Because of the importance of the Central Valley of California to shorebirds along the Pacific Flyway, considerable conservation investments have been made in the area’s agricultural fields and managed wetlands. Through their BirdReturns and Bid4Birds programs, The Nature Conservancy and the California Ricelands Waterbird Foundation pay rice farmers to flood fields to decompose post-harvest rice thatch and, in doing so, create habitat for shorebirds. Previous research by CBI and The Nature Conservancy researchers found that shorebird density (birds/hectare) increased with earlier fall flooding and in fields managed to be approximately 50% flooded, 5-10 cm deep, and with minimal straw or stubble cover in fall. Lower soil clay content and flooding consistency – either at a site that is continually flooded over many months or a site that has been flooded in previous years – was also associated with higher shorebird density. Finally, the team found preliminary evidence that fields flooded by groundwater, instead of surface water, were associated with higher shorebird density. These findings are important for guiding continued shorebird management in agricultural landscapes.
Combining the five years of data on shorebird abundance used in the original study with an additional five years of more recent data, we are going to expand our preliminary analysis on the importance of water source on shorebird abundance. Specifically, we are going to explore whether more shorebirds are found in fields flooded with surface water versus groundwater. Assuming that shorebirds prefer groundwater in the expanded analysis, our next priority is to explore why, where our first hypothesis is water quality. Using a number of public resources that sample groundwater quality (nitrates, sodium, and arsenic) and surface water quality (pH, turbidity, temperature, conductance, and dissolved oxygen), we will explore whether shorebird abundance is associated with any of these water metrics. Determining the best practices for habitat creation in agricultural landscapes is critically important for conservation and recovery of declining shorebird populations.
Project Details
Location
Date
Services Provided
Conservation Planning & Management
Scientific Research & Modeling
Spatial Analysis & Mapping
