EXAMINING METHODS TO RESTORE AND REHABILITATE NATIVE CANEBRAKE HABITAT IN SOUTHERN ILLINOIS

Giant cane (Arundinaria gigantea) is a native bamboo that forms large monodominant stands called canebrakes in bottomlands in the southeastern US. Canebrakes are valuable habitat for wildlife and function as riparian buffers to protect soils and water quality. Currently, only 2% of canebrake ecosystems remain. Thus there is interest in establishing new canebrakes as well as maintaining and expanding existing canebrakes. For field restoration, using cane rhizomes to produce transplants is possible but it is unknown when propagules should be collected and grown. For rehabilitation of existing canebrakes, preliminary studies suggest that fertilization and disturbance such as fire can be beneficial but additional broader-ranging studies are warranted. This research reports on three giant cane studies involving producing transplants from rhizomes and involving managing existing canebrakes with disturbance in southern Illinois. The main objectives of study 1 were to ascertain a) if collection season influences the proportion of rhizome propagules that grow at least one culm (culm production success) and the resultant culm growth when transplanted in a greenhouse b) if specific rhizome characteristics influence an individual rhizome’s ability to produce a culm c) if aboveground biomass could be a predictor of the amount of belowground propagules and d) if aboveground biomass, total rhizome length, number of rhizome nodes, or number of rhizome buds could be a predictor of how many culms could be produced when transplanting. Monthly, for a year, sample plots were randomly selected in the SIUC giant cane nursery. In sample plots aboveground culm measurements were collected included live culm density (#/0.25m2), dead culm density (#/0.25m2), height of the tallest culm (cm), diameter of the tallest culm (mm), and total aboveground biomass (g). Each month rhizomes were dug from the sample plots, measured (length (cm), diameter (mm), # nodes, and # live buds), and transplanted into pots and placed in the greenhouse for approximately 94 days. At that time, measurements were taken of the number of live and dead culms produced per pot and the height of the tallest culm (cm). Results indicate that rhizomes collected and transplanted in the greenhouse during winter and spring months (December-May), had significantly greater culm production success and produced significantly taller culms. Also, rhizomes intermediate in length (18-30 cm) that contained 5 to 12 nodes and 4 to 9 live buds tended to have higher than average culm production. Finally, a positive correlation existed between the amount of aboveground biomass and the number of rhizome nodes, the number of live rhizome buds, and the length of rhizomes found in sample plots. Aboveground biomass can predict the amount of belowground rhizome propagules that can be used for canebrake restoration. Study 2 is a two year continuation of work initiated in 2011 and reported on by Margaret Anderson in 2014 on the effects of fire, fertilization, and fire and fertilization combined on the growth and expansion (culm density, height and diameter) of canebrakes within the Cache River Watershed in southern Illinois. Results showed considerable year to year variability among treatments within the canebrake for some growth parameters. However, three years after disturbance, all treatments tended to have similar culm density and growth values and canebrake expansion occurred for all treatments into exterior plots. Fire alone was similar to controls in growth parameters and did not produce any long-term negative effects. Thus, fire can be used as an effective tool to reduce competition from other species, allowing managed canebrakes to persist longer than those that remain undisturbed. Fertilization used alone and in combination with fire, produced slight growth and density increases, but added costs may not warrant its use in canebrake management. Study 3 compared fire and mowing disturbances on the growth and expansion of remnant canebrakes located in southern Illinois. Eleven replications in remnant canebrakes were established throughout the Cache River watershed. Each replication contained a fire only treatment, a mowing only treatment, and a control. Measurements were taken in the dormant season early in 2012 prior to a single mowing and a single fire in March, and after each growing season thru 2014. Measurements including live and dead culm density (#m2), culm height (cm), and culm diameter (0.01 mm), were taken within subplots in the canebrake interior and exterior. Results from this study showed that mowing can be used as an effective alternative to fire for the management of remnant canebrakes through reductions in competition. Neither fire nor mowing produced negative effects of growth within the measured canebrakes or in adjacent areas. Like the previous study, all treatments including the control experienced an outward expansion of cane culms throughout the course of the study. This study shows that both fire and mowing can be used as effective tools to reduce competition within canebrakes to aid in their continued vigor