Botanica Marina Vol. 41, 1998, pp. 89-93 © 1998 by Walter de Gruyter · Berlin · New York

Biodiversity of Australian Marine Macroalgae - A Progress Report

J. M. Huismana'*, R. A. Cowana and T. J. Entwisleb

a School of Biological and Environmental Sciences, Murdoch University, Murdoch, Western Australia, 6150, Australiab Royal Botanic Gardens Melbourne, Birdwood Ave, South Yarra, Victoria 3141, Australia* Corresponding author

The biodiversity of Australian macroalgae is assessed by reference to species numbers recorded for the variousbiogeographical and political 'regions. The figures show a marked disparity between northern and southernAustralia, with the former apparently depauperate as compared to the rich flora recorded from southernAustralia. Whilst a reduction in species numbers is expected when comparing tropical to temperate regions,the situation in Australia is greatly exaggerated by relative levels of collecting and research effort. The comple-tion of an Australia-wide macroalgal flora will be severely hampered until additional effort is directed towardsthese unexplored regions.

IntroductionRecent years have seen the promotion of biodiversitystudies as essential to the future well-being of the pla-net. Recognition that human survival rests on ourpreservation of the diversity of the natural world isnot new — but that it is now discussed in political aswell as scientific arenas most certainly is. But what isbiodiversity? Simply put, biodiversity is the varietyof life — an uncomplicated definition for a complexsubject. The study of biodiversity includes a widerange of scientific disciplines, from taxonomy andsystematics, to conservation genetics and ecosystemecology. Long-term conservation and prudent man-agement of biodiversity depends upon a throughknowledge of genetic, species and ecosystem diver-sity. Generally, the first step is to enumerate anddocument the species. The 'Systematics Agenda2000', an ambitious program initiated by several in-ternational systematics societies (The American So-ciety of Plant Taxonomists, the Society of SystematicBiologists, and the Willi Henning Society), has as itsaim 'to discover, describe and classify the world's spe-cies'. It recognises three 'missions' integral to this en-deavour.

1. Discovering biological diversity, through surveys,inventories, collections, and the description ofspecies.

2. Understanding biological diversity, through phylo-genetic studies, classification, and monographing.

3. Managing systematic knowledge, through the as-sembly of knowledge into databases and its avail-ability via international information networks.

Once established, this information can then be ap-plied, if appropriate, in the sustainable utilization ofbiological diversity.

These tasks, although interrelated, can only becompleted sequentially. Without at least some pro-gress in the 'discovery' phase, no further studies canproceed. Within this framework we will present asummary of the current level of knowledge regardingthe biodiversity of the Australian marine macroalgae.Our results refer only to 'species diversity' or 'rich-ness', which equates to the total number of speciespresent in a given area (Silva 1992).

Biodiversity of Australian marine macroalgae:Present situation

Australia, as is also true for many other countries, isprimarily in the 'discovery' and 'understanding'phases of biodiversity studies in the macroalgae. De-spite a long history of phycological studies (seeDucker 1979, 1988, 1990 for further information) andthe recent publication of several excellent regionalstudies (e.g. Womersley 1984, 1987, 1994, 1996; Mil-lar 1990; Cribb 1983; Price and Scott 1992), thereremain large geographical and taxonomic gaps in ourunderstanding of Australia's macroalgae. To illus-trate the geographical disparity in macroalgal re-cords, we have constructed a chart that gives thespecies numbers thus far recorded in each of the Aus-tralian biogeographical and political regions (Table I,Fig. 2). We have used the provinces as described byWomersley (1981) and have made a further divisionbased on political boundaries (Fig. 1). We have incor-porated the Great Barrier Reef province with the So-landerian province, as the distinctness of these re-gions has been questioned by several authors (e.g.Womersley 1981) and have separated the Maugeansubprovince as 'Flindersian Victoria' and 'Flin-dersian Tasmania' (Fig. 2). Our purpose in presentingthis data is not to attempt an accurate assessment of

90 J. M. Huisman et al

Table I. Accepted names recorded for each of the regionsand percentage of the Australia-wide total.

