Goal:
Aquatic ecosystems of the Boreal Shield Ecozone (BSE) include a diversity of lakes, ponds, wetlands, streams and rivers linked over the landscape in nested drainage basins. This connectivity can lead to higher degrees of interdependence and similarity in physical, chemical and biological conditions within drainage basins than across drainage basins. Thus, the drainage basin is a logical unit of aquatic ecosystem research. Fish community surveys on the BSE mostly target larger lakes (> 100 ha) that support fisheries, and there is a tendency to interpret fish biodiversity at the landscape scale from conditions in these larger lakes. Smaller lakes and streams provide habitats and refuges for fish species that are rare or absent in larger lakes and thus contribute to the overall biodiversity and productivity of drainage basins. This research proposes to advance aquatic biodiversity assessment to the landscape scale by developing assessment methods that sample all aquatic habitats within drainage basins.
General hypotheses and some current projects:
This research will be initiated in the recovering landscape of the historical acid deposition zone in northeastern Ontario, Canada, and in nearby reference drainage basins adjacent to the impact zone. Acid rain and metals deposition in NE Ontario was at a large spatial scale, potentially influencing all types of aquatic ecosystems within each of many drainage basins, and biological recovery appears to be lagging chemical recovery in many of these waters. Working hypotheses at the outset of this research program include:
1) Interpretation of the progress of biological recovery in aquatic ecosystems is dependent on the scale of observation
2) Within acid-damaged drainage basins of NE Ontario, biological recovery varies with respect to waterbody type (lake vs river), waterbody size, landscape position, and connectivity
3) Biological recovery within acid-damaged drainage basins is primarily limited by barriers to re-colonization rather than environmental suitability