This Thursday, Dr. William R. Glass will talk about the
Northern range edge populations of Spotted Gar: local adaptation and implications for conservation
at 12:30 in the EEB lounge (BioSciences 4338)
The seminar is hosted by your EEB committee
Populations at the edge of a species’ range are often small, isolated, and exposed to harsh environmental conditions compared to populations at the core of the range. These factors can lead to edge populations evolving at a faster rate than core populations, giving rise to local adaptation in edge populations. Thus, it becomes important to conserve range edge populations if the goal is to preserve the overall diversity within a species. Local adaptation can be manifest in many forms including changes to life history, altered behaviour and ecological interactions, and genetic differentiation.
The Spotted Gar (Lepisosteus oculatus) is a Threatened fish species in Canada. The species is at the northern edge of its range in Canada and is found in three coastal wetlands of Lake Erie: Point Pelee; Rondeau Bay; and, Rondeau Bay. Spotted Gar ranges as far south as the Gulf of Mexico, is generally common, and not considered to be at risk outside the Great Lakes region. We investigated the local adaptation of Canadian Spotted Gar populations through a radio-tracking study of the home range and critical habitat utilized by the Rondeau Bay population, along with a range-wide population genetic study using microsatellite loci. It was found that the Spotted Gar in Rondeau Bay use aquatic macrophytes as cover, and inhabit areas much further offshore than a core population of Spotted Gar in the Atchafalaya River basin in Louisiana, which typically uses sunken timber for cover. Population genetic data reveal that the northern populations of Spotted Gar are distinct from southern populations. Additional population structure within the Canadian sample sites was also uncovered. The results of these two studies were used to inform the Spotted Gar Recovery Strategy and the conservation of the Canadian populations of Spotted Gar will be important for the maintenance of the overall diversity within the species.
Bill completed his undergraduate degree and PhD at the University of Windsor, where he studied local adaptations of range edge populations of fish Species at Risk in Canada. He is currently working as a post-doctoral Visiting Fellow at Fisheries and Oceans Canada studying abundance, distribution and habitat use of fish Species at Risk.