________________________________________________________ Natural Resource Inventory of Bloomington, MN 0 December 2006 City of Bloomington Natural Resources Inventory and Minnesota Land Cover Classification System Mapping Prepared for the City of Bloomington and Hennepin County Department of Environmental Services by Tony Randazzo Hugh Johnson Fred Harris of Great River Greening and David Thill of Hennepin County Environmental Services October 15, 2007 ________________________________________________________ Natural Resource Inventory of Bloomington, MN 1 October 2007 Table of Contents List of Figures.....................................................................................................................3 Introduction ........................................................................................................................4 Project Methodology ......................................................................................................... 7 Background Information ........................................................................................7 Land Cover Classification ....................................................................................15 Aerial Photo Interpretation ...................................................................................16 Field Evaluation ....................................................................................................16 MLCCS Modifiers.................................................................................................17 Land Cover Classification Results.....................................................................................20 Natural Resource Inventory Results..................................................................................27 Natural Community Area Descriptions.............................................................................30 Recommendations .............................................................................................................49 Conceptual Natural Resources/Open Space Corridors .....................................................49 Natural Areas with Potential for Rare Species..................................................................56 Natural Areas Active Management/Protection Recommendations……...........................61 References..........................................................................................................................74 Appendices Appendix A Land Cover Summary Tables........................................................................75 Appendix B Natural Areas Species Lists and Habitat Descriptions…………………......86 Appendix C Glossary of Technical Terms.......................................................................285 Appendix D MLCCS Methodology…………………………………………………….294 ________________________________________________________ Natural Resource Inventory of Bloomington, MN 2 October 2007 LIST OF FIGURES Fig. 1: Hennepin County, Minnesota…………………………………………………….6 Fig. 2: Pre-settlement Vegetation of Hennepin County, Minnesota………………..........9 Fig. 3: City of Bloomington National Wetlands Inventory..…………………………...11 Fig. 4: City of Bloomington Soil Survey Slope Gradient Map………………….…..…12 Fig. 5: County Biological Survey Sites…………………………………………...……14 Fig. 6: Bloomington Level 1 Land Cover Classification…..…………………….….....24 Fig. 7: Bloomington Level 3 Land Cover Classification…..…………………………..25 Fig. 7a: Legend for Bloomington Level 3 Land Cover Classification……………...…...26 Fig. 8: Natural Areas in Bloomington………………………………………………......53 Fig. 9: Conceptual Greenway Corridor Alignment for Bloomington...………..…….....43 Fig. 10: Natural Areas with Potential for Rare Species in Bloomington...………….......59 Fig. 10A: Ecologically Significant Natural Areas…..…………………….….................60 Fig. 11: Natural Areas with Species Lists for Bloomington...……………...……….......73 Fig. 11: Appendix Copy of Natural Areas with Species Lists for Bloomington...……...87 ________________________________________________________ Natural Resource Inventory of Bloomington, MN 3 October 2007 INTRODUCTION In 2005, Hennepin County Department of Environmental Services (HCDES) retained Great River Greening (GRG) to conduct land cover classification mapping and a natural areas assessment within the City of Bloomington, in Hennepin County, Minnesota (Figure 1). The Minnesota Land Cover Classification System (MLCCS) methodology (Appendix D) that was developed by the Minnesota Dept. of Natural Resources was utilized for this project. This project was funded by Hennepin County and the City of Bloomington. The goal of the project was to divide and classify the area constituting the City of Bloomington into appropriate land cover types, assess the relative ecological quality of the remaining natural and semi-natural areas, and recommend potential natural resources/open space corridors and management considerations. During the spring and summer of 2006 and 2007, the land cover areas, as determined through the use of aerial photo interpretation, were field checked in order to confirm and/or correct boundaries and land cover type designation. During the field check phase of the project, species lists for natural area polygons and other site appropriate coding modifiers were recorded. GRG staff identified 3297 distinct landscape areas within the municipal boundary for the City of Bloomington. All land cover was coded to the highest level of detail (Level 5) and approximately 84% of all land-use polygons were field checked at least from the edge (level 2) or higher. During the 2006/2007 field season all land cover areas identified through the air photo mapping process were field checked. All natural and semi-natural area land cover areas were visited by staff ecologists. Natural area polygons (not entirely dominated by non-native species or sufficiently disturbed to warrant an altered ranking) were field checked to a level 3 (partially visited) or level 4 (entirely visited) with species lists and DNR rankings attributed to each. ________________________________________________________ Natural Resource Inventory of Bloomington, MN 4 October 2007 During the field check process, 368 natural area polygons were identified to be of sufficient quality to receive Natural Community Quality Rankings according to the DNR’s Natural Heritage Element Occurrence Ranking Guidelines. Of the 368 natural areas, 3 were provided with the highest quality (A) ranking. Of the highest quality natural communities, there is one a high quality wetland community (Poor Fen, Sedge Subtype), a dry prairie and a dry prairie, sand-gravel subtype. 106 natural areas were given a good quality natural condition (B) ranking. For the most part, the B ranked communities are high quality wetland and floodplain communities with limited encroachment by non-native invasive species as is typical of urban natural communities. 118 natural communities were ranked as moderate quality (C) with the remainder ranked as poor quality (D) natural communities. The primary factor that determines the quality of natural communities in this urbanized community tends to be the presence or dominance of non-native, invasive species within natural community remnants and the extent of cultural uses within a remnant natural area. Given the urbanized nature of Bloomington, the identification of these remnant natural communities can serve as a valuable planning tool for the City, residents and planners in determining valuable natural resources in need of protection. ________________________________________________________ Natural Resource Inventory of Bloomington, MN 5 October 2007 ________________________________________________________ Natural Resource Inventory of Bloomington, MN 6 October 2007 PROJECT METHODOLOGY BACKGROUND INFORMATION Ecologists from Great River Greening and staff from Hennepin County Department of Environmental Services reviewed available historical records on past and present ecological conditions. These data included presettlement vegetation, Minnesota DNR County Biological Survey (MCBS) information for Hennepin County, wetland and water resource information, and the Hennepin County soil survey. Specific results from these examinations are reviewed by category in the following paragraphs to provide background details with which to better understand land use changes since the widespread settlement of the area. Pre-settlement Vegetation According to the original land survey notes (compiled in Minnesota between 1853 and 1856), the pre-settlement vegetation of what is now the City of Bloomington was comprised primarily of “Oak Openings and Barrens” and large inclusions of “Prairie” (Marschner 1974). Several of the large inclusions of prairie were found along the bluffs of the Minnesota River, with the largest area extending north and east from the river bluffs and occupying approximately one-third of Eastern Bloomington. A large portion of Northwestern Bloomington was comprised of a contiguous block of “Wet Prairie” embedded with areas of “Big Woods” of various sizes. The toe-slopes and river bottoms of the north-side of the Minnesota River were occupied by “River Bottom Forest” (Figure 2). Oak Openings and Barrens, located east of the Big Woods, was an area of fire-maintained vegetation that formed a transition zone between open prairies and unburned hardwood forests (Heinselman 1974). This area was dominated by various oak species including bur, red, white, and northern pin oak, with areas