ILLINOI SUNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN

PRODUCTION NOTE

University of Illinois atUrbana-Champaign Library

Large-scale Digitization Project, 2007.

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Natural History SurveyLibrary

The Freshwater Mussels

(Mollusca: Bivalvia: Unionidae) of the

Mackinaw River Drainage, Illinois

Kevin S. Cummings and Christine A. Mayer

Illinois Natural History Survey607 East Peabody Drive

Champaign, Illinois 61820

Center for BiodiversityTechnical Report 2001 (17)

Prepared for and Funded by

The Nature ConservancyCentral Illinois Field Office

Peoria, Illinois

I I

THE FRESHWATER MUSSELS (MOLLUSCA: BIVALVIA: UNIONIDAE)

OF THE MACKINAW RIVER DRAINAGE, ILLINOIS

Kevin S. Cummings & Christine A. Mayer

Illinois Natural History Survey

Center for Biodiversity

Champaign, Illinois 61820

INTRODUCTION

The freshwater mussel fauna of Illinois is relatively well known and has been studied for well over

100 years (Baker, 1906; Parmalee, 1967; Cummings and Mayer, 1997). However, historical

information on the Mackinaw River drainage is limited. In his "Catalogue of the Mollusca of

Illinois," F.C. Baker (1906) reported 11 species of mussels from the Mackinaw River at Kappa in

Woodford County. Dr. Max R. Matteson of the University of Illinois collected mussels at eight

sites in the basin as part of a mussel survey of the interior streams of the state in the late 1950's and

early 1960's (Matteson, unpublished data). In 1987, the Illinois Natural History Survey (INHS)

conducted a survey of the Mackinaw River drainage (Cummings et al., 1988). Another survey

was conducted by The Nature Conservancy (TNC) in 1995-96 (Retzer, 1997). In the present

study, 32 sites were sampled, focusing both on sites surveyed for fishes by the Illinois

Environmental Protection Agency (IEPA) and Illinois Department of Natural Resources (IDNR)

and on sites sampled for mussels by Cummings et al. in 1987.

The objectives of the present study were to obtain additional data on the mussels of the drainage

focusing on the Upper Mackinaw and to re-survey the Lower Mackinaw for additional species.

We will present the results from three years (1998-2000) of data collection at eight upstream sites

and from the 12 downstream sites sampled in 2000. We will also summarize previous data

collected from the drainage in order to identify areas of high diversity and areas that may be

candidates for reintroduction.

STUDY AREA

The Mackinaw River basin drains over 1100 square miles in northcentral Illinois. The Mackinaw

River rises near Sibley in Ford County and flows westerly for 130 miles through Livingston,

Woodford, McLean, Marshall, and Mason counties before emptying into the Illinois River just

south of Pekin in Tazewell County. Principal tributaries of the Mackinaw are Panther, Walnut,

and Money creeks. The region is flat to gently rolling and is crossed by several low glacial end

moraines. Three natural divisions are included in the basin-Upper Mississippi River and Illinois

Bottomlands, Illinois and Mississippi River Sand Areas, and Grand Prairie; the last division

comprises the majority of the basin (Schwegman, 1973). The southwestern part of the basin is

occupied by a large sand area that continues into the Sangamon River Basin.

The Mackinaw River is a series of pools and fast-flowing riffles with a substrate predominantly of

sand with considerable gravel, some silt, and rubble (Page et al., 1992). Gravel bars, undercut

banks, overhanging trees, and brush piles are common along the river. The banks are forested

except for sections where the land has been cultivated to the water's edge. The stream varies in

depth to six feet and has an average width of 70 feet. The Mackinaw River fluctuates greatly in

depth due to its compact drift beds and the near absence of headwater marshes and other natural

impoundments (Forbes and Richardson, 1908). The upper miles in Ford and McLean counties

have been dredged and straightened; levees have been constructed along the channel of the lower

Mackinaw River. Over 90% of the watershed is cropland and, in some areas, silt has covered

much of the natural gravel and sand substrate. Agricultural pollution, including sedimentation

resulting from poor land use, is a major source of stream degradation. Several small municipalities

discharge untreated effluents into tributaries. Impoundments on Money Creek (Lake Bloomington)

and Six Mile Creek (Evergreen Lake) provide Bloomington and Normal with their water supplies.

