Transcript The biological condition gradient: updates and opportunities

The biological
condition gradient:
updates and
opportunities
Michael Paul
Jeroen Gerritsen
Tetra Tech, Inc.
Center for Ecological
Sciences
Intro
Clean Water Act
Goal = Integrity:
 “Restore and maintain…biological
integrity” – 101(a)
Interim Goal = Aquatic Life Use:
 “…water quality which provides for the
protection and propagation of fish,
shellfish, and wildlife…” – 101(a)(2)
Intro
Biological Integrity
 The
ability of an aquatic ecosystem to
support and maintain a balanced,
integrated and adaptive community of
organisms having a species composition,
diversity, and functional organization
comparable to that of natural habitats
within a region
REFERENCE
CLASSIFICATION
Intro
Convention – Single Indicator Thresholds
Is this the tool we need?
100
90
x
Is it a race to the middle?
80
Does is protect the best sites?
(Anti-deg, ORW)
Index Score
70
60
Does it protect further
degradation?
x
50
40
30
20
x
10
0
Reference
Stressed
Is it a realistic goal for
restoration?
(TMDL prioritization;
setting realistic
expectations)
What if reference condition
varies?
Another Option: The Biological Condition Gradient
Levels of Biological Condition
1
Natural structural, functional, and
taxonomic integrity is preserved.
2
Evident changes in structure due to loss of
some rare native taxa; shifts in relative
abundance; ecosystem level functions fully
maintained.
Moderate changes in structure due to
replacement of sensitive ubiquitous taxa
by more tolerant taxa; ecosystem functions
largely maintained.
Biological Condition
Structure & function similar to natural
community with some additional taxa &
biomass; ecosystem level functions are
fully maintained.
3
4
5
Sensitive taxa markedly diminished;
conspicuously unbalanced distribution of
major taxonomic groups; ecosystem
function shows reduced complexity &
redundancy.
6
Extreme changes in structure and
ecosystem function; wholesale changes in
taxonomic composition; extreme
alterations from normal densities.
Level of Exposure to Stressors
Watershed, habitat, flow regime
and water chemistry as naturally
occurs.
Chemistry, habitat, and/or flow
regime severely altered from natural
conditions.
The Biological Condition Gradient
Natural
Variability
1
Natural structural, functional,
Minimal changes in structure & function
and2 taxonomic
integrity is
Evident changes in structure and
preserved.
3 minimal changes in function
Moderate changes in structure &
minimal changes in function
Biological
Condition
4
Major changes in structure &
moderate changes in function
5
Severe changes in structure & function
Increasing Level of Stressors
6
The Biological Condition Gradient
Natural
Variability
Natural structure and function
of biotic
community maintained
Evident
changes
in
1
2
structure
due
to loss
Minimal changes
in structure
& function
3
Biological
Condition
of
some
rare native
taxa;
Evident changes
in structure
and
minimal changes
in function
shifts
in relative
abundance;
ecosystem
Moderate changes
in structure &
4 minimal
changes fully
in function
level
functions
maintained
Major changes in structure &
5
moderate changes in function
Severe changes in structure & function
Increasing Level of Stressors
6
The Biological Condition Gradient
Natural
Variability
Natural structure and function of biotic community maintained
1
2
Biological
Condition
Minimal changes in structure & function
3
Evident changes in structure and
minimal changes in function
4 Moderate changes in structure &
minimal changes in function
Major
changes in structure
&
Extreme
changes
in structure
and
moderate changes in function
ecosystem function; wholesale
changes
in changes
taxonomic
composition;
Severe
in structure
& function
extreme
alterations from normal
- - No Effect - densities.
6
Intro
The Biological Condition
Gradient
 Conceptual
model of aggregated
biological knowledge to describe
changes with increasing stress
 Based on combination of
ecological theory and empirical
knowledge
 Regional calibration


Conceptual model
Quantitative decision model
Method
Basic idea

What attributes do we expect to see?





What attributes do we not expect to see?




Species, abundances
Habitats
Biotopes
Interactions
What is missing?
What is present that shouldn’t be?
Have experts interpret samples into the BCG
classes.
Operationalize their decisions – i.e., “train” a
model
Method
How



Classification (you know….)
Identify reference condition and
stressor gradient (you know…)
Expert panel:





Identify attributes and their metrics
Assign sites to levels of BCG
Develop rules for assigning sites
(decision criteria)
Develop model(s) for automated
replication of panel decisions
Test and iterate
Method
Evidence for “best”
 Present-day
conditions
 Historical reconstruction





