Recommendation for Native Prairie Development Indiana University Office of Sustainability Prepared by: Marie Buckingham and Zach Brown, IUOS Interns, Summer 2009 Prepared for: Indiana University Bloomington Office of Sustainability and Mia Williams, Landscape Architect Date: August 14, 2009
Introduction The primary focus of this internship was on the research and development of a methodological plan for the construction of a prairie that exclusively supports native Indiana flora and fauna. Based on research and assessments, this plan is specialized to the specific characteristics of the given site. The adviser to this project is Mia Williams, University Landscape Architect. Her goal is to create a natural, low-maintenance, native landscape in place of a homogeneous monoculture of grasses. The facilitator of this project is the newly developed Indiana University Office of Sustainability, who has created many internship projects focused on improving campus sustainability. This specific project focuses on improving campus land quality and the conservation of natural resources. The site proposed for development is the 12-acre grass field immediately west of the Tulip Tree Apartments and south of Hilltop Garden and Nature Center, within the boundaries of the Indiana University campus. According to the university landscape architect, this field was mowed consistently until May 2008. Beginning in June 2008, the field was left as an un-mowed green space with the purpose of reducing the cost and carbon footprint associated with maintenance (mowing, lawn fertilization, labor). Indiana University is often acknowledged for its beautiful and well-managed landscape. Campus landscaping requires high maintenance to ensure that the grounds continue to show this clean-cut appearance. Currently, the field proposed for this prairie development consists mostly of non-native grass species and does not provide the same aesthetic or ecological services as a native prairie would. Continued mowing of the grass or the planting of a garden in this space would require high maintenance and costs. Planting a native prairie in this site would reduce maintenance costs, saving the university money while supporting natural and local communities. A native prairie would benefit the university economically, environmentally and would increase the educational and aesthetic value of the field. Environmental Sustainability One the main priorities for the development of a native prairie on the Indiana University campus would be to improve campus environmental sustainability. A native prairie in place of the 12-acre grass field would create myriad benefits including sequestering carbon in plant growth, reducing maintenance practices and providing habitat. Prairies create habitat for birds and insects as well as small and large mammals. The vegetation provides cover for small animals to avoid predation, to nest in, and offers appropriate food sources. Prairie plants are successful because two-thirds of their biomass is in their underground root system, allowing them to flourish after winter as well as making them resilient to herbivory, fire and other disturbances. Strong and dense prairie roots also help prevent erosion and sedimentation in nearby streams by holding the soil firmly in place, making them valuable in a field near the Jordan River. 2
Dense roots also deter the growth and spread of unfavorable weeds. A particular study showed that during the first year of a prairie establishment, weed biomass dropped 92% (Blumenthal et. al 2005). These complex root systems also provide a natural filtration system for rainwater and runoff by eliminating impurities (such as through nutrient loading) and hazardous contaminants before continuing through the water cycle and recharging the groundwater aquifer (Heavy Metal Soil Contamination 2000). This is important for the given site because it is adjacent to several impervious surfaces, the runoff from which often contains pollutants. These compounds are hazardous for both humans and wildlife. Planting a prairie landscape in place of turf grasses would also eliminate some of the contaminants that enter our local environment through lawn maintenance, such as fertilizers, pesticides and broad-leaf herbicides. Because the stream flows through the university grounds, the contamination of the headwaters puts downstream ecosystems at risk of negative ecological effects. Fertilizers used in lawn maintenance can enter water systems and drastically change the streambed ecology of the ecosystem by increasing primary production. Runoff rich in macronutrients (nitrogen, phosphorus and potassium) often results in eutrophic conditions, characterized by excessive algal blooms. These blooms remove dissolved oxygen from the water, eliminating species of benthic