Port Phillip Conservation Council Inc.

A0020093K  Victoria

 

Excerpts from the 'Port Phillip Survey 1957-1963'

by the National Museum of Victoria (Mem. nat. Mus. Vict. 27-1966)

 

Click on a blue hyperlink of interest.

 

INTRODUCTION 

  • The entrance to the bay is restricted in depth by two rocky banks of dune limestone. The 200 m wide main shipping channel passes over the outer Rip Bank and the inner Nepean Bank This channel has been deepened by blasting, over the past 60 years, from a least depth of 10 m to its present declared minimum depth of 16 m. Between the two rocky banks lies a gorge with depths exceeding 100 m, while south of Rip Bank the depths increase to approximately 30 m some 1500 m offshore. The strong tidal flow through the irregular constricted entrance produces the race, which is known as 'The Rip'.

THE GEOLOGY AND GEOMORPHOLOGY 

  • Port Phillip Bay on the South Central Victorian coast, is located in a tectonically controlled depression or sunkland, bounded by two major faults, Selwyn's Fault on the east and the Rowsley Fault on the west.
  • Selwyn's Fault trends north-north-easterly with downthrow on the north-west, and controls the northern margin of the Mornington Peninsula horst. The south-eastern part of Port Phillip Bay occupies the fault-angle depression formed on the downthrown side of the fault that cuts across the Nepean Peninsula from near Cape Schanck to Dromana. It extends north towards Frankston, on the seaward side of the Mt. Martha an Mt. Eliza grandiorites (Keble, 1950; Thomas and Baragwanath, 1950). Palaeozoic rocks are sheared near the fault contact and Tertiary sediments are warped in the area. Continuation of seismic activity to recent time was established by an earthquake in 1932 with the epicentre near Mornington on the line of the fault (Holmes 1933).
  • The Rowsley Fault, which controls the western margin of the sunkland, commences 16 km west of Geelong and continues north-north-easterly for approximately 50 km to north of Bacchus Marsh. The uplifted western block, now being dissected by rejuvenated streams, forms the Brisbane Ranges, which rise in places to 230 m above the sunkland.
  • In addition to the two major structures, several subsidiary structures contribute to the present outline of the Bay. Near Geelong in the south-west, the Lovelybanks Monocline runs north for 13 km between Corio Bay and the Rowsley Fault, then trends south-west towards The Anakies.
  • East of Geelong, along the southern shores of Corio Bay, the Curlewis Monocline controls the northern edge of the Bellarine Peninsula horst, where Miocene limestones and clays are warped down to the north and pass beneath the floor of Corio Bay (Coulson, 1933).
  • The south-eastern margin of the Bellarine Peninsula is controlled by the Bellarine Fault.
  • In the north, the Beaumaris Monocline forms a north-easterly trending structure with downthrow on the south-east and uplift on the north-west. It is expressed in cliffs near Beaumaris where Pliocene ferruginous sandstones are warped into a dome near Rickett's Point. This structure controls the coastal indentation from Rickett's Point to Mentone and Mordialloc. On the upthrown side, resistant sandstones form the cliffed headlands at Ricketts Point, while on the downthrown side Quaternary and Recent deposition has occurred at Mordialloc, Carrum and Frankston.
     
  • Evidence from coasts throughout the world has clearly established the significance of the post-glacial rise in sea level that commenced approximately 18,000 years ago when sea level was some 100 m lower than at present (Shepard, 1961; Fairbridge, 1961). The rise to near its present position has flooded river valleys, estuaries and lowlands in many parts of the world. In Victoria, both Port Phillip Bay and Western Port Bay (Fig. 1) owe their present outlines to the combined effects of tectonic movements that formed the sunklands, and the post-glacial eustatic rise that later flooded them.

 

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Pages 119-124

 

MEM. NAT. MUS. VICT. 27-1966

 

PORT PHILLIP SURVEY 1957-1963.

 

VEGETATION.

 

By J. H. WILLIS,

 

Assistant Government Botanist, National Herbarium of Victoria.

 

SUMMARY

 

A brief historical account is given of the botanical collections, followed by discussion of the vascular flora and mosses living within the marine influence. This encompasses terrestrial and salt-marsh vegetation and submarine angiosperms. Lists of species and appropriate literature references are appended.

