Bloomington Bluff Prairies City of Bloomington, Central Park Wolf Prairie Nelson Prairie Hayden Prairie Ecological Inventories and Restoration Management Plan Great River Greening 35 West Water Street Suite 201 St. Paul, Minnesota 55107-2016 Bloomington Bluff Prairies Ecological Inventory and Restoration Management Plan Compiled by Ellen L. Fuge, Lead Ecologist Reviewed by Fred Harris, Lead Ecologist Great River Greening October 2003 Great River Greening, a non-profit organization, helps communities coordinate costeffective and sustained efforts to manage ecosystems of the Mississippi, Minnesota and St. Croix River valleys in the Twin Cities metropolitan area. We are primarily an implementing organization, providing on-the-ground ecological restoration and management of both public and private land. We engage thousands of volunteers in the planting of native vegetation, removal of exotic weeds, native seed collection and stewardship – work that results in an informed and involved citizenry. We also act as a catalyst, creating effective partnerships among agencies, municipalities and private landowners responsible for managing river valleys and their natural resources. Restoration ecologists and other scientists provide technical expertise. (See page 47 for more information about Great River Greening.) Ellen L. Fuge has an M.S. in Botany from the University of Minnesota and currently works as the Lead Ecologist with Great River Greening. She conducts ecological inventories and analysis, writes restoration and management plans, and acts as a burn boss on the burn crew. Previously, she worked for many years with the Minnesota Department of Natural Resources in several different capacities; as the Management Supervisor for Minnesota’s Scientific and Natural Areas (SNA) Program and as a plant ecologist with the Minnesota County Biological Survey (CBS). She edited the DNR booklet, “Going Native – A prairie restoration handbook for Minnesota landowners”. 2 Summary At the end of the last ice age a torrent of melt-water that became what we now call the Minnesota River carved out a broad valley through southern Minnesota. In Hennepin County, Minnesota, high river terraces composed of glacial till and water-washed alluvium frame the sides of this valley. Through the terraces, side streams have carved steep-sided ravines whose hot, south-facing slopes support dry prairies surrounded by oak savanna, oak and maple-basswood forests. The Bloomington Bluff prairies along Nine Mile Creek are remnants of these native plant communities spared from total conversion for agriculture and development because of the rough terrain. The Bloomington Bluff Prairies Ecological Inventory and Restoration Management Plan is the first comprehensive study of this unique area and makes recommendations for its restoration and protection. Through a contract with the Department of Natural Resources Prairie Stewardship Program, the plan specifies areas where focused management can begin to preserve remnant native plant communities and restore them where they have been disturbed. Background Many changes have taken place on the approximately 310 acres of undeveloped bluffs along Nine Mile Creek south of 104th St. to its confluence with the Minnesota River (Map 1). By the time of the original land survey in 1853, settlements and developments were too numerous for the surveyors to note in their descriptions of the township. The upland and parts of the flood plain are now densely developed. Exotic species have invaded the floodplain and forests, changing the species composition of the vegetation. The suppression of fire allowed the prairies and savanna to fill in with trees and shrubs, threatening the survival of these rare native plant communities. The City of Bloomington’s Central Park was included in the Minnesota Natural Heritage Registry in 1983 because of the occurrence of the rare plant, kitten tails (Besseya bullii), on one of the prairie remnants in the park. In 1982 there were 20-25 individual plants of kitten tails, one of the largest populations in the Twin Cities area. The range of this plant is limited to six Midwestern states. Only some of the populations of kittentails historically documented in Minnesota still remain as most have been destroyed by expansion of the metropolitan area. The Minnesota County Biological Survey visited the Nine-Mile Creek area in 1996 and recorded the unique ecological value of these lands. The significant native plant communities remaining on the bluffs are scattered remnants of Dry Prairie, Sand-Gravel Subtype. There are also Oak Woodland-Brushland and Lowland Hardwood Forest remnants associated with the prairies that contribute to the biological diversity and ecological value of this area. 3 Plan Summary In the Bloomington Bluffs Prairies Ecological Inventory and Restoration Management Plan, the ecologist evaluated several features of the area: land cover and plant species (including exotic species and remnant natural plant communities), soil types and locations of cultural features such as trails. The author also made detailed recommendations for restoring key areas. These include conducting prescribed burns, planting native species and removing invasive plants. Cost estimates are given for tasks that can be carried out by contract crews. Appendices provide detailed plant species lists, information on controlling exotic and invasive species and for managing rare species, and resources for equipment and materials. 4 Table of Contents Page Summary List of Maps 3 6 List of Figures List of Tables Appendix Table of Contents 6 6 6 Acknowledgements 9 Introduction 11 The Bloomington Bluffs project site Background and significance of site Purpose of this plan Principles guiding this plan 11 11 12 12 Description of Project Area Landscape context Reference landscapes 15 15 17 Pre-European settlement vegetation Dry Prairie, Sand-Gravel Subtype Dry Oak Savanna, Sand-Gravel Subtype Oak Woodland-Brushland Lowland Hardwood Forest Bedrock, soils and erosion Climate Recent land use Inventory Results and Management Recommendations Current land cover Plant community descriptions and Management recommendations Dry Prairie, Sand-Gravel Subtype Oak Savanna Implementation 18 19 19 19 20 20 22 23 25 25 26 26 33 37 Management schedule 37 Bibliography and References 43 Great River Greening 45 List of Maps Map 1. Location map Map 2. Bloomington Bluffs 1937 Landscape 5 Map 3. Bloomington Bluffs 1996 County Biological Survey Native Plant Communities Map 4. Bloomington Bluffs Soils and Topography Map 5. Bloomington Bluffs Prairie, Central Park, City of Bloomington Map 6. Nine-Mile Prairie Management Map 7. River Terrace Prairie Management Map 8. Kitten-tail Savanna Management List of Figures Fig a. Fig. b. Fig. c. Fig. d. Fig. e. Fig. f. Fig. g. Fig. h. Fig. i. Fig. j. Remnant prairie knoll at Nine-Mile Creek Prairie Minnesota’s biomes and landscape areas Examples of native plant communities at St. Croix Savanna SNA Trail erosion at Nine-Mile Creek Prairie South-facing dry prairie opening Nine-Mile Creek Prairie savanna restoration Path through Kitten-tail Savanna Kitten-tail basal leaves and dry flowering stalk Kitten-tail population on edge of foot path Burn unit map – Nine-Mile Creek Prairie 11 16 18 21 26 33 33 34 34 40 List of Tables Tab. a. Monthly Station Normals of Temperature and Precipitation Tab. b. Median Frost Dates and other Critical Low Temperatures Tab. c. Mean number of snow cover days Tab. d. Restoration Recommendations 22 22 23 37 Appendix Table of Contents Appendix A. Fact Sheets on Invasive, Exotic, and Rare Species Rare plant: Kitten-tails Besseya bullii Invasive trees and shrubs: Box elder Acer negundo Common buckthorn * Rhamnus cathartica Eastern red cedar Juniperus virginiana Poison ivy Rhus radicans Siberian elm* Ulmus pumila Smooth sumac Rhus glabra Tatarian honeysuckle* Lonicera tartarica Trembling aspen Populus tremuloides Invasive Forbs: Canada thistle* Circium arvense Garlic mustard * Alliaria petiolata Leafy spurge* Euphorbia esula Spotted knapweed* Centaurea maculosa Sweet clovers * Melilotus officinalis M. alba 6 A-1 A-3 A-5 A-7 A-9 A-11 A-13 A-15 A-17 A-19 A-21 A-23 A-25 A-27 A-29 Invasive Grasses: Bluegrass * Reed canary grass * Smooth brome * Poa pratensis, P. compressa Phalaris arundinacea Bromus inermis A-31 A-33 A-35 *exotic species Appendix B. Species Lists for Proposed Restoration Target Communities Dry Prairie, Sand-Gravel Subtype Dry Oak Savanna, Sand-Gravel Subtype B-1 B-1 B-3 Appendix C. Management Resources Management Record Form Daily Resource Management Log Contacts Equipment Restoration organizations and agencies Monitoring Technique (selected article) C-1 C-3 C-5 C-7 C-7 C-8 C-9 7 8 Acknowledgments This inventory and management plan has been made possible through a contract with the Minnesota Department of Natural Resources (DNR), Prairie Stewardship Program. Bryan Lueth, Urban Wildlife Manager acted as the DNR consultant and worked with the author to oversee production of the plan. Conversations with landowners and City of Bloomington staff, especially Paul Edwardson and Glen Shirley (retired), played an important role in providing information about the use and past management of the prairies. Several staff from Great River Greening contributed to this project. Fred Harris and Dan Shaw reviewed the text, plant lists, and management recommendations. Shannon Farrell assisted in developing maps. 9 10 Introduction The Bloomington Bluffs project site: Legal Description: Bloomington, MN, T27N R24W Sections 21 and 28 Background and significance of site: At the confluence of the Minnesota River and Nine-Mile Creek, in the heart of the Twin Cities Metropolitan Area, a small group of remnant dry prairies have survived on the steep south-facing river bluffs. These include Nine-Mile Prairie and River Terrace Prairie in the City of Bloomington’s Central Park along Nine Mile Creek, and several small private prairies on the Minnesota River (Map 1). The existence of these prairie remnants (Fig.a) has been locally known and appreciated for a long time. Since the 1980s, prescribed burns, invasive plant management and prairie reconstruction have been carried out on some of the historic prairie remnants along these bluffs. The Minnesota River Valley Audubon Club (MRVAC), the City of Bloomington, The Friends of the Minnesota Valley, residents and local land owners have joined together in these protection efforts. Records of ecological surveys of the site go back to 1971 when E. Cushing and M. Kanner collected vegetation lists from native plant community remnants. C. Cox and T. Morley frequented the area and recorded their observations of the natural vegetation in the 1980s and’90s. F. Harris, ecologist from the Figure a. A remnant prairie knoll at Nine-Mile Minnesota County Biological Survey (MCBS), Creek Prairie with overgrown savanna above. conducted an inventory of the site in 1995. Fuge 2003. Harris evaluated the quality of the prairies, assigned a range of BC – C ranks1, and entered the collected data in the state-wide Natural Heritage Program (NHP) Database. In 1983, part of Central Park was enrolled on the Minnesota Natural Heritage Register (maintained by the DNR Scientific and Natural Areas Program) because of a significant population of rare plants, kitten tails (Besseya bullii)(Appendix A), found there. This population of kitten tails is one of the largest known to occur in Minnesota. 1 This rank represents an evaluation based on four factors: 1) Quality - how representative is this occurrence compared to an undisturbed example of the same community type? 2) Condition - how much has the site and the community been damaged or altered from its original condition and character? 3) Viability - what are the long-term prospects for continued existence of this site? 4) Defensibility - to what extent can this occurrence be protected from human factors that might otherwise degrade or destroy it? 11 Although restoration efforts have been carried out for a number of years at private prairie parcels as well as at the City-owned prairies, there has not been a comprehensive management plan guiding the activities. As stewards for and landowners of these important remnant native plant communities, several private landowners along the bluffs and the City of Bloomington consider these to be the most important natural features in Bloomington and a real asset to the City. The purpose of this plan: The purpose of this plan is to recommend ways the site can be managed to protect and enhance its ecological value. This plan presents the results of an inventory of the natural resources and ecological condition of the site conducted by the Great River Greening Lead Ecologist. Based on these findings restoration goals and specific activities to attain these goals are set forth in this plan. The plan identifies those activities that can be conducted by contracted professional crews or the landowner. Principles guiding the plan: These three principles have guided plan development: People are part of the ecosystem Humans have significantly altered the landscape. Areas like the Bloomington prairies are part of our cultural and natural heritage. One of the guiding principles in our approach to ecological management is to respect both of these values. The goal is to provide appropriate recreational and observation opportunities and enjoyment while also recognizing and protecting the ecological quality of the site People must actively manage a site to protect and restore its ecological quality and value Ecosystems arise from complex interactions among living organisms and the physical elements (soil, climate and water) in which they exist. The landscape and vegetation of any site are the result of many such interactions and are constantly changing. Managing sites for ecological goals requires active engagement to counteract degradation from ongoing forces such as: erosion from stormwater runoff spread of invasive plant species elimination of natural processes such as fire and flooding that established and maintained the native plant communities presence of non-native earthworms that change the soil quality and vegetation composition in native forests environmental pollutants and nutrient loading fragmentation of plant communities caused by development of the land for agricultural, residential and commercial use Great River Greening’s guiding principle is that people can set a goal of increasing the ecological health of a site and then take action to achieve that goal. 12 Successful ecological management requires an adaptive approach Because every site is unique and constantly changing, management must adapt to these changes. Steps in this approach include: conducting an inventory, setting restoration goals, developing management recommendations to meet those goals, and drawing up a monitoring plan so that management can adapt to local circumstances over time. Monitoring of the results of management, conducted by qualified individuals, is the cornerstone of the adaptive approach to ecological management. 13 14 Description of the Project Area The surrounding landscape, soils, geology and current land cover of a site all provide clues about an area’s current ecological condition and how the site should be managed. This section looks at the larger landscape in which the Bloomington Bluff Prairies are located and geological, soil and land cover conditions on the property. Landscape Context At the end of the last ice age, around 10,000 years ago, a thick mantle of glacial till (sand and gravel) was deposited across most of Minnesota including Hennepin County. As melt water carried by a huge river flowed through the drift in what is now the Minnesota River Valley, it carved, sorted and redeposited the till forming a broad valley (up to two miles wide in some places) edged with high terraces of alluvial materials. The landscape continued to evolve as secondary streams cut into the sides of these terraces and vegetation became established. For thousands of years, Native Americans lived off of the plants and animals that existed along these steams and rivers. The diversity of plant communities along the river was broad and included deciduous forests, wetland communities and grasslands. Bloomington Township was originally surveyed in 1853 by Jesse Jarrett who wrote the following description: “This township is divided from the N. E. to S.W. by the waters of the St. Peter River (now called the Minnesota River), the bottoms of which are wide on the north, the upland is mostly level, on the south hilly, bottoms nearly level subject to overflow from one to ten feet. Soil on the upland is good 2nd rate, bottoms are extra 1st rate. Vegetation on the bottoms is unequalled. Grass in places as much as 8 feet and weeds at least 16 ft in height, timber very scarce. There are too great number of claims and improvements in this township to designate their location in the description.” Information from the land survey notes of the mid-1800’s, as well as climate, geology, hydrology, topography, soils and vegetation data have all been used by Minnesota’s natural resource managers to identify the different ecological biomes and landscapes throughout the state. This information has been compiled into a common set of natural resource descriptions called the Ecological Classification System (ECS) (Fig. b). More information about the Ecological Classification System can be found at the Minnesota DNR website: www.dnr.state.mn.us/ecological _services/ecs/index.html According to this classification system, Minnesota is divided into three ecological regions or “provinces” representing the major climate zones converging in the state: Prairie Parkland, Eastern Broadleaf Forest and Laurentian Mixed Forest. These regions are then further divided into sections based on variations in glacial deposits, elevation, and distribution of plants and regional climate. These sections are further divided into subsections that identify unique landscapes. 