The Vegetation of the Fitzgerald River National Park, Western Australia
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Kingia1@); 141-153 (1990) 141 The vegetation of the Fitzgerald River National Park, Western Australia T.E.H. Aplint and K.R. Newbey2' I Westem AusrralianHerbarium, Deparrnenr ofConservarion and tjnd Management, P.O. Box 104, C,omo,Wesrem AusEalia 5152 Pres€nr addrcss: 87 Clydatlale Stre€r, Como, Wesrem Australia 6152. '?Cl- Westem Ausralian Herbarium, D€parrment ofconseFarion and Land Managemed, P.O. Box 104. Como. Westem Australia 6152. Abstract Aplin, T.E.H. ad Newbey, KR The vegetaticn of dre Fitzgenld River National Paft, Weslern Austalia- Kingia 1(2): 141-153 (1990). A vegetation map of lhe Fitzgerald River National Part which accompanie,sthis psper shows 12 major plant corrmmities. A kiefaccount ofeadr ofthesedan| corftnmities d,epicledin fiatmap is provided The vegeration fornatims ngefrom woodlard ro heath, with the pedominxrt fomation being lal shflblard. Not€s on t}le physical environment are also includei. Introduction TheFitzgeraldRiverNationalPark(Park) ,of244,677 ba,]nesjn the central sourl coastofWesrem Australia, betwe€ndte towns of Bremer Bay and Hopetounalong the coastand Jenamungupand "C" Ravensthorpeinland (Figure 1). The Park was gazetteda classreserve for tie preservationof "A" flora and faunain 1954,and in 1973was madean classreserve and vestedin the National parks Authority of Westem Australia. It is registeredas an Intemational BiosphereReserve with the United Nations Educational Scientific and Cultuml Organization, the frst to be so approved in WestemAustralia. In 1970 a botanical survey w:ls conductedby the Westem Australian Herbarium !o obtain an assessmentof the botanicalresources in the Park. The vegetationmap which accompaniesthis paper was compiledby Aplin in the courseof that survey. Sincethen Newbey (1979) undertook a study of the vegetationof the central southcoastal region and someof his results havebeen incorporated in this paper. This is the frst ofa seriesofthree paperson the vegetationand flora of thepark. Accounts of the flora arepublished separately (Aplin andNewbey 1990,Newbey 1990). Historical Not€s West, Middle and East Mount Barren, three prominent featuresin rhe park, were named by Matthew Flindersin 1802. Their namesindicate his descriptionsof them. In 184 I , during his historic "barren, overland joumey, E.J. E)'re traversedthe Park. He describedit as worthless countrv". Eyre recordedtie presenceof Australian aboriginesat Culham Inlet. * DeceasedJuly 23, 1988 KingiaVol. 1,No. 2 (990) FiguIe l, Map sbowing loc-ationof Fitzgenld River Nadonal Park Many of the physical featues of the Paft, including the Fitzgerald River were namedby the surveyo; J.S. Roe who visited the areain 1847' Roe reported the presenceof good grazing land River to the north-\xestof $e PaIk. This was taken up as a pastoral leaseby along the Gairdner " J. Ilassell in 1849.I{assell named the property Jarramungup Spring, from fte aboriginalword yarra- "moitch "moitch" moitch" which means on high ground", beingtacalyptw occidentalis. The overlandtelegraph line lvhich Ian mole or lessparallel to thecoast was completed in I 877and remainedin useuntil 192?. Following the discoveryofgold andcopper at Ravensthorpe,the Phillips River Goklfield was declaredin 1900. Ravensthorpe,and its port, Hopetoun,were designatedtown sitesin 1901. Their connectingrail link, openedin 19@,rcmained in useuntil 1936. In 1902,!o prevent the westward movement of rabbits, the Number T'ro Rabbit Ploof Fence which traversedthe westemportion of the Parkinland to the coastwas constructed. It wasmaintained until 1955. Large areasof vacantCrown Land along the south coastalregion were releasedfor agricultural developmentin the 1950'sand 1960's.The main reason why thearea ofland occupiedby thePaIk was not tak€nup for farming wasis harshterrain. T"B.H.Aplin & ICR Newbey,The veg€tation of dle FiEgeraldRiver NaiionalPark Botanical collecting in the Park commencedin 1829but the fi$t vegetationmap of the areawas publishedat l:250,000scale using photo-mosaics (Beard 1972). Prior to that,most accounts of the vegetationofthe areawere sketchy (Gardner 1944, Anon. 1965). Grazing by introducedlivestock in the Park hastteen confined !o small areasalong the Phillips, Fitzgerald andHamersley Rivers. As a consequencemost of the vegetationin the Park hasremained relatively undisturbedand has not beeninvaded by alien plant species. Mining activities in the Park havebeen mainly exploratory. Thesereached their peakin f969-70 when about3 1,200 ha or 137o of thearea of thePark was pegged for mineralexploration. At that time it was proposedto open-cutmine lignite in the Fitzgerald River valley. Fortunately, subsequent drilling testsproved the lignite depositto be uneconomic(Cockbain and Van de