Establishment of the Woody Grass Arundinaria gigantea for Riparian Restoration Adam J. Dattilo1 and Charles C. Rhoades2,3 Abstract manure, applied at a rate that contributed a similar Canebrakes are dense stands of Arundinaria gigantea mass of organic matter as the hardwood mulch, also sig- (Walt.) Muhl. that covered large areas of the southeastern nificantly increased new culm number and clump area. North America. With agricultural development, cane- Our findings demonstrate that addition of manure or brakes were quickly converted to crop and pastureland hardwood mulch can significantly enhance aboveground and now occur only in small, isolated patches. There is production of A. gigantea transplants. However, survival growing interest in the use of A. gigantea and other and initial growth of untreated clumps were also ade- temperate bamboo species in riparian and floodplain quate in this study. It appears that careful site selection, revegetation in North America, but lack of detailed transplantation, and site maintenance may be sufficient information on propagation and management of woody to ensure A. gigantea establishment on many sites. perennial grasses hinders reestablishment activities. Our Practitioners should assess soil drainage, water stress, study assesses the influence of nutrient and woodchip and fertility along with herbaceous competition and mulch amendments on survival and growth of A. gigantea incidence of overbank flooding before determining the transplanted as part of a riparian restoration project in necessity of organic amendments to supplement establish- central Kentucky. After two growing seasons, culm ment of A. gigantea or other woody grasses for riparian number (aboveground stems) increased 4-fold and extent restoration. of transplanted clumps expanded 26-fold. The survival rate of transplanted cane clumps was 98%. Hardwood Key words: bamboo, buffer zone, canebrake, filter strip, chip mulch significantly increased the emergence of new floodplain forest, giant cane, organic and inorganic fertil- culms, culm height growth, and clump area. Composted izer, wood chip mulch. Introduction Arundinaria gigantea (Walt.) Muhl., commonly known Restoration of degraded riparian forest improves terres- as giant or river cane, is the only bamboo species native to trial and aquatic wildlife habitats, enhances stream aes- the United States (Marsh 1977). Arundinaria gigantea thetics, reduces streambank erosion, and protects water occurs from Florida to eastern Texas, and to the north from quality through stream corridor revegetation (Manci 1989; southeastern Missouri to Virginia (Marsh 1977; Judziewicz FISRWG 1998). Woody perennial grasses can help achieve et al. 1999). Canebrakes (dense stands of A. gigantea)cov- these goals because of their rapid growth, compact stem ered vast areas of southeastern North America prior to and root morphology, and resprouting ability. Grasses European settlement (Campbell 1985; Platt & Brantley belonging to the subfamily Bambusoideae and other 1997). In central Kentucky, one canebrake was reported to perennial species (e.g., Vetiver grass [Vetiveria zizanoides; be ‘‘15 miles [24 km] long and nearly half as wide’’ (Rodgers subfamily Andropogoneae]) are commonly used for soil 1790 in Campbell 1985). Canebrakes were most common erosion control and streambank stabilization throughout on floodplain terraces where they occurred beneath sparse the wet, humid, and semiarid tropics (Rocheleau et al. forest canopies; they also occurred within canopy openings 1988; Young 1989; National Research Council 1993). in upland forest and savannas (Farrelly 1984; Campbell Recently, practitioners and researchers have begun to 1985; Platt & Brantley 1997). Large canebrakes soon disap- test the utility of temperate bamboos for riparian revege- peared following introduction of European agriculture and tation in eastern (Harker et al. 1999; Cirtain et al. 2004; the demise of Native Americans and their traditional burn- Schoonover & Williard 2004) and northwestern (Miles ing patterns (Platt & Brantley 1997). Though cane still 1998; Diver 2001) North America. grows in small patches throughout its range, canebrakes approaching the size of those observed prior to European settlement are rare. Owing to extensive loss, A. gigantea 1 Mammoth Cave National Park, P.O. Box 7, Mammoth Cave, KY 42259, U.S.A. canebrakes (85–98%) have been designated an endangered 2 US Forest Service, Rocky Mountain Research Station, 240 W. Prospect, Fort Collins, CO 80526, U.S.A. ecosystem (Noss et al. 1995) and are a priority for conserva- 3 Address correspondence to C. C. Rhoades, email [email protected] tion and restoration (Platt et al. 2001). Ó 2005 Society for Ecological Restoration International Structural attributes of riparian