Contact Information

Office: SCA 322
Phone: 813/974-4694
Email: nhalstea@mail.usf.edu

M.S. Biology, University of South Florida, 2007
B.S. Biology, University of Wisconsin - Stevens Point, 2001

Research

I am interested in using ecological theory to predict how multiple stressors will affect community- and ecosystem-level dynamics. Much of my research focuses on 1) the non-target effects of agriculture on natural systems, and 2) disease dynamics within a larger community context. My dissertation research developed a framework by which we can predict the responses of aquatic communities and ecosystem properties when simultaneously exposed to multiple agrochemicals. My research demonstrated how the combined top-down and bottom-up effects of agrochemicals can indirectly affect aquatic disease risk through changes in snail abundance, which are important intermediate hosts of trematode parasites. In particular, I explored how agricultural intensification efforts might inadvertently lead to increased exposure to schistosomiasis, a neglected tropical disease that has major socioeconomic impacts in developing countries. This research could lead to more effective agricultural practices that improve crop yields while mitigating against increased disease risk.

Recent Publications

Rohr, J.R., Schoetthofer, A.M., Raffel, T.R., Carrick, H.J., Halstead, N., Hoverman, J.T., Johnson, C.M., Johnson, L.B., Lieske, C., Piwoni, M.D., Schoff, P.K., Beasley, V.R. 2008. Agrochemicals increase trematode infections in a declining amphibian species. Nature. 455: 1235-1239

Durbin, D. J., Gonzalez, S.M., McCoy, E.D., Mushinsky, H.R., Moore, R.D., Halstead, N.T., Robbins, K. 2009. Wildlife habitat and wildlife utilization of reclaimed phosphate-mined lands. Final Report. Florida Institute of Phosphate Research. FIPR Project Number: 02-03-147.

Raffel, T.R., Hoverman, J.T., Halstead, N.T., Michel, P., Rohr, J.R. 2010. Parasitism in a community context: Trait-mediated interactions with competition and predation. Ecology 91: 1900-1907

Rohr, J.R., Halstead, N.T., Raffel, T.R. 2011. Modelling the future distribution of the amphibian chytrid fungus: The influence of climate and human-associated factors. Journal of Applied Ecology 48: 174-176

McMahon, T., Crumrine, P., Halstead, N., Johnson, S., Raffel, T.R., Romansic, J., Rohr, J.R. 2011. The fungicide chlorothalonil is nonlinearly associated with corticosterone levels, immunity, and mortality in amphibians. Environmental Health Perspectives 119: 1098-1103

Rohr, J.R., Halstead, N.T., Raffel, T.R. 2012. The herbicide atrazine, algae, and snail populations. Environmental Toxicology and Chemistry 31: 973-976

McMahon, T.A., Halstead, N.T., Johnson, S., Raffel, T.R., Romansic, J.M., Crumrine, P.W., Rohr, J.R. 2012. Fungicide-induced declines of freshwater biodiversity modify ecosystem functions and services. Ecology Letters 15: 714-72

Guzy, J.C., McCoy, E.D., Deyle, A.C., Gonzalez, S.M., Halstead, N.T., Mushinsky, H.R. 2012. Urbanization interferes with the use of amphibians as indicators of ecological integrity of wetlands. Journal of Applied Ecology 49: 941-952

Raffel, T.R., Romansic, J.M., Halstead, N.T., McMahon, T.A., Venesky, M.D., Rohr, J.R. 2013. Disease and thermal acclimation in a more variable and unpredictable climate. Nature Climate Change 3: 146-151

Rohr, J.R., Raffel, T.R., Halstead, N.T., McMahon, T.A., Johnson, S.A., Boughton, R.K., Martin, L.B. in review. Early-life exposure to an herbicide has enduring effects on pathogen-induced mortality. Proceedings of the Royal Society of London B 280: 20131502