 

INTRODUCTION

 

Except for some historical references, the present account is concerned only with indigenous vascular plants and mosses that occur either in the water or along the bounding coastline of Port Phillip a lineal distance of approximately 152 miles. The marine algae form the subject of a separate paper by a specialist in this group. If Bay-side vegetation be limited to those plants growing only within the influence of salt water (including high tides and driven spray), then the vascular flora would barely exceed 120 species, but a strip of land one mile wide all around the shore would embrace representatives of at least 550 species.

 

COLLECTORS AND INVESTIGATORS

 

No plant had been seen by white men on the terrain that is now Victoria before George Bass landed at Wilson’s Promontory in January, 1798, and James Grant visited Western Port in March, 1801, but there is a lack of evidence that either party collected botanical specimens. However, within four months of John Murray's discovery of Port Phillip Bay, on 5th January, 1802, Captain Matthew Flinders also sailed through The Heads accompanied by a botanical genius, Robert Brown.

 

During the week that H.M.S. INVESTIGATOR surveyed the southern parts of Port Phillip, Brown made the second recorded collection of Victorian plants. For the first collection credit must go to the French botanist, M.Leschenault de la Tour, who spent several days at Western Port with Captain Emmanuel Hamelin's party on LE NATURALISTE at the beginning of April, 1802, thus forestalling the discoveries of the Englishmen in Port Phillip by only a few days. Leschenault was impressed by the fertile appearance of the Western Port coasts, but said: “The number of plants which I gathered is not great.” Robert Brown ascended Arthur's Seat (27th April, 1802), and examined the vegetation of Point Nepean peninsula, but was not present when Flinders and three crewmen climbed Station Peak (You Yangs) on May 1st. Brown returned to Port Phillip for another week's botanizing early in 1804, and he left for Hobart on the LADY NELSON (27th January) with the last party of evacuees from Lieutenant David Collins's unsuccessful attempt to establish a settlement near Sorrento. It was unfortunate that Brown’s only two sojourns on Victorian soil - both brief - should have been during summer and late ran autumn when floral activity was at a minimum; but among his trophies on the latter occasion was the showy Blue Pincushion (Brunonia australis) in a new monotypic genus bearing the Latinized form of the great collector's name. While the full extent of these earliest Victorian plant collections remains unknown, there is evidence that Brown either gathered in from or noted about 100 species at Port Phillip; the type material of eighteen new species was involved, and his actual specimens of no less than 23 Port Phillip species are housed in the National Herbarium of Victoria (at South Yarra).

 

Neither surveyor Charles Grimes, who discovered the Yarra River (January, 1803), nor Hamilton Hume and William Hovell, who trekked overland from near Albury to Corio Bay (November-December 1824), made any plant collections. But Ronald Gunn collected during “a short visit to the south coast of New Holland in March, 1835” and in 1842 he published some observations on the flora of Geelong district based on 100 species, of which only the genera are listed completely. This, apparently, was the first reference published in Australia to the plant-life of the Port Phillip region. James Backhouse, a visiting Quaker missionary, spent ten days in and around Melbourne during November, 1837; his narrative (published in 1843) certainly refers to several trees noted near the Yarra River mouth, but his contribution to early Victorian botany was negligible.

 

In the early 1840's Charles Joseph La Trobe, Superintendent of the Port Phillip District and founder of Melbourne's Royal Botanic Gardens, interested himself in the local flora. Specimens of at least fourteen species that he gathered on the heathlands between Melbourne and Brighton are now represented in the Neuchatel Herbarium, western Switzerland. Also, between 1840 and 1855 an early Melbourne settler, F. M. Adamson, sent plant specimens to Sir William Hooker at Kew, England; some were from the shores of Port Phillip. In 1851 Daniel Bunce published a list of 201 species of the Victorian flora, including many from Port Melbourne, Brighton and other parts of the Bay.

