Twin Cities development executive Stephen Bona has long since learned how to dodge sensitive wetlands and endangered critters to build new suburban neighborhoods.

But for Bona, the protected bristleberry that stalled a 40-acre development in booming northern Blaine was a shocking first.

"It caught us by surprise. We had never heard of it before," said Bona, vice president of land development at Capstone Homes, one of the most prolific homebuilders in Blaine. "It was a very difficult situation."

Capstone originally proposed designing the subdivision around three colonies of the bristleberry, a low-growing sprawling bush in the blackberry family. The state Department of Natural Resources, uncomfortable with homes so close to the plants, nixed that proposal.

So Capstone wrote a nearly $20,000 check to the DNR in order to destroy the bristleberry bushes.

"Rather than try to put a fence around these three populations, we allowed the destruction of these populations and used the compensatory mitigation to protect these species elsewhere," said Richard Baker, the DNR's endangered species coordinator.

The small plant not only delayed the project for a year, it raised some thorny questions about future growth vs. environmental protection in the north metro area.

In 2013, changes to Minnesota's endangered and threatened species standards added about 21 plants from the Anoka Sand Plain to the list, bringing the total to 57 protected species in the region. Baker said they make up 30 percent of the state's endangered or threatened species in only 2.2 percent of the state's land area.

"Among the reasons we did this was evidence that plants in the Anoka Sand Plain were under increased threat from loss of habitat and development," he said.

One reason the north metro suburbs may be the epicenter for the state's endangered species, Baker said, is that biological surveys have found rare species there that they hadn't known about.

Another reason is the extent of undisturbed terrain. Because much of the land is wetlands or uplands not suitable for farming, swaths of Anoka County remained untouched while Dakota and Hennepin counties were tilled.

For ecologists, the Anoka Sand Plain is a tantalizing opportunity to preserve the state's impressive — and often unrecognized — biodiversity.

Diverse but common plants

Ecologists Jason and Amy Husveth hiked recently through a 60-acre state-owned natural area in Blaine. Tucked between a park and an elementary school, the natural area contains more than 300 species of plants.

"That's 15 percent of the flora of native Minnesota on this site," Jason Husveth said, crouching to identify one of the gems: a threatened lance-leaved violet. He brushed aside grasses along the trail to uncover the wisp of a plant, its white blossoms the size of a dime.

It's the natural beauty of the area, not always obvious at first glance, that draws people and also causes them to worry about losing it to bulldozers.

"It's a great place to live. It's beautiful," Baker said.

Tim Kelly, district administrator of the Coon Creek Watershed District, said he sometimes fears that most people see endangered and threatened species as something exotic that exist on public TV or another continent. Preserving what's already there is cheaper and more effective than trying to bring it back, Kelly said.

"When you are playing catch-up or repair with natural resources, you can start out by multiplying it by 10 and be prepared to add zeros," Kelly said.

The Coon Creek district, working with the DNR, has issued 284 permits since last year for construction projects near wetlands and threatened species. Scientists found plants classified as endangered, threatened or of special concern in about one-third of the projects.

Finding one of those plants doesn't automatically sink a project. Rather, it starts a discussion and further study about whether the specimens are worth saving and how that can be done. Transplanting is not an option because they often need specific soil and water conditions to survive.

"Last year there were three or four different developments where that came up. There really are not clear rules how to deal with it, which has been a problem," said Jim Hafner, Blaine's stormwater manager.

While these plants may be rare in the state, they pop up quite a bit in Anoka County.

"Some of this stuff is really fairly common. You can kick the dirt anywhere in the Anoka Sand Plain and find these plants," Hafner said.

When destruction of the plants is unavoidable, the DNR accepts mitigation in the form of a payment. In the past year, three home developers and two municipalities in the Anoka Sand Plain have paid $85,233 in mitigation.

Anoka County was one of them. Last year, the county highway department paid the DNR $25,000 when some patches of protected sea-beach needle grass had to be destroyed to widen Bunker Lake Boulevard.

"It used to seem like there were pockets of sensitive ecology. Now it seems like sensitive ecology is everywhere," Anoka County Engineer Doug Fischer said. "Because our projects are highway projects and are linear in nature, our impacts in many cases are unavoidable. … You can lose a whole year if you are not on top of it."

Project under review

The county now is undertaking such a study as it plans to widen Hanson Boulevard, which crosses the main branch of Coon Creek.

Fischer said he supports creating a program for endangered species similar to the state's Board of Water and Soil Resources, which receives funding to help mitigate wetland impacts.

"When we impact a wetland … there is a process and a time frame. When we are dealing with threatened and endangered species, we don't know the time frame or what the financial mitigation will be. When we do pay, we have to use highway dollars," he said.

About a dozen years ago, it cost Anoka County $500,000 to disturb a rare orchid, milkwort and violet near an interchange along Interstate 35W. Some scientific and natural areas were set up as part of the deal with the DNR.

"It was still a bitter pill we had to swallow," Fischer said.

Baker said he's working to establish higher-quality protected areas.

"We are trying … to identify some large areas of land that are just beyond the forefront of development and perhaps protect some large areas," he said. "By doing that, it makes it easier to let go of some of those areas that are already surrounded by development and are not going to be easily conserved."

Shannon Prather • 612-673-4804