Graaff 1972). Actnl mining operationsin the Park haveinvolved the mining of copperat West River from 1908ro 1909 (Sofoulis 1958)and the quarrying of spongoliteat Twertup Creekfrom 1965 ro 1978. Exploratory shaftshave been sunk at Naendip,for copper,and at CoppermineCreek, for manganese. A Field StudiesCentre was esablished in 1981at TwertuDCreek by fte FitzseraldRiver National ParksAssociation. There arethree resident National Parkrangers who maintain the facilities in the Park. andreside in the Park. PhysicalEnvironm€nt Geology The geology of south-westernAustralia was reviewed by Johnstoneet sl. (1973), alld it is essentiallyfrom this work that the following accounton the geologyof the Park hasbeen taken. The ArchaeanYilgam Block is representedalong the northemportion of$e Park. Composedof gneissesand migmatites, with minor infoldedbelts of metasedimentswith different gradesofregional metamorphism,it has a generalnorth-west strike. Along the southem margin ofthe Yilgarn Block the Proterozoicmetamor?hics of the Albany-EsperanceBlock hend north-eastto south-eastand eastto west,almost at right anglesto tle Yilgam Block. The gneisses,granites and metasediments of the Albany-EsperanceBlock aredated at about 1,150 million years.The variation in mineralassociation and metamorphicgade is matchedexacdy by similar east-westtrending rocks in easternAntarctica, providing one of the stongest piecesof evidencefor the geologicalfit of Australia andAntarctica in the reconstructionof Gondwanaland. No sedimentsof Triassic to Neocomianage are known from the southcoast, although evidence obtained from eastof the Eucla Basin show that rift valley formation commencedas eady as late Jurassic. Theserift valleys were the precursorsof the spreadingwhich separatedAustralia from Antarctica, and stratigraphic evidence points to a pronounced marine gulf during the t ate Cretaceous. Australia becameisolated from Antarctica by the uppennostCretaceous with only a tenuouslinkjoining Tasmaniato Antarcticaalong a transformfault. The absenceof warm water indicalors in the Late Cretaceousfaunas could be due to water circulalion, asit is unlikely thatwarm watersfrom theIndian Oceancould have circulated freely in the narrow gulf until at leastthe middle Eocene.Marine sedimentsoflate Eoceneage, of thePlantagenet Group, which are well representedin the Park, consist of fine sandstone,mudstone, siltstone, I t44 KingiaVoL r, No.2 (1990) spongoliteand minor limestoneup to 100m tlick with a faunaatiesting to warm watersedimentation. This marine transgessionextends up to 270 km inland from the presentcoast line. Old beachlevels associatedwith ihis cycle of sedimentationare now at abut 150m. Laterization of the Late EocenePlantagenet Group probably occurred in the Oligocene and Early Miocene,as Middle Miocene sandstonesin the adjoining Eucla Basinare not lal€rized. A wide variety of Qualernaryunits developedaround the coasbl margin, with the dunesystem of the south coast tentatively referredto the Pleistocene. The geology of the Ravensthorpearea has been dealt with by Thom et al . (1977) while Sofoulis ( 1958)has discussed the mineral depositsof thePhillips River Goldfield. Topography ThePark lies within SwanlandofJutson(1950) and the South Coast Drainage System ofBettenay andMulcahy (1972). The opography of the CentralSouth Coastal Region was reviewed by Newbey ( 1979) andthe following accountis extractedfrom his work. The southemportion of thePark is dominatedby peaksand ridges of quartziteand phyllitic schist, which rise from 300 to 450 m aboyesea level. They include West, Middle and East Mount Barren, Mount Bland, Woolbemup Hill and the moogarup and Eyre Ranges,with Thumb Peakrising to 457 m. The peaksandridges have slolrs rangingfrom 7'to 30', thesteeper slopes becoming rockier. The coastlinebacked by theseranges is steepand rugged. Thereis an extensivewave-cut platform about60 m abovesea level. Away from the ridges the coasdinehas a narrow dunesystem. To the north of the rangesis an extensiveslighdy elevatedplain with the marginsdnining into the river systems.Drainage on the plain is local into scatteredephemeral swamps or, if unco-ordinated, gilgais. The swampfloors areapproximately 2 m below the generallevel of the plain. The two major watercourses,the Fitzgerald and HamersleyRivers, eachmeander in a geneml north to southdirection in narrowchannels in broadflat-floored gorgeswalled by spongolitecliffs, or st€eprubble slopes, 10 to 50 m high. Smallmesas and buttes are present in thegorges. ThePhillips, West, Gairtlner and Bremer Rivers each also faverse parts of the Park. All of the rivers are intermittendy flowing andsaline; all terminatein inlets which arefrequently cut offfrom the Southem Oceanby sandbars. The Stirling Scarp,consisting ofa steepto a moregende granite slope, marks the boundaryof the Yilgarn and