Date of Award

10-19-2015

Degree Type

Thesis

Degree Name

M.Sc.

Department

Earth and Environmental Sciences

First Advisor

Fisk, Aaron

Keywords

functional redundancy, stable isotopes, trophic ecology, trophic position

Rights

CC BY-NC-ND 4.0

Abstract

The Laurentian Great Lakes are home to a high biodiversity of freshwater piscivorous predators; however the trophic role of these species is poorly understood. Using stable isotopes of carbon (δ13C) and nitrogen (δ15N), I examined trophic position, niche widths and overlap of piscivorous predators across three sites in the Lake Huron-Erie Corridor (HEC). Trophic position (TP) was determined by δ15N, while habitat utilization was measured using δ13C. Across all sites and species, mean trophic position ranged from 4.0 to 5.1, were highest for Longnose Gar (Lepisoteus osseus), and lowest for Northern Pike (Esox lucius). Bowfin (Amia calva) had a larger niche width and low overlap with other predators across site, while Longnose Gar and Northern Pike had the smallest niche widths and high interspecific overlap. Variation in TP, niche width and overlap suggested different foraging behaviour, trophic interactions, and more complex food web structure in the HEC than previously believed.

Share

COinS