macroinvertebrates, fish and other aquatic organisms sensitive to such fluctuations. Prairie root systems increase the water storage capacity of the land, creating a natural bio-retention area to help mitigate stormwater runoff and flooding caused by surrounding impervious surfaces. These complex root systems create more porous matrices, increasing the soil water storage capacity. These characteristics should be considered to create a balance between the built environment of the campus and its ecological sustainability. Impervious surfaces cover approximately 16% of the land area on campus as parking lots, sidewalks and roads. Healthy watersheds should include no more than 11% impervious surfaces for appropriate drainage and flood control (Indiana University Campus Sustainabiltiy Report 2008). Impervious surfaces cause precipitation to be channeled into the environment in unnatural quantities, velocities and temperatures. Altering these variables can influence the vegetation growing on campus and thus influence the fauna attracted and supported. Invasive species tend to be successful in areas of disturbance due to their adaptability. Creating a balance between the natural and built environments on campus requires an improvement of the quality of the natural environments to accommodate for the pressures caused by the synthetic systems. Economic Sustainability Grass lawns on campus demand high levels of maintenance in order to remain in desired condition. A typical lawn on campus can be mowed up to 15 times in one year. Mowing requires maintenance staff, lawn mowers, edgers, equipment repairs and fuel. In 3
addition to these basic costs, lawns require fertilizer and irrigation to supplement the soil quality of this region. In addition to fertilization, irrigation is required during periods of low rainfall. Prairie plantings are economically viable long-term because they require little management after the first four years of development. The first years of development require seed planting, weeding, mowing and prescribed fires. Beyond the fourth year prairie maintenance is reduced to a basic pattern of two mows and one burn every three years. This process does not require any irrigation or fertilization. Prairies are nearly self-sustaining after the initial process of development. Each year the prairie occupies this space in place of a grass lawn the university will save money on equipment, fuel, staff, fertilizers and herbicides. Education and Labyrinth Development A native prairie installation on the Indiana University Bloomington campus would provide a unique educational tool for university and community students. The site could potentially offer research opportunities for students and faculty of many disciplines; as well, serve as an outdoor classroom/laboratory for experimentation. The creation of a labyrinth-design footpath within the emerging prairie would greatly enhance the site as a learning arena. The potential pathway would lead visitors through a short maze of prairie grasses and forbs, which would include educational signage about the various species of prairie vegetation and the fauna supported by these species. Aesthetics If a seed mix is constructed carefully, a planted prairie can sustain vibrant color from early spring until the first frost. A colorful display of native forbs and grasses would enhance the beauty of the campus, and would offer an increased variety of landscapes. The prairie could act as a physical entity to showcase IUB s commitment to sustainability, potentially attracting support to the IU Office of Sustainability. Further, the prairie would be a natural setting that could serve as a venue for displays of local and university art. Disturbance After the prairie has established (2-3 years), regular disturbance is necessary to manage succession and to maintain high levels of biodiversity. Woody and shrub species tend to naturally dominate the landscape of the Midwestern region, and if the prairie is not managed by disturbance the site would eventually succeed into a woodland. The best time to disturb the prairie is early spring while the vegetation is still dormant. The two most commonly used methods to disturb a prairie are prescribed burns and mowing. Burning is the preferred method because it completely removes the plant litter from the previous growing season, returning nutrients into the ground for new growth and allowing sunlight to reach seedlings. Mowing can also be an effective disturbance method, especially if the plant litter is subsequently raked off the field and disposed of. 4
