Gettel, G. M.. Cornell University, gmg7@cornell.edu
Hershey, A. M.. University of North Carolina, Greensboro, anne_hershey@uncg.edu
Pastor, J. University of Minnesota, jpastor@ub.d.umn.edu

 
THE EFFECTS OF LAKE GEOMORPHOLOGY, FISH ASSEMBLAGE, AND SPECIES RICHNESS ON FOOD WEB STRUCTURE IN ARCTIC ALASKAN LAKES.
 
The Geomorphic-Trophic Hypothesis proposes that the distribution of top fish predators on the North Slope in arctic Alaska is determined by lake geomorphology (area and depth) and stream outflow gradient. Thus, food web structure may be related to these landscape-level characteristics that constrain fish distribution. We tested the effect of four different fish assemblages and lake size, on food web structure in 13 lakes in the vicinity of Toolik Field Station, North Slope, AK. Additionally, we tested the relationship of food web structure with species richness. Benthic, pelagic, and combined whole-lake predation matrices were constructed for each site, and two descriptive statistics were computed: 1). Connectance, the proportion of all possible links that are realized, and 2). Linkage Complexity, the number of links per species. Connectance did not vary significantly with lake geomorphology, fish species, or species richness. Linkage complexity, however, increased with lake size, number of fish species, and species richness. Furthermore, food web structures in benthic and pelagic habitats differed significantly in their relationship to lake geomorphology, fish assemblage, and species richness. These results suggest that food web properties are habitat specific and controlled by landscape-level constraints on the distribution of fish, as predicted by the Geomorphic-Trophic Hypothesis.
 
Day: Wednesday, Feb. 3
Time: 04:30 - 04:45pm
Location: Hilton of Santa Fe
 
Code: CS66WE0430H