The Biological Condition Gradient and The Biological Condition Gradient and Tiered Aquatic Life Uses: Tiered Aquatic Life Uses:

With Applications in the State of MaineWith Applications in the State of Maine

United States Environmental Protection AgencyUnited States Environmental Protection Agency

Tiered Aquatic Life Uses Working GroupTiered Aquatic Life Uses Working Group

Susan P. DaviesSusan P. Davies Maine Department of Environmental ProtectionMaine Department of Environmental Protection

TALU: TALU: Tiered Aquatic Life UsesTiered Aquatic Life Uses

Stressor Gradient

Bio

Con

diti

on G

rad

ien

t

A Scientific Model

Class A/AA Class A/AA “ “as naturally occurs”as naturally occurs”

Class B Class B “support all indigenous “support all indigenous species; no species; no

detrimental change”detrimental change”

Class CClass C “support indigenous “support indigenous fish (salmonids); maintain fish (salmonids); maintain

structure and function”structure and function”

A Water Quality Standards framework

Eco

logi

cal C

ond

itio

n

Aquatic Life Use Workgroup: Conceptual Model (from Cairns 1993)

--- Historical ---

recorded condition

Increasing human disturbance

- - No disturbance - -

existing condition (hypothetical)

Natural

Degraded

1

2

3

4

5

6

- - Severe disturbance - -

TALU: TALU: Tiered Aquatic Life UsesTiered Aquatic Life Uses

Stressor Gradient

Bio

Con

diti

on G

rad

ien

t

A Scientific Model

The Scientific Model-

Stressor:Response

Concepts

Biological Responses Across the Stressor Gradient

RE

SP

ON

SE

ME

AS

UR

E

Stressor Gradient[Effect of Human Activity]

LOW HIGH

Highly

Tolerant

Taxa

DE

LT

An

om

alie

s

(

fish

)

Native Taxa

Intolerant Taxa

Courtesy of Chris Yoder, CABB

HIGH

LOW

Stressor Gradient

Bio

logi

cal C

ondi

tion

Biointegrity Indicators

Stressor Criterion

low

high

low high

Biointegrity Criterion

from Stevenson

TALU : A Scientific Model

Concept #1The Biological Condition

Gradient

Bio

logi

cal C

ond

itio

n

Increasing Effect of Disturbance[Stressor gradient]

Low High

1Native or natural condition

2 Minimal loss of species; some density changes may occur

3Some replacement of sensitive-rare species; functions fully maintained 4

Some sensitive species maintained; altered distributions; functions largely maintained

5

6

Tolerant species show increasing dominance; sensitive species are rare; functions altered Severe alteration of

structure and function

Natural

Degraded

Overview of 10 AttributesOverview of 10 Attributes Taxonomic composition and toleranceTaxonomic composition and tolerance

Attributes I-VAttributes I-V Sensitive-EndemicSensitive-Endemic through through TolerantTolerant

Non-native taxaNon-native taxa Attribute VIAttribute VI

Organism conditionOrganism condition Attribute VIIAttribute VII

Ecosystem functionEcosystem function Attribute VIIIAttribute VIII

Physical-biotic interactionsPhysical-biotic interactions Attributes IX-XAttributes IX-X

Tier 1 Tier 3 Tier 6

Attribute 1Historicallydocumented,sensitive,long-lived orregionallyendemic taxa

As predictedfor naturaloccurrenceexcept forglobalextinctions

Some may beabsent due toglobal extinction orlocal extirpation

Absent

Attribute IISensitive- raretaxa

As predictedfor naturaloccurrence,with at mostminorchangesfrom naturaldensities

Some loss, withreplacement byfunctionallyequivalentSensitive-ubiquitous taxa

Absent

TALU : A Scientific Model

Concept #2The Generalized Stressor

Gradient

Stressor Agent(s)

