Population viability of piping plovers: Effects of predator exclusion

The Great Plains population of piping plovers (Charadrius melodus) is listed as threatened or endangered and continues to decline. The effects of recently initiated management to exclude predators and a new, higher estimate of adult survival on the extinction risk of this population have not been evaluated. We estimated fledging success rates and revised a stochastic simulation model of plover demography to simulate population growth scenarios. Fledging rates without predator exclusion were 0.89 (SE = 0.10) fledglings/pair at alkaline wetlands and 0.73 (SE = 0.21) fledglings/pair at rivers and reservoirs. Predator exclusion increased local fledging rates to 1.15-2.25 fledglings/pair. Simulated population growth under current levels of management was -4.3%/year, which was higher than indicated by previous models but lower than indicated by international censuses in 1991 and 1996. A population-wide fledging rate of 1.10 fledglings/pair was needed to stabilize simulated populations. Our results indicate that the Great Plains population of piping plovers can be stabilized or increased if management activities to improve reproductive success are increased.