Lake County Wetland Creation to Enhance Migratory Bird Habitat

Transcription

1 Lake County Wetland Creation to Enhance Migratory Bird Habitat By Kurt W. Johnson Seppo H. Valppu December 2003 NRRI/TR-2004/12 Submitted to the Lake County Land Use Department University of Minnesota Duluth Natural Resources Research Institute 5013 Miller Trunk Highway Duluth, Minnesota,

2 INTRODUCTION Lake County, Minnesota has numerous wetlands, but virtually no Palustrine Emergent wetlands. There is an opportunity to incorporate County owned gravel pit rehabilitation and closure with the creation of Palustrine Emergent, and associated Palustrine Forested and Palustrine Shrub wetlands, for migratory birds. There are numerous active and abandoned gravel pits in Lake County, especially along the more populated and traveled North Shore of Lake Superior. About 20 exhausted and abandoned gravel pits are owned by the County. The County recognizes the need to rehabilitate and bring final closure to these pits. Sound information and guidelines for creating waterfowl ponds (Palustrine Emergent wetlands) for migratory birds is available in several Minnesota Department of Natural Resources (DNR) publications and from DNR personnel. Also, recent applied research at several universities and governmental agencies in the U.S. and Canada has resulted in the successful application of wetland creation and restoration techniques for Palustrine Forested and Palustrine Shrub wetlands. It would be highly beneficial to have a County specific wetland creation project for migratory birds that can be used as a model for other public and private gravel pits in the Lake Superior basin. The rehabilitation and closure of the County owned Nursery Pit offers an opportunity to create wetland and associated upland habitat for migratory birds. There are a number of publications available containing detailed information on wetland restoration and creation. The purpose of this report is not to reiterate all of this information, but to outline specific methods used for this particular wetland creation and describe their success over the project study period. Experience gained from establishing this study and long term monitoring of the site will be useful for future gravel pit rehabilitation projects within Lake County and throughout the Lake Superior basin. Project Goal To demonstrate methods for creating wetlands suitable for migratory bird habitat as part of rehabilitation and closure of Lake County owned gravel pits. Location The Lake County Wetland Creation site is located in the NW1/4 of the SE1/4, Section 20, T53N, R11W at an abandoned gravel pit (Nursery Pit) near the Two Harbors airport (Figure 1). Water flows through the site from an active gravel operation upstream and drains into the Knife River. The site is approximately 4-5 acres in size. 1

3 Wetland Site Figure 1. Lake County Created Wetland location - NW 1/4 of the SE 1/4, Section 20, Township 53 North, Range 11 West. METHODS Site Preparation Design The wetland design was based on the general specifications presented in the DNR publication A Handbook for Reclaiming Sand and Gravel Pits in Minnesota (Buttleman 1992). Site-specific factors such as the existing pond (lower pond) adjacent to the site and the small stream flowing through the site were taken into consideration. A series of three ponds were created at the site with the following characteristics: maximum 3:1 slopes water depth ranging from 0.5 to 5.0 feet irregular shoreline with islands, bays, points, and rock piles Contouring The Lake County site was graded and contoured by the Lake County Highway Department in early May 2003 to create three ponds: upper, middle, and east (Figure 2). The lower pond was already present at the site. After contouring, the surface of the pond basins was covered with 6-12 inches of clay material to serve as a liner to hold water. This was covered with 6 inches of sand/sandy loam material. Inlets and outlets were 2

4 Scale (feet) Figure 2. Map of the Lake County Created Wetland Site showing Upper, Middle, Lower, and East ponds. Numbered locations are photo-reference points. 3

