I Journal of the Royal Society of Western Australia, Vol. 4, Part 1, 1981, pp. 5-ll.
---- 1) ------rProlok,,l ggj''li rake~ rga/1. ( A.1oi.1 peripheral vegetation of Peel Inlet and Harvey Estuary, Western Australia
Dbt~ by D. J. Backshall and P. B. Bridgewater IistD nurn, School of Environmental and Life Sciences, Murdoch University, Murdoch, W.A. 6153
I, I, Manuscript received 25 July 1979; accepted 27 November 1979 SOllle I. Abstract Fifteen vegetation units, distinguished by differences in the floristic composition of vascular plant species, have been recognised from the Peel Inlet-Harvey Estuary system, Western Australia. Analysis of the epontic diatom flora within units confirms their integrity. The spatial distribution of these vascular-plant communities around the estuarine system appears to be controlled by the substrate summer salinity values, together with the vertical distance Ieath from the high water mark. Evidence from aerial photographs extending back 23 years The suggests that dynamic processes are less important than these spatial controls in determining community distribution. Exceptions to this occur only when sudden major geomorphic changes force concomitant vegetation changes.
Introduction considered to represent the least disturbed examples During 1977-78 an investigation was undertaken of a variety of soil and vegetational types. Soils of the peripheral vegetation and associated diatom of the estuary fringe are referrable to three soil flora of the Peel Inlet-Harvey Estuary System, West systems-Bassendean and Spearwood Dune systems ern Australia. This estuarine system comprises two and Pinjarra Plain soil system (McArthur and large shallow basins of 65 km2 (Peel Inlet) and Bettenay 1960). Site selection was made by field 50 km' (Harvey Estuary), joined to the sea by a reconnaissance, coupled with use of colour aerial 5km inlet channel. The basins are connected to photography taken in 1976 by the Western Austra each other by a narrow channel, which cut through lian Lands Department. The transects comprised a broad, barely submerged marginal shelf. The sedi regularly spaced releves (samples) one metre square mentology of the area has been described by Logan and spaced 5 or 10m apart, depending on the and Brown (197 5). This survey was confined to the abruptness of vegetation change. A total of 747 tidal marsh environment of both Peel Inlet and releves were collected from the estuaries. Species Harvey Estuary. cover-abundance were recorded for each releve using Ecological studies of Western Australian vegetation the Braun-Blanquet scale (Bridgewater 1971). A have shown considerable methodological variation, set of computer programs was used to print tables from empirical analysis of transects (e.g. Sauer of species and releves for each transect. These 1964), classifications based on dominant strata using tables were then examined, and 'potential differential a range of criteria (Gardner 1942, Speck 1952, species'
y Diatom comm~~~ !ant commun1t1 ~nvironmental c showed that )Jen than 2mm mtc a micro-habttat marshes in the be buffered to 193 1 levels in the s' 31 / tonic forms i!-1! / benthic cond1t1 E / ceivably affect -- / I - / p / I / I / / M I / Aclmanthes longipei 5 ..---- Mastoglia ignorata 79 I Amphora javanica 1 151-- Navicula marina R; -I Cocconeis speciosa 15 9 X Nitzchia sp. 6 N. {ongissima (de I 12 Diploneis crabro E 11 30/ Nitzchia subvitrca 30 I Dipfoneis sp. I 15 Nitzchia vitrea No 15 I Cymbella subturgic Navicula sp. I Cocconeis dis tans · 36 6 \ Nitzchia sigma vat t 10 so Aclmanthes sp. 2 5 1 \ Amplziprora angus 12 Achnanthes sp. 3 33 7.8 Opep/wra sp. I lg 46 Synedra sp. I Is A1wmoenis sp. 1 Genus A P/agiogramma sp. Nitzchia closteriw Amplwra gigantec Genus B Mastoglia sp. 2 lYI. pseudoparado. Navicula sp. 2 N. vulpina Kutz. Fragil/aria sp. l Nitzchia gracilis N. sp. 4 Diploneis smirhii Nitzchia sp. l Navicula e/egans Nitzchia brebissc 13 19t N. sp. 5 12 Amphora pro trw Figure 2.-Principal Axes Ordination of the 15 vegetation units. Figures in bold type represent vegetation units. (see Tab!~ ,2t), Ac!manthes brcv, Figures in lighter type represent values for chlorinity and total ions (Meq. L-1j !