15 The Bloomington Bluff Prairie site is located in the Eastern Broadleaf Forest Ecological Region, the Minnesota and Northeast Iowa Moraine Section and the Anoka Sand Plain Subsection of the ECS. Knowing the ecological categories helps ecologists better understand the area, the natural forces that created it and the plants that are native to it. Figure b. Minnesota’s biomes and landscape areas (Ecological Classification System – ECS) A. Red River Prairie B. Aspen Parklands C. Agassiz Lowlands D. Lttlefork-Vermilion Uplands E. Border Lakes F. Chippewa Plains G. Louis Moraines H. Nashwauk Uplands I. Laurentian Uplands J. Hardwood Hills K. Pine Moraines & Outwash Plains L. Tamarack Lowlands M. Toimi Uplands N. North Shore Highlands O. Mille Lacs Uplands P. Glacial Lake Superior Plain Q. Anoka Sand Plain R. Minnesota River Prairie S. Big Woods T. St. Paul-Baldwin Plains & Moraines U. Inner Coteau V. Coteau Moraines W. Oak Savanna X. Rochester Plateau N Y. Rochester Plateau S Z. The Blufflands Bloomington Bluffs Prairies 16 The Bloomington bluff prairies are situated within a band of mixed forest types and degraded savanna and prairie remnants along the bluffs of the Minnesota River and NineMile Creek. The surrounding landscape consists of residential housing and the Minnesota River Valley wetlands and floodplain forests. Most of the uplands are private residential lots, while much of the creek ravine and river valleys are primarily in City ownership at this location. The City of Bloomington’s lands are managed as Central Park. The park has several developed walking and biking trails along the bluff tops and valley bottom. The Minnesota Valley National Wildlife Refuge, managed by the US Fish and Wildlife Service, has two units located partially in Bloomington near the bluff prairie site. The Long Meadow Lake Unit is down stream just to the east of the 35W bridge and the Bloomington Ferry Unit is up river about three miles. The topography of the Anoka Sand Plain Subsection is level to gently rolling. Soils were formed from glacial river outwash deposits. Oak barrens and openings (savanna and prairie) dominated the subsection at the time of European settlement. Floodplain forest occupied the river valleys. Most of this subsection has been converted to agriculture and urban development. The bluff prairies of Bloomington are located on the steep sides of a ravine cut by Nine-Mile Creek through a terrace of the Minnesota River Valley at the very southern-most extent of the Anoka Sand Plain Subsection. The south facing slopes are hot and dry enough to discourage the growth of trees and brush. The Minnesota River, its predecessor Glacial River Warren and Nine-Mile Creek that drains into the Minnesota River Valley have significantly shaped the topography of the site. Aerial photos from 1937 show that there were more savanna areas and prairie openings on the banks of the river and Nine-Mile Creek (Map 2) in the past. The photos also show that the surviving prairies were more extensive and open than they are today. The invasion of trees and brush in recent decades is primarily the result of a lack of periodic fire. The historic photos also show that level ground on the terrace above the bluffs as well as the river bottoms were cleared and well established as cropland at that time. If the number of claims and improvements were numerous in this township at the time of the 1853 survey (see surveyor’s notes page 14), it is likely that the clearing of this area was well underway 84 years before the first aerial photos. As was the case in the past, the remnant Dry Sand-Gravel Prairie openings remaining today occupy the hot, dry southwest facing slopes of ravines. Flood Plain Forest is established in the Minnesota River Valley floodplain and Lowland Hardwood Forest populates the low, shaded floor of the Nine-Mile Creek ravine (Map 3). Plant communities grade into each other forming other distinct community types such as Dry Oak Savanna between the prairie and forest and Oak Woodland-Brushland between the Lowland Hardwood Forest and the prairie. Reference Landscapes To understand the ecology of a subject site and the restoration of the natural vegetation, it is often useful to consider intact plant communities at similar reference sites in the area. 17 This allows models for restorations and reconstructions to be based not only on remnant plants found at the subject site, but also on plant lists compiled from reference sites. St. Croix Savanna Scientific and Natural Area St. Croix Savanna Scientific and Natural Area (SNA) is located along the St. Croix River about ½ mile south of Bayport, MN on State Hwy 95. The similarities between St. Croix SNA and the Bloomington bluff prairies are in the slope aspect and historic plant communities (fig c). The SNA’s prairie and savanna are established on the top and side of a southwest-facing bluff made up of alluvial sand and gravel. The St. Croix savanna is made up of bur oak and pin oak that are scattered across the open gravel prairie. Much of the oak woodland on the east slope of the bluff is the result of fire suppression followed by an increase in tree and brush growth. Historically, this slope Figure c. Examples of native plant communities, Oak Savanna was more open. The northand Dry Prairie, Sand-gravel Subtype at St. Croix Savanna facing slopes and ravines at St. SNA. SNA Program 1996. Croix SNA are more heavily wooded with oak woodland and forest communities. Current management using prescribed fire and selective brush and tree removal has greatly enhanced the savanna. The diverse vegetation in the dry savanna includes the grasses hairy and side oats grama, needle and thread, and prairie dropseed. The forbs (broad leaved flowering plants) include goldenrods, sunflowers, asters, blazing star, pasque flower, prairie violets, gentians and prairie larkspur. As at the Bloomington bluff prairies, the SNA also supports several populations of the endangered plant, kitten-tails (Besseya bullii). This rare savanna species grows in the partial shade of savanna oaks. Pre-European settlement vegetation The prairies and woodlands in the Bloomington Bluffs area along Nine-Mile Creek and its confluence with the Minnesota River have been subjected to many changes perpetrated by human disturbance. The native species composition and diversity has been reduced in most cases. In many locations, exotic species have replaced native plants. Management of these remnant natural communities aimed at restoring them to a condition more representative of their undisturbed state will rely on an understanding of which plants and animals occupied these areas before human disturbance altered them. The following descriptions will support this effort. In addition, Appendix B provides lists of species typical of undisturbed native plant community types. 18 Dry Prairie, Sand-Gravel Subtype: Although the primary occurrence of prairie is in the prairie zone of western and southern Minnesota (fig b), there were historically scattered occurrences in the deciduous forestwoodland zone. Variations in slope, aspect to the sun, soil moisture and texture, and susceptibility to fire determine the location and type of prairie. In the deciduous woodland zone, prairies occur most often on droughty, sandy soils and south to west facing slopes that are well drained and hot. Grasses dominate prairies, from big bluestem and Indian grass on relatively moist sites to little bluestem, side-oats grama and porcupine grass on the drier sites. Like the grasses, broad-leaved flowering plants (forbs) also vary with moisture and soil characteristics. There are also several prairie shrub species including buck brush and leadplant. The occurrence of fire has almost completely ceased due to increased barriers such as roads, cultivated fields, cities and towns. This lack of fire has contributed to the growth of trees and shrubs on most prairie remnants both in the prairie and deciduous woodland zones. By comparing Maps 1 and 2, one can see how the prairies and savannas in the year 2000 have decreased in area due to the invasion of trees and brush compared to their extent in 1937. Dry Oak Savanna, Sand-Gravel Subtype: Savannas are transitional between forest or woodland and prairie. They are early successional communities historically maintained by fire. Savannas fill in with brush and trees succeeding to woodland when fire is suppressed. Oak Savanna is composed of scattered oak, usually bur or northern pin oak, with a ground layer of prairie species and others specific to the savanna environment. The oaks are open-grown with broad crowns of spreading branches. They may be in groups or individually scattered with prairie openings in between. Brush may be absent or present in scattered thickets. Dry Oak Savanna is commonly found on rough terrain with well-drained soils and is most common in the Deciduous Forest Zone in Minnesota. The Dry Oak Savanna, SandGravel Subtype is found on well-drained soils of glacial origin (glacial lake beds and beaches, till, river terraces, etc.) with course texture and a high gravel content (>10%). The 1937 aerial photo (Map 2) shows several areas in the Bloomington bluff area that appear to be savannas. These areas are found on the dry, gravelly ridge tops both east and west of Nine-Mile Creek. These are also the areas in which populations of the rare plant kitten-tails are currently located. Kitten-tails are among a unique group of plants indicative of oak savanna. Oak Woodland-Brushland: Oak Woodland-Brushland occurs on dry to moderately moist (mesic) sites throughout the Deciduous Forest Zone in Minnesota and grades into the more open Oak Savanna. Oak Woodland – Brushland has an interrupted tree canopy of oak and up to 70% aspen. 19 Shrubs and tree saplings dominate the understory. The ground layer is sparse, low in diversity and composed of woodland species that can survive the dense shade of the shrub layer. Oak Woodland – Brushland is a fire maintained community where periodic fires prevent the development of mature Oak Forest. The canopy trees in Oak WoodlandBrushland may be widely spaced and have spreading crowns typical of open-grown trees. Fires most likely started in adjacent prairie areas and spread to the woodland. In the absence of fire, Oak Woodland – Brushland often succeeds to Oak Forest. Conversely, without recurring fires, prairie and savanna areas can succeed to Oak Woodland – Brushland with encroaching brush and trees over time. Map 2 shows that in 1937 much of the area along the river terrace and ravines was covered with more open woodlands. Only the north-facing slopes and deep ravines show a more closed tree canopy of cooler, denser forest types. Lowland Hardwood Forest: Lowland Hardwood Forest is found throughout Minnesota. It is topographically transitional between upland and floodplain forests and is situated on broad level ground above normal flood levels. These forests are periodically subjected to high water tables and saturated soils and are populated with plants that can tolerate such conditions. The canopy is dominated by trees such as American elm (before Dutch elm disease), black ash, red elm, basswood, bur oak, hackberry, green ash, and aspen. The shrub layer is usually patchy and made up of upland and lowland shrubs such as red osier dogwood, gray dogwood, and hazel. The ground layer is populated by upland herbs such as moonseed, sweet cecily, wild ginger and bottle brush grass. The Lowland Hardwood Forests at the Bloomington Bluffs site is located in the NineMile Creek ravine below Nine-Mile Creek prairie (Map 3). Bedrock, Soils and Erosion The bedrock beneath the Bloomington bluffs is part of the Prairie Du Chien Group. These marine sedimentary rocks were deposited 525 to 450 million years ago on the floors of seas that repeatedly flooded the area. Several periods of glaciation planed off the bedrock surface and filled ancient bedrock valleys with glacial till that was re-eroded by glacial meltwater and inter- and postglacial streams. The meltwaters also deposited gravel and sand in outwash plains and lake basins. These deposits have been most recently carved and redistributed by the modern Minnesota River and its tributaries. Soil type is a major factor influencing a site’s vegetation, hydrology and sensitivity to erosion. The soils along the Bloomington bluffs are derived from glacial till. The Bloomington bluff prairies are situated on the sandy soils of a middle terrace of the Minnesota River Valley (Map 4). Terraces and ravines Several periods of glaciation have influenced the landscape of Minnesota, the last ending around 10,000 years ago. Ice advanced into Hennepin County during this time from two 20 main directions; the northeast and the southwest. First, the Superior lobe brought reddish drift materials into the area from the northeast. The Grantsburg sublobe moved up from the southwest, an off shoot of the Des Moines lobe that originated in the northwest and brought in gray, calcareous till. Advancing ice and meltwater of the Des Moines lobe and the Grantsburg sublobe picked up and incorporated much Superior lobe sediment. Till of mixed composition is exposed in cutbanks near the mouth of Nine-Mile Creek. The soils on the level tops of the terraces are composed of sandy, gravely outwash (Map 4). These sandy loams, derived from stream terraces and outwash plains, tend to be very deep, excessively well drained, and on level slopes of 0 – 8 percent. Most areas with these soils have been developed as residential urban land. The slopes of the ravines on which the prairie remnants are situated have soils identified as Hawick loamy sand. These soils occur on slopes of 18 – 40 %, are very deep (more than 60 inches), and are excessively well drained. The droughty nature of the soils and the southerly aspect of the slopes are responsible for the hot, dry conditions that support the dry sand gravel prairies. Factors contributing to erosion The terraces’ sandy loam soils on the side slopes of the ravines are prone to erosion because of small particle size and steep slopes. Established vegetation helps hold these materials. Erosion problems affecting the Bloomington bluff prairies are largely due to trails cutting down the fall line of the slopes (fig. d). Significance of organic matter and soil organisms Organic matter plays an important role in slowing water movement down a slope, increasing the water holding capacity of the soil and providing nutrients for forest and prairie plants. The soil supporting a healthy plant community is generally composed of accumulated plant materials as well as roots, bulbs, Figure d. Trail erosion at east end of Nine-Mile Creek Prairie. Fuge 2001 seeds and fungi. Bacteria and fungi slowly decompose accumulated plant material, but new plant materials continually regenerate the organic layer. High productivity and slow decomposition results in the development of a thick organic layer especially under grassland or prairie vegetation. Accumulated plant material is generally loose and spongy providing ideal conditions for root growth and cool, moist conditions for seed germination. The organic layer also provides a good insulating layer during the winter for the plants as well as hibernating insects and other animals. Mycorrhizal fungi are particularly important to the health of many plants. Mycorrhizae develop a symbiotic (mutually beneficial) relationship with plants by increasing nutrient 21 and water availability. In turn the plant provides carbohydrates for its mycorrhizal symbiont. Climate The climate of a site is an extremely important component of the resources and determines what species can grow and sustain themselves. Temperature and moisture are particularly important. This site is located in a typical continental climate with moderate precipitation and wide ranges in temperature from summer to winter. The climatological information relevant to the Bloomington bluffs is based on weather data collected at the Twin Cities International Airport in Bloomington, MN. The monthly normals for temperature range from a minimum of 4o F in January to a high of 84o F in July. Precipitation ranges from .79 inches in February to 4.32 inches in June with an annual average precipitation of 29.41 inches. Table a. Monthly Station Normals of Temperature and Precipitation 1971 – 2000 Temperature Normals (degrees Fahrenheit) Station Minneapolis -St. Paul 1971-2000 Ave Element Max Mean Min Jan 1.04 Feb 0.79 Jan 20.7 12.8 4.0 Mar 1.86 Feb 26.6 18.6 9.2 Mar 39.2 30.6 22.7 Apr 2.31 Apr 56.5 46.0 36.2 May 69.4 58.3 47.6 Jun 78.8 68.0 57.6 Jul 84.0 73.1 63.1 Aug 80.7 70.9 60.3 Sep 70.7 60.7 50.3 Oct 58.8 49.6 38.8 Precipitation Normals (Total in Inches) May Jun Jul Aug Sep Oct 3.24 4.34 4.04 4.05 2.69 2.11 Nov 1.94 Nov 41.0 32.8 25.2 Dec 25.5 19.0 10.2 Dec 1.00 From: Climatography of the United States No. 81. National Oceanic and Atmospheric Administration. United States Dept. of Commerce. National Climatic Data Center, Ashville, NC. December 1, 2001. The average date of the last freezing temperature (32Fo) in spring occurs on April 29 and on an average, the first freezing temperature in fall occurs on October 6 resulting in an average of 160 days free of frost in between. Note: gray indicates data for the location nearest the Bloomington Bluffs site Table b. Median Frost Dates and other Critical Low Temperature Thresholds (calculated for 45 years, 1948-1992) Station Chaska Farmington Forest Lake Jordan MSP-Airport Rosemount Stillwater Median Date of Last Min. Temp. in Spring 24oF 28oF 32oF 4/12 4/22 5/2 4/11 4/21 5/3 4/11 4/23 5/3 4/13 4/28 5/10 4/9 4/17 4/29 4/12 4/29 5/9 4/10 4/16 5/2 M<edian Date of First Min. Temp. in Fall 32oF 28oF 24oF 10/2 10/10 10/26 10/3 10/12 10/29 10/7 10/18 10/28 9/27 10/7 10/20 10/6 10/19 11/1 9/28 10/10 10/24 10/7 10/16 11/2 22 Days Between Median Dates 32oF 28oF 24oF 152 173 196 155 178 201 158 178 195 143 164 190 160 185 207 144 161 194 160 184 207 Ann 54.3 45.0 35.3 Annual 29.41 From: The Minnesota Climatology Working Group. Historic Climate Data/Summaries. University of Minnesota, Minneapolis, MN. Available: http://climate.umn.edu/climatology.htm. (Accessed: December 12, 2002). The average date of the first 1-inch snowfall in the fall is November 22 and the average date of the last 1-inch snow cover in the spring is April 2. The mean number of days when there is a snow cover of 6 inches is 54. Average annual snowfall is 52.5 inches. Table c. Mean number of snow cover days for indicated depths and the first and last dates of 1-inch snow cover, October 1959-May 1979. Station Average seasonal snow cover Average date of last 1” snow Average date of first 1” snow days cover in the spring cover in the fall 1” 3” 6” 12” 24” Minneapolis 100 79 Nov. 22 April 2 54 24 1 From: Climate of Minnesota, Part XIII – Duration and Depth of Snow Cover. Kuehnast, E. L., D. G. Baker and J. A. Zandlo. Tech Bull. 333-1982. Agricultural Experiment Station, University of Minnesota Recent Land Use Grazing may have been a factor on some of the prairie openings along these bluffs as suggested by fencing found at some locations. Aside for frequent use of the trails along the Minnesota River, Nine-Mile Creek and the bluff tops, there is little evidence of other human activity on these steep slopes. Many of the impacts on these areas are second hand such as invasion by exotic plants through the introduction of seed by wind, birds and animals. Accelerated erosion is undoubtedly due to trail use and the development of land above the slopes. On May 5, 1988, the City of Bloomington staff, Glen Shirley, City Forester and several members of the Minnesota River Valley Audubon Club (MRVAC) conducted a prescribed burn on part of the Nine-Mile Creek bluff prairie. On July 23 of the same year members of MRVAC cut and removed brush from the Nine-Mile Creek prairie. Brush cutting was again carried out in 1997 with funding from a Conservation Partners Grant. The overgrown wooded area between the two principal prairie areas at Nine-Mile Creek was cleared of buckthorn and burned as part of this project. This area continues to be mowed occasionally (once or twice a year). Buckthorn and other brush and trees were removed from the edges of the prairie openings and from the surrounding woodlands both north of the prairies on top of the bluff and in particular from the wooded slopes below the prairies down to the creek. River Terrace Prairie has been burned at least once in the past 10 years. A reconstruction of one of the private prairies was initiated in 2001 by brush cutting, seeding, planting plugs and burning. For many years up to his death in 2002, Dr. Tom Morley conducted a personal assault against leafy spurge in the east part of Nine-Mile Prairie. Leafy spurge is an invasive, exotic flowering plant that is described in detail on page A-25 of Appendix A. In 1991, leafy spurge was the target of official control efforts. The Friends of the Minnesota Valley have since released leafy spurge beetles on River Terrace Prairie as biological control agents to control this persistent pest. 23 Most of the prairie openings along the Bloomington Bluff area are not accessible to the general public and receive limited human use. The area subjected to the most activity is Nine-Mile Prairie off of 108th Street. Hikers, runners and bicycles use the maintained trails along the top and base of the bluff, some of which pass through prairie openings. Numerous unofficial trails attest to additional use by local residents. A tree swing has been erected at the base of the Nine-Mile Creek prairie and appears to get a fair amount of use. On one site visit in 2003, a lawn chair was found mid-slope at Nine-Mile Creek prairie set up in an area of trampled prairie grass. There is a spot of wood ash and charcoal at the eastern-most end of the prairie, near a bench and overlook, where fires are built. Some litter is found here and there, but the entire site is fairly free of debris, lawn waste and garbage. Management and restoration efforts, including prescribed burns, have taken place on several of the privately owned prairies. Landowners cut brush and monitor areas planted with natives. Biological controls have been released on several leafy spurge populations on private and city lands. Deer and burgeoning turkey populations also contribute to disturbance by browsing, trampling and scraping patches bare of soil in many of the prairie remnants and woodlands. Deer populations have decreased in recent years which reduces grazing pressure on these plant communities (B. Lueth pers. com.). The bare soils of the turkey wallows and scraping are prime targets for weed establishment in the woodland and prairies. 