Will our plants keep up with warmer springs?

Thanks to your records from Nature’s Calendar, we know that spring is getting earlier as temperatures rise. How plants will continue to respond in the future is still uncertain but I have recently looked into this question for a study published in the scientific journal, Global Change Biology.

As part of my PhD at the University of Edinburgh, I had the chance to analyse hundreds of thousands of Nature’s Calendar observations of spring timing in plants. This study used first leafing and flowering dates of 22 plant species, collected from 1998-2014 to look at two things:

  • How do different plant species respond to temperatures?
  • Will plants continue to leaf or flower at the best time for growth as temperatures rise?

How do plants know it's spring?

Plants respond to signals, or cues, in their environment to tell them when to start to grow during spring. These cues help ensure a plant grows at the best, or optimum, time to lead to successful reproduction and survival. The cues that are most important in telling plants when to produce leaves or flowers are temperature and day length. Therefore, as temperatures rise as a result of climate change, the optimum time to grow may also change.

This study found that all 22 plant species respond to spring temperatures by producing leaves or flowers earlier when temperatures are warmer. The next question I looked at was whether these plant species were flexible enough to keep up with future changes to their optimum timing.

Which plants can keep up with climate change?

The flexibility of a species to shift the time they grow, in response to temperatures changing, is called plasticity. My analyses found that 7 species; wood anemone, silver birch, alder, cuckooflower, beech, ash, and cocksfoot, are likely to be able to keep up with changes in their optimum timing through plasticity. 

Garlic mustard

I found that four species, which included native bluebells and garlic mustard, may not be able to track the optimum timing for growth through plasticity. This could put these species under pressure to adapt rapidly through natural selection. During the time it takes to genetically adapt to changed temperature conditions over several generations, plants may face other pressures on their survival. This could include increased competition and impact on their reproductive success.

This study also found that larch and sycamore may not be able to track the optimum timing. However, because these species are non-natives, there may be additional factors influencing the result, and therefore more work is needed to test these findings.

Conducting work like this is a very useful step to help identify future research questions. Nature’s Calendar data is a valuable source of information for scientists looking at how different species respond to their environment, and what this means for the future. The results from this study suggest that some plants may be able to adapt to future conditions more easily than others. Further work, including experiments, is needed to test the patterns found here.

Help us monitor animals, plants and fungi near you

Join Nature's Calendar and you records will help us improve our knowledge of how species respond to climate change. And as spring gets closer, now is the perfect time to contribute your own observations.