PARENT SESSION
Oral Session #58: Theoretical Ecology.
Presiding: M. Neubert
Wednesday, August 7. 8:00 AM to 11:30 AM. Grand Ballroom East, Radisson.

Investigating pathway proliferation in ecological networks.

BORRETT, STUART^*,1, FATH, BRIAN², PATTEN, BERNARD¹, ¹ University of Georgia, Athens, GA² Towson University, Towson, MD

ABSTRACT- Ecosystem network structure determines the direct and indirect pathways over which energy, matter, and information can flow. Increasing the number of pathways increases the number of possible ways for conservative material travel between network nodes. In the work presented here, we use structural network analysis to investigate ecosystem pathway proliferation. Each network structure has a characteristic growth rate in the number of paths between each node-node pair. We use this number as a benchmark for comparing different network structures. Specifically, we are interested in the relationship between the pathway growth rate and the ratio of indirect to direct (I/D) influence in the system. Earlier work has shown that six factors contribute to an increase in the I/D effects: system order, connectivity, feedback, direct strength, looping, and cycling. All but direct strength is related to network structure. Clearly, a higher growth rate in the number pathways will result in a greater contribution of indirect influence in the system, but the specific underlying connectance patterns have not been explored. Here, we use randomly generated ecological networks to determine the effect of connectance pattern on the characteristic pathway growth rate and I/D. Results show multiple classes of network topology with characteristic effects on pathway proliferation and I/D.

KEY WORDS: network, indirect effects, connectance pattern, random networks