Benefits of engineered habitats to seasonal bird communities on the Savannah Harbor Navigation Project, Dredged Material Containment Areas, 1994-2012

Abstract

This report presents the results of a long-term habitat and trend analyses of bird community data from a monitoring effort conducted on five Dredged Material Containment Areas (DMCAs) from 1994 to 2012. The USACE Savannah District developed and implemented a Long-Term Management Strategy (LTMS) for the DMCAs in 1996 to mitigate lost wetland habitat due to maintenance operations in the Savannah Harbor, and to provide habitat for the floral and faunal communities that otherwise would be available if not for the urban and economic development of the area. Bimonthly surveys were conducted from 1994 to 2012 to assess the effectiveness of the LTMS to provide seasonal habitat for the bird community. Archived quarterly satellite imagery was collected and analyzed from 2001 to 2011 to assess year-round seasonal habitat availability. All bird community data collected were fitted to a negative binomial (mean abundance) or Poisson distribution (mean species richness) and used to assess trends for 180 individual species and 12 species groups for spring, summer, fall, and winter seasons from 1994 to 2012. Results indicate that the Savannah DMCAs support stable to increasing populations of most species and species groups during each season, including many species ranked as regional priority species. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.

Use of Engineering With Nature® concepts on the Savannah Harbor Navigation Project, Dredged Material Containment Areas, Savannah, GA

“…To promote greater application of the EWN approach, a portfolio of demonstration projects may be useful (Banks et al 2013, Bridges et al 2018. The implementation of the LTMS on the SHNP DMCAs provides an opportunity to present an approach that is rooted in EWN principles and that provides effective and efficient management of the SHNP while providing critical open water, wetland, mudflat, and island habitats essential for seasonal waterfowl and shorebirds in the region (Calver et al 2016, Guilfoyle et al 2020 (Figure 1). Also, as a confined disposal facility (CDF) the DMCAs provide a location for the deposition of contaminated sediments from the harbor.…”

“…Monitoring of the bird communities began in 1994 and continues to the present. An introduction to the seasonal bird communities on the DMCAs from 1994 to 2012 can be found in Calver et al 2016, and long-term trend and habitat analyses of these data can be found in Guilfoyle et al (2020).…”

“…In addition, long-term trends have shown that most populations are stable or increasing, including increasing species richness during the monitoring period. Seasonal habitat availability is an important factor correlated to abundance and richness metrics for many species and species groups (Guilfoyle et al 2020). Finally, the islands constructed within the DMCAs have been successful in providing important nesting habitat for the Black Skimmer (Rynchops niger), Willet (Tringa semipalmata), Least Tern (Sternula antillarum), Gull-billed Tern (Gelochelidon nilotica), and Royal Tern (Thalasseus maximus) (Calver 2006, Guilfoyle et al 2020.…”

“…Seasonal habitat availability is an important factor correlated to abundance and richness metrics for many species and species groups (Guilfoyle et al 2020). Finally, the islands constructed within the DMCAs have been successful in providing important nesting habitat for the Black Skimmer (Rynchops niger), Willet (Tringa semipalmata), Least Tern (Sternula antillarum), Gull-billed Tern (Gelochelidon nilotica), and Royal Tern (Thalasseus maximus) (Calver 2006, Guilfoyle et al 2020. The DMCAs also support the largest breeding populations of Black-necked Stilts (Himantopus mexicanus) in Georgia (Calver 2006).…”

“…Moreover, in the LTMS, levees in the individual DMCAs can be raised periodically to increase capacity (USACE 1996). The large size of the DMCAs (approximately 2,000 ha [4,960 acres]), permits long-term use of the site, while rotational operations permit availability of designated habitats for seasonal waterfowl and shorebirds (Calver et al 2016, Guilfoyle et al 2020. This alignment of engineering of the DMCAs, along with a specific management approach to increase environmental benefits and the efforts to document benefits with long-term monitoring of the sites, are reasons why the SHNP and DMCAs represent a EWN approach to the management of CDFs.…”