SEX, DRUGS AND PLANT SURVIVAL

By Grady Semmens

Plants in areas like tropical rainforests are struggling to survive because there aren’t enough birds and bees to help them reproduce, says a new international study led by a University of Calgary biologist.

The finding raises concerns that more may have to be done to protect the Earth’s most biologically rich areas—often the source of new prescription drugs and other important substances.

Tropical rainforests and other regions that are home to the widest range of plant and animal species may be at the greatest risk of extinction, says Dr. Jana Vamosi, an evolutionary biologist and post-doctoral research associate in the U of C’s Department of Biological Sciences.

As the number of birds, bees and other pollen transporters declines around the world, competition for their attention is becoming increasingly fierce among the flowering plants that need their services for reproduction.

“Many plants rely on insects and other pollen vectors to reproduce. We’ve found that in areas where there is a lot of competition between individuals and between species, many plants aren’t getting enough pollen to successfully reproduce,” says Vamosi.

And if plants can’t survive, neither can animals, she says. “These biodiversity hot spots are important because they are where we most often find new sources of drugs and other important substances. They are also the areas where habitat is being destroyed the fastest.”

The study, “Pollination decays in biodiversity hotspots” will be published in the next issue of the Proceedings of the National Academy of Sciences and will be posted this week on the academy’s website at www.pnas.org

Vamosi and colleagues at Washington University, University of Pittsburgh, University of California, Santa Barbara and Monash University in Melbourne, Australia reviewed pollen studies from every continent except Antarctica to examine the relationship between species richness and pollination in flowering plants.

The analysis found that ecosystems with greater number of species, including the jungles of South America and Southeast Asia and the rich scrublands of South Africa, showed bigger deficits in pollination compared to the less-diverse ecosystems of North America, Europe and Australia.

“High species diversity has often been seen as stabilizing ecosystems from extinction but this shows that’s not necessarily the case,” Vamosi said. “It turns out that plants that have more species neighbouring them may have to compete harder for pollination and therefore be more at risk of extinction, especially where pollinators are in decline.”