Coastal bird community response to dredge‐spoil tidal marsh restoration at New Round Island, Mississippi, U.S.A.

Abstract

The northern Gulf of Mexico has been the focus of many coastal habitat restoration projects in the wake of new funding streams stemming from the settlement of the 2010 Deepwater Horizon oil spill litigation. One such project was the creation of New Round Island (RNDI) in Mississippi, a 86 ha island created using dredge material in 2017. The island design incorporated a novel U-shaped sand berm with multiple interconnected containment sells. In this study we sought to document changes in relative abundance of various coastal bird species. We conducted surveys for breeding and nonbreeding birds from June 2017 to May 2021, and we conducted nonbreeding surveys at two reference sites for comparison. Breeding bird numbers were dominated by colonial nesting species in years 1 and 2, which subsequently declined as vegetation cover increased. Solitary nesting species increased over time, with Wilson's Plover (Charadrius wilsonia) nest count increasing from zero in year 1 to 29 in year 5. Nonbreeding shorebird counts peaked in years 1-2 and subsequently declined, although shorebird counts also decreased at the reference sites. Relative abundance of waders (Ardeidae), rallids (Rallidae), and passerines (Passeriformes and allies) increased in comparison to reference sites. This study demonstrates the short-term benefits of this U-shaped island design to early-succession breeding species and nonbreeding shorebirds shortly after construction, with longer-term benefits to breeding Wilson's Plover and to marsh birds as vegetation fills in.

One Thousand Nesting Pairs Packed into One Hundred Square Metres: The Sad Story of the Sandwich Terns Thalasseus Sandvicensis of the Venice Lagoon

“…Dredge islands or other similar artificial sites are also commonly accepted and used for nesting by gulls and terns (Van Zoemeren et al ., 2019; Ritenour et al ., 2022). Indeed, construction of artificial islands has been used to compensate for the loss of previously used natural sites (Stienen et al ., 2005; Gamblin et al , 2022). In the present study, we found that dredge islands allow optimal productivity (0.9 fledglings per breeding attempt) for Sandwich Terns originally nesting early in the season and even from replacement clutches of late breeders (0.7 fledglings per breeding attempt).…”

Do the barrier islands of the Po Delta constitute an ecological trap for colonising Slender-billed Gulls Larus genei?

“…Dredge islands, built in the northern Po Delta over the last thirty years and those that will be built in the next years, may probably be suitable colony sites. Dredge islands or similar artificial sites are also commonly accepted and used for nesting by gulls and terns (Van Zomeren et al 2019, Ritenour et al 2022; sometimes, the building of artificial islands has been used as a way to compensate for the loss of previously used natural sites (Stienen et al 2005, Gamblin et al 2022. In southern France, the use of artificial colony sites led to an increase of 14% of Slender-billed Gulls in 2011−2017 (Schwartz et al 2022), while in the lagoon of Venice, several waterbirds regularly use dredge islands to nest (Scarton & Valle 2015, Scarton 2017.…”