24 Inventory Results and Management Recommendations: Bloomington Bluff Prairies, Central Park The City of Bloomington’s Central Park along Nine-Mile Creek contains a number of prairie openings and other remnant native plant communities. The condition of these areas ranges from small and completely disturbed to moderate sized and relatively diverse. The focus of this plan is on four prairie/savanna openings with ecological features significant to the Twin Cities Metropolitan area (Map 5). The first two, NineMile and River Terrace Prairies, are remnants of Dry Prairie, Sand-gravel Subtype with moderate native plant diversity and fairly good sized for an urban setting. The third prairie remnant (referred to here as East Bank Prairie) located on the east bank of NineMile Creek was noted in 1996 as having moderate diversity despite its small size. The fourth area, referred to in this plan as Kitten-tail Savanna, is heavily overgrown but contains one of the largest populations in the Metropolitan area of the rare plant, kittentails (Besseya bullii). Legal Description: T27N R24W SSW Sect. 21 (Nine-Mile Prairie); SWSE Sect. 21 and NWNE Sect. 28 (River Terrace Prairie); SENW Sect 21 (Kitten-tail Savanna); NWNW Sect 28 (East Bank Prairie) Location (Map 5): Nine-Mile Prairie is southeast of the intersection of 108th St. and Morgan Ave. S. on a south-facing bluff on the west bank of Nine-Mile Creek. River Terrace Prairie is located along the Minnesota River bottoms to the east. It is situated just south of River Terrace Drive on a south-facing bluff on the north bank of the Minnesota River. The Kitten-tail Savanna is on ridge top overlooking Nine-Mile Creek, north of 108th St. on the east side of the ravine. A trail and wooden steps lead up and through the small ‘prairie’ opening from the stream-side trail below. About 1000 feet south of the Nine-Mile Prairie, on the east bank of Nine-Mile Creek, there is another small prairie opening above the maintain trail along the creek. Size: Nine-Mile Prairie, River Terrace Prairie, East Bank Prairie Kitten-tail Savanna, 4.09 acres 1.30 acres 0.20 acres 0.24 acres Owner: City of Bloomington Note: The City of Bloomington owns about 6 acres of prairie remnants in this area. There are approximately another 8 acres of prairie remnants in private ownership nearby. Current Land Cover Land cover is defined as the physical cover, including vegetation (natural and planted) and human constructions (buildings, roads, etc.) present on the landscape. Alternately, land cover can be divided into “natural” (native vegetation typical of pre-European settlement) and “cultural” (human-altered) cover types. Information about existing land cover can help guide decisions about what human uses are appropriate at a site, what management efforts are needed and where restoration efforts should be focused. 25 The level uplands are completely occupied by the cultural landcover of residential neighborhoods with lawns and impervious cover such as buildings, streets and sidewalks. The prevalent natural land cover along the bluffs of the creek and river valleys is disturbed Oak Woodland-brushland. North of 106th St. an area of Mesic Oak Forest was delineated by CBS in 1996. The small remnants of Dry Prairie Sand-gravel Subtype are widely scattered on dry ridge tops and south to southwest facing side slopes. Overgrown dry oak savanna is a transitional cover type between the prairie and woodland. The location of the Kitten-tail population is one such overgrown savanna area. The expanse of prairie and savanna on these bluffs was far greater in the past (Map 2), primarily due to periodic fires that burned the marshes and droughty south-facing bluffs of the Minnesota River Valley. The hot dry conditions and the fires maintained the prairies and oak savannas, and kept trees and brush from filling in these community types as is occurring presently. This management plan specifically targets the prairie and savanna remnants. Plant Community Descriptions and Management Recommendations • Dry Prairie Sand-gravel Subtype Description – Nine-Mile Prairie: In 1996, the largest of the prairie openings in the Bloomington bluff site, Nine-Mile Creek Prairie, was described by CBS Ecologist, Fred Harris, as “a beautiful little prairie hillside (with a) beautiful array of flowering plants”. Harris assigned a BC-rank2 to the quality of this prairie. The remnant dry prairie is located on a south-facing slope on the west bank of Nine-Mile Creek, a tributary of the Minnesota River. The prairie is dominated by short grasses typical of dry prairies including little bluestem (Schizachyrium scoparium), side oats grama (Bouteloua curtipendula), drop seed (Sporobolus heterolepis) and plains muhly (Muhlenbergia cuspidata). Variations in topography support different Figure e. South facing dry prairie combinations of prairie species with specific habitat opening, Nine-Mile Creek Prairie. preferences. For instance, hairy grama (Bouteloua hirsuta) and porcupine grass (Stipa spartea) are important on the well-drained, gravelly crests of the hilltops, while big bluestem (Andropogon gerardii) and Indian grass (Schizachyrium scoparium) are more abundant in the slightly cooler, moister draws and down-slope areas with somewhat deeper soils. There is a good diversity of dry prairie forbs in the prairies. Most notable are purple and white prairie clovers (Dalea candida and D. purpurea), pasque flower (Pulsatilla nuttalliana), lead plant (Amorpha 2 This rank represents an evaluation based on four factors: 1) Quality - how representative is this occurrence compared to an undisturbed example of the same community type? 2) Condition - how much has the site and the community been damaged or altered from its original condition and character? 3) Viability - what are the long-term prospects for continued existence of this site? 4) Defensibility - to what extent can this occurrence be protected from human factors that might otherwise degrade or destroy it? 26 canescens), harebell (Campanula rotundifolia), sky blue aster (Aster oolentangiensis) and ground plum (Astragalus crassicarpus). Invasive species include encroaching natives such as smooth sumac (Rhus glabra), prickly ash (Zanthoxylum americanum), raspberry (Rubus sp.), red cedar (Juniperus virginiana), and pin oak (Quercus ellipsoidalis) especially along the margins with the adjacent woodlands. Exotic invasives of particular concern in the prairie are smooth brome (Bromus inermis), Kentucky bluegrass (Poa pratensis), crown vetch (Coronilla varia), leafy spurge (Euphorbia esula), Siberian elm (Ulmus pumila) and common buckthorn (Rhamnus cathartica). Buckthorn is well established in the adjacent woodlands. There is very little spurge on the larger, eastern part of the prairie, except for the eastern-most end by the bench and overlook, where it persists. The spurge in the west part of the prairie is well established in a loosely arranged patch on top of the hill in the most disturbed part of the remnant. Along the wooded edges of the prairie openings and into the woodlands, the invasives of note are common buckthorn, Siberian elm, and Tartarian honeysuckle. There is some birds’ foot trefoil (Lotus corniculatus) in the prairies that needs to be addressed before it becomes extensively established. Areas with particular invasive weed populations are noted on Map 6. Management: Targeted weed control, brush cutting and prescribed burning are the primary management tools needed to benefit the prairie. Seed collecting in the fall and interseeding specific areas in the spring, especially after burns, would augment natural revegetation of areas with little to no native plant cover. As fire and brush cutting push back the woodland and allow the prairie areas to reoccupy their former extent, native prairie seed will be needed to augment the exposed areas at the edges of the prairie openings. Because trees and brush have been allowed to expand into the prairies for many years, unhampered by the fires that historically kept them at bay, targeted brush cutting is needed to effectively set back invasive woody species. Many of these species will require persistent repeated cutting or cut stump treatment with herbicide. Sumac, pin oak, Siberian elm and common buckthorn are among those that will stump sprout profusely when cut. The fact sheets in Appendix A provide information on specific treatment for individual species. Cut brush must be removed from the prairie area to prevent damage to existing prairie plants. Brush may be piled and burned in areas where prairie plants have already been displaced such as in the middle of brush thickets that have been cut down. Herbaceous invasives such as spotted knapweed, crown vetch, birds’ foot trefoil and leafy spurge can be managed with an integrated pest management approach. Eliminating the disturbance that allowed their establishment, pulling and removing seed laden flowering parts, spot treating with herbicide, and the use of biological controls can be applied in various combinations to combat many of these persistent weeds. Again, species specific information is provided in Appendix A. 27 Fire is the principle management tool for native prairie. A late spring burn carried out as soon as possible will determine how much brush cutting and weed control will be required. After an initial burn, brush cutting of larger trees and shrubs as well as brush around the edge of the prairie will be needed. If burning is to be delayed for one or two years, brush cutting must be initiated to prevent further loss of prairie plants. Historically, fire maintained the prairies that once covered 2/3 of the state. Reintroducing fire through prescribed burning is the most beneficial and cost effective management tool for maintaining native prairie. Burning will help to remove accumulated litter, promote prairie seed germination and the established native plants, and remove and suppress invasive weedy species. Fire helps to remove and break down built-up litter or thatch that stifles the growing prairie plants and releases nutrients that would otherwise only slowly become available as the litter rots and decays. The increased nutrients promote seed production in the native plants. Removing the litter and blackening the area by fire also allows the soil surface to warm earlier in the spring, which promotes seed germination and stimulates the prairie plants to begin growing sooner. This gives them an advantage over competing exotic and invasive species. Careful timing of the burns will be necessary to knock down brush and suppress invasive plants in the prairie. Incorrectly timing burns can stimulate and promote the spread of many undesirable species. Mowing and cutting can be used to augment the burn regime to suppress unwanted plant populations. Correctly timing of the mowing to eliminate flowering or seed production of the targeted weeds is very important so that the effort is effective. Specific management strategies are outlined in Appendix A for weeds found on the Bloomington bluff prairies. Burning stimulates seed production of the prairie species especially the grasses. It is important to use seed collected from the site in the prairie remnants to protect the integrity of the genetics in the local plant community. The seed is collected in the fall when it is ripe (late August through October depending on the species). Although it is best to use seed within the year it is collected, when kept cool and dry, the seed can be held several years. This local seed can be used in the open patches where dense trees or brush may have been removed and in savanna areas as the canopy opens up after successive burns or cutting. Seed can be planted after burns or in unvegetated patches of bare soil by scattering it by hand and lightly raking it into the soil. Soil-seed contact is extremely important for good germination. Dry Prairie, Sand-gravel Subtype – Nine-Mile Prairie, Species List: 1995 and 2003 Combined Inventories Grasses: Big bluestem Side oats grama Hairy grama Smooth brome* June grass Plains muhly Panic grass Kentucky bluegrass* Little bluestem Andropogon gerardii Bouteloua curtipendula Bouteloua hirsuta Bromus inermis Koeleria macrantha Muhlenbergia cuspidata Panicum leibergii Poa pratensis Schizachyrium scoparium 28 Indian grass Prairie dropseed Porcupine grass Sorghastrum nutans Sporobolus heterolepis Stipa spartea Forbs: Western ragweed Thimbleweed Whorled milkweed Green milkweed Asparagus* Sky blue aster Ground plum Toothed evening primrose Harebell Bastard toad-flax Horseweed* Crown vetch* White prairie clover Purple prairie clover Larkspur Horsetail Daisy fleabane Leafy spurge* Prairie smoke Pennyroyal Dame’s rocket* False boneset Dotted blazing star Yellow flax Hairy puccoon Birds’ foot trefoil White sweet clover* Four –o’clock Wild bergamot False gromwell Large flowered beard tongue Ground cherry Wooly plantain Tall cinquefoil Pasque flower Black-eyed Susan Blue-eyed grass Canada goldenrod Stiff goldenrod Spiderwort Yellow goat’s beard* Tinker’s weed Hairy vervain Ambrosia coronopifolia Anemone cylindrica Asclepias verticillata Asclepias viridiflora Asparagus officinalis Aster oolentangiensis Astragalus crassicarpus Calylophus serrulata Campanula rotundifolia Comandra umbellata Conyza canadensis Coronilla varia Dalea candida Dalea purpurea Delphinium virescens Equisetum sp. Erigeron strigosus Euphorbia esula Geum triflorum Hedioma hispida Hesperis matronalis Kuhnia eupatorioides Liatris punctata Linum sulcatum Lithospermum caroliniense Lotus corniculatus Melilotus alba Mirabilis hirsuta Monarda fistulosa Onosmodium molle Penstemon grandiflorus Physalis virginiana Plantago patagonica Potentilla arguta Pulsatilla nuttalliana Rudbeckia hirta Sisyrinchium sp. Solidago canadensis Solidago rigidus Tradescantia bracteata Tragopogon dubius Triosteum perfoliatum Verbena stricta Trees and Shrubs: Leadplant Red cedar Scotch pine* Amorpha canescens Juniperus virginiana Pinus sylvestris 29 Northern pin oak Bur oak Smooth sumac Wild rose Black raspberry Wolfberry Siberian elm* Prickly ash Quercus ellipsoidalis Quercus macrocarpa Rhus glabra Rosa sp. Rubus occidentalis Symphorocarpus occidentalis Ulmus pumila Zanthoxylem americanum * Non-native plants Description – River Terrace Prairie: The greatest portion of this prairie is on City land while the north ~75 feet are in private ownership. The City has interacted with these landowners for many years on the management of River Terrace Prairie. The remnant is located south of 1209 River Terrace Dr. and has no official public access. There is an old recreation trail at the base of the bluff, but an adjacent neighbor stated that this trail has been closed to public use. The prairie exhibits few signs of human disturbance except near the residential lots on the top of the bluff above it. A good-sized animal den, reportedly used by fox, is located on the west slope. Wild Turkeys use the open soil around it for dusting. Deer browsing of plants, especially forbs, is notable. As with Nine-Mile Prairie, this prairie remnant was given a BC-rank by ecologist Harris in 1996 who described it as a “very nice piece of dry prairie”. It is dominated by side oats grama, June grass and little bluestem. There are distinctive patches of plains muhly and prairie drop seed. The driest crests are populated by porcupine grass and hairy grama grasses, while Indian grass and big bluestem are established in the deeper soils down slope and in swales. There is a good diversity of native forbs. Map 7 shows the location of invasive weeds on the River Terrace Prairie. Woody encroachment is primarily a problem along the edges where the prairie and woodland meet. The woodland is densely populated with the exotic shrub, common buckthorn. This shrub is working its way into the prairie along the east edge. Smooth sumac is expanding its extent mostly from the bottom of the slope in the low area to the north that divides the two branches of this prairie. Siberian elm and green ash are also found encroaching on the prairie. The west side of the prairie opening is being overtaken by an expanding, dense grove of young even-aged pin oak. Leafy spurge is well established in the southeast corner and in a small patch of prairie on adjacent private land in the north west part of the site. There are two clumps of bright orange iris-like flowers, an exotic perennial that may have been planted intentionally or inadvertently introduced by animals. The invasive nature of this plant is unknown, but its immediate removal is recommended. Management: The same management strategies apply to River Terrace Prairie as for Nine-Mile Prairie. Cutting of encroaching trees and brush, prescribed burning, seed collection and seeding of disturbed edges will all contribute to the protection of this prairie remnant. The prairie was burned in a wildfire around 1978 and a prescribed fire was conducted here in the early 1990’s. 30 Biocontrols (insects that specifically feed on leafy spurge) were released on the northwest spurge infestation in 2002. Releasing additional agents on the southeast population of this persistent plant is recommended. Dry Prairie, Sand-gravel Subtype – River Terrace Prairie, Species List: 1995 and 2003 Combined Inventories Grasses: Big bluestem Side oats grama Hairy grama June grass Plains muhly Panic grass Kentucky bluegrass* Little bluestem Indian grass Prairie dropseed Porcupine grass Andropogon gerardii Bouteloua curtipendula Bouteloua hirsuta Koeleria macrantha Muhlenbergia cuspidata Panicum oligosanthes Poa pratensis Schizachyrium scoparium Sorghastrum nutans Sporobolus heterolepis Stipa spartea Forbs: Yarrow Western ragweed Whorled milkweed Green milkweed Asparagus* Heath aster Aromatic aster Sky blue aster Silky aster Toothed evening primrose Harebell Horseweed* Purple prairie clover Daisy fleabane Leafy spurge* Pennyroyal Dame’s rocket* False boneset Dotted blazing star Yellow flax Hairy puccoon Birds’ foot trefoil White sweet clover* Four –o’clock Wild bergamot False gromwell Large flowered beard tongue Ground cherry Wooly plantain Tall cinquefoil Pasque flower Black-eyed Susan Achillea millefolium Ambrosia coronopifolia Asclepias verticillata Asclepias viridiflora Asparagus officinalis Aster ericoides Aster oblongifolius Aster oolentangiensis Aster sericeus Calylophus serrulata Campanula rotundifolia Conyza canadensis Dalea purpurea Erigeron strigosus Euphorbia esula Hedioma hispida Hesperis matronalis Kuhnia eupatorioides Liatris punctata Linum sulcatum Lithospermum caroliniense Lotus corniculatus Melilotus alba Mirabilis sp. Monarda fistulosa Onosmodium molle Penstemon grandiflorus Physalis virginiana Plantago patagonica Potentilla arguta Pulsatilla nuttalliana Rudbeckia hirta 31 Blue-eyed grass Canada goldenrod Grey goldenrod Spiderwort Yellow goat’s beard* Tinker’s weed Hairy vervain Sisyrinchium sp. Solidago canadensis Solidago nemoralis Tradescantia bracteata Tragopogon dubius Triosteum perfoliatum Verbena stricta Trees and Shrubs: Leadplant Red cedar Scotch pine* Northern pin oak Bur oak Smooth sumac Wild rose Black raspberry Wolfberry Siberian elm* Prickly ash Amorpha canescens Juniperus virginiana Pinus sylvestris Quercus ellipsoidalis Quercus macrocarpa Rhus glabra Rosa sp. Rubus occidentalis Symphorocarpus occidentalis Ulmus pumila Zanthoxylem americanum * Non-native plants Description – East Bank Prairie: On the east bank of Nine-Mile Creek there are a few very small prairie remnants. One of these on city property, referred to here as East Bank Prairie, was ranked C in 1996 by the CBS ecologist. Although it is very small, it still displays good native prairie plant diversity. The surrounding Oak Woodland-Brushland is dominated by open grown oak suggesting a more open, savanna community existed here in the past. Management: This prairie would benefit from the cutting of invasive woody plants, particularly on the perimeter. Prescribed burns would augment the cutting effort and promote the native prairie species. See Management sections for Nine-Mile and River Terrace Prairies. Dry Prairie Sand-gravel Subtype Species List: 1995 Inventory Grasses/Sedges: Big bluestem Smooth brome* Plains muhly Kentucky bluegrass * Foxtail* Indian grass Andropogon gerardii Bromus inermis Muhlenbergia cuspidata Poa pratensis Setaria sp. Sorgastrum nutans Forbes: Western ragweed Lead plant Wormwood Whorled milkweed White snakeroot Field thistle Ambrosia coronopifolia Amorpha canescense Artemesia ludoviciana Asclepias verticillata Eupatorium rugosum Circium discolor 32 Stiff sunflower Dotted blazing star Purple prairie clover Goat’s beard * Helianthus rigidus Liatris punctata Petelostemum purpurea Tragopogon dubius Non-native plants • Dry Oak Savanna Sand-gravel Subtype Description-Nine-Mile Creek Savanna: Between the west and east prairie openings at Nine-Mile Creek Prairie, there is an area where savanna restoration management has been initiated. The removal of invasive brush (common buckthorn) and some trees has opened the canopy and allowed more sunlight to