5 reinforced with rock riprap to reduce erosion and maintain water levels. Table 1 lists shoreline and size characteristics of the ponds. Table 1. Shoreline and areas for ponds and islands. Pond/Island Shoreline (ft) Area (acres) Upper Pond Middle Pond 1, Middle Island Lower Pond Lower Island East Pond Soil Amendments The original plan was to apply organic material to the surface to improve conditions for native plant growth. However, a local source of weed-free material could not be found. Scheduled cleaning of road ditches through area wetlands could have provided organic material but it was found to contain considerable amounts of reed canary grass (Phalaris arundinacea), an invasive species with little habitat value that can inhibit establishment of native plants and dominate a site if introduced. Peat from horticultural operations in adjacent St. Louis County was considered but material and transportation costs were well beyond the project budget. According to the Lake County Highway Department, suitable organic material for road projects is largely unavailable in the County. Due to all of these factors, the decision was made to forego the application of organic material to the site. If suitable sites can be found they could be incorporated into future gravel pit rehabilitation projects. Plant Establishment Wetland plants were established at the site using seed and transplants in early June Native wetland seed mixes were purchased from Prairie Restorations, Inc. headquartered in Princeton, Minnesota. Northern Wet Meadow and Northern Wet Flower seed mixes were selected for the project. Wetland plant seed was broadcast only along the pond edges to ensure they would have adequate soil moisture (Figure 3). Cover crops were also seeded along the pond edges and on upland areas to aid in establishing native species and to help prevent erosion. Seeding was conducted at the rate recommended by the seed supplier. Wetland transplants were collected at the University of Minnesota s Natural Resources Research Institute (NRRI) Fens Research Facility located approximately 45 miles north of Duluth. A variety of trees, shrubs, and other wetland plants were collected and transplanted to the study site (Figure 4). In addition to rooted transplants, willow hardwood cuttings were also planted at the study site. Wild rice seed leftover from another research project at NRRI was also sown in the ponds. The Lake County Land Department also planted red pine and black spruce tree seedlings at the site. The main goal in planting a relatively large number of species at the site was to develop as much 4

6 plant diversity as possible in order to provide habitat for a variety of migratory bird species. The following lists detail the plant species introduced. Northern Wet Meadow Seed Mix big bluestem fringed brome Canada blue joint grass giant bur-reed cord grass green bulrush fowl meadow grass red top Northern Wet Flower Seed Mix blue vervain broad leaved arrowhead Canada anemone common ox eye early goldenrod flat topped aster giant sunflower golden alexander grass leaved goldenrod joe pye weed marsh marigold panicled aster wild rye wool grass red stalked aster St. John s wort swamp goldenrod swamp milkweed tall meadow rue yarrow Cover Crops annual rye grass oats Transplants black spruce blue flag iris Canada blue joint grass Other wild rice Re-Green wheat meadow sweet ostrich fern red osier dogwood tamarack water arum willow Figure 3. Hand seeding. Figure 4. Hand transplanting. 5

7 Mulching Immediately following seeding, a uniform layer of straw mulch was applied to the terrestrial areas of the site by the Lake County Highway Department using a portable straw blower (Figure 5). Approximately 70 bales of straw were distributed on the site to moderate surface temperatures and improve moisture conditions for plant establishment and survival. Figure 5. Straw mulch application. RESULTS The authors conducted a plant survey of the Lake County Created Wetland in early September 2003 to determine vegetation establishment success on the upper, middle, and east ponds, and the island located in the middle pond. The lower pond present on the site prior to construction was not surveyed. Plant species present in and around each pond were recorded and dominant species were noted. The survey was divided into four hydrologic zones between the standing water and the surrounding upland: Standing water Water s edge (0-50 cm from standing water) Near water ( cm from standing water) Upland (greater than 250 cm from standing water) 6

8 It was not possible to positively identify some of the species present, especially the grasses, when conducting the plant survey after only one year. Therefore, it is uncertain whether or not some species were planted or naturally introduced. Plant identification should become easier in subsequent years as perennial plants mature. Plant lists for each pond and hydrologic zone follow. Species introduced as seed or transplants as part of the project construction are in bold. Other species likely established from naturally introduced seed. Asterisks denote dominant species. Latin (genus species) names for each plant species are listed in Appendix A. Standing Water beggartick *blunt spike rush brook lobelia Water s Edge beggartick bladder campion blue flag iris *blunt spike rush *bulrush buttercup chamomile Near Water aster beggartick bird s foot trefoil clover dogbane evening primrose Upland aster bird s foot trefoil black ash bracken fern chamomile clover evening primrose *goldenrod grasses East Pond *narrow-leaved cattail pondweed clover evening primrose giant bur-reed goldenrod grasses lamb s quarters *narrow-leaved cattail *grasses hemp nettle horseweed lamb s quarters oats raspberry hemp nettle horseweed *lamb s quarters oats pearly everlasting pincherry quaking aspen ragweed *raspberry St. John s wort *water plantain wild rice rush smartweed spotted water hemlock St. John s wort water arum willow sage sensitive fern sunflower swamp thistle tansy willow red elderberry red pine ryegrass smartweed sow thistle swamp thistle *tansy thimbleberry willow 7

