RATES OF NATURAL AND ANTHROPOGENIC CHANGE IN SHORELINE HABITATS IN THE KINGSTON BASIN, LAKE-ONTARIO

Shoreline habitats in the Kingston Basin have experienced continual ch ange on a wide range of time scales, as a result of physical, chemical , and biotic stresses of both natural and anthropogenic origin. Not al l change can or should be controlled. From a management perspective, s tresses can be usefully subdivided into those that originate from the lake as a whole (e.g., water-level and-chemistry changes, introduction of exotic species) and those originating from the adjacent land area (e.g., point-source contamination and sedimentation). Stresses from th e lake cannot be controlled locally, whereas those arising from terres trial activities are more easily managed. Slow rates of change are les s likely to have dramatic effects than rapid change, but a small chang e can have catastrophic effects if it exceeds the threshold tolerance of an ecosystem. Dramatic alterations to the entire ecosystem can also occur if a single, important species (e.g., a macrophyte) is adversel y affected, because of complex feedback responses between the various components of the system. Thus, management strategies should focus on those areas that are particularly susceptible to land-based stress and on stresses that are most likely to exceed the tolerance of key compo nents of an ecosystem.