title: Quantifying phytogeographical regions of Australia using geospatial turnover in species composition.
abstract: The largest digitized dataset of land plant distributions in Australia assembled to date (750,741 georeferenced herbarium records; 6,043 species) was used to partition the Australian continent into phytogeographical regions. We used a set of six widely distributed vascular plant groups and three non-vascular plant groups which together occur in a variety of landscapes/habitats across Australia. Phytogeographical regions were identified using quantitative analyses of species turnover, the rate of change in species composition between sites, calculated as Simpson's beta. We propose six major phytogeographical regions for Australia: Northern, Northern Desert, Eremaean, Eastern Queensland, Euronotian and South-Western. Our new phytogeographical regions show a spatial agreement of 65% with respect to previously defined phytogeographical regions of Australia. We also confirm that these new regions are in general agreement with the biomes of Australia and other contemporary biogeographical classifications. To assess the meaningfulness of the proposed phytogeographical regions, we evaluated how they relate to broad scale environmental gradients. Physiographic factors such as geology do not have a strong correspondence with our proposed regions. Instead, we identified climate as the main environmental driver. The use of an unprecedentedly large dataset of multiple plant groups, coupled with an explicit quantitative analysis, makes this study novel and allows an improved historical bioregionalization scheme for Australian plants. Our analyses show that: (1) there is considerable overlap between our results and older biogeographic classifications; (2) phytogeographical regions based on species turnover can be a powerful tool to further partition the landscape into meaningful units; (3) further studies using phylogenetic turnover metrics are needed to test the taxonomic areas.
authors.affiliation: Centre for Australian National Biodiversity Research, Commonwealth Scientific and Industrial Research Organisation, Plant Industry, Canberra, Australian Capital Territory, Australia.
authors.forename: Carlos E
authors.initials: CE
authors.lastname: González-Orozco
authors.affiliation: School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Malte C
authors.initials: MC
authors.lastname: Ebach
authors.affiliation: School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Shawn
authors.initials: S
authors.lastname: Laffan
authors.affiliation: Centre for Australian National Biodiversity Research, Commonwealth Scientific and Industrial Research Organisation, Plant Industry, Canberra, Australian Capital Territory, Australia; Australian Tropical Herbarium, James Cook University, Cairns, Queensland, Australia.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Thornhill
authors.affiliation: Centre for Australian National Biodiversity Research, Commonwealth Scientific and Industrial Research Organisation, Plant Industry, Canberra, Australian Capital Territory, Australia.
authors.forename: Nunzio J
authors.initials: NJ
authors.lastname: Knerr
authors.affiliation: Centre for Australian National Biodiversity Research, Commonwealth Scientific and Industrial Research Organisation, Plant Industry, Canberra, Australian Capital Territory, Australia.
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Schmidt-Lebuhn
authors.affiliation: Centre for Australian National Biodiversity Research, Commonwealth Scientific and Industrial Research Organisation, Plant Industry, Canberra, Australian Capital Territory, Australia.
authors.forename: Christine C
authors.initials: CC
authors.lastname: Cargill
authors.affiliation: Centre for Australian National Biodiversity Research, Commonwealth Scientific and Industrial Research Organisation, Plant Industry, Canberra, Australian Capital Territory, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Clements
authors.affiliation: National Herbarium of New South Wales, Botanic Gardens Trust, Sydney, New South Wales, Australia.
authors.forename: Nathalie S
authors.initials: NS
authors.lastname: Nagalingum
authors.affiliation: University and Jepson Herbaria, Department of Integrative Biology, University of California, Berkeley, Berkeley, California, United States of America.
authors.forename: Brent D
authors.initials: BD
authors.lastname: Mishler
authors.affiliation: Centre for Australian National Biodiversity Research, Commonwealth Scientific and Industrial Research Organisation, Plant Industry, Canberra, Australian Capital Territory, Australia.
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Miller
mesh_terms: D001315:Australia; D044822:Biodiversity; D002980:Climate; D010802:Phylogeny; D063148:Plant Dispersal