 

Up until 1852, virtually all botanical (and other) collections had been taken out of the Colony to museums overseas; but the arrival from Adelaide, in August that year, of Dr. Ferdinand J. H. Mueller ushered in a new era for phytological research. Bringing with him a large private herbarium of European and South Australian collectings, also a useful reference library, young Mueller received the appointment of first Colonial Botanist on 26th January, 1853. Thereafter he threw himself into a survey of the country's flora with such zeal and efficiency that, within a decade, little remained anywhere for succeeding botanists to discover.

 

By 1861 this phenomenal man had built up in Melbourne a herbarium of l60,000 specimens that was long to remain the largest by far in the southern hemisphere. During 1862 appeared the first (and only complete) volume of his elaborate, illustrated PLANTS INDIGENOUS TO THE COLONY OF VICTORIA; a few species were quoted as from Port Phillip. In April, 1863 after just ten years in the Victorian Public Service, Mueller claimed that “the botanical Investigation of the territory of our colony is now nearly completed”; and of course his investigation included most of the species now known to occupy the coasts of Port Phillip. Up to the 1880s botanical inquiry in Victoria became almost synonymous with Mueller’s own activity in field and herbarium.

 

Of the very few other workers during the 25 year period 1853-78, mention may be made of Samuel Hannaford who brought out (1856) a catalogue of the Colony's commoner plants, and of Fanny A. Charsley whose 58 lithographic plates of Melbourne wildflowers in colour (1867) contained several undoubtedly coastal species, three being exclusively so.

 

G. H. Adcock's “Census of indigenous plants of the Geelong District” (1897), was probably the best attempt, until then, at a local flora in the Colony - with the possible exception of D. Sullivan's “Native Plants of the Grampians and Vicinity” which ran as a series through volumes 2 and 3 (1882-83) of the SOUTHERN SCIENCE RECORD, but which listed only ORCHIDACEAE among the monocotyledons. Dr. C. S. Sutton broke new ground in 1911 and 1912 by publishing the first ecological account of a major plant formation on the Bay-side: his “Notes on the Sandringham Flora” gave a detailed and informative account of Greater Melbourne's heath formation, with complete list of constituent species. In 1916 appeared Sutton's complementary and equally valuable contribution, “A Sketch of the Keilor Plains Flora”; this covered the basaltic terrain bounding the western side of the Bay. Both papers were published through the VICTORIAN NATURALIST, and drew attention to the alarming rate at which these tracts of vegetation were then disappearing. A warning of what was to come had already been sounded 30 years before by an anonymous writer in the SOUTHERN SCIENCE RECORD (Vol. 2, June, 1882):

 

“Ominous signs of advancing settlement present themselves daily. Great notice-boards announcing sales of large areas, surveyors' pegs, landmarks and re snobbishly-worded notices regarding trespassers, all justify the conviction that the once famous Brighton heath-grounds will shortly become a thing of the past. The collector will therefore do well to keep what specimens he finds … in a few years these districts will be to the collector as a sealed book.”

 

T. S. Hart's close acquaintance with the plant-life of Port Phillip is evident in several other papers to the Victorian Naturalist, notably on the protective value of coastal plants (1914) and a survey of the original extent of Yellow Box, Eucalyptus melliodora, near Melbourne (1939). In Professor A. J. Ewart's long-awaited FLORA OF VICTORIA (1931) sundry species are ascribed to the sandy heathlands and basalt plains adjoining Port Phillip. The latest and most advanced treatment of the vascular vegetation has been Dr. R. T. Patton's series of four important ecological studies - Cheltenham flora, coastal sand dunes, basalt plains and salt marsh - published between 1933 and 1942.

 

Meanwhile, the marine algae were not being neglected. The eminent philologist, Professor W.H. Harvey of Trinity College, Dublin, spent four months in Victoria between August, 1854, and January, 1855, his chief collecting places on Port Phillip being at Brighton, Geelong and Queenscliff. These localities appear among others in the five volumes of his monumental PHYCOLOGICA AUSTRALICA (1858-1863). S. Hannaford also collected some algae at Queenscliff and around Geelong between 1857 and 1863. During this period Mr. H.Watts provided observations and details of new species for Harvey's works and continued to investigate Port Phillip seaweeds into the 1880's, giving a number of algal lectures to the Victorian Field Naturalists Club of which he was an early president.

