Researchers from the most prominent native plant seed bank use innovative modelling to better inform plant conservation and restoration under the pressure of future climate change.

Seed banks are sites dedicated to conserving seeds for long periods, even several decades. Perhaps the example that comes to your mind when you think of a seed bank is the Svalbard Global Seed Vault –an astonishing facility in the Norwegian Arctic that aims to safeguard the different plant species and varieties that sustain our society’s food supply, in case they are lost in their country of origin. Not all seed banks are, however, dedicated exclusively to the conservation of crops but to safeguard native species to prevent their extinction. 

However, make no mistakes: seed banks are far from being sites only to store seeds until some catastrophe occurs or a species becomes extinct. For example, more and more seed banks donate their collections for translocation projects, where certain plant populations are transported from locations at imminent risk to safer sites. Moreover, seed banks not only store seeds but also guard a great deal of information about the species and their germination characteristics that can be used for different purposes, such as academic research.  

A stellar example of this is the European Native Seed Conservation Network (ENSCONET), which brought together more than 20 European seed banks and built a unique database for the flora of this continent. This data has been used in several studies, including recent research on how germination responses vary to different environmental factors across Europe –the first study to do such a continent-wide analysis. This work highlighted the fundamental role of seed banks in providing essential information on germination ecology. However, one of the authors of this work –Dr Efisio Mattana– wanted to go one step further: to use seed bank data to predict the effects of climate change on germination.  

To do this, Mattana assembled a research team to analyse the data produced at the research centre where he is currently affiliated: the Millennium Seed Bank of The Royal Botanic Gardens, Kew, which is located in Wakehurst Place (Southern England) and houses more than 2 billion seeds of more than 39 thousand species from all over the world. The authors consolidated the list of 176 species present in the area whose germination had already been investigated by the Millenium Seed Bank and modelled how their germination responded to different temperatures and how it will be affected by the expected temperature increases. To do this, the authors focused on the effect of temperature increases in spring and autumn – the two periods when most species in the area tend to germinate – and two climate change scenarios: a more optimistic one, where temperature increases are not expected to be as severe (2.7 °C increase by 2100), and a more pessimistic one where higher increases are expected (4.4 °C increase).

The Millenium Seed Bank building at Wakehurst Place (Photo by Patche99z, Wikicommons). 

Still, one of the most novel features of this research is that authors also assessed whether these responses varied within different use categories, such as medicines, fuels and food sources, allowing the authors to determine whether any of these benefits obtained from these plants are at increased risk from climate change. 

The study results indicate that Wakehurst’s flora is at considerable risk of germination under the most pessimistic climate scenario, although this adverse effect is only predicted for spring. This finding means that in this scenario of severe temperature increase, spring temperatures are expected to be higher than those where species can germinate, putting in danger those whose germination is restricted to this season.

Some of the species from the Wakehurst Flora that were evaluated in Mattana and colleagues’ study. Top-left: Creeping buttercup (Ranunculus repens) (Photo by Matt Lavin, Wikicommons). Top-right: English bluebell (Hyacinthoides non-scripta) (Photo by AnemoneProjectors, Wikicommons). Bottom-left: Primroses (Primula vulgaris) (Photo by Robert Flogaus-Faust, Wikicommons). Bottom-right: Foxglove (Digitalis purpurea) (Photo by Matthijs van den Berg, Wikicommons). 

When the authors assessed the species separately, they found that some species were even more threatened by increases in temperature, such as the creeping buttercup (Ranunculus repens), the English bluebell (Hyacinthoides non-scripta) and primroses (Primula vulgaris). These species only manage to germinate in a narrow range of temperatures or when exposed to specific temperature combinations, which makes them more vulnerable to temperature changes. 

Surprisingly, the research also shows that the impact of temperature increase on seed germination doesn’t vary between different use categories, with all of them exhibiting a similar behaviour to the whole flora. In other words, this research indicates that there are no differences in the level of vulnerability of these groups to climate change. However, when the authors compared the phylogenetic diversity of these groups –a measure of the diversity of the different taxonomic groups that make up these groups– it shows that some groups include a greater variety of groups and may, therefore, be more resilient to the effects of climate change than others. 

These results provide a clear roadmap for the use of the seeds of these species in future conservation and restoration efforts. On the one hand, the study has identified which species will be able to respond better to the temperature increases that climate change will bring. It also highlights which species will be most vulnerable to these changes and requires additional strategies to conserve and use them. 

The methodology employed by Mattana and his colleagues can be scaled and applied in diverse regions and ecosystems. With seed banks scattered in every corner of our planet, these institutions have great potential to use the information they have accumulated over the years better to inform conservation and restoration efforts in their regions. This study offers a blueprint for a more resilient and sustainable future, where the invaluable contributions of native plants continue to thrive despite the challenges of global warming. We hope that other seed bank researchers follow Mattana’s example and be motivated to put the valuable data they hold to new use. 

READ THE ARTICLE: 

Mattana, E., Chapman, T., Miles, S., Ulian, T., & Carta, A. (2023). Regeneration from seeds in a temperate native flora: A climate‐smart and natural–capital‐driven germination risk modelling approach. Plants, People, Planet. 5(6): 908-922. https://doi.org/10.1002/ppp3.10378 

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