ZOOL 484/585 Final Exam Assignment using EPA NAWQA data
1. Calculate IBI scores for 10 sites using data files. Use Lammert and Allan (1999) IBI
scoring (Table 1 below). 25 pts
2. Identify the highest quality site and describe which taxa likely increase the IBI score at
that site. Identify the lowest quality site and describe which taxa likely decrease the IBI
score at that site. 10 pts
3. All of your sites are on the map below. Select four locations and describe potential
reasons for low or high IBI scores at each site.15 pts
Table 1. Benthic Index of Biotic Integrity (B-IBI) scoring criteria for
macroinvertebrates, from Kerans and Karr (1994), with modifications of
Lammert and Allan (1999).
Scoring Classification
Metric
1
3
5
Total Taxa
< 22
23 - 30
> 30
Mayfly Taxa
0-3
4-6
>6
Caddisfly Taxa
2-3
4-5
>5
Dipteran Taxa
3-4
5-6
>6
Relative Abundance of Omnivores 70 – 100 %
57 – 69 %
43 – 56 %
Relative Abundance of Filterers
51 – 69 %
50 – 31 %
9 – 30 %
Relative Abundance of Grazers
0 – 19 %
20 – 32 %
> 33 %
Relative Abundance of Predators
24 – 33 %
14 – 23 %
2 – 13 %
Dominance
68 – 88 %
47 – 67 %
24 – 46 %
Kerans, B.L., and J.R. Karr. 1994. Development and testing of a benthic index of biotic integrity
(B-IBI) for rivers of the Tennessee Valley Authority. Ecological Applications 4: 768-785.
Lammert, M. and J.D. Allan. 1999. Assessing biotic integrity of streams: effects of scale in
measuring the influence of land use / cover and habitat structure on fish and
macroinvertebrates. Environmental Management 23: 257-270.
Example of IBI calculations using Lammert & Allan (1999) metrics:
Actual
Observation
(no.)
Abundance
Total Taxa
Mayfly Taxa
Caddisfly Taxa
Dipteran Taxa
Relative Abundance of Omnivores
Relative Abundance of Filterers
Relative Abundance of Grazers/Scrapers
Relative Abundance of Predators
Dominance
B-IBI score Lammert & Allan (1999)
191
14
2
0
4
0.35
0.00
0.30
0.60
0.59
Total IBI
IBI score
(no.)
1
1
1
1
5
5
3
1
3
21