamii, Calotis erinacea, Eriachne aristidea,Keraudrenia integrifolia, Triodia pungens, Trichodesmazeylanicum

Midslope: Grevillea eriostachya, Solanum centrale,Brunonia australis. Alyogyne pinonianus, Codonocarpuscotinifotius, Calandrinia remota, Thryptomene maisonneuvii

Lowerslope: Rutidosis helichrysoldes, Codonocarpuscotinifolius, Helichrysum bracteatum, Rhagodia spinescens,Solanum coactiliferum, Scaevola parvifolia, Dicrastylis sp..Indigofera sp., Casuarina decaisneana, Rulingia loxophylla,Triodia basedowii. Acacia aneura

Swale: Pterocaulon sphacelatum, Vittadlnla sp.. Aristidainaequigtumis, Eremophila gilesii, Aristida contorta, Sidaplatycalyx. Cassia artemisiodes. Euphorbia drummondll,Eremophila latrobei, Salsola kali, Monachather paradoxa,Eragrostis eriopoda. Acacia aneura, Brachyscome ciliaris

TABLE 18. Species with b.f.r. > 1.5 in zones of Transect W27

Crest: Ptilotus obovatus, Crotalaria strehlowii, Calotiserinacea. Corynotheca lateriflora, Salsola kali. Acacia ligulata,Trichodesma zeylanicum. Casuarina decaisneana, Grevilleastenobotrya, Helichrysum ambiguum

Upperslope: Scaevola parvifolia. Acacia tetragonophylla,Helichrysum bracteatum, Brunonia australis, Thryptomenemaisonneuvii

Midslope: Newcastlia spodiotricha. Cassia pleurocarpa.Solanum centrale, Eremophila willsii, Helichrysum brac-teatum, Alyogyne pinonianus. Thryptomene maisonneuvii

Lowerslope: Acacia victoriae, Dicrastylis beveridgei,Grevillea juncifolia, Eremophila willsii, Amphipogon caricinus

Swale: Acacia aneura, Brunonia australis, Eragrostiseriopoda, Amphipogon caricinus

swale level and have corresponding soil andvegetation. Triodia basedowii gives waygradually to the midslope Plectrachne schinziibelt, which has high ground and low aerial cover,in contrast to the upperslope where this situationis reversed. The upperslope bushes are tallerthan the shrubs of the midslope.

The lowest ridges are rounded whereas higherones have a steep upperslope (30°-33°) with anabrupt transition to a relatively low, level crest(< 5°) which may be gently domed or irregularlyconcave. These truncated profiles are probablythe result of continued sand loss from the mobilecrests to the vegetated slopes where it is trappedand protected from wind. Bare or sparsely vege-tated mobile crest summits alternate with lowerareas with firmer sand. Triodia pungens andEucalyptus aff. terminalis occur sparsely on thecrests. Transects Wl and W2 were scored

quantitatively over an open-crested dune at thenortheast end of the third chain (Fig. 2) andacross the intervening main swale to the fourthchain. Six zones were discernible in the field, buttransects Wl and W2 did not produce a usefulzonation since their quadrats were of the samesize as individual shrubs, spinifex hummocks andpatches of bare ground, and species densities in1-m quadrats were irregularly distributed. Theywill not be discussed further. Transects W3 andW4 were taken in corresponding positions at thesouthwest end ofthe dune chains; zonations aresummarized in Tables 2 and 3 and Fig. 4. Fivezones were recognized in each case, though withsome overlap between lowerslope and swaleassemblages. The boundary between crest andupperslope floristic clusters coincides with thetopographic boundary between the steep upper-slope (20-30°) and the flatter crest (< 5°). Furtherfusion of cluster groups amalgmates slope andswale clusters first, leaving the crest distinct.Sixteen short transects, covering crest and upper-slope only, were taken across the third chainto examine this boundary more closely and tosearch for possible subdivisions ofthe crest zone:five transects at the NE end, five in the middleand six at the SW end. The reordered species-quadrat matrices and the fusion dendrograms(Buckley 1979a) showed only two non-over-lapping inclusive clusters in general:'upperslope' and 'crest'. There is a strongupperslope-crest disjunction in some transectswhilst in others the crest is marked mainly by theabsence of strictly upperslope species with re-maining species occurring in both zones. This isgenerally due to the complete absence from thattransect of strictly-crest species, and occurs onrelatively low dunes without a clear mobile crestregion. In such cases the clustering algorithmmay include in the crest group, quadrats whichare more similar to upperslope vegetation else-where. Hence, for example, Alyogyne pinoni-anus and Acacia dictyophleba are each includedrespectively in the crest zones of one only of thetransects, and in both cases they also occur in theupperslope cluster. These results are summar-ized in Table 4, where the species are rankedaccording to their relative frequencies ofoccurrence in upperslope or crest group or both.In general these short transects confirm theslope-crest floristic disjunction, and indicate thatthe crest vegetation is too homogeneous forconsistent subdivision.

