Spatial and Temporal Variability of the Index of Biotic Integrity in Three ...

TRANSACTIONS

AMERICAN

of the

FISHERIES SOCIETY

Volume 116

January 1987

Number 1

Transactionsof the American FisheriesSociety 116:1-11, 1987 ¸ Copyrightby the AmericanFisheriesSociety1987

Spatial and Temporal Variability of the Index of Biotic Integrity in Three Midwestern Streams JAMESR. KARR,1 PHILIP R. YANT,2 AND KURT D. FAUSCH 3 Department of Ecology,Ethology, and Evolution, Universityof lllinois Champaign, Illinois 61820, USA ISAAC J. SCHLOSSER

Department of Biology, Universityof North Dakota Grand Forks, North Dakota 58202, USA Abstra:t.- The index of biotic integrity (IBI) has been used to assessthe biological quality of flowing water systemsin areasthroughoutthe United States.Yet, only rarely has biotic integrity beenrelated to independentmeasuresof water or habitat quality. We showthat the IBI ranks sites similarly in two Illinois watershedswhere conditions remained relatively stable during 3 years of sampling. Further, rankings among sitesconform to prior assessments of site quality based on habitat and water quality. Neither a speciesdiversity index (H') nor any of the individual metrics that constitute IBI performed as consistentlyat ranking sites as did the IBI. Sampling should be conducted during early summer to reduce variation due to seasonalfish migration and fall recruitment of young-of-the-year fish. In an Indiana watershed subject to extensive conservation planning, the IBI reflects known habitat and water quality perturbations of both natural and anthropogenicorigin. Little or no improvement in biotic integrity was detectedfollowing implementation of numerous soil and water conservation practices.

Water resource managers have recently shown renewed interest in biological monitoring of aquatic systems(Weber 1981), but methodologies to measure biological integrity have been lacking (Karr et al. 1986). The index of biotic integrity (IBI) was developed to assessthe biological integrity of lotic systemseffectively and directly (Karr

I Present address:Smithsonian Tropical Research Institute, Post Office Box 2072, Balboa, Panama. 2 Present address:Department of Biology, University

of Michigan, Ann Arbor, Michigan 48109, USA. 3 Presentaddress:Department of Fishery and Wildlife Biology, Colorado State University, Fort Collins, Colorado 80523, USA.

1981). We define biological(biotic) integrity as the ability to support and maintain "a balanced, integrated, adaptive community of organismshaving a species composition, diversity, and functional organization comparable to that of natural habitat of the region" (Karr and Dudley 1981). During the last 5 years, several studies of fish communities have been conducted to apply the IBI throughout the midwestern United States (Fauschet al. 1984) and evaluate it under different conditions (Karr et al. 1985; Angermeier and Karr 1986; Berkman et al. 1986; Karr et al. 1986; Leonard and Orth 1986; Angermeier and Schlosser,in press). Here, we evaluate how year-to-year and seasonalvariability in stream fish communities

2

KARR ET AL.

affectsassessmentof site quality with the IBI. We collecteddata during severalseasonsand yearsin three watersheds, two in Illinois and one in In-

diana, where primary land use was agricultural. Anthropogenicimpacts were relatively constant throughoutthe sampling period in the Illinois watersheds,but the Indiana watershedexperienced intensive application of soil conservationprac-

ticesdesignedto reducesoil erosionand thereby improve water quality (Morrison 1977, 1981; Toth et al. 1981, 1982).