enter the area. The ground layer is dominated by weedy species such as nettles, thistle, bur-fruited species, and resprouting buckthorn. Figure f. Nine-Mile Creek Prairie savanna restoration. Fuge 2002 Management: The periodic mowing of this area has helped to maintain the open character of the savanna. Additional brush cutting, prescribed burning, and introduction of native prairie and savanna ground layer species will help to establish and maintain the restoration. Initially, frequent repeated burns will be needed to set back the woody species including the buckthorn. Once established, burns every 2 to 3 years may suffice. Description-Kitten-tail Savanna: Within the Mesic Oak Forest north of 106th Street there is evidence of former savanna in the form of the open-grown oaks just beyond the prairie openings on the bluffs and in the surrounding woodlands (Map 5). These knarled, low branching, spreading oaks, usually bur oaks, are now choked with dense brush and young trees. The exotic brush, common buckthorn, is one of the most common species invading these areas, but young native trees and brush are also increasing. Occasionally, prairie species, such as lead plant, sky blue aster, little bluestem grass and side oats can be found persisting in the understory. Large, scattered red cedar in the woodlands are also indicators of the once open character of these former savanna areas. Figure g. Path through Kitten-tail Savanna. Fuge 2002 33 In the very small opening called Kitten-tail Savanna (fig. f), a large population of the rare savanna plant, kitten-tails (Besseya bullii), is found (Map 8). It is said to be one of the largest populations known to exist in the Twin Cities area. In 1983, 119 plants were counted by DNR Botanist, Welby Smith. Although no count of individual plants was done in 2003, four flowering stalks of the same year were observed. Most of the plants are at the western end of the opening, crowded along the north edge of the trail that passes through this location. There are a few plants of Besseya tucked into the brush south of the trail. All of the individual plants that had flowered were on the north side of the trail. Young trees and brush have closed in Figure h. Kitten-tail basal leaves and dry flowering and severely threaten the population. This stalk. Fuge 2003 area was far more open in the past (Map 4). Kitten-tails is a plant species limited in distribution to only seven Midwestern states. It is considered rare throughout its range. In Minnesota, this plant is known to exist at only a half a dozen or so localities, although historic records indicate a more widespread distribution. Many of the surviving colonies are in or near the Twin Cities. Kitten-tails are typically found partial shade at the edge of wooded areas. Kitten-tails are specifically a savanna species, adapted to the conditions of sun and shade found in oak savanna habitat. Management: Most importantly, brush cutting will begin to open the savanna canopy and reestablish ground layer species more typical of an oak savanna. Initiate the removal of brush and trees along the south side of the trail. This will allow more sunlight to reach the existing population on the north side of the trail. Selected young trees and brush directly encroaching on the Kitten-tails can then be eliminated. Carrying out this activity in the winter will help to reduce disturbance of the ground layer. Kitten-tails will benefit from less competition in this limited space and a more open canopy. Extreme caution must be used if herbicides are to be used to suppress regrowth of trees and shrubs where they are cut to open the canopy. Developing a buffer of 10 – 20 feet around the kitten-tail population within which herbicide is not used is recommended. Even this distance may not be great enough if wind or water transport chemicals off target. Prescribed burning is an effective tool for savanna restoration and management. At the kitten-tail site in Figure i. Kitten-tail population on edge of footpath. Fuge 2003 34 Central Park, prescribed burning must also be used with extreme caution in order not to damage the rare plant population. Protect the population from burning or being severely effected by heat by wetting a large area around the plants before igniting fuels in the vicinity. A suggested alignment for re-routing the trail away from the kitten-tail population is shown on Map 8. This would reduce the damage caused by trampling and also establish a functional firebreak for future burns to manage this small savanna remnant. The current trail alignment goes directly down the fall line of the slope contributing to erosion. Erosion could be mitigated by careful positioning of a new trail alignment across the slope north of the kitten-tail population. Dry Oak Savanna Sand-gravel Subtype Species List: 2002 Inventory Grasses/Sedges: Side oats grama Smooth brome* Kentucky bluegrass * Little blue stem Foxtail* Bouteloua curtipendula Bromus inermis Poa pratensis Schizachrium scoparium Setaria sp. Forbs: Western ragweed Hog peanut Thimbleweed Queen Anne’s lace* Sky blue aster Kitten tails Tick trefoil White sweet clover* Yellow sweet clover* Plantain* Bloodroot Canada goldenrod Red clover* Ambrosia coronopifolia Amphicarpa bracteata Anemone cylindrica Daucus carota Aster oolentangiensis Besseya bullii Desmodium glutinosum Melilotus alba Melilotus officinalis Plantago sp. Sanguinaria canadensis Solidago canadensis Trifolium pretense Trees and Shrubs: Red cedar Ironwood Black cherry Pin oak Bur oak Common buckthorn* Smooth sumac Basswood Prickly ash Juniperus virginiana Ostrya virginiana Prunus serotina Quercus ellipsoidalis Quercus macrocarpa Rhamnus cathartica Rhus glabra Tilia americana Zanthoxylem americanum * Non-native plants 35 36 Implementation Management Schedules As described in the Inventory Results and Management Recommendations section, the principal management needs on the prairies and savannas are: • • • prescribed burning (burns promote prairie plants by removing competitive brush and choking litter, set back exotic cool season grasses, and boost native seed production) brush and tree removal (incl. smooth sumac, Siberian elm, common buckthorn and oak seedlings). Exotic weed and brush control (leafy spurge, spotted knapweed, common buckthorn, Siberian elm) Chemical and biological methods are available for many exotics. Note: In the following table, gray boxes indicate tasks that are of the highest priority. Table d. Restoration Recommendations Date Late spring 2004 June & August 2004 July & August 2004 Fall 2004 Winter 2004-05 Spring 2005 July & August 2005 Summer 2005 Winter 2005-06 Winter 2005-06 Task Conduct prescribed burn mid- to late May to kill brush and set back cool season exotics, especially bluegrass and smooth brome. Select one or two units to burn every year. Spot treat leafy spurge in June and August or release bio controls in June. Pull knapweed from prairie. Bag and remove flowering stalks from site. Collect prairie seed especially grasses in September and October Cut encroaching trees and brush, stack and burn in areas lacking prairie vegetation (in the middle of tree and brush thickets) Seed areas cleared of trees and brush the preceding winter Pull knapweed from prairie. Bag and remove flowering stalks from site. Trim weeds in seeded areas to keep them below 10 inches throughout the growing season. This eliminates competition and allows sunlight to reach germinating native prairie seed Continue cutting trees and brush Burn tree and brush piles cut the previous winter. Prescribed Fire Goal: The goal of prescribed burning on the City of Bloomington prairies and savannas is to maintain the structure and diversity of the plant community, set back exotic cool season grasses and forbs (blue grass and sweet clover) and remove brush and trees (raspberry and oak) that are shading the prairie and ground layer species. (See Appendix A for specific management of invasive species) Recommended burn cycle: Because the City-owned prairies are only part of the prairie remnants found in the immediate landscape, the smaller remnants have not been divided into burn units. It is always recommended to avoid burning an entire prairie remnant in order to provide refugia for plants and animals that may be harmed by fire. The refugia provide reservoirs for species that can move back into an area after it has been burned. In the case of the City-owned prairies, the neighboring prairie remnants will provide this function. If one or two units can be burned each year, the burn rotation for each 37 individual unit can be maintained at 4 – 6 years. In other words, an individual unit will be burned every 4 - 6 years which has been shown to maintain and promote prairie species and keep out trees and brush. It may be necessary to burn frequently initially (every 2 - 3 years for the first five years) to establish a strong stand of native plants. For long term fire management, a longer burn rotation is beneficial. Long-term burn management timing will be based on the status of brush, cool season exotics, and litter accumulation. An ecologist should be consulted to determine the timing of burns. As a rule of thumb, a burn rotation of every 4 – 6 years is most likely to benefit this type of prairie. Staggering the timing of burns (not burning at the same time each year a burn is conducted) will promote and maintain the structure and diversity of the prairie. Once the prairie is well established, occasional late summer or fall burns may also be considered. Fire should be allowed to move into the wooded edges all around the prairie remnants. This will begin to push back the encroaching woodland species and open up savanna areas, restoring the habitat for savanna species including the rare kitten-tails where they occur. Burn breaks can generally be raked 10-15 feet inside the edge of the adjacent woodlands. The burn units and breaks for Nine-Mile Prairie are shown in Fig. j. Burn Plan General burn prescription: Location Desired date Expected duration* Preferred wind direction** Wind speed Temperature Relative humidity T27N R24W SSW Sect. 21 (Nine-Mile Prairie); SWSE Sect. 21 and NWNE Sect. 28 (River Terrace Prairie); SENW Sect 21 (Kitten-tail Savanna); NWNW Sect 28 (East bank prairie) Mid- to late May 4-6 hours NNE to NNW 5 – 10 mph 40 – 700F 40-60% *On date of actual burn, be certain weather conditions will hold for the duration of the burn. **Wind direction will vary with wind speed, atmospheric mixing and burn unit Equipment: Drip torch, backpack pump cans, extra water, flappers, protective clothing, cell phone, matches, drinking water. A list of companies selling burn equipment is attached, however, please also note that many times the Department of Natural Resources or United States Fish and Wildlife Services will loan out equipment such as drip torches and backpack sprayers to landowners. Please contact your local offices for more information (see Appendix C - Resources). Smoke sensitive areas: The proximity of residential areas limits the direction to which smoke can go. Generally, all smoke needs to be directed down Nine-Mile Creek ravine 38 into the Minnesota River Valley. Trail use during a burn must also be controlled or visitors alerted to the prescribed burn taking place in the vicinity. Managing the burn: Firebreak preparations: A firebreak is needed between the units at Nine-Mile Creek prairie. A 10 – 15ft-wide mowed break is recommended. The grass should be mowed as short as 4” and all accumulated materials must be raked off the break well away from the area to be burned. Cutting the break in the fall preceding the burn will allow the break to green up in the spring before the burn further strengthening the effectiveness of the break. Firing techniques and ignition pattern: For the burn units on steep hills, regardless of wind direction, the burn is always initiated at the top of a hill. Two lines of fire are then continued downhill and around the burn unit in either direction. Ultimately, the two opposing fire lines meet opposite the starting point at the bottom of the hill. Fire sensitive areas: The surrounding woodlands contain large amounts of woody fuels that will burn. Generally, conditions that favor a safe prescribed fire in prairie grasses are too damp and cool for these adjacent fuels to be dangerously volatile. Never the less, wide burn breaks and caution during a controlled burn are essential to keep fire from escaping into the woodlands. Permits and notification: Obtain a burning permit in advance from the local fire department. Be certain to notify the local fire department and county sheriff immediately prior to and upon completion of the burn on the day of the burn. It’s a good idea to contact neighbors within sight of the burn so that they are not alarmed at the time of the burn. 39 Figure j. 40 Woody vegetation control Goal: The goal is to remove the shade and leaf litter of the trees and brush from the prairie. The species of concern are Siberian elm, raspberry, prickly ash, common buckthorn, eastern red cedar, smooth sumac and oak seedlings. As these species grow in size and expand the area they affect, the prairie species die out, unable to survive in the shade. The larger, eastern part of the prairie remnant is the highest quality – that is, it has the least encroachment of woody plants. It is recommended that the brush cutting begin on the west part of Nine-Mile Creek Prairie. Brush cutting at River Terrace and East Bank Prairies can focus on interior brush initially then on the perimeters where brush and trees are encroaching. Small amounts of cut material can be scattered on the prairie as long as it does not smother desirable native vegetation. Large trees and piles of cut brush must be removed from the prairie. Heavily disturbed or areas devoid of native plants may be identified for stacking and burning brush. Winter snow cover provides good conditions for burning these brush piles. Recommended procedures (see also Appendix A): Buckthorn: Buckthorn is easiest to identify and locate in a woods when most native species of trees and brush have lost their leaves in the fall or before they leaf out in the spring. This is because buckthorn greens up earlier in the spring and holds its leaves longer in the fall than most native plants and so it is the only leafy green bush in the landscape at these times of year. Buckthorn is dioecious; that is, male and female flowers are on separate plants. The female plants bear clusters of dark berries that are responsible for the rapid spread of this plant. If resources are limited, female plants can be targeted first to reduce the amount of berries and seeds. In most cases, buckthorn can be cut and left to lie on the ground. It is easiest to see and therefore cut in the spring and fall, but it can be cut any time of year. All that is required is that the person have the ability to recognize the plant with or without its leaves. For cut stump treatment of buckthorn above freezing temperatures, daub or spray the cut surface immediately with a 25% solution of triclopyr (Garlon 3A) in water. In the winter or when temperatures are below freezing, use a 25% solution of Garlon 4 mixed with bark oil such as Diluent Blue. Siberian elm: Siberian elm is best cut to the ground and treated with a suitable herbicide to prevent resprouting. For cut stump treatment of Siberian elm above freezing temperatures, daub or spray the cut surface immediately with a 25% solution of triclopyr (Garlon 3A) in water. In the winter or when temperatures are below freezing, use a 25% solution of Garlon 4 mixed with bark oil such as Diluent Blue. 41 Smooth sumac: Sumac can be cut and controlled with or without herbicide. If using herbicide, daub or spray the stump immediately after cutting with a 20% solution of glyphosate (Roundup). A non-herbicide method is to cut twice during the growing season in July and August for several years. In years when a prescribed burn is conducted, cutting may be unnecessary or only one cutting in August may be needed. Small amounts of cut sumac can be left scattered on the prairie. Eastern Red Cedar: Red cedar is a native tree that can become abundant in the absence of fire. Larger trees should cut and piled to be burned in the winter. Avoid making the burn piles on areas supporting prairie vegetation. Very small trees may be cut and left on the prairie to be consumed in prescribed burns. Other invasive brush: Other brush such as raspberry and prickly ash may be cut and burned or left on the prairie to consumed in prescribed fires. Determining how to handle the cut brush will depend on the density of the material resulting from cutting. Exotic species control Goal: The goal is to set back the spread of smooth brome, bluegrass and other non-native invasive plants and prevent them from displacing native prairie species. Recommended procedures: Cool season exotic grasses (bluegrass & smooth brome): Burning cool season exotic grasses in mid- to late May when they are actively green and growing has been shown to be effective. At this time of year, the plant is putting most of its energy into the aboveground parts of the plant and there are low food reserves in the root system. Leafy Spurge: If chemicals are used to control leafy spurge, June and August are when this plant is most receptive to herbicide - when it is in full flower. Biological controls have been shown to be effective, especially on drier sites in dense populations of leafy spurge. Spotted knapweed: Pulling knapweed at the beginning of its blooming period (the end of July and into August) has been shown to be effective. A number of years are required to eliminate the established seed bank with this method. Gloves must be worn to protect hands from this plant’s toxins. Seed heads must be bagged and removed from the site as pulled or cut plants with flowers will set seed. Birds’ foot trefoil and crown vetch: Pulling can be effective in controlling these species when populations are small. Larger infestations must be controlled with herbicide. The seed viability of birds’ foot trefoil is thought to be 4 - 41/2 years. Successive pulling throughout the growing season over a period of 5 years 42 will greatly deplete the seed bank and reduce the amount of birds’ foot trefoil displacing native prairie species on a site. Interseeding Goal: In areas where invasive plants are removed the result is often a bare patch of soil readily colonized by weeds. To discourage weeds and promote native plants, raking in local prairie seed is advantageous. Recommended procedures: Native prairie grass seed The best time to collect prairie seed is in the fall (September and October) after a spring burn. The burn helps to warm the soil earlier, remove competition and dense litter and release nutrients, all of which help native prairie plants to grow vigorously and produce elevated amounts of seed. Learn to identify some of the more common grasses on this site which are side oats grama, Indian grass and little bluestem. Collect the seed when it strips off the stalk easily indicating it is ripe. Side oats ripen first usually in early September. Indian grass can usually be collected in late September through October. Little bluestem holds on to its seeds the longest and can be collected in October. It all depends on the growing season, but these are average collection times. The seed can be spread by hand onto bare spots in the prairie caused by cutting dense stands of trees or brush, burning brush piles or other damage that exposes the soil surface. Lightly raking the area seeded and then tamping the soil will ensure good seed to soil contact necessary for good germination. It is also important not to bury the seed too deeply or germination will be poor. 43 44 Bibliography and References Bake, D. G. and J. Strub. 1963. Climate of Minnesota, Part I – Probability of occurrence in the Spring and Fall of Selected Low Temperatures. University of Minnesota Agricultural Experiment Station, Minneapolis, MN. Climatography of the United States No. 81. National Oceanic and Atmospheric Administration. United States Department of Commerce. National Climatic Data Center, Ashville, NC. December 1, 2001. Coffin, B. and L. Pfannmuller, ed. 1988. Minnesota’s Endangered Flora and Fauna. University of Minnesota Press, Minneapolis, MN. Curtis, John T. 1959. Vegetation of Wisconsin: An Ordination of Plant Communities. The University of Wisconsin Press. Harris, Fred and D. Wovcha. 1995. Site Survey Summary, Hennepin County CBS Site #2. Minnesota Department of Natural Resources. County Biological Survey. Kilde, Rebecca. 