Region

Queensland DampierianQueensland SolanderianQueensland PeronianNew South Wales PeronianVictoria FlindersianTasmania FlindersianSouth Australia FlindersianWestern Australia FlindersianWestern Australia DampierianNorthern Territory Dampierian

RecordedTaxa

10543225246863850878566718490

Percentof total

5.924.314.226.335.928.644.237.610.45.1

not a 'real' evaluation of the north-west algal flora —even a conservative estimate of species numbers fora tropical region of that size would give a total ofover 300. Womersley (1981) suggested that northernAustralia might only support around 200 species, butthis was regarded as a severe underestimate by King(pers. comm. cited in Bolton 1994). Comparisons be-tween the algal flora of the Australian DampierianProvince and its relatively well-studied counterpartsin Indonesia and the Philippines — regions reason-ably likely to have similar algal floras — clearly dem-onstrate the paucity of knowledge regarding northernAustralia (Table II). Likewise islands in the region(Table III) — the algal floras of Christmas and Cocos/Keeling Islands are virtually inknown. Thus the

the diversity of the macroalgae, but to illustrate thelevel of completion of the discovery phase. The re-sults are drawn directly from the 'Australian MarineAlgal Name Index3 (AMANI) a database of all themarine macroalgae recorded from Australia. This da-tabase is being prepared by the second author (RAC)with funding from the 'Australian Biological Re-sources Study' and is designed to be a precursor tothe planned 'Algae of Australia', a multi-volumeseries that will eventually include descriptions of allalgae found in Australia and Australian waters. Atpresent the database is nearing completion, with per-haps only 5% of species yet to be catalogued. Table Igives the number of accepted species recorded foreach region and the percentage of the Australia-widetotal (1776). The percentages given in Figure 2, how-ever, are the proportion of the total number of re-cords entered into the database. Both representationsclearly demonstrate a skewed division between north-ern and southern Australia, indicating either a par-ticularly depauperate flora for the north, or a lack ofcollecting and research effort for the region. A num-ber of authors have commented on the low diversityof marine algae in tropical as compared to cold andwarm temperate regions (Lüning 1990, Bolton 1994),a pattern apparently at odds with most other groupsof organisms. Whilst we acknowledge the rich sou-thern Australian flora is likely to have a greater spec-ies diversity than that from the tropical north, webelieve that the current disparity is exaggerated dueto varying levels of research effort. For example, inthe region extending from the North-West Cape inWestern Australia to the Northern Territory/WesternAustralian border - a coastline several thousandkilometres in length - there have been only twentyeight species of algae recorded in the literature, in-cluded in a handful of publications (earlier publi-cations catalogued by Lewis 1984, 1985, 1987; laterworks including Phillips et al. 1993; King and Put-tock 1994; Withell et al. 1994; Huisman 1996; Ka-miya et al. 1997). Over half of the recorded speciesare mangrove-associated epiphytes. Obviously this is

DAMPIERIANPROVINCE

SOLANDERIANPROVINCE

TASMANIA

500km

Fig. 1. Australian macroalgal biogeographic regionsused in this study (modified from Womersley 1981).

WA DAMDAM 2%4%

as

VICFUN15%

TASFUN12%

Fig. 2. Percentages of algal species recorded from the vari-ous biogeographical and political regions.

Biodiversity of Australian marine macroalgae 91

Table II. Comparison of taxa recorded from north-westAustralia and nearby regions.

Region

Philippines

Indonesia

Dampierian

Recorded Taxa

911452

291

Sources

Silva etal 1987

Verheij &Prud'hommevan Reine 1993

AMANI

Table III. Comparison of taxa recorded from islands adja-cent to north-west Australia (Christmas and Cocos/KeelingIslands) and comparable islands in the west Pacific.

Island Recorded Taxa Sources

RotumaLord HoweChristmasCocos/Keeling

88298236

N'Yeurt 1996AMANIAMANIAMANI

total number of marine macroalgae recorded fromAustralia is in the order of 1800. Applying the samefactor to the Australian macroalgae would thereforegive a total of around 18000. Of course, applicationof this factor implies that the undescribed species arespread evenly across the taxonomic groups and geo-graphic regions, something that is patently not true.The marine macroalgae, by definition, constitute themore visible component of algal biodiversity. If thevast undescribed pool of algae does in fact exist, it ismore likely to be drawn from the more cryptic groups- the marine nanoplankton, picoplankton and ter-restrial algae are likely suspects.

