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Madagascar loses its record: New Guinea is now the most species-rich island in the world

99 botanists from 19 countries – including three from Denmark – have mapped plant life on the world's second-largest island, New Guinea, and so far they have identified 13,634 species. This is 19 per cent more than Madagascar.

[Translate to English:] Foto af fire modne mænd i en grøn regnskov. Axel Dalberg Poulsen, noget lysere i huden end de tre andre, sidder med et prøveglas.
[Translate to English:] Axel Dalberg Poulsen under feltarbejde i Papua Ny Guinea, her i selskab med Thomas Magun fra PNG Forest Research Institute og to lokale lodsejere. Gruppen beundrer en art af Riedelia ingefær, de netop har samlet fra en trætop. Foto: Axel Dalberg Poulsen.

New Guinea is regarded by researchers as one of the last large blank areas on the world map of biology. However, an international group of researchers have now trawled through more than 700,000 plant specimens from the island – some dating back to the 16th century – and they have drawn up the first catalogue of verified species.

Their results have recently been published in the prestigious scientific journal Nature. The list includes 13,634 species of plant, and this means that New Guinea has overtaken Madagascar as the most species-rich island in the world. However, as New Guinea has not yet been fully explored, the researchers estimate that an additional 4,000 plant species will be found within the next 50 years.

Their work will help us to understand how the unique flora of New Guinea has evolved through the different eras of the earth and it will be of great value to nature management.

AU well represented

Three Danish botanists took part in the hard work. Anders Barfod and Peter Petø from Aarhus University participated specifically in the investigation of the prevalence of palms, while Axel Dalberg Poulsen, who is based at the Royal Botanic Garden Edinburgh (and a PhD from Aarhus University) examined the ginger family.

"One of the most important results of the study is that two-thirds of the plants are native, which means that they are not found outside New Guinea. This reflects the island's isolation from South-East Asia through geological time. The climate is also far more humid than, for example, the Cape York Peninsula in Australia, which was very probably connected to New Guinea until just 12,000 years ago," says Peter Petø, who is researching the trees on New Guinea as part of his PhD programme.

The researchers point out that the list is not yet complete, and new discoveries are still being made. 

Anders Barfod explains:

"When we collect plant specimens in places where no botanists have previously visited, we usually come home with species that are new to science. With regard to palms, these new finds are by no means unimpressive, reaching heights of 20 – 30 m.  It’s worth mentioning that many of these 'new' species are actually very well-known among the locals, who have names for them and often use them for specific purposes."

Many expeditions

According to Axel Dalberg Poulsen, who is a specialist in the ginger family, this kind of international research collaboration also has a very large derived value. 

"In the tropical regions of the world, our interest in preserving nature and finding answers to the big scientific questions about the development and prevalence of plants through time and space is often slowed down by our lack of knowledge about even the most important plant families. On New Guinea, you have to expect the unexpected during the fieldwork, and we have many new species of ginger waiting to be described."

The article has been many years in the pipeline, and it combines knowledge acquired through a large number of expeditions working with local foresters and botanists in some of the most deserted areas on the island of New Guinea. The authors are therefore very satisfied that one of the most prestigious scientific journals has decided to publish their article.

Further information:

The article "New Guinea has the world's richest island flora" in Nature

About the Danish researchers:

Associate Professor Anders S. Barfod
Head of Ecoinformatics and Biodiversity at the Department of Biology, Aarhus University. Researches into tropical botany, vegetation ecology and economic botany. Concurrently with other projects, he has worked on the palm flora of New Guinea since 1996, funded by, among others, the Carlsberg Foundation and Independent Research Fund Denmark.
Email: barfod@bio.au.dk
Mobile: +45 5299 3097

Peter Petø
PhD student at Aarhus University with focus on the evolution and systematics of fan palms. Has previously been employed as a palm specialist at the Royal Botanic Gardens, Kew, with focus on the palm flora of New Guinea. 
Email: peter.petoe@bios.au.dk
Mobile: +45 2169 0085 Twitter: @PeterPetoe 

Axel Dalberg Poulsen
Senior researcher at the Royal Botanic Garden, Edinburgh, Scotland. Tropical forest botanist with more than 30 years of experience.  Expert in ginger. Has so far carried out eight expeditions to New Guinea, the first in 2006 under Galathea3. PhD from Aarhus University
Email: apoulsen@rbge.org.uk
Mobile: +44 75030 90817 Twitter: @AxelGinger