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Fall Migrant Waterbird Community Structure and Stable Isotope Ecology in the Mississippi Alluvial Valley and Northern Gulf of Mexico: Use of Migratory Bird Habitat Initiative Sites and Other Wetlands

The Mississippi Alluvial Valley (MAV) was dominated by extensive lowland forests, but during the 20th century most of the MAV was converted to agricultural, aquaculture, and other human uses. These land-use changes created stopover migration and wintering habitats for waterfowl, shorebirds and other waterbird species. Before landscape modification of the MAV, shorebirds likely migrated past the MAV to wetlands along the northern Gulf of Mexico (NGoM). In 2010, the Deepwater Horizon oil spill impacted coastal marshes of the NGoM. The USDA Natural Resources Conservation Service implemented the Migratory Bird Habitat Initiative (MBHI) to provide waterbirds with wetlands inland of oil-impacted areas. My objectives were to 1) statistically model the waterbird community on wetlands in the MAV and NGoM, 2) estimate relative abundance of shorebird and other waterbirds in idled aquaculture ponds enrolled in MBHI and associated wetlands in the MAV and NGoM, and 3) collect shorebird feathers and blood for stable isotope analysis (13C/12C, 15N/14N) to assess foraging niches and potential migratory connectivity between MAV and NGoM habitats during 2012 – 2013. Consequently, autumns of these years were under a drought, extensively wet from Hurricane Isaac, and exhibited average precipitation in the post-hurricane recovery period which may have had an effect on waterbird assemblages differing by year, month, twice-monthly survey period, latitude, region, state, site, and water depth index. Latitude shifted north and water depth was narrowest when abundant wet habitat existed on the landscape in 2012. Bird abundances were greatest in 2011 and never recovered to these levels in 2012 or 2013, which may have reflected effects of drought concentrating birds on remaining wetlands in 2011 and subsequent to the hurricane. Stable isotope analysis of blood indicated spatial segregation of shorebird species. Neither blood nor feather carbon and nitrogen values revealed definitive linkage of sites between the MAV and NGoM. Shallow water habitat inland may be a limiting resource during migration for waterbirds, especially in drought years when other wetlands may have been limited. Thus, provision of wetlands (mudflat – 15 cm) by MBHI and other conservation strategies across the landscape may allow waterbirds access to needed resources during migration.

Identiferoai:union.ndltd.org:MSSTATE/oai:scholarsjunction.msstate.edu:td-3230
Date09 December 2016
CreatorsFoth, Justyn Richard
PublisherScholars Junction
Source SetsMississippi State University
Detected LanguageEnglish
Typetext
Formatapplication/pdf
SourceTheses and Dissertations

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