Restoration of floodplain landscapes: Analysis of physical process and vegetation dynamics in the Central Valley of California

The efficient management of a region's water and floodplain resources may determine the short- and long-term well-being of human communities and their surrounding environments. Formulation and evaluation of alternative development paths for water management strategies and ecological restoration are key steps in the landscape planning process addressing both management and conservation priorities. In this dissertation I present analyses that quantify vegetation patterns at multiple spatial scales emphasizing emergent patterns at the landscape scale. Special attention is placed on understanding how changes in the physical processes can be used to predict species responses over long time periods (+50 years).; My research links information on quantitative fluvial geomorphology and historical river channel migration patterns with ecological data to guide landscape planning and management of flood-prone areas. I ask: (a) how can gradient and patch hierarchy analysis be applied to the restoration of riparian vegetation; (b) how do river channel migration patterns affect adjacent ecosystems through disturbance and habitat formation; and (c) how do channel constraints and flow regulation affect landscape patterns and processes through river channel migration.; In Chapter 1, I integrate local and landscape scale variables to understand the distribution of blue elderberry (Sambucus mexicana). The results were applied in the restoration of elderberry in the Central Valley within the fluvial landscape. Chapter 2 constructs an empirical relationship between cumulative effective stream power and bank erosion on the Sacramento River, California. The relationship has been used to advise a mechanistic model of river channel migration that incorporates variable flow. Chapter 3 uses a river meander migration model to test the impact of a proposed off-stream storage unit on channel migration and subsequent vegetation recruitment. This chapter proposes a range of channel migration rates and processes necessary to dynamically maintain ecological diversity within the riparian corridor.; As a body of research this dissertation links quantitative fluvial geomorphology and landscape ecology to help explain riparian patterns and processes on large alluvial rivers. Models quantify emergent properties of the system, such as river channel migration and riparian forest dynamics, and apply them to test alterative development schemes aimed at integrating conservation and human well-being.