Eradication of Current Vegetation Glyphosate-based herbicide (e.g. Roundup or generic equivalent): The use of chemical herbicide can have negative impacts on ecosystems. Varying results have been observed through numerous studies regarding the effects of herbicide on terrestrial organisms and microorganisms. One study concluded that microorganism communities are relatively unaffected by the application of glyphosate-based herbicide (Busse 2001). Aquatic organisms are harmed to a much greater degree than terrestrial organisms. The close proximity of the headwaters of the Jordan River to the herbicide application site could negatively influence the downstream ecosystem. The active ingredient in herbicide, glyphosate, photo-degrades in a matter of hours after application if applied on a warm and sunny day (recommended), and therefore is not the main concern with negative environmental impacts. Often the surfactant chemical is what persists in ecosystems, and is what is considered to be toxic to organisms. There are certain brands of herbicide that have been developed to be safe for aquatic organisms. Chemical herbicide use has exhibited high effectiveness in the control of unfavorable vegetation compared to alternative methods and requires minimal future maintenance upon application. Black plastic tarp or cardboard: This option is an alternative to chemical use that is less impactful on the environment. However, because this method requires the material to be secured over the field vegetation, it is a time- and labor-intensive effort due to the size of the plot being managed. Prescribed burning: This option would be an effective way to eradicate the above-ground vegetation, however, the underground seed bank and rhizomes would still remain. These remains would grow back in the following season and bring competition to the prairie vegetation. Methods Soil Sampling Determining the characteristics of the soil of the site will aid in determining the native plants best suited. The primary characteristics include soil type as well as the percent moisture. Samples of the field were taken to determine the soil type as well as the percent moisture. Samples of soil were taken from three general elevation levels in the field. A topographic map indicates the general elevation of the field (Figure 1). The northwest corner of the field is on a hill and gradually slopes down to the southeast. Because there is no tree canopy providing shade, it is assumed that slope elevation, rather than solar exposure, is one of the primary factors controlling the moisture composition of the field. Elevation levels were determined by eyesight and confirmed using a topographic map of the area (Figure 1). The grade of the slope is minimal but 5
could influence the species of plants best suited for the site through the amount of moisture content. Two soil samples were taken from the peak point of elevation. Another two were taken from a moderate elevation level as well as two from the lowest point of elevation. Samples were taken from three inches below the ground surface. Organic matter such as roots and leaves were picked out of the soil samples by hand. The samples were then weighed out to roughly 20g and baked for 28 hours at 90 C. The percent moisture was calculated using the difference in soil weights before and after baking (Table 1). The soil samples were also used to determine the type of soil found throughout the field. Using a standard finger test the soil was determined to be loamy clay throughout. Figure 1: Topographic map of site, provided by University Landscape Architect 6
Table 1: Percent moisture of soil at different elevation gradients Sample Soil Mass Before Baking (g) Soil Mass After Baking (g) Percent Moisture Peak A 26.9 20.9 22.3 Peak B 18.8 14.4 23.4 Slope A 16.6 13.2 20.5 Slope B 19.8 16.0 19.2 Trough A 26.5 20.1 24.2 Trough B 20.3 14.7 27.6 Vegetation Sampling The sampling of existing vegetation provides an illustration of the species dominating the field and consequently the species comprising the seed bank. This species information is the basis for the best management strategies to control weed and invasive plant growth. Samples of plants were collected based on relative abundance throughout the field. Abundant species were collected and identified. The plants found are typical of reclaimed agricultural land in the Midwest. Table 2: Abundant plant species present in the field Common Name Johnson Grass Multiflora Rose Tall Fescue Canada Goldenrod Reed Canary Grass Timothy Grass Species Name Sorghum halepense Rosa multiflora Festuca arundinacea Salidago canadensis Phalaris arundinacea Phleum pratense 7