400 R. Buckley

10

West

20 30 40 50Quadrat number

60 70

W5

W6

W7

W7without

relocation

W8

W8without

relocation

50 100 150metres

200 250 300 350

FIG. 4. Cluster group for transects W3 to W8 inclusive. Each black square represents a quadrat, whose vertical position signifies itsallocation to a particular cluster. Cluster groups are plotted downwards from crest to swale in each transect. The characteristicspecies of each group are listed in Tables 2. 3, 5, 6, 10 and 11.

Site ARAS

The swale of site ARAS is comparatively shallowand narrow, and its sandy soils resemble those ofIowerslopes elsewhere. Transects W5 and W6were taken across it from crest to crest. Acaciamaitlandii and Didymotheca tepperi were notedfrom the swale but were not present in eithertransect. Zonations are summarized in Fig. 4 andTables 5 and 6. Four zones were recognized ineach. The lowest zones are topographicallyswales but correspond floristically andedaphically to Iowerslopes elsewhere.

Site ARHK

Site ARHK lies in subunit 5d2-AR just south of

the Olgas road. A dune runs approximatelyparallel to the road, and transects W15 and W16,30 m apart, where taken north from its crest.They were not extended to the south of the crestsince the ridges there are low, confused andbranching. The swale community characterizingthe northern end of the two transects continuesto the road. It is dominated by Acacia aneuraand understorey Eremophila latrobei overCalandrinia remota, Thyridolepis multiculmis,Eragrostis eriopoda and Monachather paradoxa.Five well separated and topographically definedzones were recognized in each transect (Tables 7and 8, Fig. 5).

Site ARVI lies near the margin of land unit5d2, and is bounded to the north and east by unit5c2. The dunes are low and confused. TransectW21 runs from a dunecrest, through a lower

Sandridge vegetation of Uluru N.P. area 401

10 20 30 40 50

Quadrat number60

North

70

South

East

W9

W10

W11

W13

W14

South

W15

wie

East

W21

W27

50 100metres

150 200 250 300 350

I8.CO

FIG. 5. Cluster groups for transects W9 to W27 inclusive. Format as Fig. 4. Characteristic species in Tables 7. 8. 9 and 12-18.

saddle, and over a second ridge. It does notdescend to the level of the lowest neighbouringswale, which is a few hundred metres to thenorth. The community represented in quadrats65 to 70 continues from the western end of thetransect to the next dune. Good clusterings existat the 4-, 5- and 6-cluster levels. Ouadrat 34 is an'outlier', and the zones given in Table 9 are basedon the 6-cluster level after relocation, excludingthis quadrat. The lowest zone (Fig. 5) bears amixed spinifex community.

