Gladstone Savanna's Natural History

Gladstone Savanna's Natural History. . This landscape has changed many times over the 12,000 years since the glaciers. A thousand years after the glaciers retreated spruce forests dominated, with mastodons and other mega fauna common. , As time passed the climate warmed drying the landscape. By 7,000 years ago the first grasslands spread far and wide dotted with grazing bison and elk herds. By 700 years ago "big woods" of sugar maple, oak, elm and basswood had replaced the prairie with only pockets of savanna here and there on the landscape., At the time of Euro-American settlement this area was listed as "scattered timber and second-rate soil," likely an open savanna with oaks scattered in a sea of grass. Minnesota savannas are open landscapes where grasses and wildflowers cover the ground between clusters of trees., Vegetation After the Railroad , By 1980 the railroad Shops on this site had been demolished. Grasses, shrubs, trees, and wildflowers had returned. Lichens began breaking down remaining asphalt patches. This natural process of landscape reclamation is called succession. But only a few native plants reappeared. Weedy non-native plants like Siberian elm and spotted knapweed proliferated., A natural area this small cannot function as a self-contained ecological system and needs a helping hand. The City of Maplewood seeded native prairie species throughout the site and manages the property with controlled burns and mowing., Forged in Flame , Periodic landscape burning favors the growth of native grasses, wildflowers and thick-barked oaks. Historically fires were caused by natural events or were intentionally set by Native Americans to help control insects and improve grazing. Today, controlled burns help keep savannas intact., Oak Savanna: A Rare Ecosystem , Two centuries ago oak savannas covered 5.5 million acres, or nearly ten percent, of Minnesota. Farming, population growth, urban development, overgrazing and the removal of fire from the landscape has reduced oak savannas to less than 55,000 acres, making them one of the rarest ecosystems on earth today., Caption: , Open tundra and spruce trees covered the area after the glaciers left., Caption: , After buildings were removed weedy species like Siberian elm and knapweed seeded into the prairie., Caption: , Controlled burns help manage the savanna., Caption: , The oak savanna at Wakefield Park (a few blocks east of here) exemplifies the pre-settlement savannas of this area.