Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Department

Biology

First Advisor's Name

Philip K. Stoddard

First Advisor's Committee Title

Co-Committee Chair

Second Advisor's Name

Jennifer S. Rehage

Second Advisor's Committee Title

Co-Committee Chair

Third Advisor's Name

M. Danielle McDonald

Third Advisor's Committee Title

Committee Member

Fourth Advisor's Name

John C. Withey

Fourth Advisor's Committee Title

Committee Member

Fifth Advisor's Name

Robert Lickliter

Fifth Advisor's Committee Title

Committee Member

Keywords

Everglades, Nonnative, Dollar Sunfish, Lepomis marginatus, African Jewelfish, Hemichromis lexournoxi

Date of Defense

3-27-2017

Abstract

Vertebrate populations are subjected to novel anthropogenic stressors that are expected to multiply exponentially in the future. Introductions of nonnative species and human-altered hydrology are among these stressors to native species communities. The Rocky Glades, located in Everglades National Park, may serve as a population sink for native species that typically do not survive the altered hydrology of the dry season, and as a source of nonnative species that may be better adapted to chronically stressful conditions. In the seasonally-flooded Everglades, the nonnative African Jewelfish invaded in the 1960s and has since shown rapid range expansion. African Jewelfish are aggressive and territorial, thus they are predicted to be more successful at acquiring space and resources, and may displace native Sunfishes. I monitored assemblages of fish across time in experimental mesocosms and solution holes and quantified survivorship and body condition of both natives and nonnatives. Overall, native Sunfish did poorly while nonnatives had higher survivorship over the course of the dry season. Unexpectedly, no evidence indicated that Jewelfish reduced survival of native Sunfish. I compared aggressive interactions between native Dollar Sunfish and nonnative African Jewelfish in Sunfish populations either sympatric or allopatric with Jewelfish. Sympatric Dollar Sunfish were twice as likely to approach African Jewelfish as allopatric ones. My study suggests native species can survive invasion through behavioral adaptation to nonnative competitors. Characterizing interactions between native and nonnative species and identifying their niche use can assist in understanding the challenges of native species conservation in the face of species invasions.

Identifier

FIDC001758

Available for download on Sunday, April 21, 2019

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