2000. Going Native: A Prairie Restoration Handbook for Minnesota Landowners. Minnesota Department of Natural Resources Section of Ecological Services Scientific and Natural Areas Program. Kuehnast, E. L., D. Baker and J. Zandlo. 1982. Climate of Minnesota, Part XIII - Duration and Depth of Snow Cover. Technical Bulletin 333. Agricultural Experiment Station, University of Minnesota, Minneapolis, MN. Marschner, F. J. 1974. The original vegetation of Minnesota. USDA Forest Service, North Central Experiment Station, St. Paul, Minnesota. Minnesota Department of Natural Resources, Natural Heritage Program. 1991. Minnesota’s Native Vegetation: A Key to Natural Communities, Version 1.5, Biological Report No. 20. Minnesota Department of Natural Resources. 2001. Ecological Classification System. (www.dnr.state.mn.us/ecological_services/ecs). Minnesota Department of Natural Resources. 1998. Original Land Survey Bearing Trees. Section of Ecological Services, Minnesota County Biological Services. MN DNR MIS Bureau. Minnesota Geological Survey, Geologic Atlas Hennepin County, Minnesota, University of Minnesota, 1989 NatureServe Explorer: An online encyclopedia of life [web application]. 2001. Version 1.6 . Arlington, Virginia, USA: NatureServe. Available: http://www.natureserve.org/explorer. (Accessed: December 12, 2002 ). Packard, Stephen and Cornelia F. Mutel, Society for Ecological Restoration. 1997. The Tallgrass Restoration Handbook: for Prairies, Savannas, and Woodlands. Washington DC: Island Press. Packard, Steve. 1993. “Restoring Oak Woodlands.” Restoration and Management Notes 11:5-16. Shirley, Shirley. 1994. Restoring the Tallgrass Prairie: An Illustrated Manual for Iowa and the Upper Midwest. Iowa City: University of Iowa Press. The Minnesota Climatology Working Group. Historic Climate Data/Summaries. Median Frost Dates and Other Critical Low Temperature Thresholds in Minnesota and Bordering Areas. University of Minnesota, Minneapolis, MN. Available: http://climate.umn.edu/climatology.htm. (Accessed: December 12, 2002). 45 United States Dept. of Commerce. December 1, 2001. Monthly Station Normals of Temperature, Precipitation, and Heating and Cooling Degree Days 1971 – 2000, 21 Minnesota. Climatography of the United States No. 81. National Oceanic and Atmospheric Administration. National Climatic Data Center, Ashville, NC. Wisconsin Department of Natural Resources. 2000. Ecologically Invasive Species. www.dnr.state.wi.us/. Department of Natural Resources. Wovcha Daniel, B. C. Delaney, G.E. Nordquist. 1995. Minnesota’s St. Croix River Valley and Anoka Sandplain: A Guide to Native Habitats. State of Minnesota Department of Natural Resources. 46 Great River Greening Helping communities restore, manage and learn about their natural environment through volunteer involvement. The Challenge Erosion, trash, and the invasion of exotic and invasive plant species are degrading our urban river valleys, reducing ecological diversity destroying wildlife habitat. Many public and private organizations are working to protect the river valleys, but these programs often lack long-term community involvement and stewardship. These problems are especially pressing in the Twin Cities metropolitan region, home to more than 2 million people. The river valleys in this area: Hold some of the region’s last intact native landscapes Serve as vital wildlife corridors for hundreds of migratory bird species Provide a water source for millions of the region’s residents Contain some of the region’s most scenic sites and vistas Great River Greening’s response Great River Greening, a nonprofit organization, helps coordinate a cost-effective and sustained effort to manage ecosystems of the three great river valleys of the metropolitan area: the Mississippi, Minnesota and St. Croix. We are primarily an implementing organization, providing on-the-ground ecological restoration and management of both public and private land. We engage thousands of volunteers in the planting of native vegetation, removal of exotic and invasive weeds, native-seed collection, and stewardship—work that cultivates an informed and involved citizenry. We also act as a catalyst, creating effective partnerships among agencies, municipalities, and private landowners responsible for managing river valleys and their natural resources. Restoration ecologists and other scientists provide technical expertise. 47 Key values Great River Greening bases its work on these values: 1. Native trees and other vegetation have ecological and sociological value: They contribute to the health and biodiversity of ecosystems; they beautify surroundings; and they enhance a community’s natural heritage and sense of place. 2. People want opportunities for direct involvement in natural resource protection and management, which help them feel connected and committed to their local natural areas. 3. Volunteer involvement in restoration and planning is one of the most effective methods of environmental education. When people work side by side to improve their environment, their communities become stronger and more vital. 4. Environmental restoration and stewardship require collaboration and inclusiveness. We are committed to: Citizen-based restoration, stewardship and education Ecologically sound implementation and evaluation Collaboration to help advance ecosystem-based management Long-term stewardship. Accomplishments—highlights Since 1995, Great River Greening has involved more than 10,700 volunteers in the planting of 35,000 trees and shrubs and 16,000 wildflowers and grasses, as well as exotic-species removal, prairie-seed collection and broadcasting, plant inventories, training programs, and ongoing stewardship. In 2000 alone, we organized 30 events attended by nearly 1,500 volunteers! We’ve also provided design and ecological consulting for numerous groups, including the city of Saint Paul Parks and Recreation Division, the Saint Paul Port Authority, the Science Museum of Minnesota, River Center, and the Greater Minnesota Housing Fund. Great River Greening’s major partners City of Saint Paul · Friends of the Minnesota Valley · Friends of the Mississippi River · Metropolitan Council · Minneapolis Park and Recreation Board · Minnesota Department of Natural Resources · National Park Service · Ramsey County Parks and Recreation · Saint Paul Audubon Society · Trust for Public Land · U.S. Fish and Wildlife Service · Private landowners About the author Ellen L. Fuge has an M.S. in Botany from the University of Minnesota and currently works as the Lead Ecologist with Great River Greening. She conducts ecological inventories and analysis, writes restoration and management plans, and acts as a burn boss on the burn crew. Previously, she worked for many years with the Minnesota Department of Natural Resources in several different capacities; as the Management Supervisor for Minnesota=s Scientific and Natural Areas (SNA) Program and as a plant ecologist with the Minnesota County Biological Survey (CBS). To Contact Us Great River Greening, 35 West Water Street, Suite 201, Saint Paul, MN 55107 651-665-9500 http://www.greatrivergreening.org 48 Siberian elm Y ng ou oa -a g e d r e v e n Green ash # y p r i ckl n an d Bu ckth or k # as h Sumac and r plum Sumac and prickly ash Legend r River Terrace Prairie N Exotic Orange Iris Leafy Spurge Invading Brush and Trees City of Bloomington Central Park Contours 50 0 50 100 Feet River Terrace Prairie Management Map created October 13, 2003. Funding provided by the Minnesota Department of Natural Resources Prairie Stewardship Program. 2000 aerial photo, Metropolitan Council Map 7 rr Legend Trails Nine Mile Prairie r r N Siberian Elm Birds' Foot Trefoil Crown Vetch Invading Brush and Trees Leafy Spurge Contours 100 0 100 Feet Nine Mile Prairie Management Map created September 22, 2003. Funding provided by the Minnesota Department of Natural Resources Prairie Stewardship Program. 2000 aerial photo, Metropolitan Council Map 6 Kitten-tail Savanna Humbolt Ave. 106th St. W. Nine-Mile e r Prairie ce Dr. ra T R i v er Prairie East Bank Prairie O ve r l ook Dr. RiverTerrace Legend City of Bloomington Central Park Remnant Bluff Prairie Sites 2000 N Trails Prairie Remnants within Central Park Contours 500 0 500 1000 Feet Bloomington Bluffs Prairies, Central Park, City of Bloomington Map created September 22, 2003. Funding provided by the Minnesota Department of Natural Resources Prairie Stewardship Program. 2000 aerial photo, Metropolitan Council Map 5 L32F U4A L55B 106th St. W. L55C Humbolt Ave. L55C L55B L55C L32F e r L55B ce Dr. ra T R i v er r l ook Dr. L28A L12A O ve L32F Legend Remnant Bluff Prairie Sites 2000 Soil Types L12A - Muskego, Blue Earth & Houghton Soil, frequently flooded L28A- Sucker Creek Fine Sandy Loam, occationally flooded L32F - Hawwick Loamy Sand,18-40% slopes L55B - Urban Land, parent material sandy gravelly outwash, 0-8% slopes L55C - Urban Land, parent material sandy gravelly outwash, 8-18% slopes N U4A - Urban Land, cut and fill, 0-2% slopes Contours 500 0 500 1000 Feet Bloomington Bluffs Soils and Topography Map created September 22, 2003. Funding provided by the Minnesota Department of Natural Resources Prairie Stewardship Program. 2000 aerial photo, Metropolitan Council Map 4 e r Humbolt Ave. 106th St. W. ce Dr. ra O ve r l ook Dr. T R i v er Legend Remnant Bluff Prairie Sites 2000 1996 County Biological Survey (CBS) Sites DRY PRAIRIE (CENTRAL) SAND-GRAVEL SUBTYPE FLOODPLAIN FOREST SILVER MAPLE SUBTYPE LOWLAND HARDWOOD FOREST OAK FOREST (BIG WOODS) MESIC SUBTYPE OAK WOODLAND-BRUSHLAND (BIG WOODS) 500 0 500 1000 N Feet Bloomington Bluffs 1996 County Biological Survey Native Plant Communities Map created September 22, 2003. Funding provided by the Minnesota Department of Natural Resources Prairie Stewardship Program. 2000 aerial photo, Metropolitan Council Map 3 Morgan Ave. S. H op n ki s R Hu mboldt Ave. d oa Lyndale Ave. S. # 108th S t. W. i v e r s o t a R e Legend Remnant Bluff Prairie Sites 2000 n 1940 bluff prairies N n M i 200 0 200 400 600 Feet Bloomington Bluffs 1937 Landscape Map created August 5, 2003. Funding provided by the Minnesota Department of Natural Resources Prairie Stewardship Program. 1940 aerial photo, UMN Borchert Map Library Map 2 Page XX 1 04th St. W. Twin Cities Metro Area H op s R ÚÊ Hum boldt Ave. d oa Morgan Ave. S. n ki 1 06th St. W. # # Bloomington 35W Bluffs R i ve r T e c a rr e Lyndale Ave. S. 108th St. W. Dr. i e v r R s o t a Over lo ok Dr. 110th St . W. Legend City of Bloomington Central Park e Remnant Bluff Prairies 2000 n i n N 300 0 300 600 900 Feet M Bloomington Bluffs Location Map Map created September 9, 2003. Funding provided by the Minnesota Department of Natural Resources Prairie Stewardship Program. 2000 aerial photo, Metropolitan Council Map 1 Page X # ##### #### ### ### Legend Trails Suggested Re-route of Trail N Kitten-tail Savanna # Kitten-tails (Besseya bullii) Invading Brush and Trees Contours 40 0 40 80 Feet Kitten-tail Savanna Management Map created October 13, 2003. Funding provided by the Minnesota Department of Natural Resources Prairie Stewardship Program. 2000 aerial photo, Metropolitan Council Map 8 108th St. k e e r e C rl Ove oo k Circle Nine-Mile Prairie M i l Legend N - Remnant Bluff Prairie Sites Wolf Prairie e Wolf Lot Lines n Trails N i City of Bloomington Central Park 400 Wolf Prairie 0 400 800 i v Feet e r R i n n e s o t a M Bloomington Bluffs Prairies, Wolf Prairie Location Map Map created September 22, 2003. Funding provided by the Minnesota Department of Natural Resources Prairie Stewardship Program. 2000 aerial photo, Metropolitan Council Map 5 k 108th St. C r e e e M i l N i n e - Legend N Wolf Lot Lines 2003 Remnant Bluff Prairie Sites 400 0 400 800 Feet Wolf Prairie in the 1937 Landscape Map created October 29, 2003. Funding provided by the Minnesota Department of Natural Resources Prairie Stewardship Program. 2000 aerial photo, Metropolitan Council Map 6 r r r Legend Trails N Remnant Bluff Prairie Sites r Wolf Lot Lines Crown Vetch Encroaching Brush and Trees City of Bloomington Central Park Contours 30 0 30 60 Feet Wolf Prairie Management Map created October 13, 2003. Funding provided by the Minnesota Department of Natural Resources Prairie Stewardship Program. 2000 aerial photo, Metropolitan Council Map 7 108th St. Nine-Mile Prairie R iv e r T e a rr c e D r. Nelson Prairie River Terrace Prairie Legend Remnant Bluff Prairie Sites N Nelson Prairie Nelson Lot Lines i City of Bloomington Central Park 0 400 800 r R Trails 400 v e Feet i n n e s o t a M Bloomington Bluffs Prairies, Nelson Prairie Location Map Map created October 28, 2003. Funding provided by the Minnesota Department of Natural Resources Prairie Stewardship Program. 2000 aerial photo, Metropolitan Council Map 5 HumboldtAve. e k 108th St. i e r e M N i n e - l C Legend N 2003 Remnant Bluff Prairie Sites Nelson Lot Lines 500 0 500 Feet Nelson Prairie in the 1937 Landscape Map created October 29, 2003. Funding provided by the Minnesota Department of Natural Resources Prairie Stewardship Program. 2000 aerial photo, Metropolitan Council Map 6 Appendix A: Fact Sheets for Rare, Exotic and Invasive Plants The following pages contain information on the habitat, phenology and niche of native and exotic plants found or potentially found in the Bloomington Bluffs plant communities. The only rare plant represented here, kitten-tails (Besseya bullii) is found in the prairie/savanna plant communities on the City property. The other fact sheets pertain to troublesome plants, both native and exotic, that compete with the native plants typical of undisturbed native communities and threaten the integrity, structure and function of those communities. Active management to control invasive plant species is essential to restoring the health of plant communities and the habitats they provide for a diverse group of native animals. Effective management of these species, which are present or potential problems in the Bloomington Bluffs area, is described in the following fact sheets. Rare plant: Kitten-tails Besseya bullii Invasive trees and shrubs: Box elder Common buckthorn * Eastern red cedar Poison ivy Siberian elm* Smooth sumac Tatarian honeysuckle* Trembling aspen Acer negundo Rhamnus cathartica Juniperus virginiana Rhus radicans Ulmus pumila Rhus glabra Lonicera tartarica Populus tremuloides Invasive Forbs: Canada thistle* Garlic mustard * Leafy spurge* Spotted knapweed* Sweet clovers * Invasive Grasses: Bluegrass * Reed canary grass * Smooth brome * • exotic species A-1 Cirsium arvense Alliaria petiolata Euphorbia esula Centaurea maculosa Melilotus officinalis M. alba Poa pratensis, P. compressa Phalaris arundinacea Bromus inermis A-2 Kitten-tails (Besseya bullii) MN DNR Natural Heritage Program Official Minnesota Status: Endangered Basis for status: Kitten-tails are a strict, midwestern endemic and are considered rare or endangered wherever it occurs. This perennial is found only in parts of Minnesota, Iowa, Wisconsin, Illinois, Indiana and Michigan. In Minnesota, it is only found in the counties of Washington, Ramsey, Hennepin, Carver, Scott, Goodhue and Dakota. It grows in a distinct habitat type that is regionally uncommon and frequently exploited. Habitat loss is the primary threat to this species. About a dozen locations of kitten-tails are known to survive in Minnesota, but several of them have been severely degraded and contain fewer than 20 plants. Threats to this plant include mining and development. Habitat: In Minnesota, kitten-tails are found on the bluffs and terraces along the Mississippi, St. Croix and Minnesota rivers in the Twin Cities area. The plants prefer gravelly soil in dry prairies, savannas and open woodlands. Description: The yellowish-green flowers are in a dense spike closely attached to the stalk. The stem leaves are alternate and partially clasp the stem. The basal leaves are large, hairy and heavily veined with scalloped or toothed edges. They stay green for a long time in the fall and can be found beneath the leave litter or among the brown grasses where they grow. The plants flower early in the spring, usually in May, the fruits ripen and drop seed by the end of June, and the spike remains visible most of the summer. Management recommendations: Providing habitat that supports the growth and spread of kitten-tails must be the goal of management in areas where kitten-tails occur. Commonly practiced prairie management techniques, i.e. fire, shrub and tree removal A-3 may be applied as long as care is taken to protect the plants from damage. Avoid management that may damage flowers and fruit to ensure successful seed production. Wherever possible, conduct management activities so that only part of a single population is affected by a particular management practice at any one time. References: NatureServe Explorer: An online encyclopedia of life [web application]. 2001. Version 1.6 . Arlington, Virginia, USA: NatureServe. Available: http://www.natureserve.org/explorer. (Accessed: December 12, 2002). Minnesota’s Endangered Flora and Fauna. 1988. Coffin, B. and L. Pfannmuller, ed. University of Minnesota Press, Minneapolis. A-4 Boxelder (Acer negundo) Effects of Invasion Boxelder is an opportunistic species native to the United States. Extremely prolific, it will inhabit many environments disturbed by humans. Boxelders produce seeds during summer and fall and the wind disperses the fruits to suitable habitats for germination. Reproduction can also take place through suckers, sprouts, and root shoots. Boxelders are aggressively opportunistic and tend to shade out smaller, herbaceous flora. Size: 30–50 feet in height, can reach 70 feet with spread equal to or greater than the height. Habit: Usually rounded to broad-rounded in outline, branches develop irregularly to support the uneven crown. Leaves: Pinnately compound with 3–5 leaflets arranged oppositely on the stem. Leaflets can be lanceolate to oblong, with margins that may be separated into several shallow lobes. Stem: Green to reddish brown, often covered with a waxy whitish bloom that can be rubbed off. Bark: Gray-brown, slightly ridged, and furrowed. Fruit: Double-winged produced by females. Flower: Male plants bear stamens in umbel-like arrangements, while the female plants produce apetalous racemes. Origin: United States and southern Canada. Mechanical Control • Large-diameter trees can be cut with a chainsaw. Re-sprouts must be recut or herbicides may be applied to the cut stump. Chemical Control Cut and spray • May to October (between first budding in May, through summer, to hard freeze in fall): Spray 25% glyphosate solution on cut stumps. Herbicide should be sprayed immediately after cutting. Chemical treatment is generally less effective during the growing season and may have to be repeated on resprouts. • Winter (from first hard freeze to first budding in May): Spray 25% Triclopyr (formulated for oil dilution) diluted in diesel fuel or dilutent oil on cut stumps. Herbicide should be sprayed immediately after cutting. Chemical treatment is most efffective at this time of year. • May to October (between first budding in May, through summer, to hard freeze in fall): In high-quality natural areas and in aquatic environments where surface water is present, apply 25% glyphosate solution formulated for use over water. Source: Wisconsin Department of Natural Resources, 1997. A-5 A-6 Common Buckthorn (Rhamnus cathartica) Effects of Invasion Common buckthorn is a problem species in the understory of maple-basswood and oak woodlands, oak savannas, and prairies. It is characterized by long-distance dispersal, prolific reproduction by seed, and wide habitat tolerance. The fruit has a severe laxative effect; birds readily distribute its seeds after eating the fruit. Once established, common buckthorn has the potential to spread very aggressively in large numbers because it thrives in habitats ranging from full sun to shaded understory. Common buckthorn leafs out very early and retains its leaves late in the growing season, thereby shading out herbaceous and low-shrub communities and preventing the establishment of tree seedlings. Size: 18–25 feet in height with a comparable spread. Habit: Large shrub or low-branched tree with a rounded, bushy crown of crooked, stoutish stems. Leaves: Dull green, ovate-elliptic-shaped, and smooth on both surfaces with minute teeth on the margins, and pointed tips. Stem: Slender, somewhat grayish, often having thorn-like spurs. Bark: Generally gray to brown with prominent, often elongate, light-colored