Two areas of the Mackinaw River were recognized as Biologically Significant Streams (Page et al.,

1992) because of their mussel and fish diversity. These areas provide the best opportunities in the

basin for the protection of large numbers of native species.

1. Mackinaw River, Alloway Creek to McLean County line, Woodford County. This

stretch of the Mackinaw River has not been channelized, and mussel diversity is high.

The water is medium- to fast-flowing with moderate turbidity. In periods of normal

flow, water depth ranges to over three feet. The substrate consists of gravel, cobble, and

sand. The wooded riparian zone varies and is predominantly Acer saccharum, silver

maple, Populus deltoides, cottonwood, and Platanus occidentalis, sycamore. Half of thissegment of the Mackinaw River was rated as a BSC "A" Stream (Bertrand et al., 1996).

2. Panther Creek from Route 24 to its confluence with the Mackinaw River, Woodford

County. Panther Creek is a natural, clear water stream with a gravel and sand substrate.

In some reaches a fine layer of silt covers the substrate. Aquatic vegetation consists of

clumps of grass in the stream and filamentous algae. Surrounding the wooded riparian

zone are row crops and pasture. This segment of Panther Creek supports a high diversityof mussel species and is a BSC "A" stream.

METHODS

The Mackinaw River drainage is Y-shaped with the Upper Mackinaw River converging with

Panther Creek to form the lower Mackinaw River (Figure 1). For purposes of this report we have

divided the Mackinaw watershed into three regions: 1. Upper Mackinaw and tributaries, 2. Panther

and Walnut creeks, and 3. Lower Mackinaw and tributaries. We considered a species to be extant

in the basin if it had been recorded alive post-1983.

Sampling techniques for freshwater mussels vary depending on the desired objective (Nelson,

1982; Isom and Gooch, 1986; Kovalak et al., 1986; Cawley, 1993; Strayer et al., 1997; Vaughn et

al., 1997; Obermeyer, 1998; Strayer, 1999; Metcalfe-Smith et al., 2000; Dunn, 2000). The most

commonly used methods are timed searches (expressed as catch per unit effort or CPUE) and area

searches (line transects or quadrat sampling). Timed searches are most effective at obtaining

information on relative abundance and species richness. Transect and quadrat sampling are better

suited for determining population 'demography and community structure. Survey costs increase

with the complexity of the sampling technique. Timed searches are usually the most cost-effective

method for most survey applications.

On this project we sampled for mussels using the timed search method. Living mussels and dead

shells were collected at eight sites in the Upper Mackinaw River basin in 1998, 1999, and 2000

(Figure 1; Tables 1 and 2: Sites 1-3, U1-U4, U6). Each site was searched for one man-hour by

hand-picking while wading. An effort was made to sample all available habitats, but particular

emphasis was placed on areas that appeared likely to support mussels (i.e., gravel riffles, runs,

and pools).

An additional site (11) was visited but only shells were collected due to water conditions. Five

sites (Figure 1; Tables 1 and 2: Sites 5, 8, U7, U9, U10) were also visited in 2000 as part of a

IDNR survey of the basin. Two sites were sampled in Mud Creek (Figure 1; Table 2: sites MU1,

MU2), a tributary to the Mackinaw River in the lower part of the basin, in 1999.

Twelve sites (Figure 1; Tables 1 and 4: 20, 22, 24-32, 34) were sampled in the lower Mackinaw

River in August-September 2000. We attempted to conduct a timed search but due to a large

number of TNC volunteers present it was not feasible to accurately record search times.

Approximately 2-4 man-hours were spent at each site.