Historical documents (descriptions, journals,
charts, aerial images)
Fish/shellfish landings records
Museum collections
Archeological evidence (middens, other
digs)
Paleo evidence (diatoms, forams, pollen)
Method
Attributes
I.
Historically documented, sensitive, long-lived,
regionally endemic taxa
II.
Highly sensitive or specialist taxa
III.
Sensitive and common taxa
IV.
Taxa of intermediate tolerance
V.
Tolerant taxa
VI.
Non-native taxa
VII.
Organism condition
VIII.
Ecosystem Function
IX.
Spatial and temporal extent of detrimental effects
X.
Ecosystem connectance
Method
Attributes: New England Fish
Sensitive taxa
N
Attribute 2 taxa: most sensitive; the first
to disappear
Common Name
19
5
3
29
15
2194
21
8221
American Brook lamprey
Banded Sunfish
Bridled shiner
Burbot
Creek chubsucker
Slimy sculpin
Swamp darter
Brook trout, wild
Slimy sculpin
Burbot
Attribute 3 taxa: moderately sensitive
Wild brook trout
Method
Attributes: New England Fish
Attribute 4 taxa: broadly tolerant of many conditions
N
521
9046
2552
10020
118
15499
1764
4485
612
1344
8832
2
Common Name
Chain pickerel
Common shiner
Cutlips minnow
Fallfish
Fourspine stickleback
Longnose dace
Pumpkinseed
Redbreast sunfish
Redfin pickerel
Spottail shiner
Tesselated darter
White perch
Fallfish
Longnose dace
Redbreast sunfish
Tesselated darter
Method
Attributes: New England Fish
Attribute 5 taxa: Highly tolerant; increased abundance in stressed sites
N
259
55137
479
4974
595
23426
187
Common Name
Banded killifish
Blacknose dace
Brown bullhead
Creek chub
Golden shiner
White sucker
Yellow bullhead
White sucker
Blacknose dace
Method
Assign sites to BCG levels
 Panel
members assign sites to BCG levels
using species composition information
 Best sites (reference) are not necessarily
Level 1!
 Capture critical information for decisions
Example site data
TALU_SampID
StationID
Station Name
WMA
Gradient
CollDate
BCG Attribute
HA03
AN0018
Level
Area (km²)
19.06
5
Pct Urban
13.98
Culvers Ck
Pct Agr
1
1.59
Pct Forest
48.40
High
Pct Wetlands
18.16
10/13/1992
Total Habitat
Score
Not Scored
FinalID
Individuals
Order
Family (Tribe)
4
Crangonyx pseudogracilis
8
Amphipoda
Gammaridae
3
Stenonema smithae
3
Ephemeroptera
Heptageniidae
3
Nigronia serricornis
2
Megaloptera
Corydalidae
4
Argia
1
Odonata
Coenagrionidae
4
Cheumatopsyche
45
Trichoptera
Hydropsychidae
5
Hydropsyche betteni
43
Trichoptera
Hydropsychidae
Method
Operationalize the Decisions
 Apply
fuzzy set theory to expert-derived
logic train:


membership functions
Results expressed as membership of levels (0 to
1)
 Discriminant

function models (Maine DEP)
Requires sizable training set of expert-assigned
sites
 Calibrate
results
other index models to BCG
Method
Application
Complete
Partial / In Development
Planning
Columbia
Estuary
Casco Bay
Narragansett
Bay
Tampa Bay
Caribbean Coral
Reefs
Application
Lessons learned
 Classification
is key!
 Struggle against taxonomic chauvinism:
bugs don’t work everywhere, fish don’t
work everywhere: use taxonomically rich
assemblages that can be sampled
frugally
Recent Developments
Multiple Assemblages

Minnesota




Calibrated BCG model for 7 classes of
warmwater streams, both invertebrates and fish
Quantitative BCG model incorporated in
Access application
Will be used to help set biological criteria for MN
waters
Region 5 states and tribes

Calibrated BCG model for cold and cooltransitional streams, both invertebrates and fish.
Recent Developments
Considerations for estuaries
 Several
habitat types in an estuary –
estuary health not dependent on single
habitat
 Legacies of overexploitation (fish, shellfish)
 Ocean changes
 Watershed/ input changes
 Direct habitat disruption/conversion
 Effects on keystone components
Recent Developments
Coral BCG
 Coral
reef scientists new to BCG conceptual model
 All have observed reef declines during their careers
 Instead of numeric data, participants viewed video
transects of shallow water reefs and rated quality of
each reef
Summary
Biological Condition Gradient

A conceptually simple framework for holding enormous, userdefined complexity



Organizes and prioritizes research needs




Scale up (more general) for communication
Scale down (more detailed) for research
Uncovers gaps in knowledge
Uncovers discrepancies in assessment conclusions
Enables hypothesis testing
Enhances communication



Independent of methods
Conceptually complete scale
Translates observation and measurement into shared
meaning
Summary
BCG: A Flexible Application
100
90
x
Exceptional
80
Good
Index Score
70
60
x
50
Fair
40
Poor
30
20
x
10
0
Reference
Stressed
Non-reference
Very poor