plugin-cootes restoration lecture

8/8/2019 Plugin-Cootes Restoration Lecture

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Chow-FraserPatricia Chow-Fraser

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Restraon of Coos Paradise Marsh: A synopsisDr. Pat Chow-Fraser

Biology 2F03 Fall 2010


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Distribution ofCanadian Great Lakes coastal wetlands


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Farming has been most harmful for coastal wetlands


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Farming has been most harmful for coastal wetlands

From GLEI (Great Lakes Environmental Indicators project)

Water Quality Index

(WQI) measures theamount of pollutants in

the wetland stemming

from surface runoff


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Urbanization impacts?

Current

home ofMcMaster

University

Turtle

habitat

90% loss of

aquatic

vegetation


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Currently, the water-shed* has relativelylarge portions ofdeveloped land that

can lead to a highloading of nutrientsand sediments.

Change in wetland hydrogeomorphology

Desjardins

Canal wasdredged and

had to becontinously

cleared of

aquatic plantsand sediment


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1. During construction of theDesjardins Canal, sedimentexcavated were placed onadjacent banks andprevented overbank floodsfrom nourishing the marshfor 100 years.

2. Sedimentation rate is alsoreduced because finesubstrate (clay) stays insuspension and is easilytransported into HamiltonHarbour.


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3. Construction oftwo dams tocontrol floodingon the UpperSpencer Creekresulted insedimentretention of atleast 60%,

further reducingsedimentnourishment inthe marsh.

4. Urbanization ofwatershedincreased totalrun-off and floodpeaks, but claysubstrate stayedin suspension andwas quicklydischarged into

HamiltonHarbour throughthe Desjardinscanal.


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5. Disturbance byexotic species, thecommon carp, canresuspendsediment and addto loweredsedimentation rate.

Relevant literature ...

Chow-Fraser, P., Lougheed, V.L., Crosbie, B., LeThiec, V., Simser, L., andLord, J. 1998. Long-term response of the biotic community tofluctuating water levels and changes in water quality in CootesParadise Marsh, a degraded coastal wetland of L. Ontario. WetlandEcol. Manage. 6: 19-42.


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1948 1973 1994

Secchi depth 40 23 22

Turbidity 31 37 54

Chlorophyll 189 54

In 1946:16 taxa, including those thatrequire good light penetration(pondweed, waterweed, etc.) In 1995:1species primarily (sago

pondweed) accounting for only1% of the aquatic vegetativecover.


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In 1946:22 taxa accounting for 46% vegetative cover,dominated by 3 different species; higher plantdiversity In 1995:8 species, accounting for 10% , primarily cattailsand some non-native species such as purple

loosestrife and the common reed from Eurasia


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According to Whillans

(1982), 76% of areal coverof emergent vegetation

present in 1800s haddisappeared to


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Now,small zooplankton(Bosmina) and rotifers

dominate.

Daphnia

Piscivores

Planktivores

Benthivores

Largemouth bass Northern pike

Eat other fish

and variety of

invertebrates

Eat phytoplankton

and zooplankton

Eat benthic

invertebrates

Alewife

Common carp Bullhead

And many immature

fish species


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31 species Piscivores and

benthivores and a fewplanktivore taxa

Northern pike,largemouth bass, whitesuckers, gizzard shad,common carp, somealewife

Good representation oftaxa; carp dominateonly in low-DOconditions

35 Species Planktivores and

benthivores; fewpiscivore taxa

Common carp,pumpkinseed

white perch, alewife Few taxa dominate;

carp dominatethroughout the marsh

In the past 30 years, water levels are too high to establish a

large emergent vegetation community


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Relationship between number of

submergent taxa found in coastalwetlands and water turbidity.

Poor water clarity prevents viable

submergent plant community to

become established.

Major contributors of nutrients today are CSO,

sediment regeneration and Spencers Creek


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When common carp spawn, they thrash

during mating and can resuspend

sediment.

When they feed, they

create poofs through

their sucking action on

the sediment.

85%

EmergentsLow Water Level

Low Water

TurbiditySediment Loading

from Watershed

Sewage

Creeks

Low

Nutrients

DiverseSubmergent

Community

DiverseBenthos with

numerous

Insect Larvae

Lower Algal

Biomass

High

Piscivore

Biomass

Low

Planktivore

Biomass

Large

Herbivorous

Zooplankton

1 2

3

4

5

6

9

Low

Epiphyton

biomass

7

8

10

11

12

13

14

15

Conceptual

food-web

model ofhealthywetland


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High Water Level

Wind ResuspensionHigh Water

TurbiditySediment Loadingfrom Watershed

Internal Loading

Sewage

Creeks

Combined Sewer

Overflows

High

Nutrients

Carp

Feeding

High Algal

Biomass

Loss of

Submergents

Diurnal

Dissolved

Oxygen Flux

Benthos tolerant

of low DO andsoft substrate

Loss of

Emergents

High

Epiphyton

Biomass

12

9

7

17

6

5

4

3

11

10

8

12

16 15

14

13

18

Small

Herbivorous

Zooplankton

Low

Piscivore

Biomass

High

Planktivore

Biomass

19

20

21

22

23

24

Carp

Spawning

25

26

28

27

29

30

Conceptu

alfood-

webmodel of

degraded

wetland


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High Water Level

Wind ResuspensionHigh Water

TurbiditySediment Loadingfrom Watershed

Internal Loading

Sewage

Creeks

Combined Sewer

Overflows

High

Nutrients

Carp

Feeding

High Algal

Biomass

Loss of

Submergents

Diurnal

Dissolved

Oxygen Flux

Benthos tolerant

of low DO andsoft substrate

Loss of

Emergents

High

Epiphyton

Biomass

12

9

7

17

6

5

4

3

11

10

8

12

16 15

14

13

18

Small

Herbivorous

Zooplankton

Low

Piscivore

Biomass

High

Planktivore

Biomass

19

20

21

22

23

24

Carp

Spawning

25

26

28

27

29

30

Conceptu

alfood-

webmodel of

degraded

wetland

Initiated by International JointCommission in 1987

Hamilton was one of 43 Areas ofConcern

RAP was developed in 1992 thatincluded marsh restoration planof Cootes Paradise


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When fish swim up to

the grates, they either

turn around or swim

into baskets..

Fish migrate out of

marsh in fall and into

the marsh in spring


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Baskets hand

sorted and

identified and

carp are sent

back to the

harbour and allothers are

allowed into the

marsh

0

10

20

30

40

1996 1997 1998

After exclusion


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Before exclusion After exclusion

400 carp/ha 10-40 carp/ha

Good

Moderately

degraded

Very

degraded

Highly

degraded


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Veryg

ood

Exce

llent


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Water levelEffluent from sewage treatment plantHigh water turbidityCarp bioturbationWind and wave actionDredging of the Desjardins CanalInfilling for road buildingBuilding of dams upstream


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The cattail species (Typha latifolia) that

could not tolerate inundation (being submersed

in water) was eventually replaced by the

putative hybrid species (Typha Xglaucai) that

could tolerate inundation.

This species is much more resistant to water-level fluctuations but is not native to the marsh


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plugin-cootes restoration lecture

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