Plants are incredibly important to the health of island ecosystems. More than building habitats for our favorite species of birds, crabs, and other animals, they have the power to change the shape of an island’s coastline and even trap greenhouse gases from the atmosphere. Plant roots hold soil together, preventing erosion, and plants on islands capture millions of metric tons of carbon per year. They also provide essential food and materials to nearby island communities. But did you know that island plants make up a huge percentage of global plant biodiversity?  

About 31%, or almost a third, of all plant species are endemic to islands (meaning they are only found there). These numbers come from a new study by scientists from around the world which tallies up all the vascular plant species (basically everything except lichen, moss, algae, and fungi) native to individual islands and archipelagos around the world. As many as 70,000 plant species worldwide could be endemic to islands—an extremely high number, considering the fact that islands only make up 5.3% of the world’s land area. This reinforces just how special islands are and what we stand to gain for global biodiversity when we restore them.  

The study, titled “Islands are key for protecting the world’s plant endemism,” with lead author Julian Schrader of Macquarie University was published in Nature on the 24th of October. It’s full of incredible statistics that underscore the importance of plants for islands and for the planet. Here are just a few: 

• 44,147 species, or 70% of all island endemics, are found only on a single island. 

• Out of 36 global biodiversity hotspots, 9 are exclusively on islands, and 3 others have a significant island component. 

• 31% of all vascular plant species are native to islands, and 21% are endemic to islands. 

• 31% of IUCN-listed species (that is, species with populations that are unstable or declining) are native to islands, but 57% of island endemics are threatened, with 14% critically endangered, 23% endangered, 14% vulnerable, and 6% near threatened. Additionally, more than half of all extinct plant species worldwide—55%–are island species. 

Island species face significant threats from habitat degradation, invasive species, and climate change. Their small populations and unique adaptations make them particularly vulnerable.  

At Island Conservation, we’ve seen the knock-on effects of holistic restoration firsthand—and rebalancing even one variable can lead to astonishing results. On Palmyra Atoll, for example, we found that removing an invasive mammal species (invasive rats) led to a 5000% increase in native Pisonia seedlings.  

Research shows seabirds prefer nesting in native trees over introduced ones. The return of the native forest will provide more breeding opportunities for seabirds, which bring important nutrients from the sea to the island through their guano, which in turn supports healthy soil and runs off to support life in the nearshore marine environment.  

Our commitment to holistic restoration means considering all aspects of ecosystem recovery from ridge to reef. Because everything is connected, highlighting island plants is key to showing the world the importance of island ecosystems in general. Join us as we work to restore islands around the world by making a donation today, and join our newsletter for updates and more exciting studies like these!