The State of The World’s Plants 2017

Cover of the State of The World’s Plants 2017 Report. Image used with permission of Kew Royal Botanic Gardens.

Orchids top the list for most traded, and endangered, plant families. This is according to the new Kew Gardens State of The World’s Plants report (SOTWP) released on May 18, 2017. The Convention of International Trade of Endangered Species (CITES) of Wild Fauna and Flora sets the rules and guidelines for traded plants. 26,567 orchids are listed in the CITES index and orchids made up 29% of CITES seizures at Heathrow.

The many plants below people’s radars is revealed by the CITES numbers. They at least show that plants we encounter have origins that may be part of a vast trade in plants, some of them endangered, and not in obvious view. Rare plant possession and cultivation is not the cultural status symbol it once was, especially in the Colonial era. However,  shipping plants around the world is still a big business per the SOTWP. Another notable number from the SOTWP: 6,075 plant species are considered invasive, many causing problems. Most solutions to invasive plants right now largely rely on herbicides like glyphosate to manage them. These are answers to only a few of the many questions the 2017 SOTWP sought to address:

Image of the report’s main questions addressed in the SOTWP Report. Used with permission of Kew Royal Botanic Gardens.

Highlights of The Report

The web version of the report gives major highlights of each section, starting with a breakdown of the kinds of plants that exist in the world and how many taxonomic families exist. Obviously, flowering plants top the list and the headline for this section observes:

“80% of the food derived from plants comes from 17 plant families”.

I’m willing to guess all 17 of those are flowering plant families. Most of what we consume and eat comes from species in only 17 out of 416 flowering plant families. Those 416 families represent 369,000 flowering plant species. Scientists also added 1,730 new vascular-plant species (lycopods, ferns & horsetails, gymnosperms, and angiosperms) to the known plants list last year. Some of these are large tree species, so it’s not necessarily small out-of-the-way plants being discovered. Biodiversity at all scales is still being uncovered.  

Another part of The SOTWP goes into the plant’s cells. 225 plants now have whole genome sequences available (compared to 777 animal genomes), with 57.7% of genomes are of crops humans use and another 17.7% are crop wild relatives, and this number is rising. Again, however, 225/400,000 total plant species underscores just how little we have explored the natural world. That said, as noted in the 2016 report, over 100,000 plants have more than one DNA sequence deposited in GenBank. There’s still a lot of wonder to be uncovered and new discoveries to be made in plants that are evolutionary chemistry labs.

A figure from the SOTWP report addressing how plants may deal with climate change, separated out by biome. Used with permission of Kew Royal Botanic Gardens.

Medicinal plants represent some 28,187 plant species have medicinal uses (~10,000 more than the 2016 report, perhaps due to an expanded definition of ‘medicinal’ to mean any plant taken as medicine, whether they truly act as medicine or not). Scientists’ discovery of more medicinal plants is likely as they continue to do more molecular/genome and clinical analyses of plants and the molecules they produce.

Climate Resilience And Vulnerability

The SOTWP also underscores areas where plants may be resilient and where they are vulnerable to climate change. For instance, an exploration of Madagascar’s plants notes that 83% of the flora is only found there, making any threats to the island’s plants potential extinction level events for many species (this is true of endemics anywhere, of course). The SOTWP also devotes a section to how plants respond to climate change (see figure at right) and what traits might make them more resilient as well as the biomes such adaptations would matter.

By contrast, it also explores the opposite: what plants are most vulnerable to extinction and climate change. Epiphytes, plants that grow on other plants, make the most vulnerable list, for instance. Further, species that don’t recover well from fires may be more vulnerable. A section is devoted to how plants are, and are projected to be affected by fires, observing that 340,000,000 hectares of land currently burn each year, on average.

The web version of the report has accessible language to nearly anyone along with lots of stunning plant pictures. The downloadable report is only slightly less easy to read and has all of the citations, deeper context, and more data displays than the web page. The SOTWP is a welcome resource for sharing the importance, opportunities, vulnerabilities, problems, and as the title says, the state of the world’s plants.

The SOTWP is worth a look and something I hope Kew plans to continue into the future, as having a window onto the world’s plants can deepen our appreciation of them and help guide decisions humans make about managing our home.

Reference

Willis, K.J. (ed.) 2017. State of the World’s Plants 2017. Report. Royal Botanic Gardens, Kew. ISBN: 978-1-84246-647-6,  © The Board of Trustees of the Royal Botanic Gardens, Kew (2017) (unless otherwise stated)