Anthropogenic Renourishment Feedback on Shorebirds: a Multispecies Bayesian Perspective

TL;DR

This study investigates how beach renourishment projects affect shorebird habitats and populations, using Bayesian models to quantify impacts on nesting and wintering grounds of multiple species along Florida's Gulf coast.

Contribution

It introduces a Bayesian approach to assess the influence of anthropogenic beach renourishment on shorebird habitat use and distribution.

Findings

Beach renourishment increases likelihood of regions not being wintering grounds for shorebirds.

Renourishment reduces probability of regions being breeding grounds for Snowy Plovers.

Habitat preferences differ significantly between breeding and wintering seasons for shorebirds.

Abstract

In this paper the realized niche of the Snowy Plover (Charadrius alexandrinus), a primarily resident Florida shorebird, is described as a function of the scenopoetic and bionomic variables at the nest-, landscape-, and regional-scale. We identified some pos- sible geomorphological controls that influence nest-site selection and survival using data collected along the Florida Gulf coast. In particular we focused on the effects of beach replenishment interventions on the Snowy Plover (SP), and on the migratory Piping Plover (PP) (Charadrius melodus) and Red Knot (RK) (Calidris canutus). To quantify the relationship between past renourishment projects and shorebird species we used a Monte Carlo procedure to sample from the posterior distribution of the binomial probabilities that a region is not a nesting or a wintering ground conditional on the occurrence of a beach replenishment intervention in the same and the previous year. The results indicate that it was 2.3, 3.1, and 0.8 times more likely that a region was not a wintering ground following a year with a renourishment intervention for the SP, PP and RK respectively. For the SP it was 2.5. times more likely that a region was not a breeding ground after a renourishment event. Through a maximum entropy principle model we observed small differences in the habitat use of the SP during the breeding and the wintering season. However the habitats where RK was observed ap- peared quite different. Maintaining and creating optimal suitable habitats for SP characterized by sparse low vegetation in the foredunes areas, and uneven/low-slope beach surfaces, is the proposed conservation scenario to convert anthropic beach restorations and SP populations into a positive feedback without impacting other threatened shorebird species.