A small team of conservationists has spent the past six months handpicking seeds from some of the rarest prairie plants and grasses in Minnesota, all in an attempt to save a dwindling pocket of turtles.
The seeds will help turn an old farm field back into the sandy open prairie it once was, expanding the nesting grounds for the threatened Blanding's turtle.
"It's one of their biggest populations left in our state, but it has suffered in recent years," said Eric Chien, field steward for nonprofit the Nature Conservancy, which is restoring the 160-acre property.
The Nature Conservancy has had its eyes on the field for years. It sits in southeastern Minnesota near Kellogg, between protected wetlands and sand dunes, in the middle of what has become one of the last stands for the Blanding's turtle in the state.
Blanding's turtles are larger than the more-common painted turtles, and less ferocious looking than snapping turtles. They have helmet-shaped shells, yellow chins and were once found throughout the Midwest and eastern United States.
Their populations fell rapidly as wetlands were lost, and now they mainly survive in small areas of Minnesota, New England and Canada.
For decades, a relatively strong population had survived in the wetlands surrounding McCarthy Lake, about a mile from ideal nesting grounds in the sand dunes at the confluence of the Mississippi and Zumbro rivers.
Every spring, about 1,000 nesting turtles — some up to 70 years old — would march out of the McCarthy wetlands, cross cornfields and burrow into the sand dunes to lay their eggs. A little while later, tens of thousands of hatchlings — most likely guided by the tree line — would try to make the trek back.
But by 2019, the population was down to an estimated 300 nesting turtles.
One of the biggest problems, and threats, is that busy County Road 84 cuts straight through that migration, dividing the wetlands from the sand dunes, said David Ruff, conservation project manager for the Nature Conservancy.
"That road is a clear hazard in terms of roadkill," he said. "But it also really exposes them to both predators and, potentially, poachers. When they're along that road, they are wide out in the open."
The restored land will be on the wetland side of the road, providing the turtles a place to nest without needing to trek across traffic to the sand dunes.
"It fills in a little fragmented hole in this general complex," Ruff said. "It's always nice to knit back natural lands for connectivity."
Ruff said it's still unclear exactly why the Blanding's population dropped from about 1,000 to about 300 over the span of a few years.
All of Minnesota's turtle species have been declining for several years, according to the state Department of Natural Resources and the University of Minnesota. Some of that is attributed to habitat loss and more frequent spring floods that can destroy nests. Predators, such as raccoons that eat eggs and young hatchlings, have also been on the rise.
But the Minnesota Zoo and the state Department of Transportation have found that cars are particularly destructive to turtle populations because they kill mature, egg-laying females. The vast majority of turtle hatchlings die in the wild long before they reach reproductive age. Populations depend on the few that survive to adulthood to keep surviving for decades, laying hundreds of eggs each spring in order to produce a handful that will live long enough to replace them.
The Nature Conservancy will turn the restored land over to the state to manage as part of the McCarthy Lake Wildlife Management Area. But not before it completes one of the more intensive restoration attempts in the area.
Rather than use combines to collect seeds from a few dozen plants, the organization has been hand collecting seeds from more than 140 plant species that bloom at different times of the year. Many of those plants are from the sand dunes that are rarely found anywhere else in the state, Chien said. They will be planted this fall, ideally right before the first snowfall, which would press the seeds into the soil and protect them from the wind and birds, he said.
"It's such a unique prairie plant community because of the dunes and the sandy soils," he said. "And we've learned from other projects the most resilient and productive restorations are the ones that mimic undisturbed prairies, with species that flower and set seeds across the whole season."
Greg Stanley • 612-673-4882