MNR was contracted to conduct an extensive natural resources inventory of the proposed 1,300+ acre  Unimin Mine, a frac-sand mine, located in Le Sueur County, Minnesota. We conducted detailed mapping of native plant communities throughout the project area, in addition to surveys for state-listed bird, vascular plant, herpetological, and butterfly species with the potential to occur in the project area.

At the direction of the MN Department of Natural Resources (DNR), we also field-mapped native prairie at a fine-scale throughout the project area, and assigned each polygon a prairie condition rank following the Condition Ranking Guidelines developed by the DNR. This was the first project in Minnesota in which a private company mapped native prairie at this scale. During our surveys, we also identified two previously unknown calcareous fens within the Minnesota River corridor, as well as a diverse array of rare vascular plants and birds, two Lepidoptera species (leadplant moth and regal fritillary), a fox snake (watchlist), and even a state-listed jumping spider.

Since development of the mine, MNR has continued to conduct long-term monitoring of the calcareous fen as a requirement of the fen management plan. Over the last ten years, we have documented vegetative changes, including population counts and extent of Carex sterilis (a state-threatened calcareous fen obligate) and expansion of herbaceous invasive species and shrubs as a measure to gauge mining activity impacts to the calcareous fen’s hydrologic recharge zone.