Key points
- Taxonomy is the science of naming, describing and classifying organisms.
- Taxonomists are scientific detectives, determining whether a species is new to science.
- The Atlas of Living Australia uses a taxonomic backbone to organise Australia’s biodiversity data.
Taxonomy is the game of the name. And genomics is the new superpower allowing taxonomists to separate and describe more species faster.
Australia is one of only 17 mega-diverse countries in the world, with a rich and unique biodiversity. An estimated eight per cent of the world’s plants and animals occur in Australia, yet only a fraction of these species are known to science.
This huge task ahead shows the importance of taxonomists! Their research builds our understanding of our biodiversity. They identify species, a fundamental building block of ecology and conservation.
Let’s take a moment to appreciate taxonomists and the importance of taxonomy for research, data and biosecurity.
How does the Atlas of Living Australia use taxonomy for biodiversity data?
Cam Slatyer is the Program Manager for National Biodiversity Data Initiatives at the Atlas of Living Australia (ALA). He manages the taxonomic backbone of the Atlas of Living Australia. It’s the ALA's core organising framework for species names, based on the National Species List (NSL).
“The ALA provides biodiversity data to a wide range of research and non-research users. That data has to be structured in a way that makes species data discoverable, and the logical mechanism we use to do that is using species names to arrange everything,” Mr Slatyer said.
“Taxonomy, the science of naming species, is a really important science and it's very structured. So, for us it's very much about tracking the passage of those names through time.”
Each species has a paper in which it was first described, and that paper is attached to the name as the authority. So, if you look at a scientific name in the ALA, you’ll see the genus, species and authority. It's the author or authority that tells you where the name actually came from. The ALA obtains all of that from a fantastic resource called the National Species List, maintained by the Australian Biological Resources Study.
“A lot of what we do in the ALA is trying to pick the logical place for things to go to give us the best data match,” Mr Slatyer said.
Why are ‘type’ specimens important and how are they used?
Taxonomists start with the ‘type’ or ‘first named’ specimens held in museums and herbaria.
“It’s the standard for the species,” Mr Slatyer said.
“It’s like knowing that a metre ruler is a metre ruler or the litre at the fuel pump is a correct litre. When a biologist or a taxonomist is studying a species, they go to the type specimen and ask, ‘how closely do the features of this individual specimen resemble those of the type specimen?’.”
Traditionally that would have been done using measurements of their physical structure. But increasingly these days, taxonomists will also use DNA.
The ALA helps make type specimens in collections discoverable online, including from overseas collections. So, someone who is interested in working on a group of species can quickly tell where specimens are held (if they've been digitised).
Why is taxonomy important?
Taxonomy is important just for the sheer understanding of the biodiversity around us.
Many of Australia’s 150,000-plus known species are unique and found nowhere else; over 41% of our birds, mammals, reptiles, fish and frogs and over 86% of our flora.
The estimated total number of Australian species is 566,398, which means that two out of every three species in Australia are unknown to science. That leaves a lot of biodiversity we don’t know about and haven’t studied.
When there’s a biosecurity incursion like varroa mite for bees, people call on taxonomists to produce the diagnostic kits that enable us to identify invasive species and detect their presence.
And with threatened species, we need taxonomists to assist with the delineation and identification of species.
Where do taxonomists work? And how many taxonomists does Australia have?
Cam said that 30 years ago, taxonomists were employed in many different organisations including museums, herbaria, departments of primary industry and universities.
Nowadays there are fewer taxonomists, who are mostly employed by museums and herbaria.
“Taxonomy isn’t taught as widely as it once was, but it’s a genuinely important discipline,” Cam said.
What do taxonomists look at to determine whether a species is new?
Dr Heidi Zimmer is an orchid researcher at the Australian National Herbarium (ANH) in Canberra, a joint venture between Parks Australia and CSIRO. She translates taxonomic and DNA-based research of species into conservation management.
Dr Zimmer said taxonomists use multiple lines of evidence to determine whether a species is new to science.
“We look at morphology—that is, what something looks like—and molecular studies, which focus on differences in genes or DNA,” Dr Zimmer said.
Other information on a species ecology, such as its geographical distribution, habitat, and for plants, flowering time and pollinators can also be useful.
“Each of these lines of evidence helps us understand who breeds with who,” Dr Zimmer said.
Heidi, with colleagues, recently described a species of narrow-range endemic orchid found in the Kosciuszko National Park.
The three main lines of evidence to support its classification as a species new to science were:
- being geographically separate from similar species
- flowering at a different time from similar species
- and having a flower structure distinct from other species, which indicated heritable genetic variation.
Generally, a species is a group of organisms that can breed with one another, but not with other groups. So, if two groups of plants have two totally different habitats, flowering times and pollinators, we can probably assume they don’t breed with one another.
“Molecular studies are particularly useful as they can reveal who has been breeding with who, both recently and in the past,” Dr Zimmer said.
New orchid species takes the (cup)cake
Dr Zimmer also worked on a collaborative project studying a tiny orchid on Norfolk Island. They compared this orchid with orchid specimens and species described in scientific journals.
They realised the flower of the Norfolk Island species was different. This meant the orchid species (Adelopetalum argyropus) previously recorded as one species occurring across Norfolk Island, Lord Howe Island and continental Australia was in fact three distinct species.
The three species face risks as they’re confined to small areas, and the habitat on continental Australia has been impacted by bushfires.
Naming and describing these new orchid species can help catalogue and conserve them.
Building the plant tree of life with modern genomics
Dr Stephanie Chen is a botanist and computational biologist at the Australian National Herbarium. She applies taxonomy to create plant family trees (phylogenetic trees) using DNA sequencing data.
Advances in DNA sequencing technologies coupled with decreasing costs have accelerated sequencing efforts in the genomic era. This enables more detailed and comprehensive phylogenetic trees to be created.
“Using DNA sequences allows us to classify living things and understand the evolutionary relationships between plant species, which is important for fields like conservation and biosecurity,” Dr Chen said.
Why taxonomy matters for invasive species management
Taxonomy is fundamental to understanding biodiversity. To manage an invasive plant species, you first need to know what it is.
Taxonomy can help reveal the origin of a species. Previously, we have used DNA sequencing to uncover and resolve a case of mistaken identity as part of a biological control project on the daisy weed flaxleaf fleabane (Erigeron bonariensis).
During her CSIRO Postdoctoral Fellowship, Stephanie developed a decision support tool called PhyloControl aimed at weed biological control practitioners and regulators.
PhyloControl brings together taxonomic data, phylogenomic trees (a diagram that shows the evolutionary relationship between organisms), spatial data, species distribution modelling, and plant traits in one visualisation application.
“PhyloControl is a risk analysis tool that helps streamline and standardise the process of making a host test list. It makes the process more transparent and reproducible,” Dr Chen explained.
Stephanie also aims to make taxonomic data and analyses more accessible and intuitive for biological control researchers.
She recently published a practical guide that details how to create and interpret phylogenetic trees.
“Working at the intersection of taxonomy, genomics and biocontrol has shown me just how essential accurate species identification is to solving problems like invasive plants,” Dr Chen said.
So next time you’re trying to remember someone’s name, spare a thought for the work of taxonomists! They’re naming and saving our unique biodiversity one species at a time. We appreciate them and their work identifying species, and building family trees for our natural world root by branch.