June 10, 2019

expert reaction to plant extinctions

A global analysis published in Nature Ecology and Evolution collates all plant extinction records documented from across the world. The unique dataset shows how many plant species have gone extinct in the last 250 years.

Dr Bjorn Robroek, Lecturer in Ecology, University of Southampton, said:

“This is an interesting piece of work. The science seems sound and thorough. The finding that extinction rates are highest in ‘biodiversity hotspots’ that are at risk due to land-use change is alarming and echoes the message put forward by the recent IPBES report (https://www.ipbes.net) that current losses in suitable habitat should be high on the political agenda. Indeed, extinction rates are likely still underestimated and more effort needs to go in getting good estimates about extinction rates in underrepresented ecosystems (not only biodiverse systems as the authors state) and plant groups, including algae. 

“That the authors found no clear pattern in evolutionary-closely-related plants regarding extinction rates is very interesting as it suggests that the reason for extinction is not linked to genetics. It is well known that plants with low investment in sexual reproduction and slow growth are vulnerable to extinction. To fully understand the importance of these findings, the next step is to link plant characteristics and the role of plant species in an ecosystem to plant extinction patterns, and to identify generalities across ecosystem and plant groups.”

Dr Alan Gray, Plant Ecologist, Centre for Ecology & Hydrology, said:

“This paper builds significantly on previous plant extinction research, including by the Centre for Ecology & Hydrology, and provides a robust database and estimate of current extinction rates in plants.

“Scientists have not studied the vast majority of the world’s plants in any detail, so the authors are right to think the numbers they have produced are large underestimates and there are likely to be extinctions that have been overlooked.

“To address this extinction crisis, humanity will need to devise solutions that include strategic policies and target funding towards conservation research and action.

“It’s time to ask not what biodiversity can do for us but what we can do for biodiversity.”

Dr Rob Salguero-Gómez, Committee member, British Ecological Society & Associate Professor, Department of Zoology, University of Oxford, said:

“Plants underpin and provide key resources to entire ecosystems worldwide. However, much of the effort to quantify the loss of species diversity worldwide has focused on charismatic species such as mammals and birds. Understanding how much, where, and how plant species are being lost is of paramount importance, not only for ecologists but also for human societies. We depend on plants directly for food, shade and construction materials, and indirectly for ‘ecosystem services’ such as carbon fixation, oxygen creation, and even improvement in human mental health through enjoying green spaces.

“The study by Humphreys and colleagues examines how much plant diversity has been lost in the last centuries, making use of detailed records that go back to Linnaeus’ times. The authors found that previously reported extinction rates for plants are largely underestimated, having found a 4-fold quantification of extinction in the last centuries compared to those present in the IUCN Red List of species. The researchers of this examination into the plant kingdom found that about 2.3 seed-forming plant species have gone extinction per year in the last 250 years, an even more alarming rate considering that the overall rate of extinction has more than doubled in the last hundred years. Interestingly, the authors found woody species (which provide key timber and non-timber forestry products) to have a greater rate of extinction, particularly in subtropical and tropical regions – the ones that tend to house a greater degree of plant diversity. The low predictive ability of the phylogenetic relationships reported in this study among sister species is of particular concern, as it makes the prediction of the winners and losers of on-going climate change ever more challenging.”

‘Global dataset shows geography and life form predict modern plant extinction and rediscovery’ by Aelys M Humphreys et al. was published in Nature Ecology and Evolution at 16:00 UK time on Monday 10th June. 

Declared interests

Dr Bjorn Robroek: No conflicts of interest. 

Dr Alan Gray:  Dr Gray’s research on plant extinctions was cited in references of the latest study. Dr Gary has previously worked with colleagues at Kew but not with any of the authors of this paper.

Dr Rob Salguero-Gómez: No conflicts of interest to declare.