PARENT SESSION
Oral Session # 84: Trophic Structure II: Terrestrial and Aquatic Systems.
Presiding: MD Moran
Thursday, August 7. 1:30 PM to 5:00 PM, SITCC Meeting Room 202.

Ecological network analysis: Weak links and indirect effects in food webs.

Fath, Brian¹, Patten, Bernard^*,1, ¹ Biology Department, Towson, MD, USA

ABSTRACT- A recent paper in Science (Neutel et al. 2002, Science 296:1120-23) uses traditional food web analysis to demonstrate the importance of "weak links" in web stability. We consider the described methodology to grossly underestimate the importance of weak links, and also the indirect effects these carry. The cited paper, regarded by Rafaelli (2002, Science 296: 1035-37) as a theoretical breakthrough to "modern formal analyses", made no reference to an already existing body of modern formal network analyses based on input-output (I/O) methods. The two literatures, "food web" and "network", coexist but overlap little even through they treat the same basic kind of model structure (mathematically, directed graphs). We consider how this arose from original conceptions of Darwin vs. Haeckel, and how conceptual dichotomy led to methodological dichotomy. Then we reinterpret the food web approach in I/O terms to produce a clearer account of energy-matter transactions in ecological networks and how indirect relationships come to dominate through the weak links in transfer processes.

Key words: ecological networks, food webs, input-output analysis, indirect effects