Genus Level Taxonomic Identification
for the Puget Sound Lowlands B-IBI
(from www.salmonweb.org)
Genus
Level 10 Metric B-IBI Descriptions
Taxon means a single taxonomic group
such as family, genus, or species. Taxa is plural. For
genus-level scoring, aquatic insects are identified to the genus level,
with the exception of chironomids, which are
identified to the family level. Non-insects are identified to the order or
family level.
Total
Taxa Richness
The total number of unique taxa is identified in each
replicate. The numbers from the three replicates are then averaged for this
metric.
Ephemeroptera Taxa Richness
The total number of unique mayfly (Ephemeroptera)
taxa is identified in each replicate. The numbers from the three replicates are
then averaged for this metric.
Plecoptera Taxa Richness
The total number of unique stonefly (Plecoptera)
taxa is identified in each replicate. The numbers from the three replicates are
then averaged for this metric.
Trichoptera Taxa Richness
The total number of unique caddisfly
(Tricoptera) taxa is identified in each replicate.
The numbers from the three replicates are then averaged for this metric.
Number
of Long-Lived Taxa
The cumulative number of unique long-lived taxa identified across all three
replicates.
Number
of Intolerant Taxa
The cumulative number of unique intolerant taxa identified across all three
replicates.
Percent
Tolerant Individuals
The total number of tolerant individuals
counted in each replicate, divided by the total number of individuals in
that replicate, multiplied by 100. The percentages from the three
replicates are then averaged for this metric.
Number
of Clinger Taxa
The total number of unique clinger taxa is identified in
each replicate. The numbers from the three replicates are then averaged for
this metric.
Percent
Predator Individuals
The total number of predator
individuals counted in each replicate, divided by the total number of
individuals in that replicate, multiplied by 100. The percentages from
the three replicates are then averaged for this metric.
Percent
Dominance
The sum of individuals in the three (3) most abundant
taxa in each replicate, divided by the total number of individuals in that
replicate, multiplied by 100. The percentages from the three replicates
are then averaged for this metric.
Percent
Dominance Example
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Step
1 Calculate
taxa totals |
Step
2 Sum 3
Most numerous Taxa |
Step
3 Calculate
Percentage |
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Taxon 1 = 10 organisms |
Pick Top 3: |
(# organisms in 3 dominant taxa /
Total # individuals) X 100 (21 / 22) X 100 |
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Total = 22 organisms |
Total = 21 organisms |
Percent Dominance = 95% |
10 Metric
Genus Level Scoring Criteria
Criteria are for genus-level
identification of most insects and chironomids to
family. Square braces indicate the value next to the brace is included in the
range; rounded parentheses indicate the value is not included.
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Scoring
Criteria |
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Metric |
1 |
3 |
5 |
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Taxa richness and composition |
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Total number of taxa |
[0, 14) |
[14, 28] |
> 28 |
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Number of Ephemeroptera
(mayfly) taxa |
[0, 3.5) |
[3.5, 7] |
> 7 |
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Number of Plecoptera
(stonefly) taxa |
[0, 2.7) |
[2.7, 5.3] |
> 5.3 |
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Number of Trichoptera
(caddisfly) taxa |
[0, 2.7) |
[2.7, 5.3] |
>5.3 |
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Number of long-lived taxa |
[0, 4) |
[4, 8] |
> 8 |
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Tolerance |
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Number of intolerant taxa |
[0, 2) |
[2, 4] |
> 4 |
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% of individuals in tolerant
taxa |
> 44 |
[27, 44] |
< 27 |
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Feeding ecology |
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% of predator individuals |
[0, 4.5) |
[4.5, 9] |
> 9 |
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Number of clinger taxa |
[0, 8) |
[8, 16] |
> 16 |
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Population attributes |
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% dominance (top 3 taxa) |
> 75 |
[55, 75) |
[0, 55) |
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10 Metric
Genus Level B-IBI Worksheet
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METRICS (averaged) |
Rep 1 |
Rep 2 |
Rep 3 |
Replicate Average |
Metric IBI Score |
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(1,
3, or 5) |
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Total number of taxa |
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Number of Ephemeroptera
(mayfly) taxa |
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Number of Plecoptera
(stonefly) taxa |
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Number of Tricoptera
(caddisfly) taxa |
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% of individuals in tolerant
taxa |
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Number of clinger taxa |
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% of predator individuals |
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% dominance (3 taxa) |
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METRICS (cumulative) |
Rep 1 |
Rep 2 |
Rep 3 |
Cumulative Unique |
Metric IBI Score |
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(1,
3, or 5) |
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Number of long-lived taxa |
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Number of intolerant taxa |
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Total B-IBI Score |
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For the percentage metrics, remember to multiply the
final computation by 100 for each replicate, e.g., % predator individuals =
(total number predator individuals / total number individuals) X 100