Recommended Implementation Plan 1. Site Preparation Proper and thorough site preparation is the most important step in a prairie development. The removal of pre-existing, non-favorable vegetation is necessary for the successful planting of a prairie. Currently, the grass field site is mostly composed of non-natives, invasives and unfavorable plants. There are a few favorable species present in small, scattered numbers throughout the field. However, these numbers are so scarce that preserving them by spot treating the abundant surrounding unfavorable plants would be a waste of labor and time. Further, this method would likely cause many of the unfavorable plants to escape treatment. The failure to successfully eradicate non-native or invasive plant species will likely result in a noxious weed population boom during the development stages of the prairie. Pressure from weed competition can potentially devastate the success of a prairie planting. It is mandatory that all invasive and nonnative species are fully eradicated before re-planting the land with prairie seed. In order to thoroughly clear the field of all pre-existing vegetation, we recommend a glyphosate-based herbicide for use over the 12-acre site. Due to the close proximity of the site under development to the headwaters of the Jordan River, we highly recommend that an aquatic-safe compound is used, such as Rodeo, AquaMaster, or AquaPro. We suggest applying the herbicide three times over a two-month period, preferably in the late summer to early fall (between August 1st and September 30 th ). Application should occur on a sunny day with little to no chance of precipitation. If the sunlight is intense, it will cause the glyphosate (the active ingredient) to photo-degrade within one day. Rain will increase the amount of chemical runoff and can potentially reduce the success of the eradication. Herbicide application in the late summer will take advantage of the natural plant behavior of distributing carbohydrates and nutrients to roots for winter storage. In this case, glyphosate will be absorbed through the leaves and be distributed to the roots of the weeds, causing both the above and belowground biomass to expire. Two weeks after the final herbicide treatment, the field should be completely barren of vegetative life. The remaining detritus should be removed from the site using hay-baling equipment. Any remaining vegetation should be removed by hand. Weeds should be pulled manually as soon as they are spotted until winter. The site should be checked before seeding to determine the status of the pre-existing field vegetation and to ensure that noxious weed growth has not re-emerged. If the field is relatively bare of vegetation, proceed to ordering seed. Otherwise, hand-pull any remaining weeds. 2. Seed List We recommend purchasing prairie seed mixes from a nursery that produces local genotype seeds. This means that the seeds in production are collected from the native remnant prairies of northern and central Indiana. Spence Nursery is an example of an excellent source for prairie seeds in the Bloomington region. They carry source- 8
identifiable local genotype seeds from Indiana. Their catalog can be accessed through www.spencenursery.com. We developed a prairie seed mix specifically for the given site with the help of EcoLogic, Bloomington-based restoration specialists. This mix is based on the results from our soil sampling, where we identified the soil type and the soil moisture content (see table 1). The following forbs and grasses form a short- rather than tall-grass prairie. We recommend a short-grass prairie because we believe that it will be more aesthetically pleasing in a university setting. Customized seed list Forbs Scientific Name oz/acre lbs Price Nodding Wild Onion Allium cernuum 1.8 1.3 $118 Common Milkweed Asclepias syriaca 2.0 1.5 $113 Butterflyweed Asclepias tuberosa 3.0 2.3 $506 Sky-Blue Aster Aster azureus 2.0 1.5 $180 Smooth Aster Aster laevis 1.3 0.9 $169 White False Indigo Baptisia leucantha 2.0 1.5 $135 Wild Senna Cassia hebecarpa 2.0 1.5 $180 Prairie Coreopsis Coreopsis palmata 0.8 0.6 $68 Tall Coreopsis Coreopsis tripteris 0.5 0.4 $113 Pale Purple Coneflower Echinacea pallida 2.0 1.5 $113 Purple Coneflower Echinacea purpurea 4.0 3.0 $90 Rattlesnake Master Eryngium yuccifolium 1.5 1.1 $101 Blue Mist Flower Eupatorium coelestinum 0.5 0.4 $540 Dense Blazing Star Liatris spicata 3.0 2.3 $675 Bergamot Mondarda fistulosa 0.5 0.4 $68 Wild Quinine Parthenium integrifolium 2.0 1.5 $338 Smooth Penstemon Penstemon calycosus 1.5 1.1 $135 Foxglove Penstemon Penstemon digitalis 3.0 2.3 $169 9