 

Dr. J. Bracebridge Wilson who organized the collection of marine specimens for the biological survey of Port Phillip, from its inception in 1888 until his death in 1895, was an assiduous algologist; his dried material at Melbourne Herbarium spans the period 1879-95, and most of it came from near The Heads. Wilson's chief literary contribution was “A Catalogue of Algae collected at or near Port Phillip Heads and Western Port”' (1892). Phycological researches were further advanced by H.T.Tisdall (1898 and 1900) and Profesor A.H.S.Lucas (1919 and 1931), while H.B.S.Womersley (1956, &c.) has more lately published numerous articles in which the seaweed flora of Port Phillip is involved.

 

R.A.Bastow gathered bryophytes and lichens - now in Melbourne Herbarium - from the Bay-side coasts at the turn of last century (1892-1905), while Dr. Ethel McLennan and Sophie Ducker have done pioneering work (1956) among the smaller soil fungi of heathlands.

 

 

MAJOR PLANT COMMUNITIES

 

Plates I –II

 

The geological formations of the Port Phillip shore-line are varied, (including as they do beach sand, dunes, calcareous eolianite cliffs, fluviatile sand (sometimes impregnated with iron and consolidated, forming bluffs where eroded by the sea), granite headlands, stony basalt plains and depositions of river alluvium. The rainfall varies from less than 17 inches per annum near Little River in the central-western sector of the Bay to 30 inches at Dromana in the south-east. Such diversity in climate and soil-types is reflected in the physiognomy and composition of the flora from place to place: there is grassland, woodland or open forest, heath, salt-marsh, also smaller aquatic, rheophytic, dune and cliff communities.

 

By far the two most extensive formations were the heath on deep fluviatile sand, stretching along the whole eastern coast from the mouth of the Yarra to Sorrento, and the grassland of the drier western basalt plains (between Newport and Geelong). Both have been discussed in detail by Patton (1933 and 1935).

 

The typical open heath, of ericoid shrubs in many plant families, blended often with a woodland in which the prevailing tree was a stunted form of Eucalyptus viminalis (the variety racemosa, principal food-plant of koalas near the coast). E. ovata was frequent on wet flats, accompanied by

E. camaldulensis with increasing clay content in soils marginal to the heathland; extensive swampy areas, as at Carrum, were dominated by dense thickets of the paperback, Melaleuca ericifolia, with associate aquatic herbs. There is evidence that the tea-tree, Leptospermum lævigatum (Pl. 1, fig. 1), an attractive and characteristic coastline tree all along the eastern side of Port Phillip, has been invading some areas of open heathland and reducing the species composition. In association with Banksia integrifolia, Acacia longifolia (var.), Styphelia parviflora and Myoporum insulare, it may frequently form a closed canopy, overhung by such creepers as Tetragonia implexicoma and Clematis microphylla and providing bower-like habitats for a few tender shade-loving species. (including corticolous bryophytes and lichens, also fungi).

 

VEGETATION

 

The heath proper was extremely rich in species, notably in the orchid, wattle, pea and epacrid groups, its facies at flowering time (July to October) recalling the colourful display of a West Australian sand-plain. Unfortunately this very attractive belt of vegetation, so interesting to the botanist, has been all but exterminated through suburban housing, draining of swamps, and agricultural developments. The few inadequate and pathetic selvages that remain are being inexorably ruined by aggressive weeds that thrive on disturbed ground (e.g., alien species of Briza, Ehrharta, Watsonia, Phytolacca, Oxalis, Salpichroa, Coprosma, Senecio and Chrysanthemoides).

 

The basalt grasslands on the western side have also been profoundly altered through grazing, building operations and the influx of numerous weeds, (e.g., Avena, Bromus, Diplotaxis, Trifolium, Lycium, Arctothcca, Cynara, Tragopogon and many other members of Compositæ). This tract of grassland was quite deficient in shrubs and very much poorer in species than the heath, to which it formed a striking contrast - the two formations were separated by salt-marsh and riparian scrub at the mouth of the Yarra.

