Graduation Year

2015

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Biology (Integrative Biology)

Major Professor

Thomas L. Crisman, Ph.D.

Committee Member

David B. Lewis, Ph.D.

Committee Member

Peter D. Stiling, Ph.D.

Committee Member

Mark C. Rains, Ph.D.

Keywords

Bird Migrations, Emergent Insects, Groundwater Pumping, Seasonality, Urbanization

Abstract

The growing human population threatens the many of the earth’s biological systems. In the last 600 years extinction rates risen from 1 extinction per million species per year (E/MSY) in the 1400’s to 50 E/MSY today. During this time period 1.5% of all known birds have gone extinct, because they could not adapt quickly enough to human mediated changes. The goal of this dissertation was to determine how urbanization and anthropogenic services needed to support urban areas impact cypress dome wetland aquatic insect and migratory bird populations that depend on them. In Central Florida cypress dome hydroperiods are driven by seasonal rainfall conditions and fill June and July with the onset of the Florida rainy season then begin drying beginning in October with the onset of the dry season. Some wetlands were strongly influenced by groundwater pumping and dried out quicker than others, a characteristic that reduced annual insect emergence. Decreased adult insect populations were associated with lower emergence rates early in the dry season led to lower utilization by insectivorous birds. Winter migratory birds significantly related with adult insect abundance during winter months (r = 0.578, p=0.049), and utilized this region at the peak in adult insect populations. Conversely, Neotropical migrants travel through the region during spring when insects are scarce, and adult insects began sharp decline suggesting that Neotropical migrants depleted populations possibly leading to interspecies competition. Neotropical migrants strongly avoided urban areas and declined by 70% in urban areas, which may contribute to declining Neotropical migratory bird populations as a lack in adequate stopover sites may limit entire species. If they are not able to adapt foraging patterns that utilize urban areas in Central Florida where urban development is increasing rabidly populations may continue to decline.

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