Biogeography of Caladenia (Orchidaceae), with special reference to the South-west Australian Floristic Region
Ryan D. Phillips A B F , Gary Backhouse C , Andrew P. Brown D and Stephen D. Hopper E BA Kings Park and Botanic Garden, Botanic Gardens and Parks Authority, West Perth, WA 6005, Australia.
B School of Plant Biology, University of Western Australia, Crawley, WA 6009, Australia.
C Biodiversity and Ecosystem Services Division, Department of Sustainability and Environment, 8 Nicholson Street, East Melbourne, Vic. 3002, Australia.
D Department of Environment and Conservation, Species and Communities Branch, Locked Bag 104, Bentley Delivery Centre, WA 6983, Australia.
E Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK.
F Corresponding author. Email: Ryan.Phillips@bgpa.wa.gov.au
Australian Journal of Botany 57(4) 259-275 https://doi.org/10.1071/BT08157
Submitted: 25 August 2008 Accepted: 12 January 2009 Published: 29 July 2009
Abstract
Caladenia contains 376 species and subspecies, of which almost all are endemic to temperate and southern semiarid Australia. Eleven species occur in New Zealand, 10 of which are endemic, and one species is widely distributed in eastern Australia and the western Pacific. Only three species occur in both south-western and south-eastern Australia. At subgeneric level, Drakonorchis is endemic to the South-west Australian Floristic Region (SWAFR), Stegostyla to eastern Australia and New Zealand, whereas three subgenera, Calonema, Phlebochilus and Elevatae occur on both sides of the Nullarbor Plain. Subgenus Caladenia is primarily eastern Australian but also extends to the western Pacific. The largest subgenera (Calonema and Phlebochilus) have radiated extensively, with Calonema exhibiting a greater concentration of species in more mesic parts of the SWAFR than Phlebochilus. Within the SWAFR, the major biogeographic division within Caladenia follows the 600-mm isohyet. Within rainfall zones, biogeographic districts for Caladenia correlate with a combination of underlying geology and surface soils. Areas of high endemism contain diverse edaphic environments. Climatic and edaphic requirements are likely to be key drivers of rarity in Caladenia, although these parameters may be acting in concert with mycorrhizal and pollinator specificity.
Acknowledgements
R. D. Phillips was supported by an Australian Postgraduate Award and grants from the Australian Orchid Foundation, the Holsworth Wildlife Research Endowment and the School of Plant Biology at the University of Western Australia. We thank the Western Australian Herbarium for providing access to specimen label data. Thanks go to the two anonymous reviewers for their helpful comments and suggested improvements for the manuscript.
Brown AP, Brockman G
(2007) Caladenia petrensis and C. saxicola (Orchidaceae), two ironstone endemics from south-west Western Australia. Nuytsia 17, 73–80.
Burgman MA,
Keith D,
Hopper SD,
Widyatmoko D, Drill C
(2007) Threat syndromes and conservation of the Australian flora. Biological Conservation 134, 73–82.
| Crossref | GoogleScholarGoogle Scholar |
Cracraft J
(1991) Patterns of diversification within continental biotas: hierarchical congruence among the areas of endemism of Australian vertebrates. Australian Systematic Botany 4, 211–227.
| Crossref | GoogleScholarGoogle Scholar |
Crisp MD, Cook LG
(2007) A congruent molecular signature of vicariance across multiple plant lineages. Molecular Phylogenetics and Evolution 43, 1106–1117.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Crisp MD,
Linder P, Weston PH
(1995) Cladistic biogeography of the plants in Australia and New Guinea: congruent patterns reveals two endemic tropical tracks. Systematic Biology 44, 457–473.
| Crossref | GoogleScholarGoogle Scholar |
Crisp M,
Cook L, Steane D
(2004) Radiation of the Australian flora: what can comparisons of molecular phylogenies across multiple taxa tell us about the evolution of diversity in present-day communities? Philosophical Transactions of the Royal Society B Biological Sciences 359, 1551–1571.
| Crossref | GoogleScholarGoogle Scholar |
Hopper SD
(1979) Biogeographical aspects of speciation in the southwest Australian flora. Annual Review of Ecology and Systematics 10, 399–422.
| Crossref | GoogleScholarGoogle Scholar |
Hopper SD, Brown AP
(2001) Contributions to Western Australian Orchidology: 2. New taxa and circumscriptions in Caladenia (spider, fairy and dragon orchids of Western Australia). Nuytsia 14, 27–307.
Hopper SD, Brown AP
(2004) Robert Brown’s Caladenia revisited, including a revision of its sister genera Cyanicula, Ericksonella and Pheladenia (Caladeniinae: Orchidaceae). Australian Systematic Botany 17, 171–240.
| Crossref | GoogleScholarGoogle Scholar |
Hopper SD, Gioia P
(2004) The Southwest Australian Floristic Region: evolution and conservation of a global diversity hotspot. Annual Review of Ecology Evolution and Systematics 35, 623–650.
| Crossref | GoogleScholarGoogle Scholar |
Hopper SD, Maslin BR
(1978) Phytogeography of Acacia in Western Australia. Australian Journal of Botany 26, 63–78.
| Crossref | GoogleScholarGoogle Scholar |
Huynh TT,
McLean CB,
Coates F, Lawrie AC
(2004) Effect of developmental stage and peleton morphology on success in isolation of mycorrhizal fungi in Caladenia formosa (Orchidaceae). Australian Journal of Botany 52, 231–241.
| Crossref | GoogleScholarGoogle Scholar |
Jones DL, Clements MA
(2005) Miscellaneous nomenclatural notes and changes in Australian, New Guinea and New Zealand Orchidaceae. Orchadian 15, 33–42.
Keighery GJ
(1996) Phytogeography, biology and conservation of Western Australian Epacridaceae. Annals of Botany 77, 347–355.
| Crossref | GoogleScholarGoogle Scholar |
Kessler M
(2002) The elevational gradient of Andean plant endemism: varying influences of taxon-specific traits and topography at different taxonomic levels. Journal of Biogeography 29, 1159–1165.
| Crossref | GoogleScholarGoogle Scholar |
Phillips RD,
Faast R,
Bower CC,
Brown GR, Peakall R
(2009) Implications of pollination by food and sexual deception on pollinator specificity, fruit set, population genetics and conservation of Caladenia. Australian Journal of Botany 57, 287–306.
| Crossref | GoogleScholarGoogle Scholar |
Ramsay RR,
Dixon KW, Sivasithamparam K
(1986) Patterns of infection and endophytes associated with Western Australian orchids. Lindleyana 1, 203–214.
Stebbins GL, Major J
(1965) Endemism and speciation in the Californian flora. Ecological Monographs 35, 1–35.
| Crossref | GoogleScholarGoogle Scholar |
Stoutamire WP
(1983) Wasp-pollinated species of Caladenia (Orchidaceae) in south-western Australia. Australian Journal of Botany 31, 383–394.
| Crossref | GoogleScholarGoogle Scholar |