Can river management improve the piping plover's long-term survival on the Missouri River?

The goal of many animal conservation efforts is to improve short-term demography, but there is growing interest in the potential for producing more fit individuals, resulting in long-lasting demographic impacts. The environments that animals experience prior to independence from their parents can have profound, life-long effects on individual fitness and population demography that managers can potentially exploit. Environmental variables can affect fitness directly through early mortality, delayed maturity, reduced probability of recruitment, decreased fecundity, or a combination of these factors. We studied the imperiled piping plover (Charadrius melodus) nesting on the Missouri River to determine if body condition affected their long-term survival, and, if so, whether these factors could be used to improve conservation and management. We captured and measured adult and hatchling piping plovers during the breeding season (April-August, 2005-2012) to obtain measures of condition (mass, wing-chord length, culmen length). We assessed the effect of environmental variables on plover growth, and the effect of chick condition at fledging on subsequent survival as an adult. Plover chicks grew faster and achieved larger body size if they hatched earlier in the season, were exposed to lower density, and were hatched in higher quality habitat compared to other chicks. Plovers that were heavier at fledging had a higher survival rate (as much as 9%) than lighter plovers during their first year as well as in subsequent years, which could make a significant impact on population viability and an individual's lifetime fitness. Where the factors that affect development are manageable, they offer an opportunity for conservation to capitalize on these long-term effects. For example, habitat creation, restoration, and protection projects should ensure that adequate food resources are available or created not only to maximize reproductive output, but also to improve the condition of offspring where possible.