Publication Date

Summer 2013

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Advisor

Scott A. Shaffer

Keywords

island creation, salt pond, waterbird

Subject Areas

Biology; Ecology; Environmental engineering

Abstract

Historically, San Francisco Bay supported the largest salt pond complex on the Pacific coast of North America, and these areas have been used by large numbers of migrating and wintering waterbirds for more than a century. In 2003, salt ponds in the South San Francisco Bay were purchased with a goal of restoring 50-90% of the 6100 ha of former salt ponds to replace lost tidal marsh habitats. However, a major challenge for the restoration project has been maintaining the abundance of non-breeding waterbirds in a smaller footprint of managed ponds. Thus, in 2009-2010, Pond SF2 was enhanced with 30 islands of two different shapes and water control structures that provided muted tidal flows with shallow water depths predicted to benefit waterbirds. To assess how non-breeding waterbirds responded to these enhancements, a spatial grid (50 m x 50 m) was used to survey SF2 weekly from October to May 2010-2012, and examine waterbird use. Of the 262,932 non-breeding waterbirds observed, only 12-15% used the islands depending on tide. Island size, shape, or both predicted the presence or relative abundance of some foraging guilds, whereas island slope, perimeter, and distance to mudflat did not improve the model's predictions of relative guild abundances. Results indicated that waterbirds were attracted to areas with shallow water depths; however, the constructed islands were not used by a large number of waterbirds.

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