Date of Award


Publication Type

Master Thesis

Degree Name



Biological Sciences


Biology, Limnology.



Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.


Electrophoretic surveys of asexual Daphnia pulex populations in coastal rock bluff ponds near Churchill, Manitoba revealed 36 unpigmented clones. Three clones dominated the assemblage in both years. Coexisting clones were not ecological analogues, and coexistence in these ponds was facilitated by seasonal shifts in fitness as well as rescue effects from ephippial egg banks. Of the three dominant clones, Clone 1 occurred in high-salinity habitats, while clones 13 and 14 were found in lower salinity ponds. In pairwise competitive interactions among the three dominant clones, clones were competitively superior in their native habitats and inferior away from them. Interactions between clones 13 and 14 showed that in the presence of H. arcticus, Clone 13 was displaced. Reproductive differences among clones in multiclonal and experimental ponds showed varying predictive ability for clonal frequencies at the next sampling intervals. Observations showed that environmental heterogeneity, competition and predation all influence the structure of this clonal assemblage. (Abstract shortened by UMI.)Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1990 .W558. Source: Masters Abstracts International, Volume: 30-03, page: 0638. Thesis (M.Sc.)--University of Windsor (Canada), 1989.