How many Minnesota plants and animals can survive in small pockets of old growth forests?

Minnesota’s great lime and sugar maple forests have been cut into smaller and smaller pockets over the past 150 years. The “Big Woods” that once ruled the state are long gone, divided into hundreds of parks and reserves.

There are still vestiges of the old forest that have never been mined, or at least have not been mined for a century. But they are separated from each other by highways, houses and farms, and it is not known which plants and animals are still able to reproduce and which are on the verge of extinction.

Foresters at the University of Minnesota are beginning a long-awaited count, with the goal of identifying every plant in what remains of the Big Woods of south-central Minnesota. Over the next two years, they will find out where some of the rarer plants, such as trilliums, still live, and see if there are ways to bring back plant life.

“We start with the plants because if the plants disappear, the pollinators disappear and the whole ecosystem disappears,” said Lee Frelich, director of the U.’s Center for Forest Ecology. “Think of a city with all these big buildings empty of people. You can still have old trees that survive, but with nothing else everything is degraded.”

The Big Woods are what explorers first called the shady forests dominated by elm, lime, red oak, and sugar maple trees that once bordered the edge of Minnesota’s prairies. Prior to European settlement, woodlands covered approximately 1.3 million acres in what are now the Twin Cities and south-central Minnesota. About 28,000 acres remain, or about 2%, Frelich said.

Although these remains have been carefully protected in state parks and science reserves, many species may need more room to regenerate.

Many plants depend on insects for pollination. When forests are separated from each other by farms and subdivisions, it can be difficult, if not impossible, for these pollinators to move from one patch to another, Frelich said.

The major stresses on forests have also worsened in recent decades, he said.

Invasive earthworms eat much of the humus and fallen leaves on the forest floor, leaving the soils more bare with fewer nutrients. High and dense populations of deer ravaged some of the young plants and seedlings before they had a chance to grow. Climate change made some pests worse and caused more flooding, which became more damaging due to the way earthworms disturbed the soil, Frelich said.

“When you lose that understory of plants, the antlers cannot function anymore because the nutrients keep going away,” he said. “Without the nutrients, the whole system becomes ‘drier’; even if you don’t completely lose species, they don’t grow as tall or as profusely.”

Frelich will be assisted by a team of citizen experts from the Minnesota Native Plant Society, who will help locate and document the plants. The U has records and seed banks dating back 150 years, so researchers should be able to get a pretty good idea of ​​what species were present before Europeans arrived.

The research will be funded by the State Trust Fund for the Environment and Natural Resources.

The hope is that the results will help forest managers bring back some species, whether that’s by hand planting seeds, moving pollen from one park to another, or hiring snipers to reduce populations. deer, Frelich said.

“If you want to solve a problem, you have to know what it is,” he said.

The results will be extremely useful to forest managers around the Twin Cities metro, said John Moriarty, senior director of wildlife for the Three Rivers Park district.

Three Rivers kept pieces of Big Woods alive, such as Elm Creek, Lake Rebecca, Carver, and Baker Parks. The park district has tried to reconnect pockets of forest to each other whenever it can, Moriarty said.

“Most of the birds that live in the maple or linden forest can fly among themselves, but when you think of small mammals, salamanders, frogs and turtles, they can’t go from one to the other. other, ”Moriarty said. “The trillium seeds are moved by ants and the ants don’t move far. So when you have a road between two pieces of wood, that’s a problem.”