Voucher specimens were deposited in the Mollusk Collection of the Illinois Natural History

Survey, Champaign, Illinois. The nomenclature in this report follows a list of common and

scientific names of mollusks prepared by the Council of Systematic Malacologists and the

Committee on Scientific and Common Names of the American Malacological Union (Turgeon et

al., 1998) except that subspecies are not recognized.

The results of the fieldwork conducted in 1998, 1999, and 2000 are presented below. A summary

of all of the known collections made in the basin (Tables 1-4) and a comparison of the historical

data with the present day fauna is presented in the discussion section that follows.

RESULTS

UPPER MACKINAW RIVER AND TRIBUTARIES 1998-2000

Fourteen species were collected from the 8 sites sampled in the Upper Mackinaw River in 1998,

1999, and 2000. All species were collected alive in at least one year of the survey (Tables 1 and

2). A total of 1418 mussels was collected during 24 man-hours of sampling with a mean of 59

mussels/man-hour. The total number of species per site ranged from 3 (Site 1) to 13 (Site 2) and

the number of live species per site ranged from 3 (Site 1) to 12 (Site 2) (Table 2). The top three

species in order of abundance were the fat mucket, Lampsilis siliquoidea (Barnes, 1823),

cylindrical papershell, Anodontoidesferussacianus (Lea, 1834), and plain pocketbook, Lampsilis

cardium Rafinesque, 1820. Together they comprised 89% of the living mussels collected. The fat

mucket was by far the most abundant species found in the upper Mackinaw River (1120

individuals; 79% of all living mussels found). The fat mucket was present at all eight sites

surveyed and was the most abundant species found at 7 of the 8 sites. Lampsilis siliquoidea

ranked 4th in the Mackinaw River survey of 1987 (Cummings et al., 1988) and was one of the

dominant species found in the headwaters. All of the species found in the Upper Mackinaw

surveys between 1998-2000 had been previously collected in the Mackinaw River drainage.

In 1995, Retzer (1997) found 2 individuals of the Illinois threatened slippershell, Alasmidonta

viridis (Rafinesque, 1820) in Henline Creek (Site U5). This species was not found alive in the

1987 survey of the Mackinaw River (Cummings et al. 1988). The present survey has added two

additional sites for this mussel in the basin (Site 2. Mackinaw River 0.5 mi S Anchor, McLean

County and Site Ul. Tributary to the Mackinaw River 3 mi ESE Anchor, Co. Rd. 4100E, McLean

County). Seven live slippershells were found in the Upper Mackinaw River at Site 2 and six

individuals were found in a tributary to the Mackinaw River at Site Ul (Table 2). Individuals were

found alive at both sites all three years. Dead slippershells were found at Sites 3 and U6.

Other notable finds in the Upper Mackinaw in 1998-2000 were the large number of species present

at Sites 2 and 3 (13 of the 14 total species were collected alive in the area). Sites 2 and 3 were two

of only three sites in the Upper Mackinaw that contained live elktoe, Alasmidonta marginata, and

the only sites where the sandshell, Lampsilis teres (Rafinesque, 1820), and white heelsplitter,

Lasmigona complanata (Barnes, 1823) were found. The Upper Mackinaw also supported a large

population of the ellipse, Venustaconcha ellipsiformis (Conrad, 1836), which was found at 7 of

the 8 sites surveyed in 1998-2000.

LOWER MACKINAW 2000

Twenty-three species were collected from the 12 sites sampled in the downstream portion of the

Mackinaw River in 2000, only 12 of which were collected alive (Table 4). A total of 110 mussels

were collected during approximately 36 man-hours of sampling with a mean of 3 mussels/man-

hour. The total number of species per site ranged from 3 (Site 26) to 13 (Site 31) and the number

of live species per site ranged from 1 (Sites 26, 34) to 7 (Sites 20, 28). The top three species in

order of abundance were the plain pocketbook, Lampsilis cardium Rafinesque, 1820, fragile

papershell, Leptodeafragilis (Rafinesque, 1820), and white heelsplitter, Lasmigona complanata

(Barnes, 1823). Together they comprised 77% of the living mussels collected. The plain

pocketbook was the most abundant species found in the lower Mackinaw River (45% of all live

mussels found). The plain pocketbook was present at all 12 sites in the Lower Mackinaw in 2000

(alive at nine), and was the dominant species at 7 of the 10 sites where live mussels were found.

