Washington, June 24 : Researchers at Queen's University say that it is possible to identify plants that are most likely to survive the climatic shifts brought about by global warming.
"Predicting the speed at which plants are likely to migrate during climate warming could be key to ensuring their survival," says Queen's Biology professor Christopher Eckert.
He says that plants growing at the outer edges of their natural "geographic range" exist in a precarious balance between extinction of existing populations and founding of new populations, through seed dispersal into vacant but suitable habitat.
"Policy makers concerned with preserving plant species should focus not only on conserving land where species are now, but also where they may be found in the future," he says.
Dr. Eckert has revealed that this observation stems from a recent study conducted by him, which has for the first time shown that natural selection gives a boost to the seed dispersal traits of the plants growing at the edges of their natural ranges.
Reported in the journal New Phytologist, the study suggests that species that are going to persist despite a changing climate must move to stay within the climate zone to which they are best adapted.
According to Dr. Eckert, their ability to relocate with shifts in regional climate brought about by global warming will largely depend on their capacity for dispersal, especially in populations near the limit of their geographical distributions.
Forming a team with undergraduate student Emily Darling and PhD student Karen Samis, Dr. Eckert set out to study geographic distribution and dispersal biology of Abronia umbellata (pink sand verbena), a flowering plant endemic to the Pacific coastal dunes of North America.
The researchers surveyed plants throughout the 2000-km geographic range, and measured seed dispersal with a wind tunnel in the Faculty of Applied Sciences.
They observed that plants at range limits produce seeds with larger wings, thereby increasing dispersal in the winds that commonly buffet costal habitats.
"The way evolution works at range limits has been brought into sharper focus by the debate over how species will respond via migration to climate warming. It's clear that these marginal populations are adapted in ways that more central populations aren't," says Dr. Eckert.
Cornell University biologist Monica Geber writes in an editorial that the Queen's team has "flipped the question of dispersal limitation on its head to ask whether range-edge populations have diverged, through adaptive evolution, from central populations to increase their colonizing ability."
As to whether the northern peripheral plant populations are worth conserving, Dr. Eckert notes that says that it may be possible if they possess adaptations that will enhance their ability to expand their range during climate change.
Studing Vaccinium stamineum (deerberry), a threatened plant related to the blueberry, his team recently showed that the capacity for seed dispersal could increase sharply towards the range limit in Canada.
Besides that, some threatened Canadian populations produce high-quality seeds that exhibit rapid germination, and particularly high seedling growth.
"These observations are consistent with our work on coastal dune plants, suggesting that our results may have general relevance and significance for species conservation in changing global environments," says Dr. Eckert.