Can Salt Marsh Restoration Bring Back the Birds?

Marsh birds such as seaside sparrows and salt marsh sparrows are in decline throughout the world, with some estimates suggesting their populations are falling by 9% annually; many species may be extinct by 2050. The primary reason is habitat loss, as marshes disappear under the pressures of sea-level rise.

To help reverse this trend, a University of Maryland professor and partners at Towson University and the National Audubon Society. Professor Andy Baldwin in the Department of Environmental Science and Technology will study the impacts of a salt marsh restoration project on shrinking bird populations in the Chesapeake Bay, and the key landscape patterns needed to support the birds that live there.

"This project is unusual in that it links site-scale ecological restoration actions to animal populations at the landscape scale, a holistic perspective fundamental to reversing declines of threatened species," Baldwin said.

A phenomenon known as open water fragmentation, or “ponding” is to blame for rapidly degrading saltmarshes throughout the Chesapeake Bay watershed and eliminating critical bird habitat. As increasingly higher tides flow into marshes, the water gets trapped in pools that can’t escape back into open waters of the bay and its tributaries. The pools grow and connect to one another, fragmenting the marshland into a patchwork of small islands that eventually erode away, turning vast swaths of marshland that once supported plants and birds into open water. 

Restoration projects are planned for thousands of hectares over the coming decade, and Baldwin and his colleagues intend to provide scientific evidence to help guide those projects to ensure they are effective at supporting marsh birds into the future.

The research team will spend the next five years surveying the nesting population of saltmarsh sparrows and seaside sparrows—two important marsh birds in the region—while the Audubon Society works to restore 400 hectares of marshland. The restoration project will use a novel technique called runneling, where channels are dug into the marsh so that pools of water can drain back into the bay and high tides are no longer trapped behind the marsh.

The team will study the ecosystem in restored areas and non-restored areas, examining how hydrologic restoration using runnels affects salt marsh vegetation, soil, and biogeochemical processes and documenting responses of nesting bird populations. Through this work, they hope to better understand the impacts of fragmentation on marsh birds, measure the outcomes of the restoration techniques and develop a restoration guide to increase efforts throughout the tidal marshes of the Chesapeake Bay.

Throughout the study, UMD College of Agriculture and Natural Resources students will assist with the field work and analysis, training and participating in real-world research and conservation practices. The study is supported by a $1.5 million award from the National Science Foundation and the Paul G. Allen Family Foundation.