vulnerability of freshwater fish communities to human mediated impacts

Vulnerability of freshwater fish Vulnerability of freshwater fish communities to human mediated communities to human mediated

impactsimpacts

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.

Watershed Impacts

Dav

id B

row

ne.

2007

. W

CS

rep

ort

2.

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.

• 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

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

• Focus on large bodied spp.

• Removed spp. that are primarily river dwelling.

• Removed spp. with single occurrences.

• 197 lakes• 20 fish species

• Lake morphology: area (ha), mean depth (m), maximum depth (m).

1a. PCA on physical lake attributes

MNDEP (m)

MAXDEP (m)

AREA (ha)

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

-0.2 0 0.2 0.4 0.6 0.8 1PCA 1

PC

A 2

AREA

DEPTH

(60.9%)

(32

.8%

)

• Water quality: Secchi depth (m), DO (mg/L), PH, TFe, conductivity (mS/cm), TDS (mg/L).

1b. PCA on physical lake attributes

TDSCOND

TFe

PH

DO

SECCHI

-0.2

0

0.2

0.4

0.6

0.8

1

-0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6

PCA 1

PC

A 2

↑ nutrients

↑ clarity & O2

(51.3%)

(19

.1%

)

logperch

Johnny darter

Iowa darter

walleye

sauger yellow perchsmallmouth bass

rockbass

burbot

white suckermuskellungenorthern pike

lake cisco

lake whitefishlake trout

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45

PCA 1

PC

A 2

2. PCA on fish species

(70.1%)

(4.4

%)

• Environmental traits:• LM1 (depth), • LM2 (area), • WQ1 (high nutrients),

• WQ2 (high clarity & O2),

• water temp (oC), • Latitude & longitude

3. CCA on environment and presence/absence of fish species

lake trout

lake whitefish

lake cisconorthern pike

muskellunge

white sucker

burbot

rockbasssmallmouth bass

yellow perch

sauger

walleye

Iowa darterJohnny darterlogperch

LNGLAT

LM1

LM2

WQ1

WQ2

TEMP

-1

-0.5

0

0.5

1

-1 -0.5 0 0.5 1 1.5

CCA 1

CCA

2

3. CCA on environment and presence/absence of fish species

(42.0%)

(37

.3%

)

• 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

Human development

Human development

EFFECTS ON LAKES• Soil erosion leads to increases in:

• sediments, • nutrients, • minerals, • pollutants such as mercury.

• Impact proportional to area logged

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.

Forestry

MiningEFFECTS 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

MiningSPECIES 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.

HydroelectricEFFECTS ON LAKES

• Reservoir creation

• Barrier to migration

• Altered flow regime

HydroelectricSPECIES 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

Climate changeEFFECTS ON LAKES• Loss of cold water habitat.

• Decreases in water levels.

• Increased water temperatures.

Climate changeSPECIES 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.

• 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.

Things to think about

Acknowledgements

• Wildlife Conservation Society

• McGill University

• Ivey Foundation

• OMNR