9 Standing Water coontail *narrow-leaved cattail Water s Edge beggartick bird s foot trefoil blue flag iris *blunt spike rush chamomile Near Water aster balsam poplar beggartick black spruce bladder campion Canada bluejoint grass clover dandelion evening primrose fireweed flat-top aster *goldenrod Upland aster balsam poplar bird s foot trefoil black spruce bluestem grass bracken fern bush honeysuckle Canada bluejoint grass Canada thistle chamomile chokecherry clover fireweed Middle Pond pondweed spotted water hemlock clovers giant bur-reed grasses *narrow-leaved cattail rush *grasses horsetail lamb s quarters meadowsweet orange hawkweed ostrich fern raspberry red pine reed canary grass rye ryegrass sage *goldenrod hop clover horsetail lamb s quarters meadowsweet oats orange hawkweed ostrich fern paper birch pearly everlasting rabbit foot clover ragweed raspberry *water plantain *wild rice smartweed St. John s wort water plantain wild rice willow sandbar willow sow thistle spotted water hemlock swamp aster swamp thistle tamarack tansy thimbleberry wheat wild strawberry wool grass red pine reed canary grass rye ryegrass sandbar willow smartweed sow thistle spotted water hemlock *tansy thimbleberry wheat 8

10 Standing Water coontail *narrow-leaved cattail Water s Edge blue flag iris Near Water bugleweed canada bluejoint grass Upland beggartick big bluestem grass black spruce Standing Water coontail *narrow-leaved cattail Water s Edge beggartick bird s foot trefoil blue flag iris *blunt spike rush chamomile clovers Near Water aster balsam poplar beggartick black spruce bladder campion Canada bluejoint grass clover dandelion evening primrose fireweed flat-top aster *goldenrod Middle Pond Island pondweed spotted water hemlock sunflower meadow sweet ostrich fern red osier dogwood tamarack white sweetclover Upper Pond pondweed spotted water hemlock giant bur-reed grasses *narrow-leaved cattail rush smartweed *grasses horsetail joe pye weed lamb s quarters meadowsweet orange hawkweed ostrich fern raspberry red pine reed canary grass rye ryegrass *water plantain yellow sweetclover *water plantain *wild rice St. John s wort sunflower tag alder water plantain wild rice willow sage sandbar willow sow thistle spotted water hemlock swamp aster swamp thistle tamarack tansy thimbleberry wheat wild strawberry wool grass 9

11 Upland aster balsam poplar bird s foot trefoil black spruce bluestem grass bracken fern bristlegrass bush honeysuckle Canada bluejoint grass Canada thistle chamomile chokecherry clover evening primrose fireweed flat-top aster *goldenrod grasses hop clover horsetail lamb s quarters meadowsweet mullein oats orange hawkweed ostrich fern paper birch pearly everlasting rabbit foot clover ragweed raspberry red pine reed canary grass rye ryegrass sandbar willow smartweed sow thistle spotted water hemlock sunflower *tansy thimbleberry wheat A total of 42 plant species were either seeded or transplanted on the site. Of these, 22 species, or just over 50 percent, were identified in the September 2003 plant survey. Approximately 50 percent of the Northern Wet Meadow seed mix, 22 percent of the Northern Wet Flower seed mix, 75 percent of the cover crops, and 100 percent of the transplants became established in the first year. It is evident that a number of the seeded species did not establish in the first year. This sometimes occurs with native species, which can take several years to establish. Should these species fail to appear in subsequent years they should be omitted from future seed mixes used on similar sites. Although 100 percent of the transplants survived the first year it is important that they are monitored in the future, as some may not adapt to the site and eventually die out. A total of 55 plant species present in the September 2003 survey were neither seeded nor transplanted, but established naturally. Although this spontaneous introduction of plant species can be beneficial, some undesirable invasive plants may also establish that interfere with the creation of a diverse wetland ecosystem. Narrow leaved cattail (Typha angustifolia), and reed canary grass (Phalaris arundinacea) are two invasive species found at the site. These species should be monitored and controlled to prevent them from dominating the wetland. Figures 6 and 7 are photographs showing the created wetland site before and after construction and planting. The created wetland was also photographed in July, August, and September 2003 from each of eight photo-reference points (see Figure 2 and Table 2) distributed throughout the site to show the vegetation progression through the first growing season. These photos are presented in Appendix B. 10