Lampsilis cardium ranked 1 st in order of abundance in the Mackinaw River survey of 1987

(Cummings et al., 1988) and was one of the most abundant species found in the lower part of the

river (Table 4).

5

All of the species found alive in the lower Mackinaw River in 2000 are common in Illinois. No

state or federally listed species were found alive or fresh-dead. Weathered-dead shells of the state

endangered rainbow, Villosa iris (Lea, 1829), and the state threatened spike, Elliptio dilatata

(Rafinesque, 1820), and black sandshell, Ligumia recta (Lamarck, 1819) were found.

DISCUSSION

A comparison of the historical species richness of the three areas based on museum records and

weathered-dead shells has revealed 29 species in the Lower Mackinaw, 24 in Panther/Walnut

Creeks and 23 in the Upper Mackinaw. Today the inverse is true: the Upper Mackinaw supports

the greatest diversity (23 extant species), followed by Panther /Walnut Creeks (21 extant species),

and then the Lower Mackinaw (19 extant species).

UPPER MACKINAW

As was mentioned in the description of the study area, the vast majority of the watershed is in row-

crop agriculture and that is particularly true in the Upper Mackinaw where much of the stream

flows through areas devoid of riparian trees. Surprisingly our survey found that the greatest

diversity (both species richness and numbers of individuals) of mussels was in the Upper

Mackinaw where agriculture has been the most intensive. Also, based upon the historical data and

shell material, no species appear to have been locally extirpated from the Upper Mackinaw (23

historic/23 extant). It is our experience that this is atypical of the vast majority of drainages in

Illinois. It is possible that the remains of some thin-shelled species have not persisted in the Upper

Mackinaw, which may have occurred there historically. However, in looking over the cumulative

species list for the basin, we are hard-pressed to identify what species might have been present that

are no long extant.

PANTHER / WALNUT CREEKS

The mussel fauna of the Panther/Walnut Creeks area is also largely intact based upon our

knowledge of the historical fauna and shell remains. Twenty of the 24 species known from the

area are still extant. Two of the four missing species, the slippershell and the spike, are listed as

threatened in Illinois and are rare statewide. The ellipse was collected at one site in the

Panther/Walnut Creek area in the 1950s but has not been collected alive since. The fourth species,

the paper pondshell, Utterbackia imbecillis (Say, 1829) is likely still present in the area (fresh-dead

shells were present at two sites) but was not found alive in recent surveys.

LOWER MACKINAW

The situation in the Lower Mackinaw River is more puzzling. Over a third of the fauna (ten

species) appear to have been extirpated from the Lower Mackinaw River and seven of the ten from

the entire drainage. Of the ten species not found alive since 1985, four appear to have been

historically uncommon in the basin based on relict shells. The rock pocketbook, Arcidens

confragosus (Say, 1829), and the pistolgrip, Tritogonia verrucosa (Rafinesque, 1820), were

represented by a single weathered-dead valve each. The flutedshell, Lasmigona costata

(Rafinesque, 1820), was present as relict shells at only two sites. The rainbow, collected as

weathered-dead shells at three sites, is listed as endangered in Illinois and has been extirpated from

the entire Illinois River watershed. Although not presently listed the flutedshell appears to be

declining in Illinois. In a survey of the Sangamon River drainage in 1987-89 only two live

flutedshells were found out of 2,083 mussels collected (Schanzle and Cummings, 1991).

Three of the species not recently recorded were probably always rare in the Lower Mackinaw. The

paper pondshell was found as a fresh-dead shell and it likely still exists in the Lower Mackinaw or

its tributaries. The creek heelsplitter, Lasmigona compressa, and cylindrical papershell,

Anodontoidesferussacianus (Lea, 1834), are typically small stream species and their absence from

the Lower Mackinaw was not unexpected. The shells of the creek heelsplitter found in recent

surveys of the basin may have been washed downstream from the upper river or nearby tributaries.

