Understanding Florida’s Stream Condition Index · PDF fileUnderstanding Florida’s Stream Condition Index Russ Frydenborg FDEP Bureau of Laboratories. Factors Affecting Aquatic

Understanding Florida’s StreamCondition Index

Russ FrydenborgFDEP Bureau of Laboratories

Factors Affecting AquaticBiological Communities

BiotaProducers: Algae, macrophytes, terrestrial

plant leaf litter, bacteria/detritus

1° Consumers: Benthic invertebrates, zooplankton,

some fish

2° Consumers:

Fish, wildlife, humans

Water quality factors

Physica

l facto

rs Human factors

pH Dissolved OxygenConductivity/Salinity

Light penetration

Temperature

Hydrology/flow

Habitat structure

Sediment/substrate

Nutrients

Dessication

Major ions Organic carbon

Toxic substancesOrganic enrichmentNutrient enrichment

Degradation of water quality:

Habitat disruption:Physical destructionSiltation/Sedimentation

Hydrological modifications

Ditching/drainingImpoundingConsumptive use

Introduction of exotics, Harvesting game species

Defining Ecological ExpectationsAbsent human interference, ecologicalcommunities have evolved in response to:

physical,chemical, andbio-geographic processes

Expectations are set by studying referencecondition (and its variability) in eachcommunity type.

Adverse Human FactorsHydrologic modifications

(consumptive use, impounding, ditching/draining)

Habitat disturbance(physical removal, sedimentation)

Degradation of water quality(toxic substances, nutrient and organic enrichment)

Introduction of invasive exotic taxaHarvesting biomass

Biological Integrity

• The ability of an aquatic ecosystem to support andmaintain a balanced, adaptive community oforganisms having:

• species composition,• diversity,• and functional organization

comparable to that of natural habitats within aregion.

Procedure to DevelopBiologically-Based CriteriaClassify aquatic systems into meaningful unitsSample biota across human disturbancegradient (define expectations)Select relevant biological attributes that providea reliable signal about human effects (nutrientimbalances)Extract and interpret patterns in the dataDevelop reasonable policy to protect designatedaquatic life use

Florida’s Stream Condition Index:1990’s Multimetric Approach

Established reference condition in varioussub-ecoregions

Best professional judgmentSurrounding land use, in-stream habitat

Sampled known impaired sitesPoint source discharge studies

Toxicity, low DO, poor habitat

Florida’s Stream Condition Index:1990’s Multimetric Approach (cont.)

Selected 7 metricsBox and whisker plots determineddiscrimination power

Aggregated by summing metrics5, 3, 1 point, depending on departure fromreference condition

Florida’s SCI Re-calibration

Develop human disturbance gradientTest disturbance gradient for each BioregionEvaluate metric response to disturbance gradient(new thresholds, new metrics)

Determination of metric variabilityPower analysis for trend detectionDevelop consistency with EPA Tiered AquaticLife Use Support guidance (TALUS)

To Ensure ScientificallyDefensible Metrics:

Develop criteria, independent from biology,to determine which sites are impaired byhumans vs. those that are not (the fabled “xaxis”)

Reference vs. Degraded SitesHuman Disturbance Gradient

Flow regime

Energy source

Chemical variables

Habitat structure

Biotic factors

domesticwastes

leavesand

twigs

naturalexcessnutrients,toxins

naturalflows

extremeflows

poolsand

rifflesuniform

nativetaxa

exotictaxa

Karr & Rossano

Human Disturbance FactorAnalysis

Landscape levelLandscape Development Intensity Index

Habitat alterationHabitat assessment data

Hydrologic modificationHydrologic scoring process

Chemical PollutionAmmonia, etc.

Summary of the LandscapeDevelopment Intensity* Coefficients

Category CoefficientNatural System 1Pine Plantation 1.6Pasture 3.4Row Crops 4.5Residential (low) 6.8Residential (high) 7.6Commercial 8.0Industrial 8.3Commercial (high) 9.2Business District 10.0

*Developed by MarkBrown, University ofFlorida, based onnon-renewableEnergy inputs,Odom’s “EmbodiedEnergy” concept.