canebrakes provide No claim to original US government works wildlife habitat and benefit water quality. The high stem 616 Restoration Ecology Vol. 13, No. 4, pp. 616–622 DECEMBER 2005 Woody Grass Establishment for Riparian Restoration density of A. gigantea canebrakes creates a habitat for by tall fescue (Festuca arundinacea). The remnant forest is a wide array of mammals, birds, reptiles, and insects restricted to a 10- to 30-m-wide streamside zone (Dattilo (Meanley 1972; Eddleman et al. 1980; Kilgo et al. 1996; 2003). These forests are dominated by American syca- Thomas et al. 1996) including several cane-dependent more (Platanus occidentalis) and Black walnut (Juglans species (Remsen 1986; Platt et al. 2001). This high culm nigra), with Ohio buckeye (Aesculus glabra) and Eastern density (16–26 culms/m2) and rapid lateral spread and redbud (Cercis canadensis) in the midstory and Coralberry height growth (up to 6 m/year and 8 m/year, respectively; (Symphoricarpos orbiculatus), Spicebush (Lindera ben- McClure 1973; Marsh 1977) also make A. gigantea a logical zoin), and Pawpaw (Asimina triloba) in the shrub layer species of choice for streamside buffer zones. Arundinaria (Homoya 1999; Dattilo 2003). In addition to tall fescue, gigantea’s compact network of rhizomes benefits aquatic the non-native species multiflora rose (Rosa multiflora), resources through streambank stabilization, sediment Japanese honeysuckle (Lonicera japonica), and Japanese retention, and bioaccumulation of nutrients and toxins stilt grass (Microstegium vimineum) are abundant at the (Welsch 1991; Geyer et al. 2000; Lee et al. 2003). For study site. Arundinaria gigantea grows in dense patches example, plant nitrogen uptake and microbial denitrifica- (<500 m2) scattered in forested valley bottoms and slopes tion reduce groundwater nitrate in A. gigantea plantings in along Hart’s Run. riparian zones in southern Illinois (Schoonover & Williard The study was conducted within a hay meadow, 20–30 m 2003). away from a narrow streamside forest. Ordovician lime- Though mature canebrakes are characterized by rapid stone and alluvium underlay the floodplain study site. Soils culm growth, the survival of transplanted A. gigantea at the planting site have moderate water-holding capacity varies widely (Feeback & Luken 1992; Platt & Brantley and soil fertility and are classified as fine-loamy, mixed, 1993), and slow growth may continue for several years mesic, Dystric Fluventic Eutrochrepts (Whitaker & Waters (Cusak 1999). Nutrient addition is recommended as a strat- 1986). Surface mineral soils (0–10 cm) contain 1–3% egy to accelerate aboveground production following trans- organic matter and 18–35% clay and have a mean pH of plantation (Hughes 1951; Feeback & Luken 1992; Bell 6.0. Soils vary from poorly drained to well drained. 2000), but field-level effectiveness of fertilization has not Groundwater in poorly drained sites saturates rooting been demonstrated. The utility of A. gigantea for stream- zones for prolonged periods during winter months; such bank stabilization and riparian corridor restoration is cur- sites are characterized by abundant crayfish burrows and rently limited by the lack of transplantation methods that wetland indicator plants. have been proven to minimize establishment failure. This study provides a replicated field-scale test of the response of A. gigantea to hardwood mulch and to organic Experimental Treatment and inorganic fertilizer amendments applied at the time of Inorganic or organic fertilizer, with or without hardwood transplantation. We quantify cane survival and growth over mulch, was applied to cane transplants to evaluate the two growing seasons to assess how the response to mulch influence of nutrients and moisture on initial A. gigantea and fertilizer, singly or in combination, differs between survival and growth. We transplanted cane in March 2002 treated and untreated transplants. This research contrib- (see details below) and applied amendments later that utes specific information regarding establishment techni- year, during the first growing season. Inorganic fertilizer ques for woody, clonal grasses and complements efforts to (196 kg N/ha, 66 kg P/ha, and 168 kg K/ha) was applied to formulate recommendations for regional stream corridor the base of each clump on three occasions (May, June, restoration. and September 2002). The fertilizer rate was based on gra- minoid forage recommendations following evaluation of total soil nitrogen and exchangeable phosphorus and Methods potassium (University of Kentucky Regulatory Services Soil Testing Lab, Lexington, KY, U.S.A.). We compared Site Description two applied rates of composted cow manure: (1) equiva- The riparian restoration study is located at the Bernheim lent to the nutrient