The spike and mucket, Actinonaias ligamentina (Lamarck, 1819), were found as relict shells at six

sites. As mentioned in the Panther/Walnut Creeks discussion, the spike is listed as state-threatened

and has undergone a drastic range reduction in Illinois. It was present as weathered-dead shells at

six sites and it appears to have been extirpated from the Mackinaw River drainage. The mucket is

the most abundant species in the Kankakee River mainstem but uncommon in other drainages in

Illinois. The reasons for its disappearance or reduction throughout Illinois are unknown. The

black sandshell was present as weathered-dead shells at five sites and is listed as threatened in

Illinois. Since 1980 the black sandshell has been found alive only in the Mississippi, Rock,

Kankakee, and Ohio rivers and a few of their tributaries.

In summary, of the nine species no longer thought to be extant in the Lower Mackinaw River:

1. Four (rock pocketbook, pistolgrip, flutedshell, rainbow) appear to have always been a

small component of the fauna. The rainbow is a state-endangered species and is very

rare statewide.

2. One (paper pondshell) is likely still extant in the Lower Mackinaw.

3. Two (creek heelsplitter, cylindrical papershell) have limited habitat available in the

Lower Mackinaw River but may also occur in the tributaries.

4. Three (mucket, spike, black sandshell) are experiencing declines in other streams in the

state. The spike and black sandshell are state threatened.

Of the 19 species found alive in the Lower Mackinaw, one species in particular was historically

widespread and common but since 1985 is known only from a single live individual. The

threeridge, Amblema plicata (Say, 1817), was present as relict shells at 12 of the 18 sites in the

Lower Mackinaw (Table 4). It is not uncommon in the Upper Mackinaw where it ranked 4' in

order of abundance. Its drastic reduction in the Lower Mackinaw is noteworthy and as yet

unexplained.

The number of individuals collected in the Lower Mackinaw was also very low. In 2000, we

collected 482 individuals from eight sites in the Upper Mackinaw in 8 man-hours (60/hr). In the

Lower Mackinaw, 110 individuals were collected from 12 sites in approximately 36 man-hours

(3/hr).

Most freshwater mussels must pass through a phase where they are parasitic upon a fish. Of the

12 species found alive in the Lower Mackinaw it is interesting to note that five species (Leptodea

fragilis, Potamilus alatus, P. ohiensis, Truncilla donaciformis, and T. truncata) almost exclusively

utilize freshwater drum, Aplodinotus grunniens, as a host. The other seven species have been

reported to use a wide variety of fishes but most of them have been found to transform on percids,

centrarchids, and cyprinids.

Fishes were collected in the Mackinaw River drainage in 1987 as part of an ongoing effort by the

INDR and IEPA to assess statewide stream quality based upon the Index of Biotic Integrity (IBI)

(Hite & Bertrand 1989; Day et al., 1990). Fifty-nine of the 80 species of fishes known from the

drainage were collected from 22 sites (Day et al., 1990; Page et al., 1992). Sites downstream from

the town of Mackinaw (Site 23) showed lower evenness, lower species richness, and lower IBI

scores than the rest of the basin. The distribution of mussels in the Lower Mackinaw parallels that

of the fishes. Of the 10 sites (24-32, 34) located below the town of Mackinaw surveyed in 2000, a

drastic reduction in the number of extant species of mussels was observed (Table 4). Comparing

the number of species known historically from each site to the number of species collected alive

post-1985 we see that on average only 27% of the historical fauna remained. For some sites (31,

32) the loss was complete. Others had significant losses in species ranging from 67% to 86%.

The most diverse site downstream of the town of Mackinaw still experienced a 47% loss in speciesrichness.

ACKNOWLEDGMENTS

This study was supported by funds provided by the Illinois Chapter of the Nature Conservancy.

