Communicating Ecology through Food Webs: Visualizing and Quantifying the Effects of Stocking Alpine Lakes with Trout

This chapter covers the concept of food web as a means to intuitively and synthetically visualize and communicate about complex interconnections among species in natural communities. Given this pervasive use of structural food webs as a teaching tool, it is perhaps surprising that they are rarely used in resource management to communicate about system-level impacts of human activities. Despite calls for more holistic approaches to "ecosystem management," a single species focus remains the norm. Broader considerations may include physical or biotic "habitat" protection, but rarely do they explicitly incorporate fundamental species interactions, such as feeding relations. In addition to qualitatively describing multivariate community changes in an intuitively tractable form, quantitative changes in web structural properties may offer novel insights into potential ecological consequences of these changes. Basic binary structural food webs provided a compact, visually accessible description of the dramatic, multivariate, community-level changes and recovery of alpine lakes in response to introduced trout. Stocked lakes with trout present had dramatically simplified food webs compared to lakes that never had fish. It has been well documented that species dynamics are difficult to infer from a simple knowledge of binary link structure alone. Similarly, nontrophic processes such as recruitment, abiotic conditions, disturbance, facilitations, and interference competition often regulate the presence and relative abundances of species in a community.