GIANT CANE RESTORATION
Giant Cane, (Arundinaria gigantea), is also commonly referred to as River Cane. It is the only species of bamboo native to North America. Historically large, extensive stands of giant cane were found throughout the southeastern United States. These areas, termed canebrakes, were a dominant feature of the southeastern frontier landscape. Since that time canebrakes have undergone a decline of over 98% in many areas. This decline is probably the result of overgrazing, altered burning practices and land clearing. Large canebrakes are now rare to nonexistent in most areas where they formerly occurred, and cane exists only as an understory plant in these areas. Many biologist consider canebrakes to be a critically endangered ecosystem. Giant cane has not been studied extensively and many aspects of its reproductive biology, and its role in the greater ecosystem of the southeast, is relatively poorly understood.
Ecological Importance of Canebrakes
Canebrakes also provide valuable habitat for wildlife. Historical accounts, along with modern surveys, identify at least 21 mammal species, 16 bird species, 4 reptile species, and over 20 species of butterflies and moths are found within canebrakes . It is likely that there are many additional species which also use canebrake habitat. The decline of canebrakes may have contributed to the loss of the Carolina parakeet, passenger pigeon, and Bachman warbler . Several butterflies and moths feed exclusively on river cane and are now listed as endangered species. Swainson’s Warbler is often found in thickets of giant cane, and some researchers have suggested that the decline of canebrakes has contributed to the rarity of this species.
Canebrakes have been shown to be effective buffers along streams and rivers, trapping sediments and nutrients from agricultural and other surface runoff. On-going studies at Southern Illinois University show that a mature canebrake (30 year-old) was found to reduce groundwater nitrates, reduce nutrients in surface runoff and reduce sediments by 100% within a 10 m buffer of the stream. In all cases, the canebrake was a more effective buffer than the adjacent forest. Velocity of runoff water decrease dramatically when entering a canebrake, allowing water to infiltrate the soil and sediments to deposit. The extensive root/rhizome structure of a mature canebrakes also provides an effective soil stabilizer along waterway a well.
Researchers at Southern Illinois University have been working with giant cane extensively for several years. In cooperation with the joint venture partners, SIU researchers have been working to develop a restoration method that is inexpensive and uses easily obtained materials to aid re-establishment of canebrakes.
Several characteristics of cane make transplanting difficult. Cane flowers infrequently and, even when it does, seed production is inconsistent therefore there is not a reliable seed source. Addition, if seedlings develop, they are often fragile and grow slowly, taking years to mature. Giant cane does often sprout new growth and spread my use of underground stems, termed rhizomes.
A variety of techniques have been tested for canebrake restoration. The most successful methods so far have been planting either bare rhizomes or planting seedlings cultivated in a greenhouse from bare rhizomes. Spring plantings have been most successful. Significant new growth usually takes an additional two to three years to re-establish. These methods require an abundant source of mature plants from an established location that can be dug up for rhizomes to be transplanted.
Cypress Creek N.W.R. has planted approximately 8 acres of cane on the refuge at 5 different restoration sites. Rhizomes used were dug from 8 different sources. Sources for propagules were restricted to canebrakes on federally owned property. Mixing cane from different genetic backgrounds in the plantings will hopefully improve survival chances for the new populations.
Across the southeast many resource management professionals are now interested in re-establishment of canebrakes. In October 2008 a workshop on giant cane restoration was held at the Cache River Visitor Center. Over 50 researchers and management professionals, from 5 different states were in attendance.
Canebrake restoration is a continuing effort in the Cache river watershed and an ongoing focus of research at Southern Illinois University.