Our knowledge of the biodiversity of New Zealand is unevenly spread. Charismatic or larger organisms such as birds, reptiles, fish and higher plants are generally well known and well-studied. We do however have more neglected corners of our biodiversity.
For a range of reasons some taxonomic groups have not been as extensively studied as the better-known groups of organisms. There may be few or no experts in that field in New Zealand; the organisms may be microscopic, have cryptic distinguishing characteristics, or may live in inaccessible places and environments. These neglected taxonomic groups, such as fungi and many groups of invertebrates, are thought to represent a significant part of our native diversity. Some of them may be threatened with extinction, but without knowing anything about them, it is rarely possible to even attempt to manage them.
Dr Peter de Lange is a Principal Science Advisor at the Department of Conservation (DoC) and a research fellow at Unitec. He collaborates with Dr Dan Blanchon from Unitec’s Applied Molecular Solutions Research Focus on a range of projects studying lichenised fungi, or ‘lichens’.
“Lichens are a significant part of New Zealand’s biodiversity, but they are poorly studied, poorly known. We are beginning to understand that they are very important bioindicators of climate change and changing forest structure and health. Because we often don’t know what species we are dealing with, we can’t effectively manage them – we need to know what we are dealing with. DoC is increasingly broadening its approach to include all forms of life in New Zealand, including more cryptic things like lichens,” says de Lange.
The last full review of the lichen species in New Zealand, started in 2009 and published in 2012 by a DoC threat classification panel, recognised 1799 different lichens and associated fungi as being found in New Zealand. The purpose of this review was to determine if any lichen species were threatened with extinction. It turned out that more than half of the species were so poorly known that they were listed as ‘Data Deficient’, and therefore could not be assigned to a threat category.
In 2016, a new threat classification panel for lichens (led by de Lange and including Unitec’s Dr Dan Blanchon) will meet again to determine the threat status for New Zealand’s lichens. The task is a daunting one, as conservative estimates now suggest we may have as many as 2500 different lichens and associated fungi in New Zealand.
“A large proportion of New Zealand lichens are considered to be ‘Data Deficient’ – in some cases we are not confident that they are actually real species,” says de Lange.
Part of the solution lies in the judicious use of molecular technologies such as DNA sequencing. While there are few active lichenologists in Australasia, worldwide there are several laboratories working on different lichen genera and families, many of which are represented by species in New Zealand. Their work, and research carried out in the Applied Molecular Solutions laboratory at Unitec by Blanchon, de Lange and Dr Sofia Chambers involves extracting DNA from lichen specimens, generating DNA sequence data and comparing this with other published sequences available in online databases. A vast amount of genetic data is available for comparison on international databases such as Genbank.
[x_pullquote cite=”de Lange” type=”left”] “Lichens are very important bioindicators of climate change and changing forest structure and health.” [/x_pullquote]
“Lichens are a little odd to work with, as they are actually communities of organisms, made up of a fungus, which ‘farms’ captured algae and/or cyanobacteria. In practice, the scientific name of the lichen refers to the fungal partner, and it is the DNA of the fungus which is usually compared,” says Blanchon. Comparison of DNA sequences can uncover or identify species new to science, confirm or dispose of species names and help us to understand the relationships between or within species worldwide. “DNA is the only reliable way of getting to grips with problematic groups – getting unknown taxa down to at least genus level. When studying lichens, without getting DNA sequence data you are dreaming if you think you are going to do a good job,” says de Lange.
Blanchon and de Lange are collaborating on a range of lichen projects, most involving the use of DNA sequence data. One interesting project involved a hunt for a mysterious ‘missing’ lichen called Ramalodium dumosum. This lichen had only been collected once (in 1981), by a collector called John Bartlett, from coastal cliffs at Huia near Auckland and was never seen again.
A thorough survey of the Manukau Harbour coastline (including an accidental discovery of a nudist beach) uncovered one possible candidate for the elusive R. dumosum. This unappealing microscopic gelatinous black lichen was taken back to the lab for DNA analysis. Comparison of the ITS DNA sequence data with Genbank sequences indicated that this specimen was actually a new species of Enchylium rather than Ramalodium, replacing one mystery with another.
Another example of the value of molecular data is from the Chatham Islands (Rekohu). Rangatira (South-East) Island is the site of an attempt to restore population numbers of the critically threatened Chatham Island Black Robin. The succession of the native plant pohuehue (Muehlenbeckia australis) had been identified as a possible barrier to the Black Robin recovery programme on the island. However, before removing the pohuehue, it was important to determine if there would be negative effects on other species. A lichen was collected from the pohuehue by de Lange, and an examination back in the lab at Unitec suggested it could be a new species. DNA data has subsequently shown that it is indeed a species previously unknown to science.
The use of molecular data can also cause surprises with common lichen species. Blanchon hosted a Royal Society of New Zealand Teacher Fellow, Glenys Hayward. Hayward and Blanchon studied the common and widespread lichen Ramalina celastri, a species found in virtually every backyard in Auckland. In Australia, the species was separated into two subspecies, but in New Zealand we only recognised one species.
Comparison of DNA sequence data from specimens collected from New Zealand and Australia showed that we should recognise two separate species, R. celastri and R. ovalis (an old name for specimens mainly found in the South Island of New Zealand and eastern Australia), adding one species to the total known lichens for New Zealand.
In addition, collaboration in worldwide studies can show that in some cases where we previously thought we had species with a worldwide distribution, we are wrong.
For example, at Unitec we are part of the PARSYS consortium, investigating members of the family Parmeliaceae all over the world.
[x_pullquote cite=”Blanchon” type=”left”] “A common species around Auckland that we have been calling Parmotrema perlatum is not in fact that species.” [/x_pullquote]
We are currently revising the species of the genus Parmotrema for New Zealand. Initial results are indicating that a common species around Auckland that we have been calling Parmotrema perlatum is not in fact that species. The species with this name has been listed as a culinary herb in places such as India – and based on our data, what we have here is not that species, which appears to be restricted to the Northern Hemisphere.
One essential step in the use of molecular tools such as DNA sequencing for studying lichen species is in the creation of voucher specimens – the preserved sample of the lichen the DNA was taken from, lodged and protected for posterity in a collection such as a herbarium.
The DNA sequence data is linked to the collection number of the specimen and this specimen can be checked by other scientists – such peer review is an essential part of the scientific process. Voucher specimens substantiate claims of occurrence and can provide useful information on the geographical distribution and ecology of species.
“Unitec is the only lichen-specialist herbarium in New Zealand,” notes de Lange. “Some other herbaria maintain lichen collections, but they may not have specialists working there or may not be actively adding to or curating their collections. Unitec provides a specific type of service to the New Zealand people that none of the other New Zealand herbaria do.”
Pullquote: “Voucher specimens substantiate claims of occurrence and can provide useful information on the geographical distribution and ecology of species”
With between 1800 and 2500 lichens to choose from, the list of projects for the Unitec and DoC researchers is nearly endless, but every puzzle they solve is a win for our understanding of New Zealand’s biodiversity.
Contact
Dr Peter de Lange
pdelange@unitec.ac.nz
Dr Dan Blanchon
dblanchon@unitec.ac.nz