We address five main questions in this paper. (1) When watershedconditionsremain relatively stable,does the IBI rank a set of sitesconsistently through time? (2) Do these rankings reflect prior assessmentsof site quality? (3) Would an individual metric or speciesdiversity index rank sites

similarly to IBI rankingsthrough time? (4) What is the best seasonfor assessingbiotic integrity?(5) Is the IBI sensitiveto the impact of known habitat and water quality perturbations, and is recovery from such degradation detectable?

both ends of the site were blocked

were made Methods

Long-term measurements of fish communities were available for Jordan Creek and Big Ditch, both near Champaign-Urbana in east-central Illinois (Mississippi River drainage), and for Black Creek in northeast Indiana (Lake Erie drainage). The Illinois streamsare describedfully in Schlosset (1982a, 1982b) and characteristicsof the Black Creek watershed are outlined in Tothet al. (1981,

with

seines. An

electric seine (Schlosser1982a) was used to capture fish on two passesthrough the complex habitat in reach 4. These sampling techniquescaptured 80-90% of species,numbers, and biomasses of fish, as discussedin detail by Larimore (1961) and Schlosser(1982a, 1985). Big Ditch.--Fish were collected from 10 100m-long sitesin Big Ditch during June and August of 1978, 1979, and 1980. Big Ditch is channelized throughout its length, has no riparian vegetation, and receivesmunicipal effluent from Rantoul, Illinois (Schlosserand Karr 1981; Schlosser1982b), between the first (upstream) and second sample sites. Habitat quality varies slightly throughout the reach sampled, but is generally homogeneous. As in Jordan Creek, most sites were seined (4.8mm mesh) until capture rates declined to near zero, which normally required five successiveseine hauls. The electric seine was used to sample sites that had some development of pools and riffles. Black Creek.--Altogether, 276 fish collections at 28 sites in the Black

Creek

wa-

tershed and one site in Wann Creek (site 13), a stream in an adjacent watershed, during 19731982. Fish sampling was part of a study on the effectsof agricultural land use and soil conservation measureson water quality supported by the U.S. Environmental Protection Agency(Morrison 1981). Almost all streams in the Black Creek watershed

had been channelized

in the

1940s

and

again during the study period, and received non1982). Most fish in all streamswere releasedafter point-source pollution in the forms of sediment, nutrients, and toxic chemicals. Wann Creek had they were identified, counted, and measured. Jordan Creek.--Fish were collected from five to been channelizedabout 20 yearsbefore our study. 14 100-m-long sites in Jordan Creek (Schlosscr Fish were captured from 100-m-long siteswith 1982a, 1982b). The stream traversesfour distinct 3.2- or 6.4-mm-mesh seinesand block seines(Toth reaches from its headwaters to the mouth: (1) an et al. 1981, 1982). A few sites were sampled with upstream channelized reach with no riparian an electric seine in April 1979. vegetation; (2) a channelized reach with an 8-10The Index of Biotic Integrity m-wide strip of riparian vegetation; (3) an unThe IBI measures 12 attributes of the fish comchannelized reach bordered by well-vegetated pasture; and (4) a higher-gradient, unchannelized reach munity (Table 1), termed metrics, that arc rated bordered by a 10-400-m-wide strip of hardwood 1 (worst), 3, or 5 (best)in comparisonto the value forest. expectedfor an undisturbedfish community in a During 1978 and 1979, fish were sampled from •trcam of similar size in the same region (Karr ct three 100-m sites in each of the three upstream al. 1986). The sum of those ratings, the IBI, varies reaches and five 100-m sites in reach 4. In 1980, from 12 to 60 in five classes:excellent (57-60), only reach 4 was sampled. Siteswere sampledfour good (48-52), fair (39-44), poor (28-35), and very times each year during April, June, August, and poor (12-23). A sixth class, no fish, is assigned October, excluding April 1978. when no fish are capturedwith repeatedsampling. Becausereaches1-3 had narrow, relatively uni- Sites with scores falling between the classesmay form channels, fish were captured by five succes- be assignedto an appropriate classby an informed sive seine hauls with a 4.8-ram-mesh seine after biologist (Karr et al. 1986).

