Transcript FPL131 - Fisheries Conservation Foundation

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
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.
David Browne. 2007. WCS report 2.
Watershed Impacts
River fragmentation
Dynesius & Nilsso. 1994. Science (266): 753-762.
Fish biodiversity
Chu et al. 2003. CJFAS (60): 624-634.
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.
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.
Methods
1.
Principal Components Analysis (PCA) on lake morphology variables
and water quality variables.
2.
PCA on fish species.
3.
Canonical Correspondence Analysis (CCA) to
examine the relationship between physical lake characteristics and
the presence/absence of fish species.
4.
Implications of human development activities and climate change on
northern Ontario fish communities.
Study area
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•
•
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Focus on large bodied
spp.
Removed spp. that are
primarily river dwelling.
Removed spp. with
single occurrences.
197 lakes
20 fish species
1a. PCA on physical lake attributes
• Lake morphology: area (ha), mean depth (m),
maximum depth (m).
1
AREA
AREA (ha)
PCA 2 (32.8%)
0.8
0.6
0.4
0.2
0
MAXDEP (m)
MNDEP (m)
-0.2
-0.4
-0.2
0
0.2
0.4
PCA 1 (60.9%)
0.6
0.8
DEPTH
1
1b. PCA on physical lake attributes
• Water quality: Secchi depth (m), DO (mg/L), PH,
TFe, conductivity (mS/cm), TDS (mg/L).
PCA 2 (19.1%)
1
↑ clarity & O2
0.8
SECCHI
0.6
DO
0.4
PH
0.2
0
-0.2
-0.2
TFe
-0.1
0
0.1
0.2
0.3
PCA 1 (51.3%)
0.4
0.5
COND
TDS
0.6
↑ nutrients
2. PCA on fish species
PCA 2 (4.4%)
0.8
Johnny darter
0.6
Iowa darter
logperch
0.4
0.2
rockbass
sauger
smallmouth bass
muskellunge
0
yellow perch
northern pike
lake cisco
walleye white sucker
-0.2
lake trout
-0.4
lake whitefish
burbot
-0.6
0
0.05
0.1
0.15
0.2
0.25
PCA 1 (70.1%)
0.3
0.35
0.4
0.45
3. CCA on environment and
presence/absence of fish species
• Environmental traits:
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LM1 (depth),
LM2 (area),
WQ1 (high nutrients),
WQ2 (high clarity & O2),
water temp (oC),
Latitude & longitude
CCA 2
(37.3%)
3. CCA on environment and
presence/absence of fish species
1
muskellunge
sauger
0.5
LM2
walleye
northern pike
-1
LNG
LAT
-0.5
WQ1
rockbass
yellow perch
TEMP
0
lake cisco
Iowa darter
Johnny darterwhite
0 sucker
lake whitefish
logperch
burbot
-0.5
smallmouth bass
0.5
1
WQ2
LM1
lake trout
-1
1.5
(42.0%)
CCA 1
Human development
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Resource potential in northern Ontario is high.
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Forestry: Northern Boreal Initiative: OMNR, 2000, provide First
Nations north of the legal limit of forestry opportunities for
commercial forestry.
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Mining: Mining exploration underway.
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Hydroelectricity: identified hydroelectric
sites.
Climate change
Human development
Forestry
EFFECTS ON LAKES
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Soil erosion leads to increases in:
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sediments,
nutrients,
minerals,
pollutants such as mercury.
Impact proportional to area logged
Forestry
SPECIES AFFECTED
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↑ 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.
Mining
EFFECTS ON LAKES
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Mine effluent and tailings
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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
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Draining and infilling entire lakes
Mining
SPECIES AFFECTED
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Mine effluent and tailings
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Toxic effluents effect on all fish species.
Physical alterations
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Depending on the area being dewatered this can impact
any fish species.
Hydroelectric
EFFECTS ON LAKES
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Reservoir creation
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Barrier to migration
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Altered flow regime
Hydroelectric
SPECIES AFFECTED
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Minimal impact on lake characteristics included in this
study.
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Creation of reservoirs or increased reservoir size may promote
species associated with LM 2 (larger lake areas) – walleye,
northern pike, yellow perch
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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
Climate change
EFFECTS ON LAKES
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Loss of cold water habitat.
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Decreases in water levels.
•
Increased water temperatures.
Climate change
SPECIES EFFECTED
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↑ water temperature, ↑ warm water species currently at
the northern extent of their range – muskellunge,
rockbass, smallmouth bass, sauger
•
Negative interactions from species moving north.
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E.g. Introduced bass have been shown to have negative
impacts on minnow communities and things that may eat
them.
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.
Acknowledgements
• Wildlife Conservation
Society
• McGill University
• Ivey Foundation
• OMNR