Landscape Development IntensityIndex

Hydrologic Modification ScoringBest, 1-2 points

Flow regime as naturally occurs (slow and fairlycontinual release of water after rains), fewimpervious surfaces in watershed; high connectivitywith ground water and surface features deliveringwater (e.g., sandhills, wetlands; no ditches, berms,etc.)

Very poor, 9-10 pointsFlow regime entirely human controlled; hydrographvery flashy (scouring after rain events withsubsequent reductions in flow, leading to stagnant ordry conditions, related to impervious surfaces andditching throughout watershed); water withdrawals &impoundments fundamentally alter the nature of theecosystem

ScoresMeasure

1 2 3 4

NH3 <0.1 >0.1 >2

Habitat >65 >50 and<65

<50

Hydro <6 6-7 8-9 10

LDI(buffer)

<200 200-350 >350

LDI (ws) <200 200-350 >350

Florida’s HDG: Combination ofother Disturbance Measures

Evaluating Metrics

Metrics12 EPT Taxa

Precision

Scoring

Redundancy

72% Chironomids

23 Total TaxaDiscrimination Efficiency

10% Collector-Filterers

13% Ephemeroptera

Reference

Metric Selection CriteriaMeaningful measure of ecological structure orfunctionStrong and consistent correlation with humandisturbanceStatistically robust, low measurement errorRepresent multiple categories of biologicalorganizationCost-effective to measureNot redundant with other metrics

Exception: “response signature” metrics

Attribute GroupsSYSTEM

PROCESSES

IDENTITY

TOLERANCE

RARE ORENDANGERED

KEY TAXA

TAXONOMICCOMPOSITION

TROPHICDYNAMICS

PRODUCTIVITY

MATERIAL:CYCLES

PREDATION

RECRUITMENT

TAXARICHNESS

RELATIVE ABUNDANCE

DOMINANCE

COMMUNITYSTRUCTURE

FEEDINGGROUPS

HABIT

VOLTINISM

INDIVIDUALCONDITION

DISEASE

ANOMALIES

CONTAMINANTLEVELS

DEATH

METABOLICRATE

TOXICITYTESTS RIVPACS

INVERTEBRATE IBIFISH IBI

INTEGRATEDBIOASSESSMENT

LIFE HISTORYATTRIBUTES

Desirable Metric Qualities

Ecologically Justified

Discriminating

Represent Integrity

Precise

Sufficient range of values

0 20 40 60 80 100HDG_rank (%)

0.5

1.0

1.5

2.0

2.5

3.0

3.5H

DG

Florida Sites Ranked According to HDG

40% of sites ‘undisturbed’

Consistent loss of speciesbeyond this point

-20 20 60 100 140 180 220HDG_rnk

-0.02

0.02

0.06

0.10

0.14

TX10

82=S

teno

nem

a sm

ithae

2

-20 20 60 100 140 180 220HDG_rnk

-0.01

0.01

0.03

0.05

0.07

TX10

79=S

teno

nem

a ex

iguu

m2

-20 20 60 100 140 180 220HDG_rnk

-0.002

0.002

0.006

0.010

0.014

0.018

0.022

TX10

78=S

teno

nem

a

Example of a SensitiveMayfly Genus(Stenonema)

Increasing disturbance

-20 20 60 100 140 180 220

HDG_rnk

-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18TX

216_

Cor

bicu

la fl

umin

ea

Example of a Tolerant Clam Species

Increasing disturbance

Incorporating “Integrity”Include Robust, Discriminating Metrics from

a Variety of Categories:

RichnessCompositionToleranceFeeding FunctionsHabitVoltinism

RichnessMeasures

Total taxaEPT taxaEphemeroptera taxaPlecoptera taxaTrichoptera taxaDiptera taxaChironomidae taxaColeoptera taxaOligochaeta taxaInsect taxaNon-insect taxaShannon-Wiener Index