12 Figure 6. Lake County Created Wetland site before construction, April Figure 7. Lake County Created Wetland site after construction and planting, September Table 2. Photo-reference point descriptions and perspective. Photo-Reference Point Description 1 North end of East Pond, facing south, southeast 2 Southeast corner of Middle Pond, facing northwest 3 South edge of Middle Pond, facing north 4 Southwest corner of Middle Pond, facing northeast 5 West edge of Middle Pond, facing east 6 West edge of Upper Pond, facing east 7 North edge of Upper Pond, facing south 8 Northeast corner of Middle Pond, facing southwest RECOMMENDATIONS A variety of different planting strategies were used at the study site to determine what has potential for future wetland creation projects. More than one year of monitoring will be 11

13 required to determine which strategies are most successful and can be recommended for other sites. However, certain general recommendations can be made for creating wetlands for migratory birds as part of gravel pit rehabilitation and closure. Site Assessment The most important criterion in assessing a gravel pit site for potential wetland creation is the ability to retain water. Water retention can be achieved by excavating below the water table or by installing dams or water control structures to impound water that may be flowing through a site. When impounding water it is also important to have clay or some other impervious material available to line the pond and prevent seepage. The potential wetland creation site should also be of sufficient size to provide adequate habitat for migratory birds and other wildlife. The recommended minimum pond size is ½ acre (Buttleman 1992). Access to topsoil or other organic material to cover the site can be beneficial for plant growth. However, be careful to avoid introducing invasive species and keep in mind that the cost of transporting topsoil can be prohibitive. Construction and Contouring Gravel pit sites often have steep slopes that must be contoured to provide suitable habitat for migratory birds and other wildlife. Steep slopes increase the rate at which water enters a wetland causing rapid changes in water levels (Shaw 2000). Maximum slopes of 3:1 are recommended and more gradual slopes of 10:1 or even 20:1 are preferred (Buttleman 1992). Pond shorelines should be irregular and have as many bays, inlets, and peninsulas as possible. Islands and rock piles should be built to establish nesting and loafing areas for migratory birds. Stumps or brush piles can also provide habitat. These can be placed in position on the ice during the winter months. Pond water depth should vary from feet to provide shallow areas for emergent vegetation to establish and deeper areas for open water. If the pond is an impoundment, the outlet should be constructed to allow overflow during periods of high rainfall or snowmelt. Plant Establishment A diverse native wetland plant community on the site provides food and cover for migratory birds and other wildlife, helps control erosion, and prevents invasive species encroachment. Wetland plants can be established with seed, transplants, or through application of donor wetland soil containing a native seed bank. It is also important to establish native vegetative cover on the surrounding upland. Seeding Gravel pit sites usually have a very limited wetland plant seed bank. Seed must come from nearby wetlands or be planted. Whenever possible use local sources of wetland 12

