Monitoring Effects of Barrier Island Restoration on Piping Plovers in Louisiana

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The federally threatened piping plover relies on sand-beach habitat year-round for nesting, foraging, and roosting, habitat that is particularly vulnerable to loss and degradation from coastal development, recreation activities, erosion, and sea-level rise. 

Monitoring Effects of Barrier Island Restoration on Piping Plovers in Louisiana

Researchers measure effects of beach nourishment on the Piping Plover's prey

The Science Issue and Relevance: The Piping Plover is a small, pale gray shorebird that relies heavily on sand-beach habitat year-round for nesting, foraging, and roosting. The sandy/coastal habitat that Piping Plovers prefer is particularly vulnerable to loss and degradation due to coastal development, recreation activities, erosion, and sea level rise. Piping Plovers were declared federally threatened in 1985.

The Isles Dernières Barrier Island Refuge (IDBIR) is a chain of barrier islands on Louisiana’s southeastern coast. Its name comes from the French phrase for “Last Island,” which refers to its historical state as a single large island on the edge of the Gulf. Today, the IDBIR includes four islands in Terrebonne Parish: Raccoon Island, Whiskey Island, Trinity/East Island, and Wine Island. The islands provide protection from storm surge to coastal communities and wetlands, and serve as critical habitat for wildlife species. The IDBIR has experienced a net loss of land over the last century. As a result of subsidence, hurricane damage, erosion, and loss of sediment input following channelization of the Mississippi River, the IDBIR lost 82.2% of overall land area from 1887 to 2002. To combat this land loss, all islands in this chain have undergone restoration efforts such as beach nourishment. Though the goal is to increase overall land area, it is unclear how long it will take for native species to recover in restored areas, and if full recovery is possible.

Methodology for Addressing the Issue: A major restoration project is planned for Whiskey Island, which has supported up to 40 wintering Piping Plovers per year in recent decades. To assess the impact of restoration on Piping Plovers and other shorebird species of conservation concern, we conduct biweekly surveys of all suitable habitat on the island. Surveys were implemented two years prior to the initiation of restoration work, and will continue throughout active restoration. We use binoculars and high-powered spotting scopes to identify Piping Plovers and other shorebirds on Whiskey Island as well as nearby islands not currently receiving restoration work. Some of the birds we observe have been uniquely marked with colored leg bands, allowing us to identify a small number of individuals and track their movements within the refuge.

Monitoring Effects of Barrier Island Restoration on Piping Plovers in Louisiana

The Isles Dernières Barrier Island Refuge (IDBIR) includes four islands in Terrebonne Parish

In addition to surveying Piping Plovers, we are interested in measuring effects of beach nourishment on their invertebrate prey. Studies have documented mass die-offs of benthic invertebrates following beach nourishment, due to burial under huge amounts of sand. The rate at which native invertebrate species recolonize restored areas can vary, and a decrease in shorebird use of restored sites has been shown as a result of prey suppression. To better understand how the recolonization process works in this unique delta ecosystem, we will compare the diversity and abundance of invertebrates in core samples taken from the intertidal zone before and after restoration. We will also measure some physical aspects of the sand, such as organic content and particle size, to use as covariates in our statistical models.

Future Steps: Continued sampling during and in the years following the beach nourishment process will help us understand both short- and long-term effects of restoration on Piping Plovers and other shorebirds, and their invertebrate prey.