Ecological Assessment: An Overview
Environmental Issues and Public Policy
Zoo 446
Fall 2001
Standard Questions
• Is there a problem?• Is it getting better or worse?• What’s causing the problem?• Can we fix it?• Is it getting better or worse?
Stressor-ResponseAssessment
ResponseAssessment
Exposure (stressor)Assessment
Risk (Condition) Characterization
RiskManagementDecision
ManagementOptions
Politics
Legal ConsiderationsSocial Factors
Public Health
Economics
Risk Assessment Risk Management
Modified from EPA 1996
Stressor Gradient
Eco
logi
cal C
ondi
tion
low
high
low high
(Eco
logi
cal V
alue
s an
d In
dica
tors
)
CWA Ultimate Goal (e.g. protect all native taxa)
Res
pons
e A
sses
smen
t(I
s th
ere
a pr
oble
m?)
Exposure Assessment
Stressor-Response Relationship
(What’s Causing the Problem?)
Ecological Risk Assessment
Stressor Gradient
Eco
logi
cal C
ondi
tion
low
high
low high
(Eco
logi
cal V
alue
s an
d In
dica
tors
)
CWA Ultimate Goal (e.g. protect all native taxa)
Res
pons
e A
sses
smen
t(I
s th
ere
a pr
oble
m?)
Exposure Assessment
Stressor-Response Relationship
(What’s Causing the Problem?)
Ecological Risk Assessment
Stressor Gradient
Eco
logi
cal C
ondi
tion
low
high
low high
(Eco
logi
cal V
alue
s an
d In
dica
tors
)
CWA Ultimate Goal (e.g. protect all native taxa)
Res
pons
e A
sses
smen
t(I
s th
ere
a pr
oble
m?)
Exposure Assessment
Stressor-Response Relationship
(What’s Causing the Problem?)
Ecological Risk Assessment
Risk Assessment
Mod. From EPA 1996
Stressor-Response Relationship
Hazard Assessment
Exposure Assessment
Risk CharacterizationQuality of LifeHuman HealthEcological Health
Stressors Physico-chemical Measurements Biotic IndicesHuman Activities (GIS & Modeling)
Diagnosis, CertaintyMultiple Lines of EvidenceIndices of Sustainability and Restorability
Observational ApproachesExperimental Approaches
Ecological Assessment Framework
Study Design
Analysis
Integration
• Objectives• Conceptual Model• Hypotheses & Indicators• Sampling Plan
• Define Expected Condition• Measure Observed Condition• Assess Human Effects (E-O)• Stressor-Response Relationships
• Determine Causes or Threats to Impairment• Develop Management Plans• Assess Management Success
Ecological Assessment Framework
Study Design
Analysis
Integration
• Objectives• Conceptual Model• Hypotheses & Indicators• Sampling Plan
• Define Expected Condition• Measure Observed Condition• Assess Human Effects (E-O)• Stressor-Response Relationships
• Determine Causes or Threats to Impairment• Develop Management Plans• Assess Management Success
Define Objectives
Conceptual ModelEcosystem Services
Analysis Plan(Hypotheses, Indicators, Sampling Plan)
Ecological Assessment Framework
Study Design
Objectives:Defining the Problem Legislatively in US
• Protect Species†• Protect Ecological Integrity *
– Physical and Chemical Integrity– Biotic Integrity: Structural and Functional
• Protect Fish, Shellfish, and Wildlife*– Interim Goal: larger and important animals
• Protect Ecosystem Services– Biodiversity support, flood control, nutrient retention,
aesthetics, sustainable productivity
* Clean Water Act Goals
† Endangered Species Act
Objectives (Support Designated Uses), Measurable Responses and Indicators
• Drinkability
• Taste, odor, toxic,
• Microbial Contamination
• Fishability
• Low DO, Temp
• Swimmability
• Water clarity
• Microbial Contamination
Stream Channel
Modification
Urbanization/Residential
Development
Forest Practices
Agriculture Mining Recreation & Mgmt
Atmospheric Deposition
DamsChannelization
DiversionsLevees
Revetments
Increasing Population
RoadsConstruction
Point SourcesWastewater
Pets
FragmentationFertilizersPesticides
RoadsMonocultureCompaction
Sedimentation
FertilizersLivestockPesticidesHabitat Alt.Irrigation
CompactionAnimal Waste
Habitat Alt.Toxic Waste
OilGravel
ExtractionHeavy Metals
Liming
RoadsConstructionHabitat Alt.