14 plant seed. Seed from areas within 100 miles north-south and 200 miles east-west is recommended (Shaw 2000). Some companies specialize in native wetland seed mixes. A custom seed mix made up of species adapted to your area can often be less expensive and provide better cover than standard wetland seed mixes formulated by the company. A cover crop made up of annual or short-lived perennial plants like oats, wheat, or annual ryegrass can be helpful in establishing native plants. These can provide quick cover and shelter the slower growing native species. Seeding should be done at the rate recommended by the seed supplier. Seed can be broadcasted or planted with a seed drill. When possible a seed drill is preferred but on rocky gravel pit sites broadcasting seed may be the only feasible option. If possible, lightly rake or drag the site with a spring-toothed harrow after seeding to incorporate broadcasted seed. Wetland seed can be planted at any time that there is sufficient soil moisture. Surrounding upland areas should be planted in the spring or late fall mid-october to mid-november (Shaw 2000). Wild rice is wetland plant of particular interest that provides cover and abundant food, especially for migratory waterfowl. It has potential for use in created wetlands provided certain site conditions are met. Wild rice prefers relatively clear flowing water, optimal depths of 1-2 feet, with minimal fluctuations in water level (Thompson and Luthin 2000). Several inches of organic muck is the preferred substrate. Established stands of competing vegetation may reduce seeding success. The seed should preferably be planted in the fall immediately after it is harvested, although wild rice seed can be wet stored over the winter and planted in the spring. Transplants Transplants of locally adapted native wetland plants can provide quick vegetative cover on a created wetland site and serve as sources of seed. Only collect plants from the wild at sites that are going to be developed or damaged by spraying, cultivation, road construction, etc. Transplants should be planted in the early spring or late fall (Shaw 2000). Avoid including invasive species when collecting transplants. In addition to rooted transplants, hardwood cuttings of certain tree species such as willow or cottonwood can also be easily transplanted on wetland sites. Collect 8-10 inch cuttings of the previous year s growth during the winter months and place them in cold storage until the spring. Plant them to a depth of approximately 6 inches with the buds facing up in areas of adequate moisture. Donor Soil Another method of introducing native wetland seed is through donor soil. Small amounts of donor soil can be applied to introduce more diversity to the site (Galatowitsch and van der Valk 1994). The donor soil seed bank should first be tested in greenhouse growth 13

15 trials to ensure it does not contain invasive species. Transportation costs for donor soil can be prohibitive depending on their proximity to the wetland creation site. Mulching Mulching can improve plant establishment on created wetland sites by conserving moisture, moderating soil surface temperatures, and preventing erosion. Wood fiber, hay or straw can be used. Weed free straw is generally preferred because of lower cost, good availability, and absence of invasive species. Straw should be applied with a straw blower at a rate of 1.5 to 2 tons per acre and crimped in with a slotted disk if possible (Buttleman 1992). Site Management Wetland creation sites should be inspected periodically in the years following project completion to ensure that project goals are being met. If problems are identified, steps can be taken to alleviate them and get the project back on track. If the site is to be designated as a wetland banking site, monitoring reports are generally required for 5 years after project completion. Invasive species control can be a major site management activity. Species such as narrow-leaved cattail, reed canary grass, purple loosestrife, and giant reed-grass can dominate a site if left uncontrolled. Early detection of these plants, followed by species appropriate control is essential to ensure the plant diversity is maintained. Although labor intensive, hand pulling plants or herbicide spot applications can be effective without damaging the surrounding native vegetation. Dams and water control structures should be periodically inspected to ensure water levels are maintained to provide adequate moisture for wetland plants. If erosion is present on the site, steps to repair it will help prevent damage to vegetation and reduce sediment accumulation in the pond. Controlling ATV access to the site can also prevent plant damage and erosion problems. ACKNOWLEDGEMENTS This project was funded under the Coastal Zone Management Act, by NOAA s Office of Ocean and Coastal Resource Management, in conjunction with Minnesota s Lake Superior Coastal Program and MN DNR Waters. The authors would also like to thank the following agencies and individuals for their help with this project: Board of Soil and Water Resources Lake County Forestry Department Lake County Highway Department Lake County Land Use Department Lake & Cook County SWCD Natural Resources Research Institute Mark Nelson Tom Martinson Al Goodman, Butch Henjum Walt Van Den Heuvel Wayne Seidel Paul Meysembourg, Tom Malterer 14

16 REFERENCES Buttleman, C.G A Handbook for Reclaiming Sand and Gravel Pits in Minnesota. Minnesota Department of Natural Resources, Division of Minerals, St. Paul, Minnesota. 65 pp. + Appendices. Shaw, D.B Native Vegetation in Restored and Created Wetlands Its Establishment and Management in Minnesota and the Upper Midwest. Minnesota Board of Water and Soil Resources, St. Paul, Minnesota. 96 pp. Galatowitsch, S.M., and A.G. van der Valk Restoring Prairie Wetlands: An Ecological Approach. Institute for Wetland and Waterfowl Research, Iowa State University Press, Ames, Iowa. Thompson, A.L., and C.S. Luthin Wetland Restoration Handbook for Wisconsin Landowners. Bureau of Integrated Science Services, Wisconsin Department of Natural Resources, Madison, Wisconsin. 108 pp. 15

