New Guinea – home to more than 13,500 species of plants – has the most plant diversity of any island in the world, according to a new study.
A group of more than 90 botanists from 56 institutions in 19 countries worked with a wide array of samples. They found that the island has 13,634 species from 1,742 genera and 264 families, with New Guinea surpassing plant diversity from other islands on Earth.
Not only is New Guinea the largest tropical island in the world, but also the most tectonically complex. It supports a mosaic of ecosystems, from mangroves and lowland rainforests to high-elevation alpine grasslands with snow-clad peaks higher than Mt. Blanc.
The latest findings puts New Guinea well ahead of biodiversity hotspot Madagascar with 16% more species.
Of the species found on New Guinea, orchids accounted for 20% of the flora in Papua New Guinea and 17% of Indonesian New Guinea, which is comparable to orchid richness in megadiverse countries such as Ecuador (23%) and Colombia (15%).
Tree species also accounted for 29% of all the flora – by comparison, the Amazon has 2.6 times more tree species, but in an area 6.4 times larger.
The findings, published in Nature, notes that two-thirds of New Guinea’s plants – over 9,300 species – are endemic, found exclusively in that region.
Since the 17th century, botanists have been identifying and naming plants collected in New Guinea, storing collections in herbaria in-country in Papua New Guinea, Indonesia and also in institutions overseas, including Kew’s own Herbarium.
However, despite notable advances in the past decades in resolving the taxonomy of many New Guinea plants, information remains scattered, as botanists worked mostly independently from each other.
Lacking a unifying effort to build a checklist to the region’s plants, great uncertainty remained as to how many plant species grew in New Guinea.
Effectively, compared to other areas like the Amazon for which plant checklists have been recently published, New Guinea remained the ‘last unknown’.
It is intended that this new plant checklist will accelerate botanical research in New Guinea and inform conservation policy and planning to help ensure the safety of the island’s flora.
Image Credits: © William Baker/RBG Kew
Rosa Medea is Life & Soul Magazine’s Chief. She writes about lifestyle including sustainable and green living.