or silvery lenticels. Fruit: Female plants have ¼-inch-diameter clusters of black, rounded fruit. Origin: Europe and Asia. Range: Nova Scotia to Saskatchewan, south to Missouri and east to New England. A-7 Mechanical Control • Prescribed burns in early spring and fall may kill seedlings, larger stems, and topkilled mature buckthorns. Burning is preferable for fire-adapted communities but should not be used if it adversely affects the community. Burning annually or biannually to control buckthorn may need to be continued for several years depending on the extent of establishment and the seed bank, which generally lasts 3–5 years. It is usually difficult to burn in dense buckthorn stands because the understory is typically well shaded, allowing little fuel build-up. • Hand pull or weed-wrench seedlings. • Weed wrench saplings up to 1inch in diameter at breast height. • Trees of 1–3 inches in diameter at breast height may be weed wrenched if they are growing in sandy soils; otherwise, cut and apply herbicide to the stump. Chemical Control • Cut and apply herbicide to tree stumps greater than 3 inches in diameter at breast height. • Basal bark treatment may be used on trees located near power lines, in difficult terrain, or in areas where it is not important to create openings in the woodland floor for reintroduction of native species. • In high-quality natural areas and aquatic environments where surface water is present, apply a herbicide formulated for use over water. • Repeat both mechanical and chemical control methods for at least 3–5 years to stop new plants emerging from the seed bank as well as the continual spread of seed from bird droppings. Underplanting disturbed areas with tolerant native species may hinder reinvasion by common buckthorn. • • • • Cut and spray May to October (between first budding in May, through summer, to hard freeze in fall): Spray 25% Triclopyr diluted in water on cut stumps during the growing season. Herbicide should be sprayed immediately after cutting. Avoid spring sap flow. Chemical treatment is generally less effective during the growing season, and there is more risk of affecting non-target plants. Winter (from first hard freeze to first budding in May): Spray 25% Triclopyr (formulated for oil dilution) diluted in diesel fuel or dilutent oil on cut stumps. Herbicide should be sprayed immediately after cutting. Chemical treatment is most effective at this time of year. May to October (between first budding in May, through summer, to hard freeze in fall): Apply 25% glyphosate solution formulated for use over water in high-quality natural areas and in aquatic environments where surface water is present. Herbicide should be sprayed immediately after cutting. Basal bark treatment Apply a band of 6% Triclopyr with oil in diesel fuel or dilutent oil on the lower 10 inches of bark, including the root collar. Source: Wisconsin Department of Natural Resources, 1997. A-8 Eastern Red Cedar (Juniperus virginiana) Effects of Invasion Eastern red cedar was rarely found in Minnesota at the time of European settlement. It occurred in remote, fire-free places such as exposed cliff faces. After settlement, fires were greatly suppressed, thus removing the primary limiting factor for red cedar establishment. In the absence of fire, red cedar can dominate natural communities. Large trees and dense stands shade or otherwise inhibit growth of desired herbaceous vegetation Red cedar is pollinated by wind; male and female flowers are on different trees. The seeds develop and mature from July through November. Seed crops vary annually, with peaks every two to three years. Trees initiate seed bearing at about 10 years of age. Peak seed production occurs between 25 and 75 years. Scattered and long-distance establishment of red cedar is primarily due to birds. Most seeds are dispersed by birds like cedar waxwings, thrushes (especially robins), kingbird, and downy woodpeckers. Establishment of red cedar is slow because seeds are not produced in the first 10 years. However, habitat modification accelerates once seeds are produced and scattered, and culminates in a canopy of red cedar with bare ground underneath. Size: Eastern red cedar is a coniferous tree that rarely exceeds 30 feet high in Wisconsin. Habit: Mature trees typically have an ovoid or pyramidal crown. Leaves: Leaves are opposite, scale-like, tightly appressed and overlapping. Stem: A single tree can have multiple trunks with a wide range of diameters Bark: Red cedar has a thin red bark that sheds or comes off in long strips Fruit: The blue-black, often glaucous (having a whitish, powdery coating) fruit is a fleshy, berry-like cone. Each fruit usually contains one to two seeds Origin: Eastern red cedar is native to eastern North America. It was an important component of cedar glades, which typically do not experience fires. Although its optimal A-9 growth occurs on well-drained, alluvial soils, red cedar is most competitive on dry sites. It is most commonly found in prairies or oak barrens on thin soils, old pastureland, or on dry, limestone hillsides where competition has been reduced. It is a problem because it has rapidly invaded some grasslands and savannas mostly due to fire suppression. Mechanical Control Fortunately, red cedar is very easy to control. The problem is not in the control methods, but in failing to recognize the consequences of doing nothing. Prevention is always the best control method. Monitoring red cedar establishment and removing trees when found will prevent the total loss of a natural community later. • Prescribed fires are the easiest and most cost-effective control method for red cedar. Small trees are killed if enough fuel surrounds the tree. Because the bark is very thin, red cedar is extremely sensitive to fire. • Large trees should be cut and burned, or the dead trees will persist for decades and cause shading effects. It does not resprout after complete cutting or burning. Chemical Control Most herbicides are ineffective or erratic in control of red cedar Source: Wisconsin Department of Natural Resources, 1999; The Nature Conservancy, 2000 A-10 Poison Ivy (Rhus radicans) Effects of Invasion Although poison ivy is not harmful to other native flora, it can cause severe irritation to humans. It is commonly found in disturbed areas such as trails, parks, yards, and recreation areas where human contact is most likely to occur. Habit: Occurs as an upright growing woody shrub or as a vine that climbs the trunks of trees or grows along the ground. Size: 24 inches in height in the shrub form. Leaves: Compound with 3 large shiny leaflets that are variable in outline. Stem: Erect on the shrub form; supported by aerial roots on the vine form. Fruit: Yellowish-white berries. Flower: Clusters of up to 25 yellow-green flowers blooming from leafless lateral branches. Origin: North America. A-11 Mechanical Control • Uproot individual plants in the fall, either before or after the leaves have fallen. Remove entire root to avoid re-sprouting. Repeat for several years to deplete seed bank. Caution: Wear gloves and protective clothing. Do not compost or burn plants. Chemical Control • In the late spring or early summer apply glyphosate or 2,4-D to the foliage with a sponge or sprayer as recommended on the label. Repeat for several years to deplete seed bank. Source: Wisconsin Department of Natural Resources, 1997. A-12 Siberian Elm (Ulmus pumila) Effects of Invasion Siberian elm flowers in spring before leaves begin to unfold. The fruits develop quickly and are disseminated by wind, allowing the species to form thickets of hundreds of seedlings in bare ground. Seeds germinate readily and seedlings grow rapidly. Size: 50–70 feet in height with a 40–50-foot spread. Habit: Open, round crown of slender, spreading branches. Leaves: Small, elliptical, smooth singly toothed leaves that reach lengths of approximately 0.8–2.6 inches, tapering or rounded at their asymmetrical base. Stem: Slender, brittle, very light gray or gray-green, usually smooth, can be slightly hairy, roughened by lenticellar projections. Bark: Gray or brown, with shallow furrows at maturity. Fruit: Single-winged circular or ovate in shape with smooth surface. Flower: Greenish, lacks petals and occurs in small drooping clusters of 2–5 blossoms. Origin: Eastern Siberia, northern China, Manchuria, and Korea. Range: Minnesota south to Arkansas and west to Utah. A-13 Mechanical Control • Girdle in late spring to mid-summer by removing a band of bark around the tree trunk, just within the bark layer (cambium). Girdling too deeply may lead to re-sprouting. Girdled trees die slowly over 1–2 years. • Hand pull or weed-wrench seedlings. • Conduct regular prescribed burns in fire-adapted communities. Saplings older than a few years may not be killed by fire and instead will require another control method. Chemical Control Cut and spray • May to October (between first budding in May, through summer, to hard freeze in fall): Spray 25% glyphosate solution on cut stumps. Herbicide should be sprayed immediately after cutting. Chemical treatment is generally less effective during the growing season and may have to be repeated on resprouts. • Winter (from first hard freeze to first budding in May): Spray 25% Triclopyr (formulated for oil dilution) diluted in diesel fuel or dilutent oil on cut stumps. Herbicide should be sprayed immediately after cutting. Chemical treatment is most effective at this time of year. • May to October (between first budding in May, through summer, to hard freeze in fall): In high-quality natural areas and in aquatic environments where surface water is present, apply 25% glyphosate solution formulated for use over water. Source: Wisconsin Department of Natural Resources, 1997. A-14 Staghorn Sumac (Rhus typhina) Smooth Sumac (Rhus glabra) Effects of Invasion Both smooth sumac and staghorn sumac are opportunistic, native prairie shrubs. These aggressive shrubs occur in clones that spread outward by rootstocks or seeds. Sumac sprouts easily and grows rapidly but requires direct sunlight to persist. Re-sprouts grow rapidly and can reach 3 feet in 1 year. Sumac can eliminate or reduce the abundance of many other species that cannot persist in the shade sumac creates. Sumac grows in a variety of habitats, including disturbed sites, such as abandoned fields, roadsides, and fence rows. Sumac also grows in native communities, such as upland prairies, oak savanna, and oak woodlands and forests. Because sumac is a native species, the management objective is usually to keep sumac under control, not to eliminate it. Size: 10 feet in height with a spreading crown of dense, multi-stemmed clones. Habit: A large, loose, open, spreading shrub with a flattish crown. Leaves: Pinnately compound with 7–31 leaflets that are green on the upper surface and nearly white on the lower surface. Leaves turn brilliantly red in fall. Stem: Twigs are smooth, stout, angular, and hairless on smooth sumac and highly pubescent on the staghorn sumac. Bark: Light brown and smooth on young plants. Pubescent on older stems of staghorn sumac. Smooth sumac has smooth bark on both young and old stems. Fruit: Red drupes develop at the end of the stems in late summer and persist into winter. Each drupe is round, has short hairs, and contains a single seed. Flower: Dioecious, greenish yellow, June to early July. Female borne in dense hairy panicles, 4–8” long; male in a bigger, looser, wider panicle. Origin: Quebec to Ontario, south to Georgia, Indiana, and Iowa. A-15 Mechanical Control • Double-cut (once in July and once in August). Cutting may need to repeat for several consecutive years to effectively control in dense populations. • Mow with a sickle-bar every year in mid to late July. • Conduct prescribed burns for prairies in spring, then hand cut stems at ground level in July and August. Sumac will re-sprout after each cutting, but dense vegetation may prevent sumac from receiving enough sunlight, causing leaves to turn yellow and eventually die. • Mow in mid-summer and conduct spring burns to stimulate herbaceous vegetation. • Keep small populations under control by conducting prescribed burns every 3–4 years. Chemical Control • During July and August apply a 20% concentration of glyphosate to freshly cut stumps. • Apply oil-based Triclopyr as directed on label to the entire circumference of each stem of the clone; no cutting is done. • Foliar application of water-based Triclopyr as directed on label or 1%–2% solution of glyphosate in areas with little to no native vegetation. Caution: The sap of sumac species may cause dermatitis in some people. Source: Wisconsin Department of Natural Resources, 1997 A-16 Honeysuckle (Lonicera tartarica) Effects of Invasion Tartarian honeysuckle can live in a broad range of plant communities with varying moisture and shade levels. Woodlands are most affected and are particularly vulnerable if the habitat is already disturbed. The vigorous growth of Tartarian honeysuckle inhibits development of native shrub and ground-layer species; eventually, they may entirely replace native species by shading and depleting soil moisture and nutrients. The early leafing of this species is particularly injurious to spring ephemerals, which have evolved to bloom before trees and shrubs have leafed out. Size: 3–10 feet in height with a 10-foot spread. Habit: Upright, strongly multi-stemmed. Upper branches are arched, with the overall effect of a dense, twiggy mass. Leaves: Smooth, hairless, opposite, simple, smooth beneath, ovate, bluish-green leaves. Leaf development begins early in the spring, before native species. Stem: Green at first, finally brownish. Bark: Older stems are shaggy. Fruit: Red, ¼-inch-diameter berry that colors in late June into July and August. Flower: Fragrant, tubular pink-to-crimson flowers arranged in pairs. Origin: Central Asia to southern Russia. Range: New England south to North Carolina and west to Iowa. Mechanical Control • Small to medium-sized plants can often be dug, pulled, or weed-wrenched, especially in spring, when the soil is moist. Mechanical removal can result in profuse re-sprouting of the plant if a portion of the root breaks off and remains in the soil. A-17 Chemical Control • Cut and apply herbicide to any honeysuckle regardless of size if soil conditions are not appropriate for mechanical control. • In high-quality natural areas and in aquatic environments where surface water is present, apply a herbicide formulated for use over water. • Repeat control methods for at least 3–5 years to stop new plants emerging from the seed bank. Underplanting disturbed areas with tolerant native species may hinder reinvasion of Tartarian honeysuckle. • • • Cut and spray May to October (between first budding in May, through summer, to hard freeze in fall): Spray 25% glyphosate solution on cut stumps. Herbicide should be sprayed immediately after cutting. Chemical treatment is generally less effective during the growing season and may have to be repeated on resprouts. Winter (from first hard freeze to first budding in May): Spray 25% Triclopyr (formulated for oil dilution) diluted in diesel fuel or dilutent oil on cut stumps. Herbicide should be sprayed immediately after cutting. Chemical treatment is most effective at this time of year. May to October (between first budding in May, through summer, to hard freeze in fall): In high-quality natural areas and in aquatic environments where surface water is present, apply 25% glyphosate solution formulated for use over water. Source: Wisconsin Department of Natural Resources, 1997. A-18 Quaking (Trembling) Aspen (Populus tremuloides) Big Tooth (Large Tooth) Aspen (Populus grandidentata) Photo by Kenneth R. Robertson, INHS Effects of Invasion Big-toothed aspen is a gap-phase tree of importance in the dry to mesic forests of Minnesota. It requires soil disturbance for establishment, and is usually found in forest gaps created by fires or harvests. The ashes found on burned soil surfaces offer optimal conditions for germination. Quaking aspen is a pioneer invader following forest fires, logging, or other episodes of disturbance. Both species produce an abundance of wind-dispersed seeds. Aspens flower in March and April; fruit ripens 4-6 weeks after flowering, generally from May to June. The seeds are small, very widely dispersed, and must germinate within a few days of their dispersal. Seedlings grow extremely fast, often at a rate exceeding three feet per year for the first decade. Clones expand radially by sprouting 3-6 feet of shallow, horizontal roots per year, depending on the site. By the time aspen individuals are 20 to 30 years old, their canopies expand and shade out other clones in the stand, thus encouraging fungal diseases to attack the shade-intolerant trees. Both species have become a concern to some land managers. While they are a natural part of early successional woods, aspens become a problem in prairies that have not been managed with fire for some time. Both species thrive on a wide variety of sites. Typically, quaking aspen is found in moist woods and along streams, while big-toothed aspen grows in comparatively drier soil. Both are found in young woods after disturbance and at the edges of mature woods. Size: Mature trees are 20 – 50 feet in height Habit: Viewed from a distance, clonal stands of aspen look dome-shaped: the tallest, oldest individuals inhabit the center and the smallest, youngest shoots grow at the outer edge of the clonal stand. Individual trees have short, rounded crowns. Branches are slender and slightly drooping. Leaves: Leaves are alternate and simple with toothed edges. Leaves are broadly ovate to heart-shaped in outline, and have strongly flattened petioles that make leaves tremble even in a slight breeze. Stem: Mature trees have a trunk diameter of 1 – 2 feet. Bark: Both species of aspen are characterized by light, green-gray bark that becomes dark and furrowed with age. Fruit: Cottony hairs on the tiny seeds cause them to be carried far by the wind. Flower: The genus Populus is in the willow family. That family is characterized by flowers and fruits arranged in catkins. A-19 Origin: Although aspens are native to Minnesota, they are sometimes invasive because their prolific clonal growth pattern allows them to shade out herbaceous species in prairies and oak savannas. Both species are found throughout Minnesota and are normally found in woods and woodland edge habitats, especially on cut over or burned land. Mechanical Control • Although it is labor intensive, girdling is most successful in clonal stands where most individuals are larger than 1" in diameter. This method is not effective on young clones that have resprouted. All stems in the clone with a diameter greater than 1" should be girdled. The girdle should be at least 2" wide around the tree to prevent the bark from bridging across the girdle. Girdle aspens in the spring up until leaves reach full size in May or June. It is easiest to separate the bark from the tree at this time. The technique of girdling requires making a cut just through the bark to the outer layer of sapwood. These cuts can be made with a bark spud (made from a sharpened car spring) or a crowbar. On smaller stems, a beveled butter knife may be used. Avoid using saws because they may cut too deeply, thus stimulating resprouting. After making the cut, insert a sharpened bark spud into the natural dividing region between the bark and the sapwood. Rotate the girdling tool around the trunk to remove the bark. Leaving the sapwood intact allows trees to continue pulling water, nutrients, and carbohydrates up from the root system. Removal of the bark prevents the shoots from sending carbohydrates to feed the roots. Roots starve slowly, and the trees usually live for 1 year after girdling. If removing trees, wait until they are completely dead. • Fire or ill-timed cutting of live aspen can make established clones very difficult to remove, and therefore is not recommended. Aspen responds to stem removal by generating an imbalance of hormones in the roots to promote the formation of root sprouts or suckers. Once the clones have been put into the hormonal "suckering mode," there are no known treatments to prevent their continued production of suckers. However, aspen may be controlled by using fire in August. Frost will kill reprouts. • Stem cutting is much less effective than girdling, but can be used as a control method. In order to avoid the formation of suckers, cutting must be timed to coincide exactly with maximum leaf-out in mid to late July, when