The tropical island borders Madagascar, and is home to more than 13,500 species of plants. Botanists estimate that 4,000 new ones could be discovered in the next few years.
New Guinea is home to more than 13,500 plant species, two-thirds of which are endemic, according to a new study suggesting it has the highest plant diversity of any island in the world - 19% more than Madagascar, which previously held the record. .
Ninety-nine botanists from 56 institutions in 19 countries examined samples, the first of which were collected by European travelers in the 18th century. Vast tracts of the island remain unexplored and some historical collections have yet to be examined. The researchers estimate that 4,000 more plant species could be found in the next 50 years, and the discoveries show "no signs of stabilization," according to the article published in Nature.
"It is a paradise full of life," said lead researcher Dr. Rodrigo Cámara-Leret, a biologist at the University of Zurich who previously stayed at the Royal Botanical Gardens in Kew.
New Guinea, which is divided into the Indonesian provinces of Papua and West Papua and the independent state of Papua New Guinea in the east, is the world's largest and most mountainous tropical island, with snow-capped peaks reaching 5,000 meters in height.
"This allows for different types of habitats, such as mangroves, swamp forests, lowland tropical forests and also montane forests, which have high levels of endemism," said Cámara-Leret. And then at the top, just below the growth limit of the plants, are these alpine grasslands. This habitat is basically exclusive to New Guinea in Southeast Asia ”.
The island lies between Malaysia, Australia and the Pacific and has a young and diverse geological history, with many species forming in the last million years. One of the most surprising discoveries was the number of plants that are unique to the island. For example, 98% of heather species are endemic, as are 96% of African violets and 95% of ginger species.
Many suspected that New Guinea would prove to have the greatest diversity, but botanical exploration on the island remains limited. Unlike Madagascar, which has had a species checklist since 2008, the island had never been systematically studied and previous estimates suggested it could have between 9,000 and 25,000 species.
In total, the researchers found 13,634 plant species divided into 1,742 genera and 264 families. “I was glad we were able to nail a number. This is not the end, it is a first step, ”said Cámara-Leret, who encourages researchers around the world to take advantage of this data set, which will be vital for the International Union for Conservation Red List assessments. of Nature (IUCN).
New Guinea has fascinated explorers and botanists for centuries. In 1700, the Englishman William Dampier brought back the first scientific specimens from the region, which inspired decades of European exploration. In 1770, Joseph Banks, who was on Captain Cook's voyage, collected a sedge, one of the first known samples to be included in the study. The taxonomy of the region slowly accumulated, with plants collected and taken to different institutions around the world.
However, inland areas remained inaccessible until after WWII and base camps could only be established with the use of aircraft. These mountainous regions proved to be the most diverse and 2,800 new species have been recorded in the last 50 years.
Botanists examined more than 700,000 specimens. More than 2,800 species of orchids and 3,900 species of trees were included in the findings. “Part of the beauty of the studio is its large scale and the sheer number of collaborators,” said Cámara-Leret, who started the project in 2018. “There was already a sense of New Guinea community, but it was scattered, and this project like that brought us all together ".
Some veteran scientists who participated in the study had lived on the island for decades, and many had spent their careers studying the taxonomy of a single family of plants. “It brought together people from different generations, like scientists just starting out, then early career researchers, and then people who have been retired for more than 20 years. We had many scientists who are retired, collaborating and freely giving their time… They have an enormous amount of knowledge and very few people are learning it from them, ”said Cámara-Leret.
Another reason it has taken so long to create a list for the island is because the region has been ruled by many different European powers. Colonial education focused on the extraction of materials and agricultural work, so taxonomic knowledge was limited. After independence, there was a new generation of scientists committed to research, but the system stifled their enthusiasm.
There is only one account written by an Indonesian and none by a Papua New Guinea in this document. The researchers hope this will encourage the two governments to produce a new generation of botanicals that will help improve conservation in the future. But botanical exploration is urgently needed to ensure that unknown species can be collected before they disappear.
“It is clear, in the context of the biodiversity crisis, that this document represents a milestone in our understanding of the flora of New Guinea and provides a vital platform to accelerate scientific research and conservation,” said Dr. Peter Wilkie from the Royal Botanic Garden Edinburgh. , who participated in the study. "Research at its finest is collaborative and this shows what can be achieved when scientists from around the world work together and share knowledge and data."
Dr. Sandra Knapp, a botanist at the Museum of Natural History who was also involved in the project, described it as an "incredible achievement."
"This should now serve as the basis for much more work and discovery in the years to come," he said.