By Christopher Chandler
Last month welcomed the second annual State of the World’s Plants (SOTWP) Symposium – a two day event based at the Royal Botanic Gardens, Kew. The symposium attracted over 250 people from 30 countries around the globe to hear about the latest discoveries and knowledge in plant science. The 2017 SOTWP report aimed to provide an overview of the current knowledge of the world’s plants, including their distribution, diversity and uses. Each of the 12 chapters of the report is also online where you can view exciting graphics and maps detailing the impact of global environmental change on the world’s plants. This year’s report had a country focus on the plants of Madagascar, an area well known for its high levels of endemism.
Everybody grouped together for photo outside the Jodrell Laboratory, Kew.
No matter how many times I hear the percentage of plant species that are endemic to Madagascar, I am always amazed! We were reminded that 83% of the 11,138 native species of plants in Madagascar occur nowhere else on earth; and if that wasn’t enough, we learnt that recent discoveries of new plant species (the majority of which are endemic) will most likely boost that figure to 87%. Other discoveries were also highlighted such as 29 new species of Begonia which have been discovered mainly in the tropical forests of Malaysia, 336 new species of Orchid in South America and South-East Asia and 27 new species of rainforest trees in the genus Sloanea (Elaeocarpaceae) mainly from the Andes and Central America .
Despite the diverse and unique biodiversity of Madagascar, habitat destruction is substantial and as a result a large proportion of the native species of vascular plants face an uncertain future. For example, the SOTWP report found that 98% of all palms in Madagascar (204 species) are endemic to the island, however 83% are threatened with extinction. Consequently, the first session of the symposium (Madagascar: megadiverse and misunderstood – how can we hope to reverse threats to biodiversity?) delved straight into this issue, although suggesting it’s not all doom and gloom for the conservation of Madagascar’s flora.
Now, there are over 120 protected areas covering 6.4 million ha (10.8% of the land surface) as well as reliable, online information for all plant species through the Madagascar Catalogue. Furthermore, efforts focusing on community-based conservation projects are successfully achieving lower rates of deforestation and increasing environmental awareness among local people. Therefore, it was suggested that a mass extinction can be averted by coordinating sustainable community-based protection of carefully selected sites that contain the majority of Madagascar’s floristic diversity.
Discussions on invasive plants from session 4.
The need to reduce threats to plant diversity was emphasised when we learnt that at least 28,187 plant species are currently recorded as being of medicinal use. This, surely, is a direct incentive to conserve biodiversity globally. In Session 5 of this year’s symposium (From field to healed: how do we detect the medicinal plants of the future?) we were joined by Her Excellency, Dr Ameenah Gurib-Fakim, the President of the Republic of Mauritius, who gave her insight on the state of medicinal plants in Africa and their documentation in Pharmacopoeias. It was concluded that a lack of understanding on medicinal plants will lead to a focus of trade on a relatively few number of species with sustainability and conservation issues. Furthermore, with an increasing demand for herbal medicines it is hugely important to document and realise the current and future medicinal benefits from plants. In Madagascar, medicinal plants are not well documented, however, plants such as the Madagascar periwinkle (Catharanthus roseus) are known for their anti-cancerous properties. Unfortunately, unsustainable land use practices, rapid population growth and disturbances, such as fire, continue to pose a threat to plant diversity.
In the third session (Wildfires: a necessary evil?), both Professors William Bond and Andrew Scott explained that fire is a key process in biodiversity hotspots and a critical component of savannah ecosystems, in order to stimulate germination, encourage new growth and rejuvenate the landscape. Furthermore, natural fires are required to limit growth in forest areas and maintain an open canopy so plants can continue to grow in the understory. Prof. Bond demonstrated his love for fires when he said: ‘Climate change may mean we’re heading back to the boring Eocene when natural fires become rare’. With there already being a divide between scientists working in grassland and forest ecosystems, the following statement ‘As long as we are planting trees, then that’s a good thing’ – you can imagine didn’t sit well with the fire-loving, savannah ecologists.
This got me thinking – Is it better to lose, for example, 50 Orchid species to make way for an increase in forest that can store vast quantities of carbon. What is more valuable in terms of ecosystem services? Do we aim to conserve as many species as we can or is it now fundamental to value nature in a sensible way for conservation and ecosystem functionality (see ref 3)? This was, of course, the title of the final session of the Symposium (Valuing nature: which plants species are most valuable?).
Prof. Philip Stevenson focused on what are the most important plants for pollinators. It was reported that three species of plants in the UK produce 50% of nectar nationally. However, whether they support a sufficient diversity of pollinator species is not clear. Whilst there is considerable concern over declines in bumblebee abundance, it was suggested that bumblebees may not be the most valuable UK pollinator. Findings from a study in 2011 found that wild insect pollinators make a much bigger contribution to UK crop production than previously thought . Consequently, Prof. Stevenson was able to conclude that the state of the world’s plants will very much depend on the state of the world’s pollinators and vice versa.
Quantities of nectar in different habitats in the UK.
Besides a great line up of speakers over the two days, 53 posters were also presented, including:
- The GlobalTreeSearch, attempting to catalogue the world’s 60,065 tree species.
- The Local Ecological Footprinting Tool (LEFT), a web-based tool providing high-quality environmental information.
Prizes for posters included one of our own, Catherine Waite from the University of Nottingham, using Unmanned Aerial Vehicles (UAVs) to investigate scale and patterns of liana infestation in the tropical forests of Malaysia (see recent blog below).
To conclude, a detailed knowledge of plants is critical to human life on Earth. This State of the World’s Plants report has identified the main threats to plants now and in the future, including climate change, land use change, invasive plants and diseases. It has also examined the emerging evidence for the characteristics of plants that will make them more or less vulnerable to future threats. The report highlighted the rapidly accumulating discoveries and knowledge on our world’s plants that can help build a solution to face the global challenges of the future.
 Pennington, T. D. 2016. Prodromus sloanearum americanarum. Opusc. Neotrop, 2, 3–24.
 Breeze, Tom D., et al. 2011. Pollination services in the UK: How important are honeybees? Agriculture, Ecosystems & Environment, 142 (3), 137-143.
 Seddon N, Mace GM, Naeem S, Tobias JA, Pigot AL, Cavanagh R, Mouillot D, Vause J, Walpole M. 2016. Biodiversity in the Anthropocene: prospects and policy. Proc. R. Soc. B, 283, 20162094. http://dx.doi.org/10.1098/rspb.2016.2094