Habitat Structure

Biological Response

Flow Regime

Energy Source

Biotic Interactions

Water Quality & Toxicity

Biological Index or

metric

Stressor Metric

This model is an explicit statement of multiple causation

The Linkage From Stressor Effects to Ecosystem Response

STRESSORS STRESS/EXPOSURE RESPONSE

Relationship Land Classes and Relationship Land Classes and Stream Macroinvertebrates in MaineStream Macroinvertebrates in Maine

ag forest mix urbanLANDTYP

0

10

20

30

40

I19

Number of

Mayfly,

Stonefly,

and

Caddisfly

Genera

preliminary results based on 424 samples

n=57 n=150 n=119 n=98

Summary BCG-GSG Framework

• A conceptually simple framework for holding enormous, user-defined complexity

• Organizes and prioritizes research needs

• Enhances communication

TALU: TALU: Tiered Aquatic Life UsesTiered Aquatic Life Uses

Stressor Gradient

Bio

Con

diti

on G

rad

ien

t

A Scientific Model

Class A/AA Class A/AA “ “as naturally occurs”as naturally occurs”

Class B Class B “support all indigenous “support all indigenous species; no species; no

detrimental change”detrimental change”

Class CClass C “support indigenous “support indigenous fish (salmonids); maintain fish (salmonids); maintain

structure and function”structure and function”

A Water Quality Standards framework

Eco

logi

cal C

ond

itio

n

Pass-Fail Aquatic Life Use Scenarios for a Hypothetical State

--- Historical ---

Increasing human disturbance

- - No disturbance - -

Natural

Degraded

- - Severe disturbance - -

--- Severely Altered ---

PASS

FAIL

1

2

3One 303d Listing Threshold?

5

6

4

Bio

logi

cal C

ond

itio

n

Increasing Effect of Disturbance[Stressor gradient]

Low High

1Native or natural condition

2 Minimal loss of species; some density changes may occur

3Some replacement of sensitive-rare species; functions fully maintained 4

Some sensitive species maintained; altered distributions; functions largely maintained

5

6

Tolerant species show increasing dominance; sensitive species are rare; functions altered Severe alteration of

structure and function

Natural

DegradedNA

B

C

AA

A

MAINE TALU

Data Analysis and Use Attainment

• Biological data put into statistical model (30 variable linear discriminant model)

• Model output is an estimation of strength of association of a sample to four water quality

classes

Class AClass A Class BClass B Class CClass C NANA

Biological community:Biological community:

NaturalNatural DegradedDegraded

% OF LINEAR MILES

ClassClass AAAA = 6% = 6%

Class AClass A = 45% = 45%

Class BClass B = 47% = 47%

Class CClass C = 2% = 2%

Designated Aquatic Life Uses in Maine

Since 1990

Miles of upgrades= 1,440

Miles of downgrades= 5

Bio

logi

cal O

utc

ome

Reducing Discharges from Lincoln Pulp and Paper Company Reducing Discharges from Lincoln Pulp and Paper Company into Penobscot Riverinto Penobscot River

1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996

A

B

C

NA

YearSecondary wastewater treatment in place

2,700

1,600

13,600

BOD5 load kg/day

A B C NARESULT

0.0

0.1

0.2

0.3

0.4

0.5

PE

R_

IMP

Relationship Between Impervious Surfaces and Water Quality Attainment in Maine

Impervious Surfaces

(Portion of Drainage)

Aquatic Life Use Attainment

~ 5%

~ 12%

preliminary results based on 424 samples

Maine TMDL Target Values Maine TMDL Target Values for % Impervious Coverfor % Impervious Cover

Class %IC-demonstrated

attainment

TMDL WLA MOS

AA<6%

Does not apply

A <6% <5% 1%

B <8% 7-10% 6-9% 1%

C <15% 10-15% 8-13% 2%

Engineered reductio

n in

effects of s

tormwater

Maine Classification AttainmentMaine Classification Attainment

Designated Use Class

Monitoring Result

Attains Class?

Next Step

A A Yes --

C B Yes Upgrade ?

A B No TMDL

B NA No TMDL

Maine Extensions of TALU: Other Waterbody and Criteria Types

• Wetland BCG- TALU– Targeted Stream/Wetland monitoring

• Marine-estuarine – tiered aquatic life standards applied in

aquaculture permitting

• Tiered Nutrient Criteria – Conceptual model: – tiered chemical limits PLUS tiered biological

response limits – algae, macroinvertebrates

Susan P. Davies, MDEP

11 22 33 44 55 66

BCG Tiers Communicate Condition

a b c d e fNatural Degraded

Acknowledgments

Maine DEP Biological Monitoring Program

Leon Tsomides, Jeanne DiFranco

Tom Danielson, David Courtemanch

National TALU Work Group and Steering Committee (including 23 States and Tribes)

Susan K. Jackson,

USEPA-HECD, Washington, DC