The sustainable management of coupled social-ecological systems, such as water resource systems, requires institutional mechanisms for managing uncertainties and building more resilient social-ecological systems. Adaptive governance is an outcome of the search for a way to manage uncertainties and complexities within social-ecological systems. The concept of adaptive governance has emerged as a product of resilience theory and theoretical insights on common pool resources management. Adaptive governance refers to flexible multi-level institutions that connect state and non-state actors to facilitate a collaborative and learning-based approach to ecosystem management. As such, it has the potential to integrate social considerations into the decision process while also dealing with uncertainties in complex water resource systems. However, little is understood on how transitions toward adaptive governance systems take place and what criteria qualify a given institutional mechanism as an adaptive governance regime. This thesis presents results on a study that was aimed at understanding the process and outcomes of transitions toward adaptive water governance by using the Cache River Joint Venture Partnership (CRWJVP) within the Cache River Watershed in Southern Illinois as a case study. Qualitative data for the study were generated through key informant interviews among members of the CRWJVP and other knowledgeable actors, document review, and participant observation. The results revealed that the transformation of the governance of the Cache River watershed through the emergence of the CRWJVP was the result of ecological crises that began a citizen-led effort to preserve the Cache River wetlands. Additionally, the transition process was facilitated through trust-building, incentives, leadership, enabling legislation, and the role of bridging organizations. The results also showed that when compared to the attributes of an adaptive governance system, the current governance system of the Cache River watershed does not fully exhibit all the ideal attributes. However, the CRWJVP is moving towards an adaptive governance regime through the recent utilization of decision-making processes for recognizing and managing conflicts and uncertainties in the management of the watershed. Barriers in the transition process and recommendations for overcoming them are also discussed in the thesis. In all, findings from this study should be of relevance to scientists and decision-makers interested in understanding and enhancing transitions toward adaptive governance for the sustainable management of land and water resources in the Cache River watershed and elsewhere.

Exotic plant species pose a great risk to restoration success in post-agricultural bottomlands, but little information exists on their dynamics during early succession of actively restored sites. Compositional trends of exotic plants may be similar to those published for natives in other systems, with an early peak in herbaceous richness followed by a decline as woody species establish. I established 16 sites in an 18-year chronosequence (1991-2008) of restored forests, with an additional four mature sites for comparison, within the Cypress Creek NWR, Illinois. Within each site, I identified all vascular plant species and quantified soil texture, total soil C, total soil N, and canopy openness at three strata (1.5m, 1.25m, & 0.75m). Trends in exotic assemblages were significantly correlated with canopy openness at all strata (all p < 0.0001). Richness of exotic herbaceous species and native herbaceous species were related to stand age consistent with a non-linear Weibull regression model (R2 = 0.543, p = 0.005; R2 = 0.483, p = 0.013, respectively). Average percent herbaceous species cover also showed a similar reduction in overall abundance for both native and exotic plants but followed an exponential decay model (R2 = 0.3777, p = 0.0039; R2 = 0.3003, p = 0.0124, respectively). Woody native richness over time conformed to a logistic model (R2 = 0.404, p = 0.012). Woody exotic plants exhibited no discernible relationship with stand age, although they were in sites of all ages. My results indicate that herbaceous exotic species exhibit successional trends similar to natives and therefore may not pose a lasting threat to restoration projects in these floodplain forests. In contrast, woody exotic species can establish earlier or later in succession, persist under closed canopy conditions, and may pose a lasting threat. Thus, bottomland restorations and mature forests are quite vulnerable to exotic plants even after canopy closure.

