Wildflowers Baffled Darwin Too

Biologist looks at the survival strategies of Ontario’s spring wildflowers

Stefan Weber

Master’s student Stefan Weber says there’s a reason trilliums carpet the forest floor before the trees come into leaf.

Not only are those spring wildflowers good-looking, they’re also smart. So says U of G master’s student Stefan Weber, who hopes to help preserve and restore dwindling communities of woodland plants and the pollinators that feed on them and, in turn, provide food for the rest of us.

Fresh from a two-month odyssey through the Carolinian forest of southwestern Ontario and Michigan, Weber is learning more about how plants work together and with pollinating species of insects, birds and mammals.

He has only begun his analysis. But he’s already seen enough to confirm that early spring bloomers ― trilliums, bloodroot, hepatica, blue phlox ― likely follow shrewd strategies to carpet the forest floor with their pollinator-friendly flowers before the canopy fills in and deprives them of light.

“Not only did plants evolve in response to pollinators, but they also evolved in response to each other,” says Weber. An arts and science grad, he began his graduate studies last fall with integrative biology professor Christina Caruso.

Beginning with the appearance of the first spring ephemerals in late March, he travelled from Michigan through southwestern Ontario. Stops included Point Pelee, Backus Woods near Long Point, and a Cambridge nature reserve that had awarded him research funding this year. Along the way, Weber looked for some 50 species of wildflowers that bloom early, including rare species such as harbinger of spring and white trout lily. Through photos and notes, he recorded floral traits ― colour, size, orientation of blooms ― and used an ultraviolet instrument to “see” flower colour as many insects do.

By combining that information with genetic data, he hopes to draw connections between species based on differences and similarities in their floral traits. Perhaps plants with varying traits compete more aggressively for pollinators, while those with similar-looking flowers effectively co-operate in attracting pollinators, he says. “Plants might work together.”

His work might ultimately help farmers and ecologists to stem a widely documented decline in numbers of pollinators.

Pollinators and plants such as those under Weber’s microscope are hugely important, says Peter Kelly, research director at the Rare Charitable Research Reserve (RCRR) in Cambridge. “You simply can’t have a lot of commercial crops without a healthy pollinator population,” says Kelly, who joined the organization two years ago after working with U of G’s Cliff Ecology Research Group. “Pollinators are also important to maintaining the biodiversity of a lot of natural habitats.”

Caruso says many species of wildflowers are also endangered by such things as grazing herbivores and the kind of human development that has already decimated much of Canada’s Carolinian forest.

Botanists and conservationists might take a clue from observing how native plants work with or against each other. Wildflower species with similar traits may live together in a bid to attract more pollinators, she says. Lose one kind and you may end up losing more. “If we start to lose wildflower species, it could affect the other wildflowers, also.”

That information might help planning for conservation, says Weber, who grew up in Delhi, Ont., and might work one day in habitat restoration.

He paid for much of his field work with a $4,000 scholarship awarded by the RCRR. That organization runs a 370-hectare nature reserve in Cambridge and has supported research by several Guelph botanists and ecologists, including projects in natural selection and plant traits, apple genetics, tallgrass prairie restoration, and butternut infection.

Weber has worked at garden centres and florist shops and can ID more than 200 species of flowering plants by sight. He’s taken plant identification courses at Guelph and worked in the U of G herbarium.

He says studying plant-pollinator interactions may also help solve Charles Darwin’s “abominable mystery” about how flowering plants developed so rapidly. Angiosperms first appeared about 130 million years ago ― a relative eyeblink in geological time ― and are the most diverse group of plants on Earth.