Monitoring Wetland Health in the Credit River Watershed

Preliminary Results and TrendsAviva Patel

Terrestrial Monitoring Goals

Identify status and trends in wetland health parameters at the watershed scale, link to watershed health

Identify spatial patterns in wetland health parameters

Provide meaningful data on which watershed management decisions can be based

Why Monitor Wetlands?

• Wetlands provide numerous functions:– Flow moderation– Water purification– Erosion control – Carbon sequestration

• Wetland Monitoring allows:– Detection of habitat loss

or degradation– Adaptive environmental

management

Credit River Watershed

Credit Valley Watershed

• Physiographic Zones– Lower: Heavily urbanized– Middle: Niagara

Escarpment & Oak Ridges Moraine

– Upper: Urban, agriculture and natural

• Monitoring Sites– 18 Vegetation Sites– 26 Amphibian Sites

Wetland Indicators

Wetland Health

Landscape

Vegetation

Wildlife

Regeneration Ground cover

Marsh birds Amphibians (frogs & toads)

Water

4 years

6 years

Wetland Cover• 6% of watershed area• <3% in Lower Watershed• Fair – Good in Middle and

Upper Watersheds• ~48% wetland loss since 1954• 81% swamp, 18% marsh

0200400600800

1000120014001600

0-1 1-4 4-10 10-30 30-50 50-100 >100

Wetland size class

Freq

uenc

yWetland size

Majority of wetlands <1ha but these contribute only 25% of total wetland area

75% of area

(ha)

Vegetation - Methods

• EMAN & CVC Methodology

• 50 m transect

• 12 subplots

• 2 x 2 m Regeneration

• 1 x 1 m Vegetation

• All taxa identified to species& percent cover recorded

Vegetation - Indicators

– Richness– Diversity– Locally and Regionally

rare species– Floristic Quality

Assessment• Mean Coefficient of Conservatism (mCC)• CC 8-10• Average Wetness• Average Weediness• Weediness Score -3

Vegetation - Results

• 465 herbaceous and woody plants identified to species level (37% of watershed total)

8%

17%

53%

4%

2%

0%

6% 10% 0%TreeShrubForbFernVineRushGrassSedgeOther

82% native

Vegetation – species richness & diversity

• Temporal Trends

– Increasing plant species richness and diversity

• Increasing knowledge of sites

• Changes in monitoring team

Ground Vegetation

Richness

Diversity

Vegetation – native species• Temporal patterns

– Proportion of native species decreasing over time

0.76

0.78

0.8

0.82

0.84

0.86

0.88

0.9

0.92

2005 2006 2007 2008Year

Prop

ortio

n of

Nat

ive

Spec

ies

Vegetation – native species

• Spatial patterns– Proportion of native species

• Lower < Middle and/or Upper

0.50

0.60

0.70

0.80

0.90

1.00

2005 2006 2007 2008

Year

Prop

ortio

n of

Nat

ive

Spec

ies

LowerMiddleUpper

Vegetation – weedy species

• Temporal patterns– Number of weedy species (Weediness score - 3) is

increasing

0

1

2

3

2005 2006 2007 2008

Year

Mea

n -3

Per

Site

Vegetation – weedy species

• Spatial patterns– -3 weedy species different among zonesLower > Middle & Upper

0

1

2

3

4

5

2005 2006 2007 2008Year

Num

ber o

f Spe

cies

LowerMiddleUpper

Amphibians - Methods

• Marsh Monitoring Program protocols

• Calls recorded to estimate amphibian numbers and species– C1 – calls not overlapping– C2 – calls overlapping– C3 – full chorus

Amphibians - Indicators

Frogs and toads:

– Richness– Abundance– Site Occupancy

0

0.5

1

1.5

2

2.5

3

3.5

4

2003 2004 2005 2006 2007 2008

Year

Spec

ies

richn

ess

per s

ite

Amphibians – trend analysis

• Nine species detected, only mink frog not detected• No observable trend in amphibian species richness,

abundance or site occupancy over the monitoring period

Amphibians – number of species per site

Amphibians – spatial analysis• Species richness varied between physiographic

regions– Lower < Middle and/or Upper

Amphibian Species Richness

00.5

11.5

22.5

33.5

44.5

5

2003 2004 2005 2006 2007 2008

Year

Spec

ies

richn

ess

per s

ite

LowerMiddleUpper

Amphibians – spatial analysis

• Spring Peeper absent from Lower zone

• No full chorus of any frog or toad species detected in Lower zone

Photo credit: Toronto Zoo

Summary

• Relatively stable plant and amphibian richness and diversity

• Relatively stable trends in plant wetness index and coefficient of conservatism

• Data suggest urbanization is affecting native biodiversity– Lower Watershed has fewer amphibian species and lower

proportion of native plants than Middle and Upper Watershed

• Increasing numbers of -3 level weedy species in watershed

Future Work

• Increase number of sites

• Panel design to minimize impact on sites

• Addition of hydrology and water quality parameters

Thank you

apatel@creditvalleyca.ca