Date on Master's Thesis/Doctoral Dissertation


Document Type

Doctoral Dissertation

Degree Name

Ph. D.



Degree Program

Biology, PhD

Committee Chair

Eason, Perri

Committee Co-Chair (if applicable)

Page, Robert

Committee Member

Page, Robert

Committee Member

Campbell, Todd

Committee Member

Emery, Sarah

Committee Member

Cobbs, Gary

Author's Keywords

population genetics; Nile monitor; Argentine black and white tegu; microsatellites


This dissertation examines the population genetic dynamics of two Florida invasives: the Nile monitor (Varanus niloticus) and Argentine black and white tegu (Salvator merianae). I also provide insights into the introduction histories of both species. This study was developed as part of a collaborative effort with the Florida Wildlife Commission to expand our knowledge of these highly detrimental, invasive lizards. All research activities involving animals and animal tissues were approved by the University of Louisville’s Institutional Animal Care and Use Committee (IACUC Proposal #: 12024). I start with a brief introduction into what makes invasive species successful from a conservation genetics perspective, and discuss how conservation biologists can use genetic data to manage invasive populations. The dissertation is then divided into four data chapters which are designed to stand as independent manuscripts. Chapters II-III have been published in Amphibia-Reptilia, and Chapter IV has been accepted by the Journal of Heredity. Chapters II and III describe how novel microsatellite markers were developed for both species via 454 pyrosequencing. We successfully developed 17 polymorphic loci for V. niloticus and 10 polymorphic loci for S. merianae. Chapter IV examines the population structure, degree of connectivity, and introduction history of three invasive V. niloticus populations in southern Florida. The results of these analyses demonstrate that all three populations have limited genetic diversity and are highly differentiated from one another. Our results also suggest that these populations resulted from independent introduction events that occurred within the past few decades. We conclude by advising wildlife managers to focus management efforts on containment of existing populations and intensification of monitoring efforts on potential migration corridors. My final data chapter (V) focuses on the population structure, degree of connectivity between populations, and most likely introduction scenarios of two invasive S. merianae populations in Florida. The results of this study also demonstrate that S. merianae populations have limited genetic diversity and show significant levels of differentiation. Furthermore, we also found some evidence of migration between populations, and our introduction analyses suggest that both populations originated from an unknown ghost population. We recommend that managers focus on containment rather than eradication strategies, and increase monitoring efforts of the pet trade and potential migration corridors. I conclude this dissertation by summarizing my findings and proposing future directions in which I wish to examine this system further (chapter VI).