911 for Threatened Plants
A well-intentioned hiker who wanders off the trail at Cascade Head to capture a scenic photo may unintentionally trample one of the last existing populations of the seabluff carnation, known to scientists as Silene douglasii var. oraria.
There are three remaining populations in the world--all in Oregon, where the flower is listed as "threatened." They grow precipitously along the cliffs of Cascade Head, seven miles north of Lincoln City on the Oregon coast. The spectacular headland is a Nature Conservancy preserve and United Nations Biosphere Reserve.
Scientists hope to restore threatened plants in the Pacific Northwest. They have reintroduced native plant species and helped repopulate vulnerable areas for years, but Willamette University Professor Susan Kephart is trying a new tack. Instead of planting annuals, the quick and easy way to repopulate coastal prairies, she coordinated the planting of nearly 1,000 perennial seeds and seedlings by students, local citizens and Earthwatch volunteers.
Her restoration and research findings were featured as the October cover story in The American Journal of Botany and have generated inquiries from around the world.
Kephart and Willamette student Diana Lofflin posed several critical questions: Can we successfully reintroduce rare plants? Do plants with a more diverse genetic background have higher survival rates than inbred plants? How can we best restore native populations?
"We found that continued inbreeding within a closely related group of plants is linked to poor seedling survival and affects the viability of future generations," Kephart said.
Willamette University students and Earthwatch Institute volunteers from around the world helped Kephart and Lofflin compare seedling establishment of the rare coastal plant with its more widespread relatives in the Cascade Mountains.
The seabluff carnation is one of many species scattered across fragmented habitats in isolated, at-risk plant communities, and may be losing the genetic diversity that would help it cope with future threats. It is affected by coastal development, trampling, damage from seed predators and browsing deer. Climate change may pose another yet-unstudied threat.
The good news is that Kephart's research shows that it is possible to reintroduce rare plants, even on grazed areas.
"But the plants with a more diverse genetic background have a better chance of survival than inbred progeny," Kephart said. "It's the same idea as not marrying your cousin. Lethal genes in a family lineage can hide in individuals, but they can come together in offspring, leading to stunting or death."
Kephart's research shows that inbred offspring are, in fact, stunted and have yellowed leaves, while outbred plants are larger and put forth more abundant flowers.
She has studied native plant populations at Cascade Head for more than 20 years; the current reintroduction project began in 1998.
Kephart and her students would like to see self-sustaining seabluff carnation populations restored to their historical habitat, along with continued protection of native grasslands.
"Oregon's headlands were once mostly native flower prairies," Kephart said. "Although reintroduction is a relatively recent and potentially important restoration tool, its benefits are still uncertain since much research remains to be done."