title: Metapopulation viability of an endangered shorebird depends on dispersal and human-created habitats: piping plovers (Charadrius melodus) and prairie rivers.
abstract: BACKGROUND
  Many species are distributed as metapopulations in dynamic landscapes, where habitats change through space and time. Individuals locate habitat through dispersal, and the relationship between a species and landscape characteristics can have profound effects on population persistence. Despite the importance of connectivity in dynamic environments, few empirical studies have examined temporal variability in dispersal or its effect on metapopulation dynamics. In response to this knowledge gap, we studied the dispersal, demography, and viability of a metapopulation of an endangered, disturbance-dependent shorebird. We examined three subpopulations of piping plovers (Charadrius melodus) on the lower Platte and Missouri rivers from 2008-2013. High flow events from an upstream dam on the Missouri River in 2010 and 2011 allowed us to assess the effect of total habitat loss and the subsequent creation of new habitat associated with a large disturbance at one 'natural' study location. The other two sites within the metapopulation, which were maintained by anthropogenic activities (e.g., mining, development, habitat restoration), were largely unaffected by this disturbance, resulting in a controlled natural experiment.
  
  
  RESULTS
  High flow events were associated with increased emigration, decreased immigration, and decreased survival in the subpopulation that experienced high flows. Following the high flow event, immigration into that subpopulation increased. Dispersal rates among subpopulations were negatively correlated with distance. The metapopulation had a low probability of extinction over 100 years (0 %) under the current disturbance interval and associated dispersal and survival rates. However, persistence depended on relatively stable, human-created habitats, not the dynamic, natural habitat (47.7 % extinction probability for this subpopulation).
  
  
  CONCLUSIONS
  We found that functional connectivity, as measured by the rate of dispersal among subpopulations, increased as a result of the high flow event in our study metapopulation. Plovers also increased reproductive output following this event. Although the study metapopulation had a low overall probability of extinction, metapopulation persistence depended on anthropogenically created habitats that provided a small but stable source of nesting habitat and dispersers through time. However, all subpopulations remained small, even if persistent, making them individually vulnerable to extinction through stochastic events. Given the highly dynamic nature of habitat availability in this system, maintaining several subpopulations within the metapopulation and stable sources of habitat will be critical, and this species will likely remain conservation-reliant.
authors.affiliation: Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA 24061 USA.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Catlin
authors.affiliation: U.S. Geological Survey, Woods Hole Coastal and Marine Science Center, Woods Hole, MA 02543 USA.
authors.forename: Sara L
authors.initials: SL
authors.lastname: Zeigler
authors.affiliation: School of Natural Resources, University of Nebraska, Lincoln, NE 68583 USA.
authors.forename: Mary Bomberger
authors.initials: MB
authors.lastname: Brown
authors.affiliation: Nongame Bird Program, Nebraska Game and Parks Commission, Lincoln, NE 68503 USA.
authors.forename: Lauren R
authors.initials: LR
authors.lastname: Dinan
authors.affiliation: Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA 24061 USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Fraser
authors.affiliation: Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA 24061 USA.
authors.forename: Kelsi L
authors.initials: KL
authors.lastname: Hunt
authors.affiliation: Nongame Bird Program, Nebraska Game and Parks Commission, Lincoln, NE 68503 USA.
authors.forename: Joel G
authors.initials: JG
authors.lastname: Jorgensen
keywords: Conservation reliance; Dispersal; Disturbance; Extinction; Population viability analysis; Recolonization; Rescue effect; Successional processes