Summary- Effects of nutrient stress

Summary- Effects of nutrient stress

This collaborative project between me and Nick Gotelli was the renewal of DEB 98-05722. During this award period, we focused more intensiely on how atmospheric deposition of nutrients is changing the dynamics of the detritus-based food web that has co-evolved with its host, the northern pitcher-plant Sarracenia purpurea. We tested three hypotheses:

1. Nitrogen derived from atmospheric sources and nitrogen from captured prey are used equivalently by the Sarracenia food web and the plant itself;
2. The trajectory of assembly of the Sarracenia food web is independent of initial starting composition, habitat type, and the type of, and rate at which, nutrients are supplied;
3. Host plant growth morphology is independent of food web structure and nutrient supply.

We used the results derived from two new field experiments and two new greenhouse experiments to continue our development of Markov models of food web assembly and coupled differential equation models of food web dynamics. These models will be used to predict the responses of integrated communities to environmental stress. The research revealed the importance of anthropogenic stressors on co-evolved systems, and contributed to a deeper understanding of the assembly of food webs by contrasting effects of top-down and bottom-up forces on the dynamics of non-equilibrial assemblages.