Western Australian Flora Statistics 2020 Flora Statistics

Statistics for the Western Australian flora at or below the rank of species for all groups traditionally managed by herbaria, including vascular plants, algae, fungi, lichens, mosses and slime moulds.

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Summary

Comparison of 2020’s data with the previous year.

2020 marks twenty years since the publication of two significant floristic analyses based on the same taxonomic names data set, taken on 20 January 2000. These two publications—The Western Australian Flora – a Descriptive Catalogue (Paczkowska and Chapman, 2000) and Species richness and endemism in the Western Australian flora (Beard, Chapman and Gioia, 2000)—presented a modern baseline for measuring the growth of our knowledge about the Western Australian flora.

In 2003, with the introduction of FloraBase 2, we began publishing a yearly summary of WA floristics for the vascular flora. Initially, this was directly comparable to the tables presented in the two publications above, but over time more comparative data points were added to allow further analysis of various flora data categories. In 2006, in recognition of their under-representation in documenting WA's flora, we added similar calculations for the cryptogamic flora. Since 2019, the figures have been calculated by software written by Paul Gioia and Ben Richardson. In this time, the quality of the statistics has relied upon the work done by Herbarium staff.

An overview of the progress made in the last twenty years:

  • The number of published vascular plant species occurring in WA in 2000 was 9,640; in 2020 it is 11,807. In 20 years, there have been 2,167 new species names published and recognised as part of the WA flora.
  • The number of published native species occurring in WA in 2000 was 8,588; in 2020 it is 10,493. In 20 years, there have been 1,905 new indigenous species names published (95 taxa per year).
  • The number of published cryptogam species occurring in WA in 2006 was 1,571; in 2020 it is 2,906. In 14 years, there have been 1,335 new species names published (also 95 taxa per year).

Note: figures will include revisionary work where existing species have been assigned to another genus, as well as subspecies that have been raised to species level. However, as the previous name is then marked 'non-current', the totals still stand as valid.

For the vascular plants:

  • the addition of 235 vascular plant names to the Census of Western Australian Plants database (including 186 synonyms);
  • there are 58 additional vascular taxa recognised as occurring in the State: 50 native taxa and eight naturalised taxa;
  • the number of published vascular species rose by 98 to 11,807, including 91 native species and seven naturalised species;
  • there are nine fewer species containing infraspecies, presumably as these subspecies were raised to species rank;
  • an additional four named hybrids have been recognised;
  • a decrease of 31 putative vascular plant taxa (that is, those awaiting analysis and description);
  • manuscript names stayed steady and phrase names (down by 31 to 1,143), due predominantly to their transition into published taxa;
  • so, for the tenth year in succession, there has been a decrease (-31) in the number of putative taxa yet to be researched and published, from 1,194 in 2019 to 1,163 in 2020;
  • at this rate of reduction (31 taxa per year) and assuming no further discoveries and no increase in taxonomic resource in the State, it would take about 38 years to complete the inventory of just the vascular plant taxa in the State.

For the cryptogams:

  • the net addition of 362 cryptogam names entered into the Census of Western Australian Plants database (including 87 synonyms);
  • the number of new alien taxa and alien species is 15 (meaning that all taxa added were at the rank of species);
  • the number of native cryptogam taxa now numbers 2,919, of which 2,891 are at the rank of species; an increase of 274 taxa from the previous year;
  • an additional 274 current published native cryptogam species are now recorded in the Census: 57 fungi, one lichen, 15 slime moulds, 199 algae, and two mosses;
  • for most cryptogam groups apart from lichens, the gap between the estimated number of species from the literature and the known described taxa recorded in the WACensus is significant (see the notes for each cryptogamic group below for estimated total numbers).

And finally, 2020 is the first year (at least in modern times) that there have been more cryptogam taxa added into the Census than vascular flora!

Notes

Dicotyledons
Used in its traditional sense to retain compatibility with previous tables and for ease of use. ‘Dicotyledons’ now refers to a paraphyletic assemblage of the Nymphaeales, ‘magnoliids’ and ‘eudicot’ clades, see our systematic sequence.
Species
A published name at the rank of species.
Taxa
Commonly refers to a published name at any rank, but these statistics only refer to taxa at or below species rank.