Large stands of Arundinaria gigantea (Walt.) Muhl., called canebrakes, were vital to wildlife and lowland ecosystem functions and historically covered millions of acres in the southeastern United States. Since European settlement, human disturbance (i.e, clearing for agriculture and fire suppression) has caused giant canebrakes to become critically endangered ecosystems. Increasing evidence suggests the loss of canebrakes has directly impacted riparian ecosystems, resulting in increased soil erosion, poorer water quality, and reduced flood control. Cane's ecological importance has led to an increased interest in canebrake restoration in riparian zones. To examine the role that cane plays in nutrient cycling and to attempt to determine targeted restoration sites, a four phase research strategy was designed to determine physical and chemical properties of existing riparian stands of native giant cane and their associated soils. Phase one was a GIS analysis to determine what geographical features may be used in selecting sites within a landscape suitable for canebrake restoration. First, common physical site characteristics for 140 existing southern Illinois canebrakes were determined. Soil taxonomy and pH were used to represent soil characteristics and percent slope was used as a topographic metric. These factors, combined with digital elevation models and land cover in GIS were used to identify the potential suitability of sites within the watershed for canebrake plantings and general riparian restoration. The following soil characteristics were determined to be associated with giant cane success: percentage of area containing slopes of 3 percent or less, fine to coarse-silty textures, pH of 5.3 - 6.7, effective cation exchange capacity of less than 30 units, available water holding capacity greater than 0.12, bulk density of 1.37 - 1.65 g cm-3, and percent clay of 11 - 55. Eighty-percent of existing giant cane sites were found within these slope and soil characteristics. The total area of potential riparian canebrake landscapes based on these parameters is 13,970 hectares (35,600 acres) within the Cache River watershed. The remaining three phases examined the role that cane plays in nutrient cycling. Phase two determined the pools and cycling of nitrogen and carbon in canebrakes and compared those to nearby agricultural and forested riparian areas. Phase three quantified the N2O and CO2 fluxes from canebrakes and adjacent forested areas. Phase four included methods to quantify nutrient content of leaf litter and live leaves from existing canebrakes to estimate the nutrient use efficiency of cane. Further, a decomposition study was conducted to calculate the decomposition rate of cane leaves and to explore the litter quality attributes of giant cane. The primary purpose of phase two was to compare the effects of perennial riparian vegetation (giant cane and forest) and annual crops on soil quality, nitrogen cycling, and physical properties. This was to determine if any of them have a significant influence on giant cane distribution, while focusing on nitrogen dynamics to help determine why giant cane is a successful riparian buffer species. Five study sites in the Cache River watershed that had cane, agricultural fields (corn-soybean rotation), and forested areas adjacent to one another were selected. Data were collected on soil texture, carbon/nitrogen ratios, bulk density, nitrogen content (as ammonia and nitrate), and net nitrogen mineralization rates. The crop sites had significantly lower soil C:N ratios than both forest and cane (9.8:1 vs. 10.9:1 and 10.7:1, respectively), though all sites had ratios less than 25:1, indicating a tendency toward nitrogen mineralization. Forest soils had significantly higher rates of net mineralization than cane (19.0 μg m-2 day-1 and 6.6 μg m-2 day-1, respectively), with crop not significantly different from either cane or forest (8.0 μg m-2 day-1). Cane had higher levels of soil carbon and nitrogen when compared to forest and crop soils. Cane can be successful in wetter areas than previously thought, implying that the range of conditions that will support cane is broader than previously thought. Overall, there were few identifiable soil controls on giant cane distribution, or those that differentiate long-standing canebrakes from the nearby crop and forest land. For Phase three, nitrous oxide and carbon dioxide emissions were measured monthly for one year in riparian canebrakes and forests in southern Illinois to determine the rates of greenhouse gas (GHG) fluxes in bottomland riparian areas. Carbon dioxide emissions had a strong correlation with soil temperature (p < 0.001, r2= 0.54), but not with soil water content (p > 0.05), and were greater during the warmer months. Nitrous oxide emissions had a correlation with soil water content (p=0.470, r2 = 0.11), but no relation with soil temperature (p > 0.05), nor a difference across time. Vegetation type did not appear to influence GHG fluxes. Riparian CO2 and N2O emission rates were higher than documented cropland emissions, indicating riparian restoration projects to reduce NO3 delivery to streams may affect N2O and CO2 emissions resulting in an ecosystem tradeoff between water quality and air quality. Leaf deposition, N resorption efficiency and proficiency, and decomposition rates were analyzed in riparian stands of Arundinaria gigantea in southern Illinois for the first time in Phase four. Leaf litter was collected from five established canebrakes monthly over one year and a decomposition study was conducted over 72 weeks. Live leaves, freshly senesced leaves, and decomposed leaves were analyzed for carbon and nitrogen content. Leaf litterfall biomass peaked in November at twice the monthly average for all but one site, indicating a resemblance to deciduous leaf fall patterns. Nitrogen and carbon levels decreased 48% and 30%, respectively, between live leaves and 72 weeks decomposed. High soil moisture appeared to slow decomposition rates, perhaps due to the creation of anaerobic conditions. Cane leaves have low resorption proficiency and nutrient use proficiency, suggesting that these riparian canebrakes are not nitrogen limited. These results will help improve our understanding of the role that giant cane plays in a riparian ecosystem and help focus cane restoration efforts in southern Illinois.