% EPT% EPT (no Baetidae or Hydropsychidae)% Ephemeroptera% Ephemeroptera (no Baetidae)% Plecoptera% Trichoptera% Trichoptera (no Hydropsychidae)% Diptera% Diptera (no Chironomidae)% Chironomidae% Coleoptera% Oligochaeta% non-insects% 5 dominant% 10 dominant

CompositionMeasures

FeedingMeasures

% Collectors% Scrapers% Shredders% Filterers% PredatorsCollectors taxaScrapers taxaShredders taxaFilterers taxaPredators taxa

HBIBCI CTQaBeck's Biotic IndexIntolerant taxa% tolerant% ClingersClingers taxa% SemivoltineSemivoltine taxa

Tolerance andOther Measures

Two Approaches to AssessingMetrics

Compare extremesreference vs. impaired

Compare across contiuum of disturbanceHuman Disturbance Gradient

Bio

logi

cal r

espo

nse

REF Impaired

Works for extremes, but what about TALUS axis?

Bio

logi

cal r

espo

nse

Human disturbance

Noise on both axes!

Bio

logi

cal r

espo

nse

Human disturbance

Refine human disturbance scale,select best biological metrics

Mul

timet

ric in

dex

Human disturbance gradient

Index with Ideal Response

Chironomid Taxa :Reference vs. Impaired

Num

er of chironomid taxa -2

2

6

10

14

18

22

26

Reference Impaired

Num

er of chironomid taxa

-2

2

6

10

14

18

22

26

<= 1.5 (1.5,2] (2,2.5] (2.5,3] > 3

Chironomid taxa vs. HDG

R = 0.38

Human Disturbance Gradient

(Discard metric)

% D

iptera

-10

10

30

50

70

90

110

% Diptera : Reference vs.Impaired

Reference Impaired

% D

iptera

-10

10

30

50

70

90

110

<= 1.5 (1.5,2] (2,2.5] (2.5,3] > 3

% Diptera vs. HDGr = 0.01


(Discard metric)

Florida Index

-5

5

15

25

35

Florida Index: Reference vs.Impaired

Reference Impaired

Florida Index

-5

5

15

25

35

<= 1.5 (1.5,2] (2,2.5] (2.5,3] > 3

Florida Index vs. HDG


R = 0.72

Good metric, but substitutestronger Florida Sensitive Taxa

Correlation for Metrics and HDG

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90

Sensitive taxa

EPT taxa

Florida Index

Clinger taxa

Very Tolerant %

All Tolerant %

Trichop taxa

Eph taxa

Very tolerant taxa

Clinger %

Eph %

Trichop %

Total Taxa

Tanytarsini %

Filter-feeder no Chuemat.

Dominant %

Filter-feeder %

Tanytarsini %

Diptera taxa

Tanytarsini taxa

Long lived %

Chironomid taxa

Attri

bute

Absolute Spearmans r

voltinism

feeding

structure

compositionrichness

richnessrichness

tolerance

tolerancehabit

TaxaRichness

0

10

20

30

40

50

60To

tal n

umbe

r of t

axa

Median 25%-75% Non-Outlier Range

Outliers


EphemeropteraTaxa

0

1

2

3

4

5

6

7N

umbe

r of E

ph. t

axa


TrichopteraTaxa

0.8 2.4 4 5.6 7.2Human disturbance gradient

0

2

4

6

8

Num

ber o

f Tric

hopt

era

taxa

% Tanytarsini(Sensitive midges)


0

10

20

30

40%

Tan

ytar

sini

% Filterers

0

20

40

60

% F

ilter

er


Long-livedTaxa

-1

0

1

2

3

4

5

6N

umbe

r of l

ong-

lived

taxa


ClingerTaxa


0

5

10

Num

ber o

f clin

ger t

axa

% Dominance

20

40

60

80

% D

omin

ance


Sensitive Taxa

0

5

10

15

Num

ber o

f sen

sitiv

e ta

xa


% VeryTolerant Taxa


0

30

60

90

% V

ery

tole

rant

indi

vidu

als

SCI vs.Human Disturbance Gradient

1.2 1.6 2.0 2.4 2.8


0

20

40

60

80

100

SC

I

Median 25%-75% Non-Outlier Range Outliers

r = 0.72


SC

I

0 2 4 6 8 10

0

20

40

60

80

100

SCI from 1992 to 2001

Bio-regions of FloridaBio-regions of Florida

Southeastern Plains Ecoregion (#65) 65f – Southern Pine Plains and Hills 65g – Dougherty/Marianna Plains 65h – Tifton Upland/Tallahassee Hills

