Vulnerability of freshwater fish communities to human mediated impacts

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