Purple Prairie Clover Petalostemum purpureum 4.0 3.0 $135 Prairie Phlox Phlox pilosa 0.5 0.4 $84 Obedient Plant Physostegia virginiana 1.5 1.1 $338 Common Mountain Mint Pycnanthemum virginianum 1.5 1.1 $253 Yellow Coneflower Ratibida pinnata 1.5 1.1 $51 Showy black-eyed susan Rudbeckia fulgida speciosa 2.0 1.5 $225 Sweet black-eyed susan Rudbeckia subtomentosa 2.0 1.5 $113 Royal Catchfly Silene regia 0.5 0.4 $338 Rosinweed Silphium integrifolium 1.0 0.8 $68 Compass Plant Silphium laciniatum 2.0 1.5 $225 Prairie Dock Silphium terebinthinaceum 2.0 1.5 $450 Stiff Goldenrod Solidago rigida 2.0 1.5 $225 Showy Goldenrod Solidago speciosa 2.0 1.5 $338 Ohio Spiderwort Tradescantia ohiensis 2.0 1.5 $338 Hoary Vervain Verbena stricta 1.3 0.9 $56 Culver's Root Veronicastrum virginicum 0.8 0.6 $169 Grasses Scientific Name lbs/acre lbs Little Bluestem Andropogon scoparius 3.0 36.0 $540 Side-Oats Grama Bouteloua curtipendula 2.0 24.0 $288 Canada Wild Rye Elymus canadensis 2.0 24.0 $240 Virginia Wild Rye Elymus virginicus 1.0 12.0 $1,080 Switch Grass Panicum virgatum 0.5 6.0 $60 Prairie Dropseed Sporobolus heterolepis 0.5 6.0 $1,800 10
Total cost $11,219 3. Planting the Prairie The best time to seed prairies is after November 1 st (dormant seeding) or in early spring. We recommend seeding the prairie mix in November so forb seeds will undergo coldmoist stratification. This process will give them an advantage over the grass species in the first growing season. The seeds should be planted by using a no-till seed drill. The no-till seed drill will plant the seeds in a way such that they are randomly distributed so grasses and forbs are mixed together. Because this drill will not till the soil, there is little concern for erosion. However, because the site is on a minor gradient, there is concern that seeds might wash down-slope. To prevent this, placement of a photo-degradative erosion blanket could be used to mitigate loss of seeds. We recommend an alternative to the erosion blanket: to increase the number of seeds planted, which should guarantee that enough will remain in the original site of planting to grow. We also recommend hiring an ecological restoration company to access no-till equipment. Specifically, we recommend using the services of EcoLogic. 4. Maintenance The first year of the prairie will require monthly mowing of the site to roughly 4-6 inches. This will reduce competition from weeds while the favored prairie plants are establishing. Mowing will cause little damage to the prairie species because they tend to increase underground biomass before above-ground. Through June, July and August the prairie will need to be monitored weekly for weed growth. A list of common invasive species is located in table 2. Identifying these weeds will require trained maintenance because the weeds should not be allowed to become fully grown, thus do not have easily identifiable characteristics. Invasive monitoring should occur once a month for the first growing season. It is extremely important that the prairie is maintained diligently during the first five years of development. In the second year the prairie should include the same weed maintenance, but will only require one mow to 4-6 inches. The mowed material should be raked off to allow sunlight to the prairie seeds. The third and fourth years of the prairie development will both include prescribed burns during early April or March. This disturbance method will favor forb growth over grasses. Regular weeding should take place until after the fifth year. The prairie should then be burned every three years. During years between burns the prairie should be mowed to 4-6 inches in early spring. 11
Works Cited Many of these citations are not referenced in-text, since the information collected was through personal interviews conducted throughout the summer internship. 1. Blumenthal D.M. Jordan N.R. Svenson E.L. 2005. Effects of Prairie Restoration on Weed Invasions. Agriculture Ecosystems & Environment 107(2-3):221-230. 2. Busse, M.D., Ratcliff, A.W., Shestak, C.J., Powers, R.F. 2001. Glyphosate Toxicity and the Effects of Long-Term Vegetation Control on Soil Microbial Communities. Pacific Southwest Research Station, CA. 3. Dorsett, Michael. Personal interview. 10 July 2009. 4. Goehl, Spencer. Personal interview. 4 August 2009. 5. Heavy Metal Soil Contamination. USDA. NRCS. 2000. Soil Quality - Urban Technical Note 3. <ftp://ftp-fc.sc.egov.usda.gov/il/urbanmnl/appendix/u03.pdf>. 6. Indiana University Sustainability Report. 2008. Indiana University, Bloomington. 7. Kaufman, Sylvan R., Kaufman, Wallace. 2007. Invasive Plants: A Guide to Identification, Impacts and Control of Common North American Species. Stackpole Books, PA. 8. Middleton, Elizabeth. Personal interview. 16 July 2009. 9. Packard, Steven and Mutel, Cornelia F. 2005. Tallgrass Restoration Handbook: For Prairies, Savannahs, and Woodlands. Island Press. 10. Powers, Rachel. Personal interview. 12 August 2009. 11. Schultz, Peggy. Personal interview. 7 July 2009. 12. Symstad, Amy J. 2008. Does Biodiversity-Ecosystem Function Science Apply to Prairie Restoration? Ecological Restoration. 13. Tungsevick, Kevin. Personal interview. 12 August 2009. 14. Wilson, Scott D. and Gerry, Ann K. 1995. Strategies for Mixed-Grass Prairie Restoration: Herbicide, Tilling, and Nitrogen Manipulation. Restoration Ecology 3 (4):290-298. 12