Food webs

Figure 1. Simplified food-web structure in the Waikato River ecosystem.

Large rivers, such as the Waikato River, receive inputs of carbon from a range of sources such as upstream reservoirs which may act as hotspots of phytoplankton production, inputs of carbon from tributary sources draining wetlands and lakes, seasonal leaf-fall from exotic willow trees, internal phytoplankton and zooplankton production within the main river, and inputs of marine-derived carbon from migrating fish and shrimps. Understanding the relative significance of these various inputs and trophic pathways that lead to the nutrition of consumers, such as fish, is essential knowledge for enhancing productivity and maintaining ecological health.

Current projects

Michael Pingram is developing food web models to determine the significance of different energy sources to the Lower Waikato River. This involves quantifying food resources and energy flow through food webs, determining the relative significance of algal production compared terrestrial inputs, understanding the roles of tributary junctions and side-arms in food web resilience. (Michael Pingram).
View poster "Pingram, M., Collier, K., Hamilton, D., Hicks, B. and David, B. 2011. Food webs in New Zealand’s longest river.Vienna, April 11-14, 2011." here.