Elizabeth A. Roznik
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Ecology, Behavior, and Life History
Amphibians are the most threatened group of vertebrates, yet we know very little about most species because they are small, secretive, and difficult to study. I use detailed field studies and lab experiments to investigate the ecology, behavior, and life history of rare and common species, and make recommendations to improve conservation efforts for these species. My research has focused on the gopher frog (Lithobates capito) in Florida and the dusky gopher frog (Lithobates sevosus) in Mississippi, which have both declined due to habitat loss and degradation, Australian rainforest frogs (Litoria spp.) that are threatened by the disease chytridiomycosis, and treefrogs (Hyla spp.) that are negatively affected by the introduced Cuban treefrog (Osteopilus septentrionalis) in Florida.


Disease Ecology
The disease chytridiomycosis has driven the greatest loss of biodiversity caused by disease in recorded history. This emerging fungal disease has caused catastrophic declines or extinctions in hundreds of amphibian species around the world. I am interested in the drivers of chytridiomycosis, including the influences of frog behavior, environmental conditions, and their interactions with habitat structure. My goals are to understand (1) how thermal and hydric preferences influence infection risk, (2) how infected frogs alter their behavior, and the consequences of these changes, (3) how natural thermal regimes affect pathogen growth and reproduction, (4) how canopy openings, such as those created by severe storms, influence frog microclimates and infection risk, (5) how infections influence frog reproduction, and (6) how infection risk interacts with climate change.

Invasion Ecology
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Biological invasions alter community structure and threaten biodiversity worldwide. Identifying the mechanisms underlying the invasion process can inform management decisions to reduce the abundance of invasive species and their impacts on invaded communities. The Cuban treefrog was accidentally introduced to the Florida Keys in the 1920s, and has been spreading north ever since. I am using a landscape experiment in conjunction with lab experiments to investigate mechanisms facilitating this invasion. I am also evaluating behavioral and physiological traits of Cuban treefrogs that are undergoing natural selection in their introduced range. This information will help us understand how this invasive species is impacting native ecosystems, how it is adapting to its introduced range, and where range expansion may occur in the future.

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Gopher frog (Lithobates capito)
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Green-eyed treefrog (Litoria serrata)
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Invasive Cuban treefrog (Osteopilus septentrionalis)
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