Increasing temperatures across the globe are forcing plants to either adapt or migrate away from the equator, or to higher elevations, as the environment changes their habitats. While not all species have yet been affected, a new study shows that it will not be long until they will reach a climatic tipping point.
Almost a quarter of the world’s population, and many vital ecosystems, could be affected by plant migration due to climate change.
Studies on bistort and moss campion from New Mexico to Alaska by Daniel Doak of the University of Wyoming and William Morris of Duke University showed how plants at the edges of the southern range (i.e. the limit) of the distribution had lower survival times but grew faster in some years, despite warmer temperatures.
According to Professor Doak: “Populations there are no less stable [in the south] than those in the north”, however the research also indicated that once climatic changes becomes severe, these species will no longer be able to sustain themselves.
As Professor Morris explained: “Up to a point we may see little effect of warming for many organisms. But past a climatic tipping point, the balance of opposing effects of warming will likely cease, leading to subsequent rapid declines in populations.
“But understanding when we will reach this limit is a problem, especially for mountain systems, where most current climate models are unable to predict exact climate change in the complicated topography.
“At the far southern limit of the species, in New Mexico, they already live only very near the summits of the peaks, so there is nowhere to go up. And that is close to true in parts of Colorado as well,” added Prof. Morris. Given this, it will not be long until the southern limits of the species’ distribution is dramatically changed.
Think of a washing machine…
You put the clothes in. With some soap powder they become clean, which takes them from the original dirty state to a clean one - this can be likened to an increased rate of growth. However, in this case, while growing they fray a little, and this is like the species’ survival rates.
But if the machine goes on too long, the clothes begin to shrink and become useless; this is what has been suggested is happening with bistort and moss campion – once it reaches tipping point it makes it difficult, or even impossible, to come back. After all, how many of us can re-grow that shrunken jumper?
Although the Intergovernmental Panel on Climate Change (IPCC) and scientists agree that these predictions for change around the world are accurate, it is difficult to quantify the exact degree due to the many unknown factors involved. However, this study goes so far as to suggest that the future of plant species inhabiting cold environments may be hanging by a thread.
The Day of the Triffids may not be upon us just yet but to compensate for climate change, plants are growing faster and will have to keep moving until eventually they can go no further. There are no experts advising on what will happen when they reach that point. Let’s just hope they don’t start fighting back.
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