Cryptogams

Statistics for the cryptogamic flora groups were first compiled in 2006. For these, the statistics should only be considered adequate or representative for the lichens, myxomycetes and for the mosses (bryophyta) of the Perth region. For the remaining groups, specialists have provided the following estimates of the actual number of species that could be found to occur in WA once adequate field and taxonomic studies have been made.

Fungi (both macro- and micro-fungi)
Pascoe (1991) suggests the ratio of plants to fungi is about 1:10 in Australia, i.e. 25,000 plants (native and exotic), and 250,000 fungi. So, if WA has 14,000 vascular plants, then the estimated number of fungi in WA would be 140,000 (Neale Bougher, pers. comm.).
Lichens (lichenised fungi)
Ray Cranfield (pers. comm.) suggests that even with the recent publication of a State census of lichens (Cranfield, 2004), there are likely to be in the order of another 70 taxa likely to be discovered in coming years.
Algae (including marine macro- and micro-algae, dinoflagellates, diatoms and freshwater macro-algae)
John Huisman (pers. comm.) notes that the estimated number of macroalgae occurring in WA is 1,400, given that much of the northwest remains to be explored and we are still uncovering new records/species in all parts of WA. He also notes that “my earlier compilation of diatom/dinoflagellate and other microalgal records for WA included around 600 diatoms and 150 dinoflagellates (the other groups were negligible); marine and freshwater were included. The multiplication factor used by Watson et al. (1995) to estimate the world’s algal species was x10, so WA’s microalgae will probably add up to approximately 7,500 spp.” If we also allow around 100 species of freshwater macroalgae, then the putative number of algae will total some 9,000 taxa.
Bryophytes (the paraphyletic assemblage of mosses, liverworts and hornworts)
Streimann & Klazenga (2002) list 212 moss taxa occurring in WA, and McCarthy (2003) lists 90 taxa of liverworts and hornworts. As these figures are comparable in size to those listed for the Australian Capital Territory (a region one-thousandth the area), we might expect there are a number of bryophytes yet to discover. Conservatively, the estimated number of taxa occurring in WA could be put at 400 (Ray Cranfield, pers. comm.)
Myxomycetes (slime moulds)
After the publication of a census of slime moulds (Knight and Brims, 2010) the estimated maximum number of taxa occurring in WA may be put at 200 (Karina Knight, pers. comm.)

References

  • Biggs, L. and Chappill, J., (2008). An annotated census of the mosses of the Perth Region, Western Australia. Nuytsia 18 (1) : 1–30.
  • Cranfield, R.J., (2004). Lichen Census of Western Australia. Nuytsia 15 (2) : 193–220.
  • Huisman, J.M., Cowan, R.A. & Entwisle, T.J. (1998). Biodiversity of Australian marine macroalgae — a progress report. Bot. Mar. 41: 89–93.
  • Knight, K.J. and Brims M.H. (2010). Myxomycota census of Western Australia. Nuytsia 20: 283–307.
  • McCarthy, P.M. (2003). Catalogue of Australian liverworts and hornworts. Flora of Australia supplementary series. Australian Biological Resources Study, Canberra.
  • Pascoe, I.G. (1991). History of systematic mycology in Australia. In: History of Systematic Botany in Australasia. Ed by: P. Short. Australian Systematic Botany Society Inc. pp. 259–264.
  • Streimann, H. and Klazenga, N. (2002). Catalogue of Australian mosses. Flora of Australia supplementary series. Australian Biological Resources Study, Canberra.
  • Watson, R.T., Heywood, V.H., Baste, I., Dias, B., Gamez, R., Janetos, T., Reid, W. & Ruark, G. (1995). Global Biodiversity Assessment. Summary for Policy-Makers. Cambridge University Press, Cambridge, New York, Melbourne. 46 pp.

Compiled by Alex Chapman; last updated on 1 June 2020.

Recommended figures
  • Current Taxa: The actual number of known taxon names in Western Australia
  • Published Species: A conservative estimate of the number of well-documented species