Conservation Biology
A large part of my work as a Research Scientist at the Memphis Zoo is focused Applied Conservation Biology. This encompasses projects that are in situ (reintroductions, field surveys, endangered species assessments), ex situ research (reproductive physiology, assisted reproductive technology, cryopreservation), and a combination of both (ecological fitness of captive-released animals). The following are some examples of current/past projects.
I am spearheading a partnership between Memphis Zoo (USA) and Tropical Ecosystem Research Network (Sri Lanka) to establish the first Conservation, Awareness, Research, and Education Center in Sri Lanka. Construction is planned for early 2024.
This project is aimed at linking and leveraging living and preserved biological collections at zoos and natural history museums. By creating a stronger partnership between these institutions, our goal is to increase the impact of both on scientific discovery. (Click for publication)
One of the main focuses of my work is to examine the development, morphology, and behavior of captive-bred and cryo-derived individuals compared to their natural counterparts. (Click for publication)
We use field studies on model species to understand the obsticles captive-reared individuals face when exposed to a complex natural enviroment. (Click for publication)
With our collaborator Dr. Lori Neuman-Lee (Arkansas State University), we have a number of graduate students conducting their research on animals at the zoo. (Click for publication)
On of our on-going efforts are to maintain an active captive-breeding colony that can serve as a source population for reintroductions. Reintroductions are aimed at building new wild populations of critically endangered species, such as the dusky gopher frog. (Click for video)
Part of our work is focused on building capacity in local conservation organizations, such as Jambatu Center for Amphibian Conservation (Ecuador), and increasing the success of ex situ conservation. (Click to learn more about Jambatu)
Cryopreservation is an exciting way to conserve species and genetic diversity. Through comparing species within and across families, looking at species' conservation status, and testing out new methods, we are working to increase the effectiveness of cryopreservation as a tool for wildlife conservation. (Click for pubs)
When encountering new taxa, we work to understand their reproductive biology and develop tailored assisted reproduction technologies (hormone injections, in vitro fertilization). These mehtods are compared across species to maximize it's use for the conservation of threatened and endangered amphibians. (Click for pubs)
Through our collaborations with The Amphibian Foundation, we are working to build up the captive-breeding program for the Gopher Frog, which is Georgia’s rarest frog species. (Click to learn more from The Amphibian Foundation)
We are conducting a series of research comparing the endoparasites and microbiomes of amphibians across the urban and forested landscape around Memphis.
Through our collaborations with Rimba and Project Pteropus, we are working to promote the importance of flying foxes as durian pollinators in Malaysia. (Click to learn more about Project Pteropus)
A recent focus of mine has been establishing cross-institutional collaborations to make better use of the wealth of biological information in the living collections at zoos. As zoos transition to conservation organizations, it is imperative for us to maximize the accessibility of zoo collections.
Behavioral Ecology
Much of my work in tropical biology and behavioral ecology is focused on parental investment of treefrogs. This included my dissertation work, which was the first empirical study of parental care in a Southeast Asian amphibian (conducted at the Sakaerat Environmental Research Station, Thailand). Other work includes on-going collaborations with the Kam Lab at Tunghai University (Taiwan).
Systematic observation and quantification of the unusual egg attendance behavior of a pond-breeding frog with maternal egg attendance in natural settings, as well as experimental manipulations to confirm its adaptive significance. (Click for publications)
Examining plasticity in amphibian parental behavior in response to predator threats and the consequences for their dependent offspring using a bamboo-breeding treefrog in Taiwan with paternal egg attendance. (Click for publications)
Examining the extreme anti-predator behavior exhibited by adult frogs during egg attendance, often against predators, such as katydids, that are a source of danger to both adults and their embryos. (Click for publications)
Comparing embryonic development and hatching time in response of various hatching cues, such as predation, submergence, and desiccation. Investigating ways in which cues are transmitted, received, and affecting the hatching behavior of embryos. (Click for publications)
Natural History
I have always been fascinated by animal behavior. Much of our knowledge of behavior stems from incidental natural observations. The following are some observations of diet, breeding, and predation of vertebrate and invertebrate species that I have published, including a new species discovered during my work.
Multiple male breeding during delayed rainy season by Hansen's bush frog (Thailand). * Featured cover, Herpetological Review * (Click for publication)
Rare predation events of frogs and frog eggs by nursey web spiders (Thailand). (Click for publication)
Predation of multiple species of frog eggs by the Yellow-spotted Keelback Watersnake (Thailand). (Click for publication)
Foam nest construction and leaf-wrapping by the old world flying frog - Rhacophorus kio (Thailand). (Click for publication)
Male territorial combat and vocal interaction in the common shrub frog (Sri Lanka). * Photo by Tharaka Priyadarshana * (Click for publication)
Caiusa pooae - new frog egg predator discovered through field observations (Thailand). * Photo and description by Rognes 2015 * (Click for publication)