most resources have been translocated to stems and leaves and root resources are at their lowest. This initial cut must be followed by repeated hand cutting of sprouts in the same growing season or again at maximum leaf-out in subsequent growing seasons. Follow-up cuttings should be made by hand to allow the competing, shade-producing vegetation to remain standing. Ideally, the initial, well-timed cut will cause up to a 50% reduction in stem density. Cutting can be done with loppers, a chain saw, power brush cutters, or a brush hog. • Cutting can be effective if coordinated with some other mechanical control on sites other than natural areas. A large clone may have the overstory cut, followed by a leveling of the resprouts using heavy site scarification equipment. This has proven to be a cost-effective option in aspen control, but can be damaging to other vegetation in the area. • Scarifiers such as roller choppers, discs, and root rakes can be used to mechanically control aspen. If possible, a single pass in July should be followed by a second pass in August (after resprouting) for optimal control. Based on field experience, multiple passes during the growing season are more effective than a single pass. Chemical Control • Basal injections or basal bark applications of triclopyr to uncut stems are the best means of controlling aspen chemically because application is easy and injury to other species is minimal. Every stem of the clone must be treated. Some damage to surrounding vegetation should be expected with these techniques. • Young suckers or cut clones can be treated with a wick application of 25% glyphosate active ingredient (a.i.) on the stems, although this method has not proven completely effective. The herbicide 2-4D also works as a foliar application. Source: Wisconsin Department of Natural Resources, 1999; Illinois Natural History Survey (INHS), 1990 A-20 Canada Thistle (Cirsium arvense) Photo by Merel R. Black Effects of Invasion: Canada thistle is an alien species capable of crowding out and replacing native grasses and forbs. It is detrimental to natural areas where it occurs, particularly non-forested communities, and it can change the natural structure and species composition where it becomes well established. Prairies, barrens, savannas, and glades are susceptible, particularly those sites that have been disturbed as well as those undergoing manipulative restoration management. It is important to control this species prior to restoration work. The plant grows in clonal patches of all female or male plants. As a result, some patches produce seeds and others do not. Seeds mature quickly and are capable of germinating within 8 to 10 days after the flowers open, even if the plants are cut when flowering. Most seeds germinate within one year, but may remain viable in the soil for up to 20 years. Seeds are mostly dispersed by wind and sometimes by water runoff. Small sections of broken roots are capable of producing new plants. Canada thistle is considered a noxious weed under Minnesota law and should not be allowed to go to seed. Size: Canada thistle is a 2 to 5 foot (0.6 to 1.5 meters) tall herbaceous plant with deep, wide spreading, horizontal roots. The root system is usually within a foot of the surface, but may extend 6 feet deep or more in loose soil. The horizontal roots stemming from the fibrous taproot of a single plant can spread 10 to 12 feet in one season, resulting in a circular infestation 20 feet across. Aerial shoots are sent up in 2 to 6 inch intervals, and generally produce basal leaves the first year and flowering stems the next year. Habit: Canada thistle is a clone-forming perennial. The grooved, slender stems branch only at the top and are slightly hairy when young; becoming covered with hair as the plant grows. Leaves: The oblong, tapering, sessile leaves are deeply divided, with prickly margins. Leaves are green on both sides with a smooth or slightly downy lower surface. A-21 Fruit: Seeds are small (3/16 inch or 0.5 cm long), light brown, smooth and slightly tapered, with a tuft of tan hair loosely attached to the tip. Flowers: Numerous small, compact (3/4 inch or 1.9 cm. diameter), rose-purple or white flowers appear on upper stems from June to September. Origin: Canada thistle is native to Europe, not Canada, as its name suggests. Its current range encompasses the northern portion of the United States east of the Rocky Mountains. Mechanical Control: Repeated pulling, routine mowing or selective cutting will eventually starve underground stems and effectively reduce an infestation within 3 or 4 years. The ideal time to cut is in the very early bud stage when food reserves are at their lowest point. Plants cut 8 days or more after flowers have opened should be removed from the site because seeds mature quickly. Cutting should be completed prior to flowering and seed set. If seeds are ripe, cut flower heads must be removed from the site immediately to avoid further seed dispersal. Plants should be pulled or cut at least three times during the growing season -- for example, in June, August, and September. Some persons have had success killing individual plants by cutting the top and putting table salt down the hollow stem. Prescribed fire can be effective in controlling this species and is a preferred treatment. Late spring burns between May and June, effectively discourage this species, whereas early spring burns can increase sprouting and reproduction. During the first 3 years of control efforts, burns should be conducted annually. Healthy, dense prairie vegetation can produce enough competition to reduce the abundance of Canada thistle. On severely disturbed sites with heavy infestations, such as cropland or abandoned cropland, the site could be plowed and sowed to a cover crop (wheat, alfalfa, and rye), if practical and desirable. The following May, the cover crop should be plowed under and desired native species should be seeded. Tillage disturbance of soil may provide ideal conditions for reinvasion and for introduction of other exotics. Grazing is not an effective control measure as the prickles prevent livestock from grazing near Canada thistle. Chemical Control: Control of this species with herbicides in natural areas is not recommended, as the herbicide can damage native vegetation more than the damage caused by the thistle. However, spot application of the amine formulation of 2,4-D using a wick applicator or hand sprayer can control individual stems if necessary. Infested lands that are not considered high quality natural areas may be controlled using a foliar application of a 1-2% active ingredient solution of glyphosate in spring when plants are 6-10 inches tall. Spot application of Transline (a formulation of clopyralid), according to label instructions can control this plant. Individual plants of Canada thistle should be treated with a wick applicator or hand sprayer. The herbicide Transline is selective for broadleaf plants. To reduce vapor drift and improve plant up-take of the chemical, a surfactant may be added to the spray solution. Precautions should be taken to avoid contacting nontarget plants with the solution. A foliar application of a 1-2% solution of Roundup (a formulation of glyphosate) applied in spring when plants are 6-10 inches (15.2 -25.4 cm) tall is an effective herbicide treatment. Individual plants should be spot-treated with a wick applicator. Roundup normally kills the entire plant, including the roots, when applied in this manner. Roundup is a nonselective herbicide and precautions should be taken to avoid contacting nontarget plants with the solution. Sources: Wisconsin Department of Natural Resources, 2002 Vegetation Management Manual, Vol. 1, No. 2. Illinois Nature Preserves Commission, approved 02/06/90 A-22 Garlic Mustard (Alliaria petiolata) Effects of Invasion Garlic mustard is a rapidly spreading woodland weed that displaces native woodland wildflowers. It dominates the forest floor and can displace most native herbaceous species within 10 years. Garlic mustard is a biennial that produces hundreds of seeds per plant. Seeds are dispersed on the fur of mammals, by water, and by humans. The seeds can remain viable for 5 years. Size: 12–48 inches in height as an adult flowering plant. Leaves: First-year plants consist of a cluster of 3 or 4 round, scallop-edged, dark-green leaves rising 2–4 inches in a rosette. Second-year plants have alternate, round, scallopedged, dark-green leaves progressing up the 1 or 2 stems. Stem: Second-year plants generally produce 1 or 2 flowering stems. Fruit: Slender capsules 1–2.5 inches long that produce a single row of oblong black seeds with ridged seed coats. Flower: Second-year plants have numerous small white flowers that have 4 separate petals. Root: Slender, white taproot with an S-shaped top. Origin: Europe. A-23 Mechanical Control • Hand pull at or before the onset of flowering, making sure to remove at least the upper half of the root to eliminate budding at the root crown. • Cut the flower stalk as close to the soil surface as possible just as flowering begins. Cutting before the plant flowers may promote re-sprouting. • Burn in fall or early spring (before wild flower growth). Burn annually for 3–5 years until depletion of the seed bank. Chemical Control • Apply a 1%–2% glyphosate solution to the foliage during the late fall or early spring before wild flower growth. • Apply a 1% Tryclopyr solution to the rosettes in early spring before wild flower growth. Source: Wisconsin Department of Natural Resources, 1997. A-24 Leafy Spurge (Euphorbia esula) Effects of Invasion Leafy spurge is alleleopathic and spreads rapidly, crowding out desirable species. A number of spurges hybridize with leafy spurge; they are all referred to as leafy spurge. The plant can reach densities of up to 1,800 stems per square yard. The plant’s deep root system makes eradication difficult. The plant can expel its seed up to 15 feet by explosive ejection from the seed capsule. The seed of leafy spurge has a high germination rate, and the established plant spreads rapidly through vegetative reproduction. Leafy spurge can be catastrophic to grasslands for both economic and ecological reasons. In only a few years spurge can displace native grasses and forbs by shading them out and dominating available moisture and nutrients. Habit: An erect, deep-rooted Eurasian perennial. Size: 6–36 inches in height. Leaves: Linear, alternate and apetiolate, bluish-green in color. Stem: Erect and hairless Fruit: Ovoid, minute mottled-brown seeds contained within a capsule. Flower: A loose umbel consisting of 2 kidney-shaped flower leaves on a short stem that are topped by 2 yellow-green petal like bracts around tiny flowers. Origin: Europe and Asia. Mechanical Control • No mechanical control methods have been found to be effective. A-25 Biological Control • Pasturing goats in areas infested with leafy spurge. • Experimental insect control with beetles and a midge species is reducing populations. • The allelopathic effects of black walnut inhibit plant growth. Chemical Control • Scattered patches can be treated at an application rate of 2 lbs./acre of picloram in the late spring and early fall. Do not use in high-quality natural areas that lie within 30 feet of area. • A 70% reduction of large infestations can be achieved with an annual application of .5lbs./acre of picloram in the late spring. • An application rate of 5.7 lbs./acre of quinclorac plus a 2.8 lbs./acre picloram will provide 85% control of leafy spurge after 9 months. • An application rate of .12lbs/acre of quinclorac applied immediately after cutting the shoot tops. • A 90% reduction within 1 year was achieved with a 3% solution of fosamine applied to blooming plants in June and July. Follow-up application annually for 3–4 years is required. • Repeated application of glyphosate may be used to treat small patches. Source: Wisconsin Department of Natural Resources, 1997. A-26 Spotted Knapweed (Centaurea maculosa) Effects of Invasion Spotted knapweed attains high densities on sunny sites, reducing the frequency of native species. Infestation can also contribute to poor water quality and erosion by increasing run-off and sedimentation. Plants average 1,000 seeds per plant. Seeds are viable for 7 years and germinate throughout the growing season. Habit: Biennial or short-lived upright perennial forb. Size: 3–4 feet in height. Leaves: Alternate, pale, rough 1–3 inches in length. Leaf margins on lower leaves are divided about halfway to the midrib. Upper leaves are more linear in shape. Stem: Slender, hairy, erect, growing in a branched pattern, 2 feet in height on drier sites and up to 4 feet in height on moister sites. Seeds: ¼ inch and brownish. Notched on one side of the base with a short tuft of bristles at the tip. Flower: Lavender flower head has stiff bracts marked with fine, vertical streaks and tipped in with dark, comb-like fringes. Root: Stout, elongated root. Origin: Eurasia. Mechanical Control: • Dig or pull the entire root. • Conduct prescribed burn followed by selective pulling or digging. A-27 Chemical Control: • Use foliar application of a 3% water-soluble solution of Triclopyr with dye. To protect native fauna, avoid getting herbicide on the flowers. • Apply .2–.5 lbs./acre of Piclorum for 2–3 years in the fall when the plant is in the rosette growth stage or in spring during the bud-to-bloom stage. Do not use Piclorum near water or on sandy soils with ground water 10 feet or less below the surface. • Apply 1–2 lbs/acre of Dicamba for at least 2 years. • Apply .25 lbs./acre of Clopyralid or a mixture of .19 lbs./acre of Clopyralid and 1 lb./acre of 2,4-D. • During the rosette stage, spray a 2,4-D low-volatile ester, oil-soluble amine, or water-soluble amine formulation at 2 lbs./acre. Biological Control: • Experimental results have yielded a 95% reduction using two seed-head attacking flies Urophora affinia and U. quadrifasciata. Consult the USDA for more information about biological controls and their availability. Source: Wisconsin Department of Natural Resources, 1997. Minnesota Department of Natural Resources, 1995. United States Department of Agriculture, 1971. A-28 Yellow Sweet Clover (Melilotus officinalis) White Sweet Clover (Melilotus alba) Photo by John M. Randall, TNC Effects of Invasion: Sweet clovers are fire-influenced, aggressive, weedy plants that produce populations with high rates of fluctuation. Both species degrade native grasslands by overtopping and shading native sun-loving species. Sweet clovers are members of the legume family. Both white and yellow sweet clovers are biennials. After germination in late spring or summer, the plants put their energy into developing a healthy root system. Plants are strictly vegetative in the first year and have a small, branched stem with clover-like leaves. First-year plants can be found in late summer. In the second year, plants may be seen in late April or early May. By that time, individuals have a strong taproot and a root crown from which new shoots appear. Plant height is dependent on root development and growing conditions; healthier plants are taller. Sweet clovers flower from late May through September, set seed, and die. Both plants produce small, hardy seeds that remain viable in the soil for as many as thirty years. Burning produces excellent growing conditions for clover by scarifying seeds and stimulating germination. During the next year following a burn, many flowering plants generally emerge. Size: In the second year, plants may appear bushy, and grow from three to six feet in height. Habit: First year seedlings are leafy, green, few-stemmed and around a foot tall. Second year plants generally have three main stout stems arising from the root crown. The 3 – 6 foot plants are conical and bushy. Leaves: Leaves are alternate, divided into three finely toothed leaflets, with the middle leaflet occurring on a distinct stalk. A-29 Fruit: The legume is ovoid, leathery and wrinkled, longer than the calyx, and scarcely dehiscent, with one or two small seeds. Flower: Yellow and white sweet clovers appear very similar except for the distinguishing yellow or white flowers. Yellow sweet clover is usually smaller than white sweet clover and blooms earlier. The flowers are packed densely on the top four inches of an elongated stem. Each small flower is attached to the stem by a minute stalk. Origin: Sweet clovers are native to Europe and Asia. They were brought to North America in the late 1600's as an agricultural crop for forage and honey production. These clovers also fix nitrogen, and thus became popular as soil enhancers. The chemical used in the production of the blood thinner Warfarin was first discovered in sweet clover. Due to the economic values of white and yellow sweet clover, these species will continue to be planted despite the problems they pose for land managers. Both species are found in all fifty states, although they are most frequently found in the states of the Upper Midwest and Great Plains. Sweet clovers grow well in direct sunlight or in partial shade. Neither species can tolerate complete shade. Sweet clovers seem to prefer calcareous or loamy soils, and are most frequently found in open, disturbed, upland habitats such as prairies, savannas, and dunes. Mechanical Control On grasslands managed with prescribed burning, it is possible to greatly reduce sweet clover by burning two years in a row. Burning should be done early the first year (before green-up--usually in early to midApril) to stimulate germination. The burned area should be checked in late summer for first year plants. If plants are found, another burn should be conducted the next year in early to mid May. If burning is conducted before the buds are developed, the plants will resprout. Heavily infested areas may need this burning sequence repeated after a few years. The fire may be of low intensity--just enough to touch the stems. Damaged plants wither quickly if they are not completely destroyed by fire. For small patches or those areas not completely burned, a flame gun (torch) may be used when the vegetation is damp to avoid burning surrounding prairie. Another burning strategy is to mow later in the summer, allow the cut plants to dry, and then burn. This can be stressful to the native vegetation and should not be done annually. Small amounts of sweet clover can be controlled by hand-pulling in late fall after first-year plant rootcrown buds have developed, or in May or June before second-year plants flower. Pulling is easier when the soil is wet. Plants can also be cut at ground level with brush loppers. If pulling is tried too early, many plants may be missed, and those with succulent stems may break off and resprout. But pulling must be done before seeds are set; otherwise cut plants will have to be removed from the natural area. It is necessary to inspect the area a couple of times in summer for late flowering plants. For very dense small patches, cutting with a power brush-cutter using a heavy duty saw blade is effective. The stand should be cut just before flowering, and checked a week later for individuals missed or partly cut. It is necessary to conduct annual inspections to remove scattered individual plants. Disturbed areas such as fox dens provide habitats that can allow sweet clover to greatly increase over time if not controlled. Habitats adjacent to managed areas should also be inspected to reduce sweet clover invasion on managed sites. Due to the long viability of sweet clover seeds (up to 30 years) and continued agricultural use, these plants generally must be managed on a continuous basis. Chemical Control Sweet clover can be managed using mechanical controls, and should not require chemical use. Source: Wisconsin Department of Natural Resources, 2002; The Nature Conservancy, 2002 A-30 Kentucky Bluegrass (Poa pratensis) Canada Bluegrass (Poa compressa) (c) John M. Randall/The Nature Conservancy Effects of invasion: Because bluegrass grows early in the season (when most other species are still dormant), it can spread very quickly. However, its shallow root system makes it susceptible to high soil temperatures and low soil moisture. Bluegrass has successfully invaded both remnant and restored prairies, savannas, and barrens. Establishment can be attributed to intentional introduction, past mowing, grazing, or cessation of fire. If left unattended, bluegrass can out-compete native prairie grasses and forbs, and will dominate shaded areas resulting from woody species invasions. Description: Most