 

Small occurrences of mangrove (Avicennia marina) accompanied the halophytic vegetation under tidal influence in Swan Bay and at the mouth of Kororoit Creek (near Seaholme), but Avicennia was virtually destroyed at the latter place by a thick deposit of oil discharged into the Bay about June, 1950 - see comments by Willis (1951), and Fawcett (1951). Dominants of the saline marsh (pl. I, fig. 2) are chiefly members of the Chenopodiaceae (viz., succulent species of Arthrocnemum, Salicornia and Suaeda), but Disphyma (pl. II, fig. 1), Frankenia, Wilsonia and Selliera may each form extensive almost pure societies. This formation keeps remarkably free of weeds, Atriplex hastata being one of the few successful alien intruders. Patton has dealt with the coastal salt-marsh “in extensor” (1942) , and also with the sand dune flora (1935) - a pioneer community of relatively few hardy species and some weeds (e.g., Lagurus, Melilotus, Arctotis. Marram Grass (Ammophila arenaria) has been deliberately planted on some unstable dunes to prevent sand drift.

 

Even more limited is the strand flora on beach sand within the influence of high tides. Only about seven species are concerned in this zone, the most interesting component being probably Coast Spinifex or Silver Grass (Spinifex hirsutus) (Pl. II, fig. 2) which sends its robust cord-like rhizomes for yards across the bare sand. Sea Wheat-grass, Agropyron junceum, is an introduction that occasionally serves to stabilize sand washed by high tides; it has been noted at Beaumaris, Seaholme, St. Leopards and Queenscliff. Atriplex cinerea and two species of Cakile (Sea Rocket) have a remarkable capacity for rapid colonization of loose beach sand.

 

The cliffy sections of the Bay exhibit a varied assortment of shrubs and herbs, some being confined to such habitats as are within reach of blown spray, e.g., Alyxia buxifolia and Calocephalus brownii. (Pl. II, fig. 2.) Many plants encroach onto sea-cliffs from the surrounding formations, notably heathland; and it is sometimes difficult to decide whether a particular species is to be regarded as an intruder or a natural component of the cliff flora. Some eucalypts and acacias are undoubtedly intruders, although they may reach the cliff-edge - perhaps through natural erosion by the sea. Probably the rarest among Port Phillip’s cliff-dwellers is Lasiopetalum baueri, of which only two old bushes are now known to survive (at Red Bluff, Sandringham).

 

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List D (Dunes and sea-cliffs (68 species):

 

The 15 species below are those from List D that seem to be  most characteristic of heath areas.

 

Lepidosperma gladiatum        Coast Sword-sedge

Lomandra longifolia               Spiny-headed Mat Rush

Dianella revoluta                    Black-anther Flax Lily

Acianthus reniformis               Mosquito Orchid

Calidenia latifolia                   Pink Fairy Orchid

Pterostylis cucullata               Leafy Greenhood Orchid

Clematis microphylla              Small-leaved Clematis

Pultenea tenuifolia                  Bush-pea

Kennedia prostrata                 Running Postman

Pelargonium australe             Austral Stork’s Bill

Lasiopetalum baueri               Slender Velvet-bush

Dichondra repens                    Kidney-weed

Solanum laciniatum                Kangaroo Apple

Lobelia alata                           Angled Lobelia

Olearia ramulosa                    Twiggy Daisy-bush

 

References: (Selected examples only appear here)

 

Audus, J. W. 1933. Excursion to Frankston.  Vict. Nat.  50:  172

Daley, C.,     1920. Excursion to Rosebud.   Vict. Nat.  37: 23-27

Patton, R. T. 1933. Ecological Studies in Victoria, Part I. (The Cheltenham Flora)  Proc. Roy. Soc. Vict. new ser.  45:  205-218

Sutton, C. S. 1911. Notes on the Sandringham flora.  Vict. Nat. 28: 5-20

Sutton, C. S. 1912. Supplementary notes on the Sandringham flora.  Vict. Nat. 29: 79-96

Tisdall, H. T. 1900. Excursion to Blackrock.  Vict. Nat. 16:  183-84

Willis, J. H.   1945  Excursion to Beaumaris (regeneration of plants on fire area).  Vict. Nat. 61: 162-63

 

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Last updated on 2000-04-16:  www.vicnet.net.au/~phillip