BoatingFishing
Fish Intro.,Poisoning
NOx
SOx
Air ToxicsLiming
Changes in flow, timing,
amount,pathway
Changes in sediment
load
Changes in Vegetation
Chemical Loading;Toxins
NutrientsO2 Demand
Acid/Base
Mobilizationof heavy metals
Physical Habitat
Changes in Biological Assemblages
Water QualityChemical Habitat
modified from Bryce et al. 1999
Natural Stressors/Geographic Setting (Climate, Geology, Latitude, etc.)
Human Activities
Stressors
Endpoints
Conceptual Model
Study Plans• Surveys
– Use: primarily to assess condition of ecosystems and establish probable exposure problems or threats
– Pros• Realistic Responses• Realistic Exposures
– Stressors– Human Activities
– Cons• Expensive• Time consuming• Poor cause-effect
determination
• Experiments (Bioassays)– Use: primarily to establish
exposures at which undesirable effects occur
– Pros• Cost-effective
• Relatively Rapid
• Establish cause-effect
– Cons• Unrealistic Responses
• Unrealistic Exposures– Stressors not natural
Ecological Assessment Framework
Analysis
Stressor-Response Relations
Human Effects Assessment
Stressor Indicators
Land Use Indicators
Expected Condition
Response Indicators
Ecological Understanding
Observed Condition
Land Use Indicators
Response Indicators
Stressor Indicators
Stressor Indicator
Str
esso
r In
dica
tor
Res
pons
e In
dica
tor
Res
pons
e In
dica
tor
Human Activities – BMPs
Land Use Indicators
Land Use Indicators
Human Activities – BMPs
o o
oo
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o
o
oo
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Observed Conditions
& Relations
Stressor Indicator
Str
esso
r In
dica
tor
Res
pons
e In
dica
tor
Res
pons
e In
dica
tor
Human Activities – BMPs
Land Use Indicators
Land Use Indicators
Human Activities – BMPs
o o
oo
o
o
o
o
o
o
o
oo
oo
o
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o
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Expected Condition
Observed Conditions
& Relations
Stressor Gradient
Eco
logi
cal C
ondi
tion
Stressor Criterion
low
high
low high
(Eco
logi
cal V
alue
s an
d In
dica
tors
)CWA Ultimate Goal (e.g. protect all native taxa)
Stressor Gradient
Eco
logi
cal C
ondi
tion
Indicator of BI (e.g. change in species composition)
BioCriterion for IBI based on Protecting Goal
Stressor Criterion
low
high
low high
(Eco
logi
cal V
alue
s an
d In
dica
tors
)CWA Ultimate Goal (e.g. protect all native taxa)
Stressor Gradient
Eco
logi
cal C
ondi
tion
Indicator of BI (e.g. change in species composition)
BioCriterion for IBI based on Protecting Goal
Stressor Criterion
low
high
low high
(Eco
logi
cal V
alue
s an
d In
dica
tors
)CWA Ultimate Goal (e.g. protect all native taxa)
Stressor Gradient
Eco
logi
cal C
ondi
tion
Indicator of BI (e.g. change in species composition)
BioCriterion for IBI based on Protecting Goal
Stressor Criterion
low
high
low high
(Eco
logi
cal V
alue
s an
d In
dica
tors
)CWA Ultimate Goal (e.g. protect all native taxa)
Stressor Gradient
Eco
logi
cal C
ondi
tion
Indicator of BI (e.g. change in species composition)
BioCriterion for IBI based on Protecting Goal
Stressor Criterion
low
high
low high
(Eco
logi
cal V
alue
s an
d In
dica
tors
)CWA Ultimate Goal (e.g. protect all native taxa)
Criteria for Indicators (NRC)
• General Importance• Conceptual Basis• Reliability• Statistical Properties• Temporal & Spatial
Scale• Data Requirements• Skills Required
• Data Quality• Data Archiving• Robustness• International
Compatibility• Costs, Benefits, and
Cost-Effectiveness
NRC Recommended Indicators• Extent and Status of Nation’s Ecosystems
– Land cover type and area– Land use
• Ecological Capital– Total species diversity, Native species diversity– Nutrient runoff, Soil organic matter
• Ecosystem Function and Performance– Carbon storage, Productive capacity, Net primary production, – Lake trophic status, Stream oxygen– Nutrient use efficiency and Nutrient balance of ag. ecosystems
Multimetric Indices of Biotic Integrity
• Multiple variables combined into one index– Species richness– % Sensitive Species– % Predator Species– 6-10 variables responding to different stressors
• Good summary • Easy to communicate• More reliable in broad use, but not as sensitive as
refined, single-indicator responses
Response Indicators
• Change in Species Composition• Change in Ecosystem Function• Loss of Native Species in Sensitive
Assemblages (Microbes and Invertebrates)• Loss of Health of Tolerant Organisms (e.g.,
Fish and Wildlife)• Loss of Native Species of Tolerant
Organisms
Stressor Indicators
• Nutrient Enrichment• Decrease in Dissolved
Oxygen Concentration• Sedimentation• Changed Temperature• Habitat Alteration • Habitat Loss• Biotic Indices:
– % High P spp.