Site ARDR

Two sites were examined in subunit 5d2-OL: siteARDR, immediately north of the old DockerRiver road where it runs north by west of the

Olgas; and site ARSO, by the direct road fromthe Olgas to the Sedimentaries. The sandridgesat ARDR are low, and their crests riddled withrabbit warrens. The main dunes form a singleanastomosing system running between the oldDocker River road and the road which circles theOlgas to the west. The dense acacia woodland onsurrounding sandplain extends between thedune branches, but is nowhere surrounded bydunes on all sides. It was therefore not includedin transects W7 and W8, which were taken fromNW to SE between the two ridges of a forkeddune. Transects W9 (WNW-ESE) and WIO (N-S) were taken from one solitary oval dune toanother, each of W7 and W8. Transect Wll(ENE-WSW) descends abruptly from the top ofthe highest dune in the area to a 'lowerslope'Casuarina decaisneana stand over spinifex. This

402 R, Buckley

dune was the only one at this site bearingEucalyptus aff. terminalis. The lowerslopecommunity consisted almost entirely of Triodiabasedowii, Calandrinia remota and Aristidabrowniana. Transect W12 (W-E) drops sharplyfrom a large dune into a wide flat swale withsparse mulga and then climbs gradually onto asmaller dune. Vegetation is dense, wth speciessuch as Thryptomene maisonneuvii, Keraudreniaintegrifolia and Dicrastylis beveridgei, elsewherecharacteristic of slope zones, occurring here ontop of the low sandhills. Acacia maitlandii,Acacia ietragonophylla and Helipterumstipitatum, characteristic of lower slopes andouter swales in areas of higher relief, were foundon the topographic upperslopes, as was a seed-ling of Baeckea polystemona, elsewhere amidslope species. Rhagodia spinescens, else-where common in swales, was present on themidslope at this site. The relative abundances ofsandhill species differ slightly from subunit 5d2-AR. Plectrachne schinzii is absent, and Triodiabasedowii extends well up the slopes. Grevilleaeriostachya, normally associated with Plec-trachne schinzii, is rare, while Casuarinadecaisneana is common, and Grevillea juncifoliaoccurs abundantly in the outer swale. Ptilotuspolystachyus, Bonamia rosea, Halgania cyaneaand Pimelea trichostachya were noticeably morecommon at this site than in subunit 5d2-AR.

Only three quadrats of transect W7 lie in thetopographic crest. In consequence, these wereclustered with the upperslope group. Inaddition, the mid-lower slope transition issparsely vegetated, and a largely azonal bare-ground cluster was formed, comprising theseplus quadrats from the swale. The remaindershows poor zonation and was classified as a two-group mosaic. These points are shown clearly inFig. 4 and are recognized in the zonationsummarized in Table 10. The crest and upper-slope are well defined in transect W8 (Table 11).Three further groups were recognized, but theseare poorly separated (Fig. 4).

Neither transect W9 nor transect WIO descendinto a mulga swale. Two lowerslope groups maybe distinguished in transect W9, but they havebeen amalgamated in Table 12 since they are nottopographically separated. The remaininggroups form four distinct topographic-floristiczones in each transect. The upperslope group intransect WIO is very small, but I have distin-guished it from the crest group since it differs

floristically, and occupies a topographicallyadjacent but distinct position (Fig. 5; Table 13).

Only two slope zones were recognized intransect Wll (Table 14, Fig. 5). In addition, twoquadrats in the centre of the lowerslope zonewere separated as a distinct termite-moundcommunity. The first four species listed for thisgroup (Table 14) were confined to the mound.Transect W12 is comparatively long (785 m), andcrest and upperslope are not satisfactorilydifferentiated at the five-cluster level as above(Table 15; Fig. 5). Finer division splits the swalegroups before the upper dune regions, and theabove zonation as therefore retained.