17 APPENDIX A Lake County Gravel Pit Restoration 2003 Plant List aster balsam poplar beggartick big bluestem grass bird s foot trefoil black ash black spruce bladder campion blue flag iris blue vervain blunt spike rush bracken fern bristlegrass broad leaved arrowhead brook lobelia bugleweed bulrush bush honeysuckle buttercup Canada anemone Canada bluejoint grass Canada thistle chamomile clover common ox eye coontail cord grass dandelion dogbane early goldenrod evening primrose fireweed flat-topped aster fowl meadow grass fringed brome grass giant bur-reed giant sunflower golden alexander goldenrod grasses grass leaved goldenrod great St. John s wort green bulrush Aster sp. Populus balsamea Bidens cernua Andropogon gerardii Lotus corniculatus Fraxinus nigra Picea mariana Silene vulgaris Iris versicolor Verbena hastata Eleocharis obtusa Pteridium aquilinum Setaria sp. Sagittaria latifolia Lobelia cf. kalmii Lycopus sp. Scirpus sp. Diervilla lonicera Ranunculus sp. Anemone canadensis Calamagrostis canadensis Cirsium canadensis Anthemis cf. nobilis Trifolium sp. Heliopsis helianthoides Ceratophyllum demersum Spartina pectinata Taraxacum officinale Apocynum androsaemifolium Solidago sp. Oenothera biennis Epilobium angustifolium Aster umbellatus Glyceria striata Bromus ciliatus Sparganium eurycarpum Helianthus giganteus Zizia aurea Solidago sp. Gramineae undiff. Solidago sp. Hypericum pyramidatum Scirpus atrovirens 16

18 hemp nettle hop clover horsetail horseweed joe-pye-weed lamb s quarters marsh marigold meadowsweet mullein narrow-leaved cattail oats orange hawkweed ostrich fern panicled aster paper birch pearly everlasting pincherry pondweed quaking aspen rabbit foot clover ragweed raspberry red elderberry red osier dogwood red pine red stalked aster red top grass reed canary grass rush rye ryegrass sage sandbar willow smartweed sow thistle spotted water hemlock St. John s wort sunflower swamp aster swamp goldenrod swamp milkweed swamp thistle tag alder tall meadow rue tamarack tansy Galeopsis tetrahit Trifolium aureum (T. dubium) Equisetum arvense Conyza canadensis Eupatorium maculatum Chenopodium album Caltha palustris Spiraea alba Verbascum thapsus Typha angustifolia Avena sativa Hieracium aurantiacum Matteuccia struthiopteris Aster lanceolatus Betula papyrifera Anaphalis margaritacea Prunus pensylvanica Potamogeton sp. Populus tremuloides Trifolium arvense Ambrosia artemisiifolia Rubus idaeus Sambucus pubens Cornus stolonifera Pinus resinosa Aster puniceus Agrostis alba Phalaris arundinacea Juncus sp. Secale cereale Lolium multiflorum Artemisia sp. Salix exigua (S. interior) Polygonum sp Sonchus arvensis Cicuta maculata Hypericum sp. Helianthus sp. Aster lucidulus Solidago uliginosa Asclepias incarnata Cirsium muticum Alnus rugosa Thalictrum dasycarpum Larix laricina Tanacetum vulgare 17

19 thimbleberry water arum water plantain wheat white sweetclover wild rice wild rye grass wild strawberry willow wool grass yarrow yellow sweetclover Rubus parviflorus Calla palustris Alisma plantago-aquatica (A. subcordatum) Triticum aestivum Melilotus alba Zizania palustris/aquatica Elymus virginicus Fragaria virginiana Salix sp. Scirpus cyperinus Achillea millefolium Melilotus officinalis 18

20 APPENDIX B Reference Point Photographs Lake County Wetland Photo Reference Point 1 July 2003 August 2003 September

21 Lake County Wetland Photo Reference Point 2 July 2003 August 2003 September

22 Lake County Wetland Photo Reference Point 3 July 2003 August September 2003

23 Lake County Wetland Photo Reference Point 4 July 2003 August September 2003

24 Lake County Wetland Photo Reference Point 5 July 2003 August September 2003

25 Lake County Wetland Photo Reference Point 6 July 2003 August September 2003

26 Lake County Wetland Photo Reference Point 7 July 2003 August September 2003

27 Lake County Wetland Photo Reference Point 8 July 2003 August September 2003