Pieter Johnson

Assistant Professor

pieter.johnson@colorado.edu
303-492-5623
Ramaley N344
Dr. Johnson's home page

Ph.D., University of Wisconson, 2005

Research Interests

My research focuses on two pervasive and inter-related forms of biological change: disease emergence and species invasions. Both have important consequences not only for individuals and populations, but for entire ecological communities and ecosystem processes. Invasions and disease also have costly economic and health repercussions for human societies. I use long-term data, ecological experiments and modeling approaches to examine the factors that drive disease emergence and biological invasions, and how changes in disease and invasion levels, in turn, affect community interactions and ecosystem processes in aquatic environments. Study systems with which I have the most experience include trematode-induced malformations in amphibians, fungal pathogens of zooplankton ( Daphnia ) and the aquatic invaders Bythotrephes longimanus (spiny water flea) and Bellamya chinensis (Chinese mystery snail).

My current research program is directed at three inter-related focal areas: (i) Cross-scale drivers of disease emergence; (ii) The functional role of disease in ecosystems; and (iii) Interactions among invasions and habitat alteration. All have immediate relevance to both fundamental questions in ecology and applied conservation issues.

Recent Publications

Johnson, P. T. J., Chase, J. M., Dosch, K. L., Gross, J., Hartson, R. B., Larson, D., Sutherland, D. R. and S. R. Carpenter (2007).  Aquatic eutrophication promotes pathogenic infection in amphibians. Proceedings of the National Academy of Sciences 104: 15781-15786.

Johnson P.T.J. , Preu ER, Sutherland DR, Romansic JM, Han B, and Blaustein AR. (2006) Adding infection to injury: Synergistic effects of predation and parasitism on amphibian malformations. Ecology 87: 2227-2235.

Johnson, P. T. J. and K. B. Lunde (2005). Parasite infection and limb malformations: A growing problem in amphibian conservation. Pp. 124-138 in Amphibian Declines: the Conservation Status of United States Species, M. J. Lannoo (ed). University of California Press.

Johnson, P. T. J. and J. M. Chase. (2004). Parasites in the food web: Linking amphibian malformations and aquatic eutrophication. Ecology Letters 7: 521-526.

Johnson, P. T. J. , Lunde, K. B., Zelmer, D. A. and J. K. Werner (2003). Limb deformities as an emerging parasitic disease in amphibians: Evidence from museum specimens and resurvey data. Conservation Biology 17: 1724-1737. *[Featured in Science 301: 904].

Johnson, P. T. J. , Lunde, K. B., Thurman, E. M., Ritchie, E. G., Wray, S. W., Sutherland, D. R., Kapfer, J. M., Frest, T. J., Bowerman, J. and A. R. Blaustein (2002). Parasite infection linked to amphibian malformations in the western United States. Ecological Monographs 72: 151-168. *[Featured in Science 286: 2434]