Metapopulation viability of an endangered shorebird depends on dispersal and human-created habitats: piping plovers (Charadrius melodus) and prairie rivers

Abstract

BackgroundMany 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.ResultsHigh 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).ConclusionsWe 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s40462-016-0072-y) contains supplementary material, which is available to authorized users.

Demographic response of Piping Plovers suggests that engineered habitat restoration is no match for natural riverine processes

“…AHY true survival was lowest during the flood, which may be attributable to nonbreeding Piping Plovers exhibiting lower survival than breeding Piping Plovers (Catlin et al 2015, Weithman et al in press). With all sandbar habitat on the Gavins Point Reach inundated during the flood (2011), many individuals did not have the opportunity to breed, while others dispersed elsewhere (Catlin et al 2016), leading to the lowest AHY fidelity that we observed. Of those that moved to other breeding locations (the few sandbars that remained above water), many experienced catastrophic nest failure .…”

“…Moreover, lower densities were related to a higher proportion of double brooding , which may also increase reproductive output. Our results indicated that these fecundity parameters, coupled with increased immigration (Catlin et al 2016), drove the growth of the population following the flood.…”

“…Not only does the amount of habitat matter, but its proximity to existing sources of birds is also important. Piping Plovers on the Missouri River and elsewhere exhibit relatively high site fidelity between years, with young prospecting locally for their first nesting locations , Davis et al 2017, and exchange among local breeding populations is relatively low (Catlin et al 2016). These pieces of evidence indicate that the future construction of sandbar habitat should be in close proximity to the already existing postflood sandbars on the Gavins Point Reach.…”

Effects of climate change and anthropogenic modification on a disturbance‐dependent species in a large riverine system

“…The PLT and LCL subpopulations were predicted to have low extinction probabilities (0.0 and 0.003, respectively), supporting populations totaling 123 and 58 adults, respectively, after 100 yr (Table ; Catlin et al. ). The GVP subpopulation had a greater risk of extinction (0.48) and would likely only support approximately 22 adults by year 100 given the current disturbance regime (Table ; Catlin et al.…”

“…We used this baseline model as the foundation for all model scenarios simulated in this study, and field data and parameters that underlie this model can be found in Catlin et al. ().…”