New Harvard Forest Publications: Nutrient Transformation and Bacterial Diversity in Pitcher Plants

In April's Ecology, former research assistant Jess Butler and her co-authors Nick Gotelli (University of Vermont) and Aaron Ellison (Harvard Forest Senior Ecologist) reported the surprising finding that the complex food web of macroinvertebrates inhabiting leaves of the pitcher plant Sarracenia purpurea contribute little to the nutrient budget of this carnivorous plant. Rather, bacteria provide the key link between the detritus-based ("brown") food web living in the pitchers and the producer-based ("green") food web that depends on the plant for food. In a follow-up publication to appear in Environmental Microbiology, Harvard post-doc Celeste Peterson and a group of co-authors from Harvard's Departments of Organismic & Evolutionary Biology and Microbiology & Molecular Genetics, Harvard Forest, and Howard University describe the diversity of these bacteria in three bogs in Massachusetts. Peterson et al. show that the presence of the top predator in the pitcher plant's brown food web, larvae of the mosquito Wyeomyia smithii increases bacterial species richness in the pitchers. So although the food web may not directly provide nitrogen to the plant, the food web does control the diversity of the species that do provide that nitrogen.

Butler, J. L., N. J. Gotelli, and Ellison, A. M. 2008. Linking the brown and green: nutrient transformation and fate in the Sarracenia microecosystem. Ecology 89: 898-904.

Peterson, C. N., S. Day, B. E. Wolfe, A. M. Ellison, R. Kolter, and A. Pringle. 2008. A keystone predator controls bacterial diversity in the pitcher plant (Sarracenia purpurea) microecosystem. Environmental Microbiology (in press)