Harvested rice fields provide critical foraging habitat for wintering waterfowl in North America, but their value depends upon post-harvest treatments. We visited harvested ricefields in the Sacramento Valley, California, during the winters of 2007 and 2008 (recent period) and recorded their observed status as harvested (standing or mechanically modified stubble), burned, plowed, or flooded. We compared these data with those from identical studies conducted during the 1980s (early period). We documented substantial changes in field status between periods. First, the area of flooded rice increased 4-5-fold, from about 15% to >40% of fields, because of a 3-4-fold increase in the percentage of fields flooded coupled with a 37-41% increase in the area of rice produced. Concurrently, the area of plowed fields increased from <22% to >35% of fields, burned fields declined from about 40% to 1%, and fields categorized as harvested declined from 22-54% to <15%. The increased flooding has likely increased access to food resources for wintering waterfowl, but this benefit may not be available to some goose species, and may be at least partially countered by the increase of plowed fields, especially those left dry, and the decrease of fields left as harvested.We encourage waterfowl managers to implement a rice field status survey in the Sacramento Valley and other North American rice growing regions as appropriate to support long-term monitoring programs and wetland habitat conservation planning for wintering waterfowl.
Additional publication details
Changes in the status of harvested rice fields in the Sacramento Valley, California: Implications for wintering waterfowl.