More quantitative, dynamical foodwebs Jonsson, Cohen, Carpenter - PDF document

More quantitative, dynamical foodwebs Jonsson, Cohen, Carpenter (2005) Other Consumers Primary Consumers Primary Producers How does biomass change as trophic height increases? Constraints on Primary Production

Charles Elton Arthur Tansley Alfred Lotka Vladimir Vernadsky The founders of the ecosystem concept 2. Cedar Bog Lake - Minnesota

3. Trophic-Dynamic view of Cedar Bog Lake Gosz et al. 1978 - Lindeman’s followers

Ecosystem feedbacks Top-down vs. bottom-up Trophic Cascades (Lakes) Carpenter and Kitchell (Serengeti) McNaughton et al. Figure 18_12

Bottom-up effects Net Primary Production Plant biomass Herbivore grazing web Detrital web Decomposition Degradable Export Detrital mass Import Refractory Refractory Accumulation Detrital mass Partitioning of net primary production (Cebrian 1999) Compared across all sorts of ecosystems… Plant N and P, and herbivory (Cebrian 1999) Increasing C:N, C:P Think stoichiometry!

Detrital production and refractory accumulation (Cebrian 1999) Increasing C:N, C:P Now make a prediction Questions: Which end of the spectrum is terrestrial Fraction of NPP vs. aquatic? Which line is a. Herbivore chain b. Detrital chain c. Refractory storage low high C:N or C:P % N or P high low

Predict differences between Lindeman’s two chains 1. Phytoplankton 2. Macrophyte Predict differences between Lindeman’s two chains 1. Phytoplankton 2. Macrophyte Higher C:N, C:P Lower C:N, C:P

BIOTIC AVAILABLE UNAVAILABLE CARBON

NITROGEN PHOSPHORUS