Living On the Edge

Natural selection favors plants that live on the edge of their natural geographic range, according to a recent study from Queen’s University published in the journal New Phytologist. An example of these plants is the pink sand verbena, depicted above, that grows along North America’s Pacific coastal dunes.

This finding emphasizes the need to preserve not just the current habitat of these plants, but their surroundings as well. Their ability to spread their seeds and take root in these currently vacant areas may prove to be crucial as they try to find more hospitable temperate zones.

"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," says Christopher Eckert, a Canadian biology professor at Queen's University in Kingston, Ontario. "It's clear that these marginal populations are adapted in ways that more central populations aren't."

Using a wind tunnel, Eckert demonstrated that plants living along the range limits produce seeds with larger wings that allow them to travel further along winds that are common to coastal habitats.

Eckert also recently demonstrated that the seed dispersal ability of the Vaccinium stamineum (deerberry) seems to increase sharply as it approaches its range limit in Canada.

-- Greg Soltis

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Image Credit: Queen’s University