We would like to thank Tim Tear, Matt Herbert, and Shelly Miller (TNC) for making this study

possible. We would also like to thank the volunteers from the Illinois Chapter of the TNC: Karen

Billo, Bill Davison, Michele DePhillip, Tracy Galarowicz, Mike Goodman, Tharran Hobson,

Shannon Horn, Brenda Hoyle, Carol Huggins, Kathy Kubaca, and Jo Skoglund for help in

collecting specimens.

LITERATURE CITED

Baker, F.C. 1906. A catalogue of the mollusca of Illinois. Ill. State Lab. Nat. Hist. Bull. 7(6):51-136.

Bertrand, W.A., R.L. Hite, and D.M. Day. 1996. Biological Stream Characterization (BSC):Biological Assessment of Illinois Stream Quality through 1993. Illinois EnvironmentalProtection Agency Report No. IEPA/BOW.96-058. December 1996. 40 pages + map.

Cawley, E.T. 1993. Sampling adequacy in population studies of freshwater mussels. pp. 168-172 in K.S. Cummings, A.C. Buchanan, and L.M. Koch. (eds.). Conservation andManagement of Freshwater Mussels. Proceedings of a UMRCC Symposium, 12-14 October1992, St. Louis, Missouri. Upper Mississippi River Conservation Committee, Rock Island,Illinois. 189 pp.

Cummings, K.S., and C.A. Mayer. 1997. Distributional checklist and status of Illinoisfreshwater mussels (Mollusca: Unionacea). pp. 129-145 in K.S. Cummings, A.C. Buchanan,C.A. Mayer, and T.J. Naimo, eds. Conservation and management of freshwater mussels II:Initiatives for the future. Proceedings of a UMRCC Symposium, 16-18 October 1995, St.Louis Missouri. Upper Mississippi River Conservation Committee, Rock Island, Illinois. 293pp.

Cummings, K.S., C.A. Mayer, and L.M. Page. 1988. The freshwater mussels (Mollusca:Bivalvia: Unionidae) of the Mackinaw River in Illinois. Illinois Natural History Survey,Section of Faunistic Surveys and Insect Identification Technical Report. 1988(3):1-25 +appendices.

Day, D.M., R.W. Sauer, and W.A. Bertrand. 1990. An evaluation of the fisheries of theMackinaw River basin in central Illinois. Transactions of the Illinois State Academy of Science83(1-2):82-100.

Dunn, H.L. 2000. Development of strategies for sampling freshwater mussels (Bivalvia:Unionidae). pp. 161-167 in R.A. Tankersley, D.I. Warmolts, G.T. Watters, B.J. Armitage,P.D. Johnson, and R.S. Butler (eds.). Freshwater Mollusk Symposia Proceedings. Part II.Proceedings of the First Freshwater Mollusk Conservation Society Symposium. OhioBiological Survey Special Publication, Columbus. 274 pp.

Forbes, S.A., and R.E. Richardson. 1908. The fishes of Illinois. Illinois State Laboratory ofNatural History, Danville. cxxxvi + 357 pp.

Hite, R.L., and B.A. Bertrand. 1989. Biological Stream Characterization (BSC) : A biologicalassessment of Illinois stream quality. Illinois State Water Plan Task Force Special Report.13:1-42 + map.

Isom, B.G., and C. Gooch. 1986. Rationale and sampling designs for freshwater musselsUnionidae in streams, large rivers, impoundments, and lakes. pp. 46-59 in B.G. Isom (ed.).Rationale for sampling and interpretation of ecological data in the assessment of freshwaterecosystems. ASTM (American Society for Testing and Materials) Special TechnicalPublication. 894:

Kovalak, W.P., S.D. Dennis, and J.M. Bates. 1986. Sampling effort required to find rarespecies of freshwater mussels. pp. 34-45 in B.G. Isom (ed.). Rationale for sampling andinterpretation of ecological data in the assessment of freshwater ecosystems. ASTM (AmericanSociety for Testing and Materials) Special Technical Publication. 894:

Metcalfe-Smith, J.L., J. Di Maio, S.K. Staton, and G.L. Mackie. 2000. Effect of sampling efforton the efficiency of the timed search method for sampling freshwater mussel communities.Journal of the North American Benthological Society 19(4):725-732.

