Siobhan FennessyKenyon College

Assessing the Ecological Condition of Wetlands on a Watershed Basis using a Rapid Method:

The Cuyahoga River as a Case Study

Wetlands in the US

To date, nearly 55% of wetlands in the U.S. have disappeared (Dahl 1990)90% loss in Ohio Results in loss of ecosystem services that wetlands provide

Stressor Gradient

Ecol

ogic

al In

tegr

ity Ultimate Goal: to protect ecological integrity

low

high

low high

(e.g., land-use or other human activity gradients)

How do Ecosystems Respondto Disturbance?

Tiered Assessment Methods

Comprehensive Assessment- level 3– Reference based– Data collection averages 4 hours for 4 people– Index of Biotic Integrity

Rapid Assessment- level 2– Data collection averages 1-2 hours for 1-2 people– Calibrated to Comprehensive Assessment– Combines stressor and condition metrics– Ohio Rapid Assessment Method

Landscape Assessment- level 1– GIS analysis– Calibrated with comprehensive assessment

Leve

l of E

ffor

t

Level of Detailed Inform

ation

Application on a watershed scale: the Cuyahoga River Basin

The Cuyahoga River Basin• 815 square miles• 3% of state land area, houses 16% of population • Designated a Great Lakes Area of Concern due to legacy of industrial pollution

The Cuyahoga River fires: catalyst for environmental protection

Current Issues: urbanization

Courtesy Cuyahoga River RAP Committee

Study design: selecting sites for assessment

Define the sample frameWetlands mapped by the Ohio Wetland Inventory

– 5 classes

EMAP study designSample points selected using “GRTS” designProvides a spatially balanced sample with ordered points

All 3 levels of assessment employed

•1600 points generated for whole watershed

• Goal to sample 200

• 366 sites sampled

• of these, 243 wetlands

Randomized Sample Points

Site Access and Sampling- what did we do?

Overview of ORAM metrics

Size ofhydrogeomorphic

unit

Physical habitat

Plant communitycharacteristics

Special features(endangered spp.

etc.)

Buffer andsurrounding

land use

Hydrology

Total Score

0 906530 50

Condition Category 1

ConditionCategory 2

ConditionCategory 3Low 2

Comprehensive Sampling

At 10% of sites: – Vegetation IBI– Amphibian IBI

At all sites:– Soils, standard chemical

and enzymatic analysis

The site view…

366 total sites

No wetland found17%

Wetlands sampled70%

Access denied13%

Fate of sampled points

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

0 25 50 75 100 125 150 175 200 225 250 275 300 325 350 375

Ordered distribution of scores for all sites sampled

Rap

id A

sses

smen

t Sco

rePreliminary Project Results

Urbanization and wetland conversion…

Diversity of wetland types

Depressional37%

Impoundment7%

Riverine37%

Slope14%

Fringing4%

Bog1%

N = 243

Impaired16%

Meets34%

Superior50%

Geauga County Wetland condition

67 wetlands

Impaired20%

Meets61%

Superior19%

Portage & Stark Counties

108 wetlands

Impaired25%

Meets67%

Superior8%

Cuyahoga and Medina Counties 12 wetlands

Total acres per condition category

298.5

1289.3

1985.9

Impaired GoodSuperior

Mean wetland size per condition category

1.2

5.2

8.01

0

1

2

3

4

5

6

7

8

9

Impaired Good Superior

Wetland condition categories

ha

100 m

250 m

500 m

1000 m

2000 m

4000 m

Landscape Analysis- multiple scales of influence

Landscape Development Index (LDI)

LDI = Σ (%LUi * LDIi)*100

where %LUi = percent of area under land use iand LDIi = LDI coefficient for land use i

LDI coefficientsNatural areas = 0 Pasture = 1.08Row Crops = 3.25 Urban = 4.65Suburban = 4.04

Variance explained in ORAM scores by LDI scores.

0

2

4

6

8

10

12

14

100 250 500 1000 2000 4000

*

*

**

0

5

10

15

20

25

30

35

40

45

50

100 250 500 1000 2000 4000

*

*

0

2

4

6

8

10

12

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16

18

100 250 500 1000 2000 4000

*

**

*

0

5

10

15

20

25

30

35

40

100 250 500 1000 2000 4000

* * *

*

*

Var

ianc

e ex

plai

ned

(r2)

Buffer Distances (m)

Depressional Impoundments

Riverine Slope

Diemeke et al. in prep

Nutrient Retention in Watershed

101,000 tP-sorptionCapacity

114,000 tTC

8,090 tTN

1,500 tTP

1180 HaArea

Total Population

sampled

The annual P load to Lake Erie is 17,500 t, the TP held in 198 wetlands sampled account for 10% of this annual load

The P-sorption capacity of wetlands sampled accounts for 5 times the annual load of P to Lake Erie

Average ORAM =55

All Wetlands

Average ORAM =43

Agricultural Average ORAM =57

Natural

Landscape development in100 m buffer

Average ORAM =57

Size < 12 acres

Average ORAM =40

Size > 1 acre

Average ORAM =29

Size < 1 acre

Average ORAM =67

Size > 12 acres

Size Size

In sum: what factors most affect wetland condition?

Diemeke et al. in prep

Conclusions

Historically, our preoccupation with the quantity of wetlands has led us to overlook a loss of quality

Preservation and restoration efforts require information on current environmental condition

Preservation and restoration must take into account the landscape setting of the wetland

Thanks to so many people!

•U.S. Environmental Protection Agency for funding andtechnical help

Mary Kentula, Tony Olsen

•Kenyon CollegePat Heithaus and students

•Ohio EPAJohn Mack, Mick Micacchion

•Cuyahoga Remedial Action Plan committeeJim White, Marie Sullivan