INDEX OF BIOTIC INTEGRITY IN STREAMS

3

T^BLœ1.--Criteria for scoringindex of biotic integrity metricsfor JordanCreek and Big Ditch, Illinois, and Black Creek, Indiana. Score, Black Creek

Score, Jordan Creek and Big Ditch

Metric Number

I (worst)

3

5 (best)

->16 ->4 ->4 ->4 ->4

1 (worst)

3

5 (best)

1-6

7-9

->10

0 0 0 0

1 1 1 I

->2 ->2 ->2 ->2

0-50

51 - 150

off

Fish species(total)

0-5

6-15

Darter species Sunfish species Sucker species Intolerant speciesa

0-1 0-1 0-1 0-1

2-3 2-3 2-3 2-3

Individuals

Percent of individuals

0-100

101-200

-> 201

_>151

as:

Green sunfish

l 1-100

Omnivores

45-100

6-10 21-44

Insectivorouscyprinids Top carnivores

0-20 0-2

21-44 3-10

Hybridsb

4-10

Diseasedb

6-10

0-5

20-100

6-19

0-20

45-100

21-44

0-5 0-20

45-100 11-25

0-20 0

21-44 >0--1

45-100 >2

2-3

0-1

4-10

2-3

0-1

2-5

0-1

6-10

2-5

0-1

a Jordan Creek and Big Ditch: Ambloplitesrupestris,Cottusbairdi, Etheostomaexile, Etheostomazonale, Hypentelium nigricans, Lepomis megalotis,Moxostoma duquesnei,Notropis heterolepis,Noturusfiavus, Phoxinus erythrogaster.Black Creek: Erimyzon oblongus,Minytrema melanops,Percina maculata, Phenacobiusmirabills.

b Because datawerenot availablefor thesestreams,all sampleswerescoredas 5 for this metric.

Metrics are grouped into three classes:species portion of diseasedor hybrid individuals, so these richness and composition, trophic composition, metricswere assignedscoresof 5 (Karr et al. 1986). and fish abundance

and condition.

Each metric

reflectsthe quality of a different portion of the fish community that responds to a different aspect of the aquatic system. The rationale for each is outlined in Karr et al. (1986). The IBI was calculated for each sample date according to methods in Karr (1981), Fausch et al. (1984), and those recently presented in ex-

Data Analysis

panded form in Karr et al. (1986). Criteria for the

We used the Friedman test (Conover 1980), a nonparametric two-way analysis of variance on ranks, to assessthe similarity of IBI over time at sites in Jordan Creek and Big Ditch. To distinguish sets of sites with IBI values that were not different, we used a multiple comparison procedure analogousto the Student-Newman-Keuls test

number of speciesexpected at each site were based on knowledgegained from extensive sampling of the three watershedsand by inspection of the data (Table 1). Intolerant speciesand trophic classifi-

for parametricanalysisof variance.The procedure is a nonparametricvariation on Fisher'sleast-significant-differenceprocedure(Conover 1980). We also evaluated the tendencyof ranks to be similar

cation of fishes were determined

through time at siteswithin a watershed with Kendall's coefficient of concordance (W: Conover 1980), which has a value of 0 when ranks are random from period to period, and I when ranks agree completely. Kendall's coefficient is just a proportion of the Friedman statistic and has the same significancelevel. Its scaling from 0 to 1 provides a more intuitive assessment of the consistencyin ranking sitesamong sample periods. Data from nine Big Ditch sites were used to

with the aid of

regional ichthyological references (Smith 1979; Trautman 1981). Scoring criteria varied somewhat according to local conditions. Black Creek criteria varied from those used in Jordan Creek

and Big Ditch as a result of analysis of Raisin River data (Fausch et al. 1984). Different expectations for Black Creek arise from its more north-

erly location and its position in the Great Lakes rather than the Mississippi River watershed. Because only two sampling methods were used and becausethey produced similar results within each stream, criteria for scoringthe metric for number of individuals were set for each stream using the relative catch per effort for all samples from that stream. Finally, no data were available on the pro-

determinewhether separatemetrics (suchas total number of species)or Shannon-Weiner diversity (H') ranked sites consistently through time. We calculatedKendall's W using the IBI scores,each of 10 metrics individually, and H'. We also calculatedthe rank correlations(Spearman'srho) be-

4

KARR ET AL.

