Download IBI Slides Part 4

Case Study
Development of an Index of Biotic
Integrity for the Mid-Atlantic Highland
Region
McCormick et al. 2001
Mid-Atlantic Highlands
Assessment (MAHA)



Many believe that IBIs must be watershed
and or ecoregion specific
Several IBIs have been developed for specific
ecoregions of the Mid-Atlantic Highlands
McCormick et al. used a widespread sampling
regime of 1st to 3rd order streams throughout
the upland ecoregions of the mid-Atlantic
Highlands attempting to develop a single IBI
for assessing fish assemblages within the
region
Methods
MAHA Sites
About 450 sites
were selected
based on a
probabilistic
sampling
(randomly
selected within
cells)
Ecoregions
McCormick et
al. 2000;
found no
effect of
ecoregion on
fish
communities.
Journal of the North American
Benthological Society 19(3):385-404
Fish and Habitat Sampling


Fish communities were sampled during
spring low flow conditions over three
years
Water chemistry, physical habitat, and
landscape variables known to be
responsive to a variety of
anthropogenic impairments were
sampled at selected site
MAHA Stressors
Ecoregion Impairments
Reference Selection

Used three reference definitions for selection
and setting scoring thresholds

Least restrictive


Moderately restrictive


Water chemistry and RVHA
Water chemistry, land use, road density, and quantitative
habitat filters
Highly restrictive

Moderately restrictive criteria and watershed condition
class
Metric Screening


Combined habitat variable and fish data to
identify suitable metrics
MAHA IBI screened 58 candidate metrics




Scoring range
Variability
Responsiveness
Redundancy
Results
Mid-Atlantic IBI Metrics

9 were selected (to include at least 2 in
each metric category)
Mid-Atlantic IBI Metrics
•
•
•
•
•
•
•
•
•
Number of native Cyprinid species ^ (Log)
Number of native benthic species ^ (Log)
Proportion of individuals in the family Cottidae
Sensitive species richness (Log)
Proportion of tolerant individuals *
Proportion of non-indigenous individuals *
Proportion of invertivore - piscivore individuals
Proportion of macro-omnivores *
Proportion of (clean) gravel spawning species
* = negative scoring metric
^ = Exclude tolerant species
(Log) = Scaled
# Native Cyprinid Species

Positive scoring metric



Declines with increasing
watershed impairment
Exclude tolerant species
Scaled by log drainage
basin
# Native Benthic Species

Positive scoring metric




Decreases with increasing
sedimentation and loss of
quality benthic habitat
Linked to benthic
macroinvertebrates and
sediment supply and
transport
Exclude tolerant species
Scaled by log drainage
basin
Proportion Cottidae

Positive scoring metric



Declines with degradation of
all habitat measures and
increasing nutrient loading
Linked to human activity in
watershed
Found to be dominant in all
reference streams w/in the
Cheat basin
Sensitive Species Richness

Positive scoring metric



Declines with increasing
human activity in the
watershed, turbidity, and AMD
High scores indicate intact
watershed with minimal
impairment
Scaled by log (drainage
basin)
Proportion Tolerant Individuals

Negative scoring metric


Increases with degraded water quality,
physical habitat, and watershed condition
Indicative of physical or chemical
impairment
Proportion Non-Indigenous
Individuals



Negative scoring metric
 Not associated with
physico-chemical
impairment
Measures biological
pollution
Increased nonindigenous individuals
means decreased
“integrity”
Telescope Shiner
Proportion Invertivore / Piscivore
Species

Positive scoring metric



Declines with increased
habitat degradation
Linked to habitat quality
(particularly pools) and
stability
Speaks toward a
systems ability to
support long lived top
predators
Brown Trout
Proportion of MacroOmnivores

Negative scoring metric


Increases with increasing
nutrient loading and
habitat alteration leading
to shifts in food
availability
Dominant in impaired
streams & those with
missing links in food
web (i.e. Unbalanced)
Proportion Clean Gravel
Spawning Species

Positive scoring metric



Declines with sedimentation,
reduced substrate quality, and
channel degradation
These fishes rely upon
interstitial spaces within clean
gravel for egg development
and reproductive success
Indicates that sediment
deposition and transport
ability is not limiting
River Chub
Discussion


Fish assemblage variable were found to be
highly correlated to wide-ranging disturbance
gradients
Standardized consistent fish-assemblage
sampling methods, coupled with quantitative
physical, chemical, and landscape data,
allowed for the development of a sensitive
and regionally applicable index of fish
assemblage integrity