Publication Date

Summer 2017

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Studies

Advisor

Lynne Trulio, Ph.D.

Keywords

breeding success, habitat enhancement, population recovery, threatened, western snowy plover

Subject Areas

Wildlife conservation; Wildlife management; Biology

Abstract

The Pacific Coast population of the western snowy plover (Charadrius nivosus nivosus; plover) is listed as a federally threatened species under the U.S. Endangered Species Act due to poor reproductive success from anthropogenic habitat loss, and high predation pressure. Plovers in the South San Francisco Bay use dry salt evaporation ponds, and wildlife-managed ponds, to breed and winter. However, the South Bay Salt Pond Restoration Project aims to restore up to 6,110 hectares of this habitat back to native tidal marsh, which will force plovers to breed in smaller areas and in higher densities. In order to recover plovers in these unique conditions, remaining habitat can be enhanced using oyster shells, which may camouflage breeding plovers, and decrease predation. This study evaluated the effect of oyster shell enhancement on plover breeding success by comparing nesting density, success, and brood behavior between enhanced and unenhanced areas. Plovers did select to nest in enhanced areas; however, nest survival did not increase relative to unenhanced areas. Brood behavior was also affected by enhancement, though highly correlated with the location of optimal foraging habitat. It is likely that enhancement will only improve nesting success if predators are concurrently controlled. Ultimately, plovers may benefit from the application of oyster shells as it attracts nesting effort, and may be strategically used by resource managers.

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