Fanny Schertzer, via Wikimedia

Mangroves, such as this one in East Africa, are among the most threatened of plant biomes, according to a new report. Fanny Schertzer, via Wikimedia

First, the good news: A report by the Royal Botanic Gardens at Kew in England has provided the first comprehensive assessment of the world’s plants. That assessment concluded that, excluding algae, mosses, liverworts and hornworts, there are approximately 390,900 plant species known to science, of which an estimated 369,000 are flowering plants.

And that total seems destined to rise: An additional 2.034 species were discovered in 2015 alone – including a tree called Gilbertiodendron maximum, which grows up to 145 feet high in the forests of Gabon; ninety new species of Begonia; five new species of onion; and an insect-eating plant in Brazil.

But then the bad news: The same report determined that 21 percent of those plants are in danger of extinction.

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That latter figure was derived by applying criteria established by the International Union for the Conservation of Nature, which compiles Red Lists of threatened species of fauna and flora, and examining satellite images to determine changes in land cover between 2001 and 2012. The biggest factor by far is habitat destruction in the form of agriculture, deforestation and construction and development.

Mangroves underwent the most significant change, with more than a quarter of their area transformed over the course of the decade, lost mostly to shrimp farms and golf courses  – although the losses were partially offset by mangrove growth in other areas. Tropical and subtropical coniferous forests saw changes of almost 25 percent.

Invasive plant species are also considered a major problem, with approximately 5,000 species worldwide threatening native plants and damaging natural ecosystems. Ultimately, climate change is also expected to take its toll, with more than 10 percent of the planet’s vegetation considered highly vulnerable to climatic variability.

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The report — which took a team of 80 scientists more than a year to compile — is intended to be the first of an ongoing, annual assessment, to help the development of conservation strategies.

“This is the first ever global assessment on the state of the world’s plants," said Professor Kathy Willis, director of science at the Royal Botanic Gardens, Kew in a press release. "We already have a ‘State of the World’ (for) birds, sea-turtles, forests, cities, mothers, fathers, children even antibiotics but not plants. I find this remarkable given the importance of plants to all of our lives — from food, medicines, clothing, building materials and biofuels, to climate regulation. This report therefore provides the first step in filling this critical knowledge gap.”

“But to have effect, the findings must serve to galvanize the international scientific, conservation, business and governmental communities to work together to fill the knowledge gaps we’ve highlighted and expand international collaboration, partnerships and frameworks for plant conservation and use.”