Southern Coastal Plains Ecoregion (#75) 75a – Gulf Coast Flatwoods 75b – Southwestern Florida Flatwoods 75c – Central Florida Ridges and Uplands 75d – Eastern Florida Flatwoods 75e – Okeefenokee Swamps and Plains 75f – Sea Island Flatwoods

Southern Florida Coastal Plains Ecoregion (#76) 76a – Everglades 76b – Big Cypress 76c – Miami Ridge/Atlantic Coastal Strip 76d – Southern Coast and Islands

65f 65g65h 75e

75f

75c

75b

75d

76b76c

76d

75a

76a

Panhandle

Peninsula

Northeast

0.6 1.2 1.8 2.4 3.0-2-101234567

0.6 1.2 1.8 2.4 3.0 0.6 1.2 1.8 2.4 3.0

HDGNE Ecoregion Peninsula Ecoregion Panhandle Ecoregion

Florida Mayfly Taxa vs. HDG

Mayfly Taxa

Sensitive Taxa

0.6 1.2 1.8 2.4 3.0-6-4-202468

101214161820

0.6 1.2 1.8 2.4 3.0 0.6 1.2 1.8 2.4 3.0

HDG

NE Ecoregion Peninsular Ecoregion Panhandle Ecoregion

Florida Sensitive Taxa vs. HDG

HDG

Clingers

NE Ecoregion0.6 1.2 1.8 2.4 3.0

-2

0

2

4

6

8

10

12

14

Peninsula Ecoregion0.6 1.2 1.8 2.4 3.0

Panhandle Ecoregion0.6 1.2 1.8 2.4 3.0

Florida Clinger Taxa vs. HDG

Site

0102030405060708090

100

SC

I90% Confidence Interval: SCI =/- 15 points

Data from Repeat Visits

“Poor”“Fair”

“Good”DescriptionSCI

0-3940-6970-100

SCI can reliably detect 3 categoriesbased on 1 sample

Number of categories:~ 15 points x 2 = 30 points100 / 30 = 3 categories

“Very poor”“Poor”“Fair”

“Good”“Excellent”

DescriptionSCI

0-1920-3940-5960-7980-100

SCI Can Reliably Detect 5Categories Based on 2 Samples

SCI

ReferencesitesTest sites

Num

ber o

f site

s

Impairment

SCI

ReferencesitesTest sites

Num

ber o

f site

s

V. Poor OutstandingGoodFairPoor

Con

ditio

n of

the

Bio

tic C

omm

unity

[Spe

cific

to E

coty

pe] Evident changes in structure and minimalchanges in function

Moderate changes in structure andminimal changes in function

Natural structure and function of biotic community maintained

Minimal changes in structure & function

Human Disturbance GradientLOW HIGH

Major changes in structure &moderate changes in function

Severe changes instructure & function

SCI Categories and TALUS Axis

3

2

1

5

4

6

Excellent

Good

Fair

Poor

Very Poor

Existing Applications of SCIAmbient MonitoringImpaired Waters Rule (TMDLs)Point Source PermittingWatershed (NPS) StudiesBMP Effectiveness Studies

ConclusionsThe SCI is effective in regulatory programsDiscriminatory power of metrics

Comparing extremes identifies strong metrics,but includes some “noisy” metricsHuman Disturbance Gradient improvesmetric selection and provides an independentmeasure for comparing biological response

Understanding Florida’s Stream Condition Index · PDF fileUnderstanding Florida’s Stream Condition Index Russ Frydenborg FDEP Bureau of Laboratories. Factors Affecting Aquatic

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