Climate change is here...

Climate change will play Russian roulette with extinctions – we don’t know what will be next…

by Jordan Holmes

Dr Mick Hanley, ecologist
at Plymouth University

Storm surges, flooding and sea-level rise are now common in the news. Over Christmas, the media was full of images of flooded homes, fields under water, high winds and torrential rain. But outside in the park, the daffodils were in flower. What does this mean?

Recent research shows that plants are responding to climate change, but not always in the way we predict. Science has a tendency to disregard results we can’t explain as anomalies, but a new review paper challenges these views, arguing that unexpected deviations are just as important as expected responses for predicting the outcomes of what is arguably the biggest challenge we now face: climate change. 

This review by Hanley and lead author Professor Camille Parmesan, also of Plymouth University, came about after a conference session on the effects of climate change on plants in Sacramento in 2014. The aim of the meeting and review was to spur on new research in this area.

Dr Mick Hanley is a researcher in ecology at Plymouth University. Specialising in plants and their responses to climate change, he feels that the impacts are inevitable. “After 30 years of climate change research, we’re little better at predicting how plant communities will respond to it,” he says. “The time frame doesn’t matter – if species are lost, we can only say ‘I told you so’. And there is a time lag between cause and effect.”

What most concerned Mick was the lack of predictive capability, and the fact that people in power are only just starting to listen, despite the fact that Camille Parmesan has travelled all over the world, including presentations given at the White House, to speak on climate change and policy. Hanley notes that The Paris conference of 2015 is a start towards some improvement, but there is a long way to go.

“Already there are more frequent, and worse, storms, floods, fires, droughts. Australia and South Africa, both biodiversity hotspots, have seen increased droughts and fires,” he says. “This disturbance … of a group particularly at risk, of 8000 species in South Africa – 6000 endemic – and 8000 in Western Australia, in environments where conditions are already extreme… have already seen horrific extinctions, caused by humans through changes in the fire regime and land use.”

Predicted changes in Australian climate will affect plant distributions. Source: CSIRO (2001)^.

Past research

After experiments on elevated CO2 and its effect on plant community development, Mick moved on to an EU project on coastal defence. This integrated natural ecosystem defences, such as sand dunes and marshland, with hard engineering flood mitigation strategies. This gave rise to his interest in sea rise and storms, as low-lying areas become increasingly at risk. Mick ran experiments on the effect of salt water flooding on plants, and his research showed sea water rise and flooding will change plant community assemblage. Some plants cope better with submergence than others, which will have repercussions for coastal ecosystems.

This meant Mick was in the perfect position to collaborate with Camille on a review of all the literature around plants and climate change. Their paper covered 4000 species across the globe.

Climate change is here

Mick believes that the most important points from his research are that while we don’t know everything, we shouldn’t ignore departures from expectation, as they can give valuable insights into the effects of climate change on plants. There is also a lot of room for more research, particularly in how warming affects so-called autumn delay and its ecological repercussions for plants that require a cold snap for germination, and in the combined effects of increased CO2 concentration with the expected temperature rise. Climate change can no longer be avoided, but to cope with it, it must be understood. 

Reference

Parmesan, C., Hanley, M. E. (2015) Plants and climate change: complexities and surprises. Annals of Botany 116: 849–864, 2015 doi:10.1093/aob/mcv169, available online at www.aob.oxfordjournals.org 

This article was originally submitted as a science communication assignment, for part of the BSc (Hons) Conservation Biology degree. It has been edited before posting here.