The hot and cold, wet and dry of river food webs
January 11, 2013
Dr. Tim Jardine
School of Environment and Sustainability
University of Saskatchewan
Seminar: Friday, January 11 @ 3:45
Rm. 106, Biology Lecture Theatre
W.P. Thompson (Biology) Building
Abstract: The observation that peaks in species richness occur in tropical regions is a well-studied phenomenon that has been called “ecology’s oldest pattern”. Less well-understood are the implications of this pattern for ecosystem structure and function. Streams and rivers in Australia provide a template to study changes in food web organization across latitudinal gradients because of the continent’s extensive north-south coastline and productive tropical wetlands. Here I examine underlying carbon sources supporting food webs and patterns in the length of food chains in streams that span 25 degrees in latitude. Algal carbon contributed strongly to invertebrate food webs in all regions, especially so in productive tropical and subtropical streams, and a common predator (longfinned eels) fed approximately one trophic level lower in the tropics compared to temperate systems. These patterns provide evidence for short, productive, inter-connected food webs in the tropics, and have implications for the maintenance of populations of iconic species such as barramundi and estuarine crocodiles.