of the cool season grasses that begin growing early are not native to Wisconsin prairies. Bluegrass can be distinguished vegetatively from other early grasses by its narrow blade, which is V-shaped in cross section, and by the leaf tip, which is shaped like the bow of a boat. Kentucky bluegrass is distinguished from Canada bluegrass by the shape of the stem. In Kentucky bluegrass the stem is round; Canada bluegrass has a flat stem. Their effects on the natural systems are equivalent and therefore should be treated as one problem. Many of the other cool-season European grasses (brome, timothy, orchard grass, quack grass, etc.) have similar growth habits and can be controlled using the techniques discussed below. Distribution and habitat: Kentucky bluegrass was introduced as a cultivar from Europe, and has been bred into multiple cultivars since its introduction. Because of its extensive use for lawns and in pastures, it is common in most grasslands, even those managed for native species. Canada bluegrass is also naturalized from Europe. Kentucky bluegrass is a common lawn and pasture grass. Canada bluegrass is often mistaken for Kentucky bluegrass, but is distinguished by forming extensive sods in dry, sterile soils (especially acidic soils) that cannot sustain the more common Kentucky bluegrass. Kentucky bluegrass is usually found on more mesic and fertile soils, although it will grow on dry neutral or alkaline soils. A-31 Mechanical Control A controlled fire can dramatically reduce bluegrass in a native or planted prairie, savanna, or barrens. Fire will also set back the woody species whose shade encourages the proliferation of cool-season grasses. In southern Wisconsin, a late April or early May burn will destroy three to eight inches of new growth. Timing of burns may change on a year-to-year basis depending on weather conditions. Observing bluegrass growth is essential for effective control by burning. Fire is most effective when bluegrass is three to eight inches high. Burning at this time kills new growth and removes accumulated leaf litter. Burning off the moisture-retaining blanket of leaf litter increases stress on the shallow-rooted bluegrass by exposing the darkened surface to the sun. This helps reduce the competitive ability of bluegrass by encouraging summer dormancy and decreasing the chance of flowering and seed production. The effect is most pronounced on dry prairies and barrens. Burning can reduce bluegrass by more than 90%, but it is rarely 100% effective. Burning at the right time also improves the competitive advantage of native, warm-season grasses and forbs. Native species emerge later and benefit from the elimination of duff and a darkened soil surface. When converting areas dominated by cool-season grasses into prairie, it is helpful to reduce the grass cover and seed bank before planting native seeds. This can be accomplished by any combination of tilling, smothering the grass, or applying herbicide. Till several times a year for at least one season to expose the seed bank and prevent further growth of the grass sod. Herbicide use followed by a season of tilling is also effective. On small sites, grasses can be killed by covering with black plastic or layers of newspapers during the growing season. Chemical Control Herbicide use is not recommended to control bluegrass on grasslands or savannas where there are native prairie plants. However, herbicide may be required on severely degraded areas or where prairie restoration is beginning. In such cases, the herbicide glyphosate has proven effective when used according to label applications. Source: Wisconsin Department of Natural Resources, 2002 A-32 Reed Canary Grass (Phalaris arundinacea) Effects of Invasion Reed canary grass reproduces by seed or creeping rhizomes and spreads aggressively. It prefers disturbed areas but can easily move into native wetlands. In less than 12 years, reed canary grass can form large, monotypic stands that harbor few other plant species and therefore are of little use to wildlife. Reed canary grass dominates an area by building up a tremendous seed bank that can eventually erupt, germinate, and recolonize treated areas. Reed canary grass is difficult to eradicate; no single control method is universally applicable. Size: 2–9 feet in height. Habit: A large, coarse, cool-season, sod-forming, perennial wetland grass. Sprouts early in spring, forming a thick rhizome system that dominates the subsurface soil. Blades: Erect, hairless stem with gradually tapering leaf blades 3.5–10 inches long and .25–.75 inches wide. The ligule is highly transparent. Panicles: Compact, erect or slightly spreading (depending on the plant’s reproductive stage), ranging from 3–16 inches long with branches .5–1.5 inches long. Flowers: Single flowers occur in dense clusters in May to mid-June. They are green to purple, changing to beige over time. Seeds: Shiny brown. Origin: Eurasia and North America. A-33 Mechanical Control • Small, discrete patches may be covered by black plastic for at least one growing season then seeded with native species. This method is not always effective and must be monitored because rhizomes can spread beyond the edge of the plastic. • Prescribed burns in late spring or late fall may help reduce the population if repeated annually for 5–6 years. The application of 1.5% glyphosate solution will “brown off” reed canary grass enough to conduct burns. A late spring burn followed by mowing or wick application of glyphosate to the emerging flowering shoots will eliminate seed production for that year. Burning is ineffective in eliminating dense stands of reed canary grass that lack competition from native, fire-adapted species in the seed bank. • Mowing twice yearly (early to mid-June and early October) may help control reed canary grass by removing seed heads before the seed matures and by exposing the ground to light, which promotes the growth of native wetland species. Discing the soil in combination with a mowing or burning regimen may help by opening the soil to other species. • Hand-pulling or digging may work on small stands in the early stages of invasion. • A bulldozer can be used to remove reed canary grass and rhizomes (12–18 inches deep), after which native species should be seeded. Discing or plowing can also be used in this way. • Repeated cultivation for one full growing season followed by dormant seeding near the first-frost date. Combine with spot herbicide application in sections too wet for early or late cultivation. Chemical Control Cut and spray • Tie the stems of small clones together just before they flower, then cut them and apply glyphosate in a 33% solution to the cut stems. • Perform foliar application of a 5% glyphosate solution designed for use in wetlands in early spring when most native species are dormant to the foliage. Remove the dead leaves from the previous year before applying herbicide. Two herbicidal applications may be necessary to ensure complete coverage. Mow in mid-September then apply herbicide in October (after big bluestem is dormant). • Perform wick application of a 5% glyphosate solution designed for use in wetlands in the first to third weeks of June, followed by a late June to mid-July burn. This technique reduces reed canary grass cover, depletes the seed bank, and stimulates native seed banks. • In non-aquatic environments, apply Dalpon and trichloracetic in late fall or early winter at a rate of 20lbs.–40 lbs./acre on dried foliage. Source: Wisconsin Department of Natural Resources, 1997. Minnesota Department of Natural Resources, 1995. A-34 Smooth (Awnless) Brome (Bromus inermis) Seed head Photos: Minnesota DNR-Angela Anderson Field of brome Effects of Invasion: Smooth brome is a cool season exotic that is especially troublesome in disturbed portions of native plant communities and restorations in the tallgrass and mixed prairie regions. Although less invasive than Kentucky bluegrass, with which it often occurs and is managed, it is also less responsive to management. Smooth brome has been widely planted as a forage and cover crop. Although perhaps not as invasive as Poa pratensis, with which it often grows, it is highly persistent. It forms a dense sod that often appears to exclude other species, thus contributing to the reduction of species diversity in natural areas. Size: Bromus inermis is a perennial cool season grass that grows 2 - 3' high with a hairless erect stem. Brome roots have been known to reach a depth of 4.7 feet. Habit: Bromus inermis is a deeply rooting, rhizomatous, sod-forming perennial grass. The drought resistance of smooth brome is probably accounted for in part by its deeply penetrating root system. The heavy concentration of total root mass near the surface is the result of smooth brome's creeping rhizomatous habit. Old brome fields develop a "sod bound" condition in which shoot density is reduced and symptoms of nitrogen deficiency are exhibited. Because of its fairly distinctive foliage and habit of growing in solid patches Bromus inermis is easily recognized at all seasons. Its early green-up makes it especially easy to detect during the spring months. Leaves: The leaf blades are smooth, flat, 4-5 inches long and 1⁄4-3/8 inches wide with a conspicuous “M”or “W”-shaped constriction in the middle. Fruit: Lemmas are all unawned or with very short awn. Flowers: The inflorescence is an erect, open panicle with ascending branches that are sometimes reflexed, blooming May – July. Origin: Bromus inermis is a Eurasian species ranging from France to Siberia, apparently introduced in the United States by the California Experiment Station in 1884. Within the United States smooth brome has been introduced in the northeastern and northern Great Plains states as far south as Tennessee, New Mexico and California. It has become naturalized from the maritime provinces to the Pacific coast north to Alaska to California and through the plains states. Within the United States, "northern" and "southern" agricultural strains have been developed. The southern strain is more tolerant of drought and heat than the northern strain. Mechanical Control Both experimental studies and management experience indicate that burning or cutting smooth brome in the boot stage is perhaps the most effective means of control. Smooth brome is in boot stage between midApril and late May when the plant has reached a height of 18 to 24 inches and the flowering head is still A-35 enclosed within the sheath. This is somewhat later than would be recommended for other management purposes such as control of Kentucky bluegrass. Research indicates that a well-timed burn that treats Bromus inermis in boot or early flower may be more effective than mowing at the same susceptible period. It appears that late May burns would be optimal in the northern plains for reduction of smooth brome. One close mowing when the plants are 18-24 inches tall (followed ideally by 3 repetitions), may improve chances of selectively controlling this species. The best conditions for damage are hot, moist weather at the time of cutting, followed by a dry period. Chemical Control Its habit of occurring frequently in nearly pure swards renders Bromus inermis a good target for selective control by timed, close mowing or use of herbicides. An early study of brome control found Tordon (picloram) most effective at rates of 1.1 to 2.2 kg/ha, or treatment with Roundup (glyphosate) at 0.5 to 1.1 kg/ha before flowering. It appears that April or May applications of glyphosate at 2 kg/ha may be an effective management technique for controlling smooth brome in pure patches. Sources: NatureServe. 2003. NatureServe Explorer: An online encyclopedia of life [web application]. Version 1.8. NatureServe, Arlington, VA. Available http://www.natureserve.org/explorer. (Accessed: July 14, 2003). Element Stewardship Abstract for Bromus inermis, The Nature Conservancy, 1987 (updated May 2000) Minnesota invasive non-native terrestrial plants, an identification guide for resource managers, MN DNR, 2003 A-36 Appendix B: Species Lists for Proposed Restoration Target Communities The following species lists contain the common plants of intact remnant communities in Minnesota. These species lists have been compiled from Curtis (1959), Wovcha et al. (1994) and from plant inventory lists compiled by Cynthia Lane, Ph.D., former staff ecologist with Great River Greening. • • Dry Prairie species list Oak Savanna species list (Appendix Table 1) (Appendix Table 2) Appendix Table 1. Dry Prairie species list This species list has been compiled from Curtis (1959), Wovcha et al. (1994) and from plant inventory lists compiled by Cynthia Lane, Ph.D., ecologist with Great River Greening. Latin Name Common Name Shrubs: Amorpha canescens Prunus americana Prunus virginiana Rhus glabra Rosa arkansana Symphoricarpos occidentalis Lead-plant American plum Choke cherry Smooth sumac Prairie rose Wolfberry Graminoids: Andropogon gerardii Bouteloua gracilis Bouteloua hirsuta Bouteloua curtipendula Carex heliophila Cyperus lupulinus Elymus canadensis Koeleria macrantha Panicum oligosanthes Muhlenbergia cuspidata Schizachyrium scoparium Sorghastrum nutans Sporobolus heterolepis Stipa spartea Big bluestem Blue grama grass Hairy grama grass Side-oats grama A species of sedge Hop-like cyperus Canada wild rye Junegrass Scribner’s panic grass Plains muhley Little Bluestem Indian Grass Prairie dropseed Porcupine grass Forbs: Anemone cylindrica Antennaria plantaginifolia Apocynum cannabinum Long-fruited Thimbleweed Large-leaved pussytoes Indian Hemp B-1 Artemisia ludoviciana Asclepias tuberosa Asclepias verticillata Asclepias viridiflora Aster ericoides Aster oolentangiensis Campanula rotundifolia Comandra umbellata Coreopsis palmata Dalea purpureum Delphinium virescens Euphorbia corollata Gnaphalium obtusifolium Hedioma hispida Helianthemum bicknellii Helianthus pauciflorus (rigidus) Heuchera richardsonii Lespedeza capitata Liatris aspera Liatris punctata Lithospermum canescens Lithospermum incisum Physalis heterophylla Potentilla arguta Rosa arkansana Solidago nemoralis Solidago ptarmicoides Solidago rigida Tradescansia bracteata Viola pedatifida White Sage Butterfly Milkweed Whorled Milkweed Green milkweed Heath Aster Sky-blue aster Harebell Bastard toadflax Stiff tickseed or bird foot coreopsis Purple prairie clover Prairie larkspur Flowering spurge Sweet everlasing Mock pennyroyal Hoary frostweed Stiff sunflower Alum root Round-headed bush-clover Rough blazing star Dotted blazing star Hoary puccoon Narrow-leaved puccoon Ground-cherry Prairie cinquefoil Prairie rose Gray goldenrod White aster Stiff goldenrod Western spiderwort Prairie Violet B-2 Appendix Table 2. Oak Savanna species list This species list has been compiled from Curtis (1959), Wovcha et al. (1994) and from plant inventory lists compiled by Cynthia Lane, Ph.D., ecologist with Great River Greening. Canopy Trees Latin Name Quercus macrocarpa Quercus ellipsoidalis Populus tremuloides Prunus serotina Common Name Bur oak Northern pin oak Quaking aspen Black cherry Shrub Layer Amorpha canescens Ceanothus americanus Cornus racemosa Corylus americana Rhus glabra Rosa arkansana Prunus virginiana Amelanchier laevis Symphoricarpos occidentalis Salix humilis Leadplant New Jersey tea Gray dogwood American hazelnut Smooth sumac Prairie rose Chokecherry Juneberry Wolfberry Prairie willow Groundlayer Graminoids: Andropogon gerardii Aristida basiramea Bouteloua curtipendula Bouteloua hirsuta Carex muhlenbergii Carex pennsylvanica Elymus canadensis Koeleria macrantha Muhlenbergia cuspidata Panicum oligosanthes Panicum virgatum Schizachyrium scoparium Sorghastrum nutans Sporobolus heterolepis Stipa comata Stipa spartea Big bluestem Three-awn grass Side-oats grama Hairy grama Muhlenberg’s sedge Pennsylvania sedge Canada wild rye, nodding wild-rye June grass Plains muhly Scribner’s panic grass Switch grass Little bluestem Indian grass Prairie dropseed Needle grass Porcupine grass Forbs: Anemone cylindrica Antennaria neglecta Antennaria plantaginifolia Artemisia ludoviciana Thimbleweed Pussytoes, white Plantain-leafed pussytoes or large-leafed pussytoes Prairie sage B-3 Artemisia frigida Asclepias tuberosa Asclepias verticillata Asclepias viridiflora Aster ericoides Aster oolentangiensis Aster sericeus Astragalus crassicarpus Besseya bullii Calylophus serrulata Campanula rotundifolia Coreopsis palmata Dalea candidum Dalea purpureum Delphinium virescens Desmodium illinoense Euphorbia corollata Fragaria virginiana Galium boreale Geum triflorum Gnaphalium obtusifolium Helianthemum bicknellii Helianthus hirsutus Helianthus occidentalis Hilianthus rigidus Heliopsis helianthoides Heterotheca villosa Heuchera richardsonii Hieracium longipilum Lespedeza capitata Liatris aspera Liatris punctata Lithospermum canescens Lithospermum caroliniense Monarda fistulosa Oenothera biennis Oxalis violacea Penstemon gracilis Penstemon grandiflorus Physalis virginiana Rudbeckia hirta Sisyrinchium campestre Smilacina stellata Solidago nemoralis Solidago ptarmicoides Solidago rigida Teucrium canadense Tradescantia occidentalis Verbena stricta Prairie sagewort Butterfly milkweed Whorled milkweed Green milkweed Heath aster Azure aster Silky aster Buffalo-bean, ground-plum Kitten-tails Toothed-leafed evening primrose Harebell Stiff tickseed or bird-foot coreopsis White prairie clover Purple prairie clover Prairie larkspur Illinois tick-trefoil Flowering spurge Wild strawberry Northern bedstraw Prairie smoke Sweet everlasting Hoary frostweed Woodland sunflower Western sunflower Rigid sunflower Early sunflower Hairy golden aster Alum root Long-bearded hawkweed Round-headed bush-clover Rough blazing star Dotted blazing star Hoary puccoon Hairy puccoon Wild bergamot Evening primrose Violet wood sorrel Slender beard-tongue Large-flowered beard-tongue Ground cherry Black-eyed Susan Blue-eyed grass Starry false Solomon’s seal Gray goldenrod White aster Stiff goldenrod Germander Western spiderwort Hoary vervain B-4 Appendix C: Resources The following pages contain forms to help plan and track management activities on native plant communities. In addition, agencies, suppliers and consultants that can answer questions, supply tools and equipment, and provide management services are listed. Many of these contacts have websites that offer links to numerous other resources. C-1 C-2 Activity____________________________________________________________Date (MM/YY)_________________________ Resource Management Record Project: Personnel: Management location (attach map) Description of work (attach additional information if necessary): Follow-up work required? Date(s): / / to / / NO YES (explain): Post-work evaluation required? NO YES (explain): Record Preparer:______________________________________________________________________ C-3 C-4 Daily Resource Management Log Date Activity Total worker hours Date Activity Total worker hours SUBTOTAL SUBTOTAL From Column 1 TOTAL HOURS SUBTOTAL C-5 C-6 Contacts: Minnesota Department of Natural Resources (DNR) Division of Wildlife: Bryan Lueth, Urban Wildlife Manager DNR Carlos Avery Game Farm 5463 – C W. Broadway Forest Lake, MN 55025 (651)296-3779 [email protected] Division of Forestry: Art Widerstrom, Regional Forester MN DNR 18310 Zodiac St. Forest Lake, MN 55025 (651)982-9720 X224 [email protected] United States Fish and Wildlife Service (USFWS) Minnesota Valley National Wildlife Refuge Rick Schultz, Refuge Manager 3815 E. 80th St. Bloomington, MN 55425-1600 (952) 858-0701 [email protected] Friends of the Minnesota Valley Holly Buchanan, Land Conservation Manager 3815 East 80th St. Bloomington, MN 55425-1659 (612)858-0720 [email protected] Equipment: Prairie restoration: Seed and plant materials: Landscape Alternatives 1705 St. Albans St. Roseville, MN 55113-6554 (651) 488-3142 C-7 Minnesota Native Landscapes 14088 Hwy. 95 NE Foley, MN 56329 (320) 968-4222 www.mnNativeLandscapes.com Shooting Star Native Seeds P.O. Box 648 Spring Grove, MN 55974-0648 (507) 498-3944 Prairie Restorations, Inc. P.O. Box 327 Princeton, MN 55371 (763) 633-4342 www.prairieresto.com Restoration consultants and contractors: Great River Greening 35 W.Water St. St. Paul, MN 55107 www.greatrivergreening.org Prairie Restorations, Inc. P.O. Box 327 Princeton, MN 55371 (763) 633-4342 www.prairieresto.com Minnesota Native Landscapes 14088 Hwy. 95 NE Foley, MN 56329 (320) 968-4222 www.mnNativeLandscapes.com Natural Restoration Resources 2013 Walnut Ave. N.W. New Brighton, MN 55112 (651)636-3462 [email protected] C-8
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