Anthony Ragnar Ives, Professor of Biological Sciences and head of the Ives lab at University of Wisconsin-Madison, will give a presentation of his research:
Ecosystems that show huge changes through time can reveal the ecological forces that stabilize or destabilize natural systems. Midges in Lake Mývatn, Iceland, are an extreme example, with abundances that fluctuate over four orders of magnitude in irregular cycles lasting 4-8 years. Based on research conducting for over 40 years, we suspect that these fluctuations are caused by the midges' ability to deplete their food supply. If this hypothesis is correct, then Mývatn will be a rare example in which the interactions between herbivores and their food create a highly unstable ecosystem.
Midge fluctuations affect most species in the aquatic community, and also many species on shore that experience a pulse of midge adults during the midge emergence periods. The effects of midges are seen in species that fluctuate synchronously, or asynchronously, with midges. By analyzing these patterns, and by performing experiments to investigate possible underlying mechanisms, we hope to understand how the midge fluctuations are transmitted through the aquatic and terrestrial Mývatn food webs.