Site ARSO

Two transects, W3 and W14, were taken at siteARSO, running in a NW—SE direction from adune in subunit 5d2-Ol near the direct Olgas-Sedimentaries road'! The swale communitydiffered from that common in other parts of landunit 5d2. This is probably due in part to increasedwater supply caused by local topography, and inpart to soil differences. Acacia pruinocarpa,Eremophila latrobei and Grevillea juncifoliawere common'in the other swale. Swale acaciaswere heavily parasitized by Amyema maidenii,and the understorey contained Calotismulticaulis, Rutidosis helichrysoides, Indigoferasp., Pterocaulon sphacelatum, Aristidainaequiglumis, Rhagodia nutans, and Sidaplatycalyx, Aristida contorta and Cymbopogonobtectus dominated the central swale grass layer.A hybrid Cassia was found, probably Coligophylla x C nemophila var. zygophylla (J.Maconochie, pers. comm.; Herbarium Austra-liense coll. no. ANU 27133). Five zones wererecognized in transect W13 and four in W14 (Fig.5; Tables 16, 17). In addition, a separate'treebase' assemblage occupied two quadrats atthe base of a single Eucalyptus terminalis in theswale of transect W13.

Site ARCS

Shortly before this study a line had been cut andsurveyed from Curtin Springs Station to the newAyers Rock village site (Fig. 1). A dune on thisline, site ARCS, is described here as repre-sentative of land unit 5c2. To the west of site

ARCS lies a soft spinifex community dominatedby Triodia pungens, Grevillea juncifolia. Acaciatetragonophylla, Eremophila willsii, and Acaciaaneura. Grevillea juncifolia and Eremophilawillsii are less commqn in the swale to the east,but a number of Hakea eyreana bushes occur,the first being 235 m from the crest. This is 50 mfurther into the swale than the first Acaciaaneura, often the most characteristic central-swale species. Transect W27 was taken acrossthe dune. Five zones were recognized, but over-lapped considerably (Table 18, Fig. 5).

Conclusions

These results and field observation support thefollowing generalizations.(1) There is a consistent vegetation pattern onthe sandridges, recognizable in the field and inbinary floristic belt transects.(2) Different species have topographic rangesof different breadth, but these ranges areconsistent between sandridges.(3) Floristic change up the sandridges is gradualexcept: (a) where there is a sharp edaphicboundary between a sandy lowerslope and aclayey swale, and (b) where there is a sharptopographic boundary between a relatively flatcrest and a steep upperslope.(4) Swale assemblages are very variable and arerelated to soil type as described by Perry &Lazaddes (1962). Largely, they resemble frag-ments of sandplain communities, as noted byChippendale (1963).(5) The sandridge assemblages are more con-stant. On the higher dunes typical of the maindunefields, the crest assemblage is most distinctand is most consistent between sandridges andbetween different dunefield areas.(6) Vegetation on the crests of lower dunesresembles that on the slopes of high dunes.Similarly, vegetation of shallow sandy swalescorresponds to that of the sandy lower slopes ofridges whose swales are deep and clayey.(7) Some floristic variation between sandridgeareas is not associated with differences in duneheight or soil type: for example, the distributionpatterns of the spinifexes.

The above suggest that the dune-swale floristicgradient is largely explicable by soil pattern, asare vegetation differences between high and lowdunes. Edaphic and other factors responsible for

Sandridge vegetation of Uluru N. P. area 403

vegetation pattern in the dunefields will bediscussed further in later papers in this series.

Acknowledgments

This study was completed whilst the author was aPh.D scholar at the Department of Biogeo-graphy and Geomorphology, AustralianNational University. The North AustraliaResearch Unit provided a Toyota four-wheeldrive and field gear. The Northern TerritoryReserves Board (now the Conservation Com-mission) gave permission for me to work andcollect in Uluru National Park and SeniorRanger Derek Roff and his staff provided adviceand logistic support. I should also like to expressappreciation for assistance rendered by the staffof the CSIRO Rangelands Research Unit andthe Arid Zone Research Institute in AliceSprings, and particularly for species identi-fications by Peter Latz and John Maconochie ofAZRI.

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404 R. Buckley

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Note added in proof

Since this paper was submitted for publication,the following change in nomenclature hasoccurred: Euphorbia wheeleri and E,drummondii are now Chamaesyce wheeleri andC, drummondii respectively.