-'Mhos x 10-2). Dashed Jines define sahm y, Amphora macile where E equols euh~line, P equals polyhaline and M equals mesohaline. Cocconeis scutel Thalassothrix sp Cocconeis dehes Epithemia sp. l Cocconeis apicu Navicula sp. 3 Nitzchia comprt Pleurosig111a str1 ~ Epithemica sp. ' Aclmanthcs sp. Grammatophorc Pinnularia {egll1 P. splendida Ht Sandy Cocconeis p/ac~ ~n Tidal Marsh Sclt Pan Older Dunes Navicula lrra v E Beach Rtdge Pimmlari<:p ~ / E ~ Cocconeis "P· Fignre 3 ,-Schematic diagram of important physical features of the peripheral estuarine environment, vegetation. unidts th~~ GramlllafntJ!/01 salinity types along a hypothetical transect. Figures denote the vegetation units, while the salinity types are md1cate · M equals mesohaline, P equals polyhaline, E equals euhaline. 8
J 1.4 4Y §2 T -- Journal of the Royal Society of Western Australia, Vol. 4, Part 1, 1981. piatom communities and floristically defined vascular caveats in mind, an analysis of diatoms found in ;nt communities may well be affected by different each of the 15 vegetation units was attempted. Pn'vironmental1 conditions. Aleem ( 1950), however, ehowed that benthic diatoms seldom penetrate deeper Four widely distributed replicate sites were chosen 5 h.10 2 mm into the marsh surface. Diatoms form for each of the vegetation units noted in Table 2. 1 'micro-habitat of mucilage on the surface of salt Soil surface scrapings from each site were cultured ~1 arshes in the Peel-Harvey system, so they could in petri dishes in the laboratory. A sterilised solution be' buffered to ~orne extent from the high salinity of ~sugar and yeast extract was applied as required, levels in the soils of the mature marshes. Plank to keep the scrapings moist for a period of three tonic forms J:?!!Y also be .temporarily deposited in weeks before being examined. In this way, species benthic cond1tlons, and, If sampled, could con dormant in the soil were encouraged to become ceivably affect the results obtained. With these active and more readily observed. Table 3. Diatom species located in vegetation units Vegetation units (see Table 2)
1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 [wj_~Lj~~I~-
Aclmanthes. longipes Agardh + ]![astoglw .rgnm:ata Rust . ... . + Amphora Javamca A.S...... + j Navicula marina Ralfs in Pritchard + Cocconeis speciosa Gregory + Nitzchia sp. 6 ···· ···· .... ···· ···· ···· + X N. /ongissima (de Brebisson ex Kutz) Ralfs in Pritchard + Diploneis crabro Ehr...... + Nitzchia subl'itrea Rust. + L, Dip/oneis sp. I .... + 9 Nitzchia vitrea Norm. ... + Cymbella subturgida Rust. + Naricula sp. I + Cocconeis distans A.S...... + Nitzchia sigma var. rigida Grun. ex Van Heurck + Aclmanthes sp. 2 ...... + Amphiprora angustata Hendey + Aclmanthes sp. 3 + Opeplwra sp. 1 + Sl'nedra sp. I + inomoenis sp. 1 + Genus A + Plagiogramma sp. 1 ...... + Nitzchia closterium (Ehr.) Wm. Smith -t- Amphora gigantea Grun. in A.S. +I+ Genus B + + Mastog/ia sp. 2 + + ]\[, pseudoparadoxia Rust. + + Nm•icula sp. 2 + + N. vulpina Kutz. + Fragillaria sp. 1 + Nitzcltia gmcilis Hantz. + ····j.... N.sp. 4 ...... + Dip/one is smithii (de Brebisson) Cleve + + Nitzchia sp. 1 ...... + + Nm•icula elegans Wm. Smith + + + + Nitzchia brebissonii Wm. Smith + + N. sp. 5 ...... + + + )\e 2). Amphora proteus Gregory + + + Aclmanthes bret'ipes Agardh + + •linity, Amphora macilenta Gregory + + Cocconeis scutellum Ehr . .... + + ····j + + Thalassot!trix sp. 1 .... + + l .... + + Cocconeis debesi Rust. + + + Epithemia sp. 1 .... + + + Cocconeis apiculata A.S...... + + + Nm•icula sp. 3 ...... + + + + Nitzchia compressa (Bail.) Boyer + .... I+ + + + Pleurosigma strigosum Wm. Smith I~ + + + + + Epithemica sp, 2 ...... + + + + + + Aclmanthes sp, 1 ...... + G;ammatophora macilenta Wm. Smith + + + + + Pmnularia legumen Ehr. + + + + + P. sp/endida Hust...... + + + Coc~oneis placentula Ehr. + + N_m'tcula lyra var. elliptica A.S. + l Pmnularia ambigua Cleve .... + +I+++ + + + + +I++ + Amphora graeffii (Grun.) Cl. + A. sp. 2 .... + j···· + + + + + Nitzchia sp. 2 + + + N. sp. 3 .... + + + A1elosira sp. I ...... + + Cymbel/a yarransis A.S.Ci. + + Genus C + + and Cocconeis sP:··I :::: :::: :::: thus: Grmnmatoplwra marina (Lyngb.) Kutz + 1•••·1····1+ .... +