• % Urban Land Use• % Agricultural Land
Use• % Impervious Surface• Width Riparian Buffer• Proximity of Use to
Habitat
Land Use Indicators
Muskegon Watershed Land Use Regions
B. Pijanowski
M. Colunga
Effects of Human Activities DifferWith Activity and Habitat and Endpoint
Ecological Assessment Framework
Integration
Cause/Threat Assessment
Restoration/ Protection Assessment
Management Options
Management Decision & Implementation
Stressor Level
Eco
logi
cal R
espo
nse
(e.g
. Eco
-Int
egri
ty)
ok
Acceptable
Natural
Stressor-Response Relationship
A B
Everglades, South Florida, USA
P Algae
CaCO3
P harvest & Stability+-?
+Growth
Conceptual Model for Everglades Mats
Change in Floating Mat Cover = f (Distance from P Source In Everglades)
6 8 10 12 140
102030405060708090
100%
Mat
Cov
er
Distance from P Source (km)
Change in Number of Native SppIn Everglades
6 7 8 9 10 11 12 13 14Distance from P Source (km)
1
2
3
4
5
6N
ativ
e D
iato
m T
axa
Deviation in Spp Relative Abundance from Reference in Everglades
6 7 8 9 10 11 12 13 14Distance from P Source (km)
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9P
erce
nt S
imil
arit
y
TP on Gradient
Distance from input structures (km)
Sediment P on Gradient
Algal Responses
in the Everglades
Dosing Facility
Total Sediment Total Sediment PhosphorusPhosphorus
(mg/kg)(mg/kg)Contour MapContour Mapfor WCA-2Afor WCA-2A
Total Sediment Total Sediment PhosphorusPhosphorus
(mg/kg)(mg/kg)Contour MapContour Mapfor WCA-2Afor WCA-2A
E 0
E 1E 2
E 3
E 4
E 5
F 0
F 1
F 2
F 3
F 4F 5
U 1
U 2
U 3
S F W M D T ran sect S ite
W a ter C o n tro l S tru ctu re
Risk Assessment Risk Management
Modified from EPA 1996
Response-StressorRelationship
HazardAssessment
ExposureAssessment
RiskCharacterization
RiskManagementDecision
ManagementOptions Politics
Legal ConsiderationsSocial Factors
Public Health
Economics
Sampling Sitesfor
KY – MI Stream Survey
A Stream Problem….. excessive Cladophora
SAIN Conceptual ModelLandscape Development ClimateGeology
Nutrients Flow Stability
Diatom Biofilm
Thick Diatom Mat
Cladophora filaments
ScrapingHerbivores
Collector-Gatherers
Predators
SAIN Sampling Sites
Parameters Assessed
• Discharge• Temperature• Canopy Cover• Conductivity• pH, alkalinity
• NO3+NO2, NH4, TN
• PO4 (SRP), TP
• Silica• Chloride• Total Suspended Solids
• Water Column Chl a• Periphyton Cover and
Thickness
• 3 3-rock clusters for algal biomass & species composition **
• Inverts on 10 rocks5
• 5-rock clusters for invertebrate biomass & species composition **
• ** Only sampled 1/8 wk.
ALGAL METHODS
Sample Algae(Targeted orMultihabitat) Split Sample
Take to Lab
Assay Pigments withSpectrophotometer
Identify and Count Algae Microscopically Dry & Burn
Cell Density
Species Relative Abundances
AFDM Chl a
Phaeophytin
Assess AlgalBiomass Visually
In FieldVisual BiomassMacroalgae &Microalgae
Rapid Periphyton Survey
• View Bottom at Sites along Transects
• Characterize % Cover of Different Algal Types
• Characterize Thickness of Each Algal Type
Peak Cladophora Biomass
10 100TP Concentration (ug P/L)
0102030405060708090
100%
Cla
doph
ora
Cov
e r
10 100 1000Average TP (g P/L)
0.00.10.20.30.40.50.60.70.80.9
Si m
i lar
ity
t o R
efer
ence
Similarity of Diatom Composition Between Test and Reference Assemblages
Standard Questions
• Is there a problem?• Is it getting better or worse?• What’s causing the problem?• Can we fix it?• Is it getting better or worse?
Recommended
