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Vulnerability of freshwater fish communities to human mediated impacts

Vulnerability of freshwater fish communities to human mediated impacts. Jenni McDermid 1 and David Browne 1,2 1 Wildlife Conservation Society Canada, Peterborough, ON 2 Canadian Wildlife Service, Gatineau, QC. Background. Most threatened and altered

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Vulnerability of freshwater fish communities to human mediated impacts

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  1. Vulnerability of freshwater fish communities to human mediated impacts Jenni McDermid1 and David Browne1,2 1Wildlife Conservation Society Canada, Peterborough, ON 2Canadian Wildlife Service, Gatineau, QC

  2. Background • Most threatened and altered • 20% of freshwater fish have become threatened, endangered, or extinct • Canada is rich in freshwater ecosystems • Yet degradation of these waters is becoming increasingly more evident.

  3. Watershed Impacts David Browne. 2007. WCS report 2.

  4. River fragmentation Dynesius & Nilsso. 1994. Science (266): 753-762.

  5. Fish biodiversity Chu et al. 2003. CJFAS (60): 624-634.

  6. Land use decisions • Northern Ontario contains a wealth of natural resources of significant economic importance: • Hydroelectricity • Mining • Forestry • As development moves northward land use decisions need to be based on baseline information. • Particularly important for aquatic systems.

  7. Methods • Focused on lakes and existing scientific information. • Fish Species Distribution Data System of the Ontario Ministry of Natural Resources. • Presence and absence of fish species in lakes in northern Ontario. • Biases of existing information: • Primarily larger lakes • Sampling targeted towards larger bodied fish.

  8. Methods • Principal Components Analysis (PCA) on lake morphology variables and water quality variables. • PCA on fish species. • Canonical Correspondence Analysis (CCA) to examine the relationship between physical lake characteristics and the presence/absence of fish species. • Implications of human development activities and climate change on northern Ontario fish communities.

  9. Study area • Focus on large bodied spp. • Removed spp. that are primarily river dwelling. • Removed spp. with single occurrences. • 197 lakes • 20 fish species

  10. 1a. PCA on physical lake attributes AREA DEPTH • Lake morphology: area (ha), mean depth (m), maximum depth (m). (32.8%) (60.9%)

  11. 1b. PCA on physical lake attributes ↑ clarity & O2 ↑ nutrients • Water quality: Secchi depth (m), DO (mg/L), PH, TFe, conductivity (mS/cm), TDS (mg/L). (19.1%) (51.3%)

  12. 2. PCA on fish species (4.4%) (70.1%)

  13. 3. CCA on environment and presence/absence of fish species • Environmental traits: • LM1 (depth), • LM2 (area), • WQ1 (high nutrients), • WQ2 (high clarity & O2), • water temp (oC), • Latitude & longitude

  14. 3. CCA on environment and presence/absence of fish species (37.3%) (42.0%)

  15. Human development • Resource potential in northern Ontario is high. • Forestry: Northern Boreal Initiative: OMNR, 2000, provide First Nations north of the legal limit of forestry opportunities for commercial forestry. • Mining: Mining exploration underway. • Hydroelectricity: identified hydroelectric sites. • Climate change

  16. Human development

  17. Forestry EFFECTS ON LAKES • Soil erosion leads to increases in: • sediments, • nutrients, • minerals, • pollutants such as mercury. • Impact proportional to area logged

  18. Forestry SPECIES AFFECTED • ↑ Sediments and nutrients will ↓ lake clarity and species associated with this attribute – lake trout. • Such species have previously been found to be particularly sensitive to changes in quality of spawning habitat. • ↑ nutrients may have a slight beneficial effect on species associated with higher TDS – walleye, northern pike, and yellow perch. • Mercury has negatives effects on reproduction, behavior and growth and survival of young.

  19. Mining EFFECTS ON LAKES • Mine effluent and tailings • Mine effluent released to surface or ground water contaminated by metals, acids, salts. • Gold mine: cyanide (highly toxic) to remove gold from ore. • Physical alteration by rerouting of water • Draining and infilling entire lakes

  20. Mining SPECIES AFFECTED • Mine effluent and tailings • Toxic effluents effect on all fish species. • Physical alterations • Depending on the area being dewatered this can impact any fish species.

  21. Hydroelectric EFFECTS ON LAKES • Reservoir creation • Barrier to migration • Altered flow regime

  22. Hydroelectric SPECIES AFFECTED • Minimal impact on lake characteristics included in this study. • Creation of reservoirs or increased reservoir size may promote species associated with LM 2 (larger lake areas) – walleye, northern pike, yellow perch • Primary impact on river species and species that migrate into rivers for spawning. • Changing water levels in reservoir can effect shallow spawning fish like pike, walleye, and minnows

  23. Climate change EFFECTS ON LAKES • Loss of cold water habitat. • Decreases in water levels. • Increased water temperatures.

  24. Climate change SPECIES EFFECTED • ↑ water temperature, ↑ warm water species currently at the northern extent of their range – muskellunge, rockbass, smallmouth bass, sauger • Negative interactions from species moving north. • E.g. Introduced bass have been shown to have negative impacts on minnow communities and things that may eat them.

  25. Things to think about • Need better understanding (fish and development impacts). • Identify areas of subsistence use. • Incorporate fish into land use planning as an important feature. • Both mines and hydro-development effect water more than other land feature. • Impact on remote tourism.

  26. Acknowledgements • Wildlife Conservation Society • McGill University • Ivey Foundation • OMNR

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