Kew Gardens State of World's Plants report finds 1,730 new species

The report, involving 128 scientists from 12 countries, reveals why some plants are more vulnerable than others to global threats such as climate change, disease, or pests, and presents data never seen before on patterns affecting plants in different regions.

Among the 1,730 plant discoveries revealed from the past year in Kew's second state of the world plants report are 5 new species of Manihot from Brazil (relatives include cassava, manioc and tapioca) and 29 new species of Begonia, found mainly in the forests of Malaysia.

There were also discoveries of seven new species of Aspalathus (Redbush) and a new parsnip species named in Turkey, as well as 9 new species of the climbing vine genus Mucuna, used in the treatment of Parkinson’s disease, which were found and named across South East Asia and South/Central America.

The American ash species pathogen, emerald ash borer EAB, could cost the US over $300bn according to the research and is now threatening Europe.

Kew science director Prof. Kathy Willis said, at the launch of the report, which coincided with a visit by Prince Charles to the gardens:

"Currently there is a disconnect between plants and people – as our cities lose their trees, respiratory and mental health problems are increasing. This report is one of many steps Kew is taking to raise the profile of plants, so that the world at large starts to understand their significance.

"It’s an exciting time to be drilling into data on the plant world. Plants are the foundation of the world’s ecosystems and hold the potential to tackle some of our most pressing issues, as we try to strike a delicate balance between our needs and those of the natural world. 

"We’ve tried to make sure that this year’s State of the World’s Plants report goes beyond the numbers to look at the natural capital of plants - how they are relevant and valuable to all aspects of our lives. From the technological advances allowing us to unravel the mysteries of plants to the detailed study of their characteristics - molecular to morphological -  we are able to get a better picture than ever before of what we have that is valuable and what is most vulnerable.  I hope this will enable us to have a global conversation about what we need to protect and conserve."

Willis led the team which authored the chapter on climate change that looks at the winners and losers in the plant world under a changing climate. They reveal that plants with thicker leaves and bark, more efficient water use strategies, deeper roots and higher wood density are better able to cope with future climate change. These include increases in drought, fires, temperature and CO2. Deeper roots are found to be better able to withstand drought as are trees with high wood density. Thicker leaves and taller grasses appear to do better in higher temperatures but conversely shorter trees do better overall. Plants that possess a combination of these traits will be the winners according to these findings. 

Willis said: "It’s a different way of thinking, to look across biomes and examine which traits plants already possess that allow some to better tolerate the cocktail of climate change that will impact our ecosystems. The interesting fact to emerge is that the suite of ‘beneficial’ traits are, on the whole, the same the world over and are as true in a temperate forest as in a desert."

The report also reveals that at least 28,187 plant species are recorded as being of medicinal use. It also asks why fewer than 16% (4,478) of the species used in plant-based medicines are cited in medicinal regulatory publications, and reveals that there are 15 alternative names for each medicinal species. The report suggests how this can be streamlined and improved in databases like Kew’s Medicinal Plant Names Service.

The report also looks at the big issues facing plant health globally with a focus on the methods being used to control the spread of pests and pathogens. It calculates that $540bn/yr is the potential cost to world agriculture if the spread of invasive pests and pathogens is not stopped. 

The main reason for the scale of the problem is the increase in trade and travel due to globalisation which has contributed to the spread of pests and pathogens around the world. Trade in live plants is especially dangerous and the report recognises the need for stricter biosecurity measures.

The report lists the top 20 pests known and the efforts to control them. Maize in Africa is being decimated by the Armyworm leading to starvation as well as rising food prices worldwide.

The report reveals that each year around 340 million hectares of the Earth's surface burns which is more than the size of India. Kew’s Sarah Wyse, who co-authored the chapter in this report, has been doing work on plant flammability traits and reveals her findings. 

A lot of fire research focuses on the broad scale effects of fire such as changing climate. However, society can't hope to make fire management decisions without information about the effects of changes in landscape flammability resulting from changes in plant composition. 

A fire resilient landscape in the future would require land managers to consider avoiding planting large monocultures of highly flammable species - as has happened in Chile. Instead, the report states that things like 'natural fire breaks' consisting of less flammable species should be encouraged, so if fires do occur, they are more likely to only affect smaller areas.  

Other headlines in this year’s report include:

  • The number of plants with assembled whole genomes now stands at 225 and has risen by over 60% the last year alone. Rice registered the largest increase in the numbers sequenced.
  • The country focus of this year’s report is Madagascar and concludes that 83% of Madagascar’s 11,138 native species of vascular plant occur nowhere else on earth.
  • Within plant conservation policy, as a result of Conference of the Parties to CITES (CoP17) an additional 304 species have been added to over 31,517 plant species  listed on the CITES Appendices - lists of species afforded different levels or types of protection from over-exploitation. It reveals that there are many individual orchid species that are as threatened as the White Rhino, like Asian slipper orchids and many of Madagascar’s orchids. CITES legal plant trade into the EU in 2014 was worth US$286million with 2,320 plant taxa imported. The Illegal trade within the EU in wild species was estimated to be worth between €8-20 billion annually (EU 2016). 
  • 6,075 vascular plant species are now documented as invasive. The report reveals that 44% of studies on the control of invasive plants in natural ecosystems examine the use of chemical methods
  • New research reveals that there is only 53% congruence between Important Plant Areas (IPAs) and Important Bird and Biodiversity Areas (IBAs) across Europe and Mediterranean region. 
  • Extinction risk is examined in more depth this year from the perspective of which plant traits help predict their fate,  concluding the epiphytes and late bloomers may be more vulnerable to extinction than other plants.  It argues that reliable predictors of extinction risk are needed to improve conservation planning.  This is the first review on this scale that examines the evidence for those traits that might influence extinction risk in plants.

Kew's State of the World’s Plants Symposium is on 25 -26 May, 2017. Kew will be at the RHS Chelsea Flower Show in the Discovery Zone, showing themed around the State of the World’s Plants report. The display features new plant discoveries such as Nymphaea thermarum, highlights from Madagascar and plants capable of withstanding extreme environments in this climate-threatened world.   

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