9 Journal of the Royal Society of Western Australia, Vol. 4, Part 1, 1981.
Where species identification was not possible a maritimus community will inevitably result in shore w. code . name was used. Descriptions and drawings of line re~ression, and consequent build-up of silt i~ unidentified diatoms may be found in Backshall other s1tes. 0977), or copies may be acquired from the authors. Identification of species was achieved using This effect is another problem associated with the the following works: Crosby and Wood (1959), occurrence of Cladophora mats. Regeneration of the Wood et a/. 0959), Wood (1961a, 1961b, 1963) shoreline appears rapid in regions where the Sali and Hendey (1964). comia ~uinq!teflora-Suaeda austrqlis community occurs (I.e. m areas where shorelme stabilization The distribution of diatoms (Table 3) shows that is proceeding naturally), but is lacking on the eastern more than 50% of the species were unique to in shore of Peel Inlet. The introduction of colonising dividual vegetation units, although approximately VI species (e.g. Suaeda australis, Atrip/ex hastata) v. half of these were accounted for by groups 1, 5, and into freshly deposited Cladophora mats could be ~ B 6. Unique species present in groups 2 and 4 add useful management tool in preventing erosion and s justification for distinguishing these vegetation units. aiding rapid assimilation of the Cladophora. ' F Groups 10, 11, 14, 15 are, however, distinguished only by their paucity of diatom flora. This is probably a reflection of long periods of surface Acknowledgements.-Thanks are due to Mr. J. Johns for desiccation on these more elevated sites. Nitzchia assistance with diatom taxonomy, and Mr. P. Wilson for discussions on the Chenopodiaceae of the south-west. Dr R compressa, Cocconeis p/acentula, Pinnularia /egumen Fields provided valuable background data for the siudy and P. splendida indicate some affinity between area. Special thanks are due to Ms. K. Gom and Ms. J groups 1 and 6. The Arthrocnemum bidens com Jolly for typing and cartographic assistance. ' munity (group 1) is typically found on the emerg ing fringes of salt marsh concavities, while Salicor nia-Suaeda community (group 6) occupies a similar References zone on the emerging banks of the estuaries. The Aleem, A. A. (1950).-The diatom community inhabiting mud suggested similarities may be because the communi r?!~18B~ Whitstable, Kent. New Phytol., 49: ties occupy sites of regular water fluctuation while Backshall, D. J. (1977).-The Peripheral vegetation of the differences in salinity of these 2 habitats appear to Peel-Harvey Estuarine system. Unpublished B.Sc. be reflected by differences in the diatom flora of Honours thesis, Murdoch University, the communities. Similarly, although the Sa/icornia Beard, J. S. and Webb, M. J. (1974).-Vegetation Survey of Western Australia: Great Sandy Desert-Part I Suaeda community and the Sa/icomia quinqueflora Aims, objectives and methods. University community may have unique species of diatoms, a Western Australia Press, Perth. clear relationship between them is indicated by the Beeftink, W. G. (1962). Conspectus of the phanerogamic common presence of Amphora proteus, Nitzchia salt plant communities in the Netherlands. Bioi. sp. 5, Cocconeis scutellum, Achnanthes brevipes, Jaarboek Dodonacea, 30: 325-362. Blackall, W. and Grieve, B. J. (1974).-How to know Western Amphora macilenta and Thalassiothrix sp. 1. Both Australian Wildflowers. Parts I, II, III, University vascular-plant communities are found at similar Western Australia Press, Perth. elevations above high water mark, but with different Bridgewater, P. B. (1971).-Practical applications of the soil salinities. ZUrich system of phytosociology, Proc. Roy. Soc. Viet., 84: 255-262. Bridgewater, P. B. (1974).-Peripheral vegetation of Western The overall distribution of diatom species is port Bay, Proc. Roy Soc. Viet., 87: 69-78. similar to that reported by Round <1960) with many Carter, N. (1948).-A comparative study of the algal flora species exhibiting a strong preference for different of two salt marshes. J. Ecol., 20: 341-70. habitats, while others demonstrate a wider tolerance. Ceska, A. and Roemer, H (1971).-A computer program Lack of the common planktonic genera Rhizosolenia, for identifying species-releve groups in vegeta Chaetocerous and Coscinodiscus would seem to con tion studies. Vegetatio, 23: 255-277. Chapman, V. J. (1938).