Spatial variation in population dynamics of northern Great Plains piping plovers

Abstract

Metapopulation dynamics are determined not only by within-patch birth and death processes but also by between-patch movements of individuals (emigration and immigration). To conserve and manage a species that has a metapopulation structure, defined by local populations that are distributed among patches of suitable habitat, we need to understand each of these vital rates. For the federally listed northern Great Plains Charadrius melodus (Ord, 1824) (piping plover), managers assumed a metapopulation structure consisting of four breeding groups with low, balanced dispersal, which resulted in low extinction risk in a simulation-based viability study. The degree to which the northern Great Plains piping plover breeding population functions as a metapopulation depends on the rate of movement amongst breeding areas. Sources of variation in survival, dispersal probabilities, and dispersal distances were examined for hatch-year and adult piping plovers breeding in the northern Great Plains from 2014 to 2019 focusing on four management units (U.S. Alkali Wetlands, Lake Sakakawea, Garrison Reach of the Missouri River, and Lake Oahe). Additionally, renesting probabilities, renest reproductive success, and reproductive output were investigated from 2014 to 2016 in each of these areas to understand within-patch productivity. This report includes two major sections: (1) a presentation that includes the context, results, and implications of the study, followed by a detailed text methodology, and (2) an appendix that provides synthesized estimates of piping plover vital rates from throughout their range. River and alkali wetland habitats seem to be of higher quality than reservoir habitats, although alkali wetland habitats have lower annual survival, lower reproductive output, and lower fidelity probabilities than riverine habitats. Habitat availability drove dispersal probabilities and dispersal distances for hatch-year and adult piping plovers. Renesting propensity and renest reproductive success were generally low, suggesting that renesting is an uncommon and unproductive strategy to replace most lost reproductive attempts. Estimates indicated high connectivity between the U.S. Alkali Wetlands and the northern river units (Lake Sakakawea, Garrison Reach, Lake Oahe) of the Missouri River, suggesting that the assumed metapopulation structure and population viability may need to be reassessed.