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Sampled Red List Index for Plants

Monitoring conservation status and global trends for plant species worldwide.
The SRLI interactive map showing hotspots of threatened plants.

The Sampled Red List Index (SRLI) for Plants was established as part of Kew’s response to the 2002 decision by the parties to the Convention on Biological Diversity to reduce the rate of loss of biodiversity by 2010. The Red List Index method, which was at that time only in use for vertebrate groups, was considered the optimum approach for Kew’s plant-based contribution. This was both due to its firm foundation in the internationally recognized IUCN Red List categories and criteria, and because the individual assessments of plant species from which the Index is constructed would be of value in their own right in guiding conservation action for thousands of plant species. Now beyond the 2010 deadline, the SRLI for Plants project continues to provide a measure of the status of plant species worldwide, responding directly to our new global biodiversity targets, namely the Aichi Target 12, the Global Strategy for Plant Conservation Target 2, and the UN Sustainable Development Goal 15.

While the Red List Indices for birds, mammals and amphibians rely on repeated assessments of the conservation status of all species in the group in question, the far greater number of known plant species (c. 400,000) makes repeated comprehensive assessments impractical over the 5-10 year timescales in which we wish to detect change. A sampled approach is therefore adopted for plants, with Kew staff actively contributing to the development of the SRLI methodology. All known gymnosperms are included, complemented by a sample of 1,500 species drawn for each of the other groups treated for the SRLI for plants: bryophytes, pteridophytes, monocots and legumes. Legumes were chosen to represent other flowering plant families in the absence of a comprehensive species list from which a random sample could be drawn.

During Phase I (2006-2010) IUCN Red List assessments for the sampled species were prepared, based on herbarium specimen data, GIS analysis, published literature and, where available, expert input. The results of Phase I were presented as the First Report of the IUCN Sampled Red List Index for Plants, published to coincide with the tenth Conference of the Parties to the Convention on Biological Diversity in Nagoya.

Plants Under Pressure - A Global Report (2010)

Plants Under Pressure - A Global Report (2012)


Pie chart showing percentage of plants classed as endangered: 4% Critically Endangered. 7% Engandered. 11% Vulnerable, 10% Near threatened, 63% Least Concern, 5% Data Deficient.
One in five plants are threatened with extinction (2010). [Critically Endangered (CR), Endangered (EN), Vulnerable (VU), Near Threatened (NT), Least Concern (LC), Data Deficient (DD)]

The format was designed to engage national policy-makers and environment correspondents worldwide, and the launch resulted in unprecedented national and international media coverage (c. 300 high profile media articles and > 100,000 blogs). The SRLI was the first study to tackle these headline questions from a globally representative sample of plant species, and it allowed policy-makers to understand which plants are most threatened, where and why to a degree of detail that has so far only been possible for vertebrates. For the first time we are now able to say that plants are more threatened than birds and as threatened as mammals worldwide, and to appreciate that conversion of natural habitats to agricultural use directly impacts one in three threatened plant species.

Results from Phase I marked the starting point for the SRLI for Plants. They provided the baseline against which future changes can be tracked - and showed clearly that urgent action is needed if we are to avoid losing one in five of our plant species. From this snapshot of the status of biodiversity in 2010, RBG, Kew is embarking on the reassessment of species from the sampled red list, starting with the monocots and legumes. Over the next five years these reassessments will contribute to our understanding of the changing status of the world’s plants over time. We will be aiming to mobilise an extensive global network of botanists, academics and conservationists to establish an international monitoring scheme, and, with our partners, begin targeted fieldwork to monitor those species which are most at risk of extinction.

The results of Phase II (2015-2020) will provide a vital component of the State of the World’s Plants report, an annual report on the status of the plant kingdom, quantifying trends in the risk of extinction of plants worldwide.

Project partners and collaborators

Natural History Museum, London
Zoological Society of London

Missouri Botanical Garden

Project funders

Charles Wolfson Trust
Defra (International Sustainable Development Fund)
Esmée Fairbairn Foundation
World Collections Programme

Rio Tinto

Annex material

Key publications 2008-2015

Brummitt, N. A., Bachman, S. P., Griffiths-Lee, J., Lutz, M., Moat, J. F. et al. (2015). Green plants in the red: a baseline global assessment for the IUCN Sampled Red List Index for Plants. PLOS ONE 10 (8): e0135152.

Brummitt, N. A., Bachman, S. P., Aletrari, E., Chadburn, H., Griffiths-Lee, J., Lutz, M., Moat, J. F., Rivers, M. C., Syfert, M. M., & Nic Lughadha, E. (2015). The Sampled Red List Index for Plants, phase II: ground-truthing specimen-based conservation assessments. Philosophical Transactions of the Royal Society B-Biological Sciences 370 (1662): 20140015.

Syfert, M. M., Joppa, L., Smith, M. J., Coomes, D. A., Bachman, S. P. & Brummitt, N. A. (2014). Using species distribution models to inform IUCN Red List assessments. Biological Conservation 177: 174-184.   

Rakotoarinivo, M., Dransfield, J., Bachman, S. P., Moat, J. F. & Baker, W. (2014). Comprehensive red list assessment reveals exceptionally high extinction risk to Madagascar palms. PLOS ONE 9 (7): e106619.

Bachman, S., Moat, J. F., Hill, A. W., de la Torre, J. & Scott, B. (2011). Supporting Red List threat assessments with GeoCAT: geospatial conservation assessment tool. Zookeys 150: 117-126.

Rivers, M. C., Brummitt, N. A., Meagher, T. R. & Nic Lughadha, E. (2011). How many herbarium specimens are needed to detect threatened species? Biological Conservation 144: 2541-2547. Available online.

Rivers, M. C., Bachman, S., Meagher, T. R., Nic Lughadha, E. & Brummitt, N. A. (2010). Subpopulations, locations and fragmentation: applying IUCN red list criteria to herbarium specimen data. Biodiversity and Conservation 19, 2071-2085. Available online.

Plants under pressure a global assessment. The first report of the IUCN Sampled Red List Index for Plants. Royal Botanic Gardens, Kew, UK. 2010 and 2012

Brummitt, N., Bachman, S. P. & Moat.J. (2008). Applications of the IUCN Red List: towards a global barometer for plant diversity. Endangered Species Research 6:127-135. Available online.

Baillie, J. E. M., Collen, B., Rajan, A., Akcakaya, H. R., Butchart, S. H. M,, Brummitt, N., Meagher, T. R., Ram, M., Hilton-Taylor, C. & Mace, G. M. (2008). Toward monitoring global biodiversity. Conservation Letters 1: 18-26. Available online.