Effects of surrounding land use on playa inundation following intense rainfall

Many isolated wetlands that fill by rainfall, such as playas, have been affected by sedimentation in heavily modified agricultural landscapes. Conservation plantings and buffers reduce sedimentation in wetlands but also may reduce the frequency of inundation. We studied the effects of surrounding landcover on the responses of playas in southwestern Nebraska to heavy rain events using aerial photography, ground surveys, and GIS landscape analyses. Using a generalized linear mixed model, we found that playas in rangeland were more likely to become inundated than playas in cropland, and both were more likely to become inundated than playas in fields enrolled in USDA's Conservation Reserve Program (CRP), typified by tall, dense grasses. Inundation was also positively related to rainfall amount and playa size. Our results highlight the significance of maintaining playas in native prairie and underscore the importance of planting and managing appropriate mixes of native shortgrass and/or mixed-grass prairie species surrounding playas to mimic the vegetative structure of native prairie. In light of historic wetland losses, a reduction in the probability of flooding for individual playas in CRP must be weighed against the protection from sedimentation that buffers afford wetlands in cropland and other beneficial influences of CRP in the landscape.