-Studies in salt marsh ecology, !. firm that the species encountered are indicative of Ecol., 26: 144-179. surface changes, rather than planktonic drift-ins. Chapman, V. J. (1962).-The Algae. MacMillan Press, London. Crosby, L. H. and Wood, E. J. F. (1959).-Studies of Interaction of peripheral and submerged vegetation Australian and New Zealand diatoms. II. Nor mally Epontic and Benthic genera. Trans Roy. One of the major environmental problems in the Soc, N.Z., 86: 1-58. Peel-Harvey system is high productivity of the alga Gardner, C. A. (1942).-The vegetation of Western Australia C /adophora. During winter storms massive amounts with special reference to climate and soils. !. of algal material are deposited on shorelines, often Roy, Soc. West Aust., 28: xi-lxxxvii. Grieve, B. J. and Blackall, W. (1975).-How to Know Westall with severe results on the !uncus maritimus com Australian Wildflowers. Part IV. UniversitY plex. Massive deposition can cause death or debili Western Australia Press, Perth. tation of the !uncus and consequent erosion. Coloni Havel, J. J. ·(1975).-Site-vegetation mapping in the northern sation of the large masses of Cladophora is often Jarrah Forest (Darling Range). 1. Definition of effected by Atriplex spp. and Suaeda australis. This site-vegetation types. W.A. Forests Department latter species commonly colonises organic deposits, Bulletin 86. Hendey, N. I. (1964).-An Introductory account of the smalle,r e.g. Zostera deposits at Westernport Bay, Victoria. algae of British Coastal Waters. Fishery Investi At some points on the shores of Peel Inlet Scirpus gations, Series IV. H.M.S.O, London. maritimus appears to also colonise areas of light Logan, B. W. and Brown, R. G. (1975).-Interim report oil investigations of the sedimentology of Peel a!ld Cladophora deposition. There appears to be a com Harve)' inlets. Mimeo. Geology Dept., UniversitY petitive interaction between S. maritimus and J. Western Australia, Perth. maritimus on these sites which warrants further Maarel, E. van der (1969).-0n the use of ordination models investigation. Degradation of the established !uncus in Phytosociology. Vegetatio, 22: 275-283. 10 of Western Australia, Vol. 4, Part 1, 1981.
w. M. and Bettenay, E. (1960).-The development Wood, E. J. F., Crosby, L. H. and Cassie, U. (1959). sult in shore. and distribution of the soils of the Swan coastal Studies on Australian & New Zealand diatoms. plain, Western Australia. CSIRO Australian Soil III. Descriptions of further discoid species. Trans, up of silt in Publication, 16. Roy. Soc. N.Z., 87: 211-219. and Ellenberg, H. (1974).-Aims and Wood, E. J. F. (1961a).-Studies on Australian & New Zea of Vegetation Ecology, Wiley, New York. land diatoms. IV. Descriptions of further seden ated with the tary species Trans. Roy. Soc. N.Z., 88: 669-698. !ralion of the F. E. (1960).-The diatom flora of a salt marsh on the River Dee. New Phytol., 59: 332. Wood, E. J. F. (1969b).-Studies on Australian & New Zea ere the Sa/i. land diatoms. V. The Rawson collection of J (1%4).-Geographical reconnaissance of W.A. sea- recent diatoms. Trans. Roy. Soc., N.Z., 88: 699- community . shore vegetation. Aust. J. Bot., 13: 39-69. stabilization 712. >n the eastern N H. (1952).-The ecology of the metropolitan sector Wood, E. J. F. (1963).-Studies on Australian & New Zea of colonising · of the Swan Coastal Plain. M.Sc. Thesis, Uni land diatoms. VI. Tropical & subtropical versity of Western Australia. species. Trans. Ro)•. Soc. N.Z.,, 90: 190-218. ex hastata), v. and Maarel, E. van der (1973).-The Braun ; could be a Blanquet approach. In Handbook of Vegetation Wood, E. J. F. (1964).-Studies in microbial ecology of the erosion, and Science, V, Classification and Ordination. (Ed. Australasian region. Nova Hedwigia,, VIII: 453- lwra . R. H. Whittaker), 617-726. W. Junk, den Haag. 568.
. J. Johns for p. Wilson for h-\\cst. Dr. R. for the study m and Ms. J,
nhabiting mud Phytol., 49: etalion of the published B.Sc, y, lion Survey of Desert-Part I University
phanerogamic herlands. Bioi.
know TVestern III, University ltions of the 'roc. Roy, Soc.
n of Western- 87: 69-78. he algal flora 341-70. mter program Jps in vegeta~ 7. :h ecology, J,
Millan Press,
).-Studies of Jms. II. Nor l. Trans Roy .
.tern Australia and soils. J. ?ii. ~now Western f. University
the northern Definition of i Department of the smaller shery Investi m. ·im report on of Peel and )t,, University
1ation models 5-283. 11