| The historical formation of aquatic ecosystems and the regional environmental processes acting at the watershed level are important components in the conservation of aquatic ecosystems which are often neglected. This thesis integrates the fields of community and landscape ecology, conservation biology, multivariate statistics and geographical information processing in an attempt to examine the ecology of fish communities within 550 inland lakes in the Great Lakes - St. Lawrence basin of Ontario with respect to their local and regional environment and historical lake formation. These lakes have been grouped into six geographic regions: Wellington, Bruce Peninsula, LaCloche, Sudbury, Wawa, and Algoma.; Two new constructs have been created which describe lakes based on their historical formation: “relict” and “solus”. A relict lake is defined as a lake that was once part of a large waterbody presumably sharing a common species pool that has since receded to form a number of smaller lakes. A solus lake is defined as a lake formed in isolation which was never a part of a larger water system or species pool.; Differences in fish community structure, environment, and species-environment relationships were examined between proximally paired relict and solus lake regions using a suite of multivariate statistics. The results of this study conclude that relict and solus lakes have significantly different local and regional environments, fish community structure, and species-environment relationships. Striking similarities were also found between relict and solus lakes and landbridge and oceanic islands, respectively, regarding historical formation, extinction and colonization potential, and community structure. The results strongly suggest that solus lakes and their surrounding watersheds represent ecologically distinct aquatic systems within Ontario containing unique environments and fish species assemblages. Recommendations are made for the inclusion of solus lake regions as provincial “Areas of Natural and Scientific Interest”. Therefore the recognition of lakes as historical constructs which I term relict and solus provides insight into conservation planning for fish biodiversity. |