TABLE2.--Index of biotic integrity values for 14 sitesin Jordan Creek and 10 sites in Big Ditch, 1978-1980. Sitesare arrangedvertically from upstreamto downstream.An empty cell indicatesa site was not sampled. 1978

Site

Jun

Aug

1979

Oct

Apr

Jun

1980

Aug Jordan

Oct

Apr

Jun

Aug

Oct

Mean+SD

Creek

lB IC

34 34

38 38

38 42

34 36

34 36

48 44

36 38

37_+5.0 38_+3.5

IE 2A 2B

34 44 44 44

46 54 50 54 52 42 50 48

40 46 44 36 44 46 46 48 48 52 50 52

42 36 40 42 48 54 50 52 48 52 50 52

40 44 44 42 42 54 56 56 52 50 52 48

39+4.3 43+3.7 45_+3.3

3A 3D 3E 4A 4B 4C 4D 4E

44 44 50 42 40 48 52 52 50 52 52 50

32

2D

40 46 46 48 42 52 54 50 52 54 50 54

I

42

46

42

2 3 4 5 6 7 8 9 10

28 32 34 38 40 38 34 40 48

40 38 32 44 46 42 40 46 46

38 38 42 48 48 40 44 48 46

40

46 52 52 52 52

42_+3.9

54 52 50 50 50

54 50 50 52 50

56 56 52 54 52

46

44

34 34 44 48 42 44 34 42 48

36 32 36 40 46 38 40 42 44

a 36 40 34 44 44 42 42 44 46

54 56 46 56 48

43_+ 3.0 51_+3.5 51_+3.8 53+2.5 52_+2.6 50_+3.4 52+2.0 51 _+2.0

Big Ditch 44 ñ 2.0

35_+4.1 36+ 3.4 37_+4.8 44_+ 4.1 44-+2.9 41 _+2.4 39_+4.1 44-+2.9 46_+ 1.5

a Site was dry.

tween IBI

and each metric

score for mean

ranks

over all data.

Analysis of covariance (Snedecorand Cochran 1980) was usedto determine if higher quality sites were more variable than lower quality sites(Taylor and Taylor 1979) in Big Ditch and Jordan Creek. This analysis of pooled Jordan Creek and Big Ditch data, each identified to stream (group), is usedto determineif the regressionslopesthrough the two groups are different from a single pooled slope.

Two-way and three-way analyses of variance were used to evaluate patterns in the IBI for two of the study streams. For Jordan Creek the two factorswere sites(10) and months (4: April, June, August, and October). The Student-NewmanKeuls multiple-comparisons test (Sokal and Rohlf 1981) was performed on the resultsof the analysis of variance. For Black Creek, IBI values were potentially subject to site differences, seasonal differences,and year-to-year differences,with the latter deriving from either natural variation or soil conservationactivities of project staff. Three-way analysisof variance was usedwith data from four

(March-April, May-July, and August-October)for 4 years (1974-1977). In the analysis of variance, the three-way interaction was taken as the error estimate

for F-tests.

Recent concern for the problem of dependent

observations(pseudoreplication)when the same sites are sampled over time (Hurlbert 1984) led us to redo some of these analysesusing analysis of variance with repeated measures. For Jordan Creek, three samples were available for each of 2 years over 14 sites in four groups;for Big Ditch, two samples were available for each of 3 years over nine sites in three groups. Results

Spatial Variation in IBI and Concordance through Time

Jordan Creek and Big Ditch data were analyzed to determine

whether

the IBI

ranked

sites simi-

larly for successivesamplesbecausemajor changes in site quality were not apparent in either stream during the period sampled. We also determined whether IBI rankings accorded with prior assesssites(5, 15, 12, and 13) arrangedin three seasons ments of site quality.