Despite our poor state of knowledge regarding cer-tain regions of Australia, it is unlikely that furtherstudy will increase the total number of macroalgalspecies by more that two-fold. Silva (1992) gives thetotal number of macroalgal species worldwide at ar-ound 6500 to 7000. Entwisle and Huisman (1998) es-timated the total number of species of algae in Aus-tralia, including all taxonomic groups. Extracting themacroalgal component of their estimates gives a totalof around 2000 species.

breakdown of species recorded from the variouszones demonstrates an almost complete ignorance ofcertain regions of northern Australia, with the pre-ponderance of studies dealing with southern Aus-tralia. A superficial survey of the major floristic lit-erature reinforces this observation; southern Aus-tralia is well catered for with the publications of H.B. S. Womersley (1984, 1987, 1994, 1996) and beforethem Harvey's Phycologia Australica (1858, 1859,1860, 1862, 1863). Publications dealing with northernand north-western Australian macroalgae are farfewer in number and invariably based on limited col-lections (e.g. Womersley 1958). This situation is wellrecognised by Australian phycologists — a recentworkshop held to discuss plans for the 'Algae of Aus-tralia' project (Flora of Australia - Workshop Series.Algae, 8-10 June 1992) had, as one of its primaryrecommendations, the need to increase collecting ef-fort in northern Australia.

Thus our knowledge of the algal flora ranges fromgood (the southern Australian flora, particularly oncethe remaining volumes of Bryan Womersley's floraare completed), to very poor (the north-west region).It is clear that we have great deal more exploratoryand descriptive work to do before we can make anyconclusions about the real biodiversity of the Aus-tralian macroalgae.

Predictions

Biodiversity lends itself to sweeping statements andwhat are apparently outlandish estimates. The GlobalBiodiversity Assessment (Watson et al 1995) gives thenumber of described algal species as 40000 and esti-mates that the total number is around 400 000. The

The future

Perhaps the single most important constraint onmacroalgal biodiversity studies is the lack of suitablytrained and employed phycologists. In Australia atpresent they number less than ten, with several ofthose employed on a part-time basis. Very few holdappointments in herbaria and the situation in univer-sities is variable - in the latter there is often pressureto partake of greater 'resource' oriented research(read dollars). And the prospects for taxonomy arenot encouraging. The trend away from basic researchand the continual diminishing of the research dollarare hardly enticing to students contemplating a careerin algal taxonomy. In Australia in the past twentyyears there have been many students awarded doctoraldegrees for research into marine macroalgal tax-onomy, but at present only one of those holds a perma-nent position as a taxonomist. It is not surprising thatthose staff remaining at universities are less than en-thusiastic about recommending taxonomy as a career.If we are to pursue the goal of an Australia-wide algalflora, there will need to be a substantial increase inboth training and opportunities for phycologists.

The 'Australian Biological Resources Study', in itsendeavours to publish the cAlgae of Australia', hassupported, and is likely to continue to support, phy-cological floristic research, but it cannot be expectedto be the saviour of the phycological community. Re-cent tightening of government expenditure has forcedthe redirection of research funds, and ABRS has hadto reassess its involvement in phycological research.Whilst the enthusuasm for the 'Algae of Australia'project remains, financial constraints have slowed itsprogress and have added to the general disillusion-

92 J. M. Huisman ei al

ment felt by potential contributors. But what willcure this malaise? Unfortunately there does not ap-pear to be an easy fix. In a perfect world algal taxon-omists would hold positions in all herbaria and uni-versities, they would conduct their research unfet-tered by financial constraints, and governmentswould recognise the inherent value of biodiversitystudies. Obviously this is never going to be a reality.Perhaps the most valuable characteristics for futuretaxonomists will be perserverence and an enduringbelief in the worth of their studies. Combine thosewith some innocent enthusiasm and we might yet seean Australia-wide algal flora.

Acknowledgements

Financial support to JMH and RAC was provided bythe 'Australian Biological Resources Study'. Assoc.Professor Michael Borowitzka (Murdoch University)designed the database and is thanked for his support.Thanks also to Professor Margaret Clayton (MonashUniversity) who convened the symposium and sug-gested the topic.

Accepted 7 October 1997

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