About
This SNA is located within Sand Dunes State Forest in Sherburne County. It takes its name from the Uncas skipper, a member of the "banded skippers" (subfamily Hesperiinae) listed as an endangered species in Minnesota. Small and fast, this butterfly has a shape that's been compared to a fighter jet.
According to MBS ecologist Robert Dana, the only resident population of the Uncas Skipper known to have existed in Minnesota inhabited several dune areas in the Anoka Sand Plain, one of which is within this SNA. Numerous surveys documented the species' occurrence in this area from the 1960s through the late 80s, but it has not been reported in the state since that time.
The main range of this species reaches from the Dakotas westward, so Minnesota's population has always been thought of as outlier. Here, it demonstrated a close association with the sparsely vegetated environment of the dunes and—in particular—reliance on a grass called hairy grama (Bouteloua hirsuta), on which the females exclusively laid their eggs and the hatching larvae depended. Decline of this required dry grassland habitat may be a factor in the species apparent disappearance from the state in recent decades.
Also among this site's most ecologically significant natural features is a 223-acre dry barrens oak savanna, a native plant community with a state conservation ranking of imperiled to critically imperiled or (S1 to S2). This is a relatively open community, with total tree cover typically only 25-50%, and a sparse to patchy shrub layer. It is characterized by widely scattered bur and northern pin oak, with an understory of prairie grasses and wildflowers. Accordingly, management has focused on restoring and maintaining the open character of this community through prescribed burns and removal of encroaching woody vegetation, including planted pines not naturally occurring on the site.
The mosaic of native plant communities here also includes Southern dry mesic oak (maple) woodland, alder and tamarack swamps, sedge meadow, and a small (5-acre) fen.
This is one of Minnesota's most compelling natural landscapes, with stories of the past and present expressed in rolling dunes, rare butterflies and gnarled, open-grown oaks. Come in summer to see the classic plants of the dry barrens oak savanna in bloom: hairy puccoon and golden aster, Virginia ground cherry and silky prairie clover. Walk carefully near the dunes, which offer fragile habitat for seaside three-awn grass, annual skeleton-weed and creeping juniper. Consider, as you do, how the landscape might appear through the eyes of an Uncas Skipper.