Roberto Brenes
Ph.D. Candidate
Research
My research is building from previous UTIA studies
that examined the relative susceptibility of amphibians to the emerging
pathogen, ranavirus. In 2008 and 2009, Dr. Jason
Hoverman, Dr. Matt Gray
and Dr. Debra Miller
tested 19 amphibian species from eastern North America and determined that
susceptibility differed among taxonomic species, families and orders (Hoverman
et al. in review). My research is
expanding this foundational work and testing the relative susceptibility of an
additional 21 amphibian species from other regions of North America. Using the
collective data set, I will perform phylogenetic analyses that relate ranavirus
susceptibility to evolutionary lineages and ecological characteristics of the
host species so that generalizations can be made regarding trends in
susceptibility to ranavirus among North American amphibians. I’m also performing a second series of
experiments that is examining community level interactions of different host
species exposed simultaneously to ranavirus and measuring the concomitant
changes in aquatic ecosystem trophic structure following a ranaviral disease
die-off. This series of experiments will
determine if the outcome of ranavirus epizootic events is driven by the
amphibian species that are present in an aquatic ecosystem. Finally, I’m exploring the possibility that
ranaviruses are transmitted among amphibians, reptiles and fish. Die-offs in the wild and captivity suggest
that ranaviruses with very similar genomes appear to cause ranaviral disease in
each of these groups. The occurrence of
pathogen transmission among three vertebrate classes is unknown in
double-stranded DNA viruses, and has major implications for the persistence of
this pathogen in aquatic ecosystems. I
will be challenging amphibian, turtle, and fish species with three ranaviruses
isolated from a bullfrog, box turtle, and pallid sturgeon. If transmission occurs, I will subsequently
assemble an aquatic community in outdoor mesocosms with one species from each
vertebrate class, and test whether transmission occurs under more natural
conditions.
The objectives of my
doctoral research are to:
1)
Identify host
characteristics that are linked to susceptibility to ranavirus,
2)
Determine the
effect of community composition on the likelihood of ranavirus emergence, and
3)
Examine the
possibility of interclass transmission of ranavirus among amphibians, reptiles
and fish.
Collaborators:
UT AgResearch, UT East Tennessee Research and Education
Center, UT College of Veterinary Medicine,
and UT Center of Excellence in
Livestock Diseases and Human Health.
Personal
Hello!
I grew up in a small
town near San Jose, Costa Rica. I graduated with a B.S. in Biology from Universidad de Costa Rica. I met Dr. Gray in 1999 and worked with him as
a visiting research scholar for 2 years during his doctoral research at Texas Tech University. Thereafter, I studied the natural history of Necturus beyeri under Dr. Neil Ford
at University of Texas-Tyler, and secured a M.S. in Biology in 2003. For the next 5 years, I worked on research in
Panama examining ecosystem effects of amphibian die-offs associated with
chytridiomycosis. In 2009, I accepted a
life science instructor position at Turtle Mountain Community College
in North Dakota. In 2010, I started my
Ph.D. in the UT Center
for Wildlife Health with Dr. Gray and Dr. Miller.
Publications
Colon-Gaud, C., M. R. Whiles, K.
R. Lips, C. M. Pringle, S.S. Kilham, R. Brenes,
and S.D. Peterson. Stream invertebrate responses to a catastrophic
decline in consumer diversity. Journal of the North American Benthological Society 20(4):1185-1198
Colon-Gaud, C., M. R. Whiles, R.
Brenes, S.S. Kilham K. R. Lips, C. M. Pringle, S.
Connelly , and S.D. Peterson. 2010. Functional
redundancy and resource facilitation between tadpoles and insect grazers.
Freshwater Biology 55: 2077- 2088
Connelly, S., C. M.
Pringle, R. J. Bixby, R. Brenes, M. R. Whiles, K. R. Lips, S. Kilham, and A. Huryn. Changes in stream
primary communities resulting from large-scale catastrophic amphibian declines:
can small-scale experiments predict effects of tadpole loss? Ecosystems
11:1262-1276.
Brenes, R. and Neil, B. Ford. 2006 Seasonality and movements of the Gulf Coast Waterdog (Necturus beyeri) in East Texas.
Southwestern Naturalist 51(2):1-6.
Lips, K. R., F. Brem, R. Brenes, J. D. Reeve, R. A. Alford, J. Voyles, C. Carey, L. Livo, A. P.,
Pessier, and J. P. Collins. 2006. Emerging infectious disease and the loss of
biodiversity in a Neotropical amphibian community.
Proceedings of the National Academy of Sciences 103 (9):3165-3170.
Whiles, M.,
K. R., Lips, C. Pringle, S. S., Kilham, R. J. Bixby, R.
Brenes, S. Connelly, J. C. Colon Gaud, M. Hunte-Brown,
A. D. Huryn, C. Montgomery, and S. Peterson. 2006.
The Consequences of Amphibian Population Declines to the Structure and Function
of Neotropical Stream Ecosystems. Frontiers in
Ecology 4(1): 27-34
Gray, M. J., L. M. Smith, and R. Brenes. 2004. Effects of agricultural cultivation on demographics of
southern high plains amphibians. Conservation Biology 18.1386-1377.
Contact Information
Email: rbrenes@utk.edu
Phone: 865-974-3897
(Research in Texas playa lakes)
UT Department of
Forestry, Wildlife and Fisheries