Just Published: State of the World’s Plants
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The report – prepared by Kathy J. Willis and Steve Bachman with contribution from 80 experts from the Kew Royal Botanic Gardens in London – provides, a first-time ever baseline assessment of our current knowledge on the diversity of plants on earth, the global threats these plants currently face, and the policies in place and their effectiveness in dealing with these threats.
The authors write: “Our main findings not only illustrate the incredible amount of information that is already available about the world’s plants but also the significant knowledge gaps. By synthesising our current understanding of the State of the World’s Plants, we hope that its findings will galvanise the international scientific, conservation, business and governmental communities to take positive action to work together to fill the knowledge gaps highlighted and expand international collaboration, partnerships and frameworks for plant conservation and use.”
On the diversity of plants, the report estimates 391,000 vascular plants known to science of which 369,000 are flowering plants. Around 2,000 new vascular plant species are described each year.
In 2015 these included a massive leguminous tree (Gilbertiodendron maximum), more than 90 species of Begonia, 13 new species from the onion family, and discovery of a close relative of sweet potato (Ipomoea batatas). Most were found during fieldwork, some in herbarium specimens, while one of the largest carnivorous plants known (1.5m in height) a new insect-eating plant, Drosera magnifica was first discovered on Facebook. However, there are still large parts of the world where very little is known about the plants. Identification of these important plant areas is now critical. Similarly, we still only know a fraction of the genetic diversity of plants and whole-genome sequences are currently available for just 139 species of vascular plants.
Knowledge of the impacts of climate change on plants is known for some regions of the world, but there are still large areas for which little or no research exists. In those areas where good data is available, clear impacts are visible including changes in flowering times, turnover in plant communities and movement of species with changing climates.
All but one of the world’s biomes have experienced more than 10% change in land-cover type in the past decade due to the combined impacts of land-use and climate change.
A large global movement of alien invasive plant species is occurring. Around 5,000 species are now documented as invasive in global surveys. These plants are causing large declines in native plants, damaging natural ecosystems, transforming land-cover and often causing huge economic losses. Those that are most invasive share a similar life-form – which is the ability to die-back during unfavourable seasons and survive as bulbs, rhizomes, tubers, root buds or seeds. Japanese knotweed is a classic example of this life-form which survives underground as a rhizome.
There are many emerging threats also occurring with plant diseases caused by fungal, bacterial and viral pathogens. Research effort into these diseases is skewed towards countries with a wealthier research infrastructure.
Given the threats associated with climate change, land-use change, invasive plants and diseases, best estimates lead us to believe that 21% of the world’s plants are currently threatened with extinction.
International trade in endangered plants is causing additional pressure on wild biodiversity and strict enforcement of international legislation is crucial. Adoption and implementation of policies such as CITES (Convention on Trade in Endangered Species) other international legislative instruments, such as the Nagoya Protocol, already appear to be having some effect at enabling countries to best conserve and utilise the biodiversity they hold.
How many vascular plant species are known to science, and how do we know this?
How many vascular plant species new to science were named in 2015?
What is our current status of knowledge on the genetic diversity of plants and plant evolutionary relationships?
How many plant species currently have a documented use and what are they used for?
Which areas of the world are the most important to protect because of their incredible plant diversity?
What is the current status of plant knowledge in individual countries? A focus on Brazil.
How is climate change affecting plant species, populations and communities globally?
Where in the world are the greatest changes occurring in land-cover type and what are the main drivers of this change?
How many plant species are now classi ed as invasive and what are the predominant life-forms of these invasive plants?
What diseases pose the biggest threats to plants globally and where is the greatest concentration of research effort into these diseases?
What is our best estimation of how many plants are threatened with extinction?
What is the current status of international trade in endangered plant species and how effective are current policies at policing unsustainable or illegal international trade?
How many countries are now parties to the 2014 Nagoya Protocol on Access and Benefit Sharing of plant genetic resources and what are the early signs of its effectiveness?