INDEX

OF BIOTIC INTEGRITY

IN STREAMS

5

Jordan Creek IBI values generally increasedin a downstream

direction

• Excel Ient

with two or three distinct

regions discernible (Table 2; Figure 1). A Friedman two-way analysis of variance (six dates; 14 sites) showed that Jordan Creek sites differed in their IBI values (P < 0.001), with some siteshaving higher scoresthan did other sites (Table 2). Concordance(W) oflBI ranking was 0.75 for these samples,indicatingthat, althoughthe IBI did not rank the 14 sites identically each time they were sampled, rankings were highly concordant. Sitesin Jordan Creek (Figure 1) differed significantly in IBI values(P < 0.05, multiple comparisons test). Downstream sites 3D-4E had similar high IBI values; upstream sites lB and 1C had low scores,and intermediate values were recorded at sites 2A and 2B. Other sites formed transitions

between these groups. These groups were concor-

dant with major habitat variation alongthe stream channel. As noted briefly in the Methods and in more detail in Schlosser(1982a, 1982b), reach 4

(highest IBI values) is a high-gradient, unchannelized stream with a border of hardwood forest, whereas reach 1 (lowest IBI values) is a channelized stream with uniform substrate and no riparian vegetation to buffer the stream from adjacent intensive agricultural land use. Reaches 2 and 3 are intermediates between these two extremes, a

Good

Fair O

Poor

3C- E•li----

I--

? soBIGDITCH

]Good

H

rn 40 H

30

Upstream 2

3

Downstream 4

5

6

7

8

9

10

SITE

FIGURœ1.--Index of biotic integrity (IBI) scoresat sample sites in Jordan Creek and Big Ditch, Illinois (1978-1980). Shaded bars span sites whose mean IBI

valuesare not significantlydifferent(Student-NewmanKeuls test; P < 0.05).

fact reflected in IBI scores for those areas.

Friedman two-way analysis of variance of the six collectionsfrom sites 2-10 in Big Ditch (site (Schlosserand Karr 1981; Schlosser1982b; An1 was excludedbecauseit was dry in August 1980; germeierand Schlosser,in press). Table 2) showed significant (P < 0.001) differData from JordanCreek and Big Ditch alsosugences among site rankings. Concordance of these gestedthat variability of IBI values at each site site rankings was 0.78, again indicating that the was related to quality of the site and quality of the IBI ranked sites similarly each time they were entire stream. Higher-quality sitesin each stream sampled. Multiple comparisons tests (Figure 1) were lessvariable through time than were lowershowed that sites 5, 6, 9, and 10 had the highest quality sites (analysisof covariance, P < 0.001; IBI values. Sites 7 and 8 had values lower than slopesfor the two streamswere not significantly those of the first group but higher than those of different), but Jordan Creek sites were more varisites 2 (nearest the municipal effluent) and 3. Site able than Big Ditch sites (Figure 2). This is an 4 had valuesbetweenthose of the two low-scoring apparent paradox, becauseJordan Creek sites were groups.The municipal effluent introduced above generally of higher quality than Big Ditch sites. site 2 (average75 x 106L/d) was clearly reflected Differences in habitat heterogeneitybetween the in the sharp decline in IBI from site 1 to site 2. watershedsaccount for this paradox (see DiscusTotal phosphorus,for example, averagedfrom 1.3 sion). mg/L in winter to 2.5 mg/L in autumn at site 2 Our analysissuggests two principles.First, good but declined progressively to less than 0.2 mg/L sitesexhibit lessvariability in their rankingsover at site 10 in all seasons(Schlosser and Karr 1981). time than do poor sites.Conversely,overrating of Habitat varied more subtly along Big Ditch than poor sitesis more likely than underratingof good along Jordan Creek, but even that subtle variation sites.Both principlesmake sensebiologicallybewas suggestedby the higher IBI values at sites 5, causesites with poorer habitat quality show less 6, 9, and 10 when compared to sites 7 and 8, stability in fish community structurethan better which had been more recently channelized

sites (Schlosser,in press).

6

KARR ET AL.

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