Graduation Year

2010

Document Type

Thesis

Degree

M.S.

Degree Granting Department

Biology

Major Professor

Thomas Crisman, Ph.D.

Keywords

Neotropical migrant, Urban impacts, Land use

Abstract

Migratory bird communities are sensitive to landscape alteration. Urban development significantly impacts bird communities on breeding grounds, as well as en-route during migration. One current theory is that Neotropical migratory birds are not limited by breeding or wintering habitat constraints but by food and habitat availability along major migration routes. The eastern flyway is the route taken by neotropical land-birds through eastern North America that follows coastal areas denoted by intense urban development. Coastal areas funnel birds to major departure points along the northern coast of the Gulf of Mexico and the western coast of Florida. Birds were monitored for 12 consecutive months along a decadal time gradient of urban development. Cypress domes are present through a broad scale of urban development in Hillsborough County creating ideal natural sampling units for long term monitoring of wetland bird communities in urban areas. Residential non-migratory bird communities were least influenced by development and did not change significantly with urban development. Neotropical and short-distance migratory birds, however, declined significantly for both richness and bird abundance with increased urban land cover. Migratory birds positively correlated with forested area at a spatial scale of 500 meters surrounding sites. Wintering migrants hit a critical point in development between 10 and 20 years of age, after which they disappeared. Neotropical migrants were most sensitive to declines significantly at sites classified as heavily degraded by the UMAM (Uniform Mitigation Assessment Method) a 'wetland integrity index'.

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