Nelson, D. 1982. Sampling for mussels. pp. 41-60 in A.C. Miller (compiler) Report offreshwater mollusks workshop (19-20 May 1981). U.S. Army Engineer WaterwaysExperimental Station, Vicksburg, Mississippi. 184 pp.

Obermeyer, B.K. 1998. A comparison of quadrats versus timed snorkel searches for assessingfreshwater mussels. American Midland Naturalist 139(2):331-339.

10

Page, L.M., K.S. Cummings, C.A. Mayer, S.L. Post, and M.E. Retzer. 1992. Biologicallysignificant streams. An evaluation of the streams of Illinois based on aquatic biodiversity.Illinois Natural History Survey, Center for Biodiversity, Technical Report. 1992(1):vi + 485pp.

Parmalee, P.W. 1967. The fresh-water mussels of Illinois. Popular Science Series Vol. VIII.108 pp.

Retzer, M.E. 1997. Assessment of the water quality, fish, mussel communities of the MackinawRiver, Illinois. Final report under USEPA grant # X995714-01-0, The Nature Conservancy,Central Field Office, Peoria, Illinois.

Schanzle, R.W., and K.S. Cummings. 1991. A survey of the freshwater mussels (Bivalvia:Unionidae) of the Sangamon River basin, Illinois. Illinois Natural History Survey BiologicalNotes 137:1-25.

Schwegman, J.E. 1973. Comprehensive plan for the Illinois nature preserves system. Part 2.The natural divisions of Illinois. Illinois Nature Preserves Commission, Springfield, Illinois.32 pp.

Strayer, D.L. 1999. Statistical power of presence-absence data to detect population declines.Conservation Biology 13(5):1034-1038.

Strayer, D.L., S. Claypool, and S.J. Sprague. 1997. Assessing unionid population with quadratsand timed searches, pp. 163-169 in K.S. Cummings, A.C. Buchanan, C.A. Mayer, and T.J.Naimo, eds. Conservation and management of freshwater mussels II: Initiatives for the future.Proceedings of a UMRCC Symposium, 16-18 October 1995, St. Louis Missouri. UpperMississippi River Conservation Committee, Rock Island, Illinois. 293 pp.

Turgeon, D.D., A.E. Bogan, E.V. Coan, F.G. Hochberg, W.G. Lyons, P.M. Mikkelsen, J.F.Quinn, Jr., C.F.E. Roper, G. Rosenberg, B. Roth, A. Scheltema, M.J. Sweeney, F.G.Thompson, M. Vecchione, and J.D. Williams. 1998. Common and scientific names ofaquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. AmericanFisheries Society, Special Publication 26:ix-526.

Vaughn, C.C., C.M. Taylor, and K.J. Eberhard. 1997. A comparison of the effectiveness oftimed searches vs. quadrat sampling in mussel surveys. pp. 157-162 in K.S. Cummings,A.C. Buchanan, C.A. Mayer, and T.J. Naimo, eds. Conservation and management offreshwater mussels II: Initiatives for the future. Proceedings of a UMRCC Symposium, 16-18October 1995, St. Louis Missouri. Upper Mississippi River Conservation Committee, RockIsland, Illinois. 293 pp.

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Table 1. Mackinaw River drainage study sites: historical to present.

Site Site County MRM/ Misc. INHS TNC INHSNo. I I Hist. '80-'90 '87 '95 '98-00

UPPER MACKINAW RIVER

1* Mackinaw River, 2.5 mi SW Sibley, T24N, R7E, sec. 4 Ford ___ _ X

2* Mackinaw River, 0.5 mi S Anchor, T24N, R6E, sec. 5 McLean ___X X

3* Mackinaw River, 1.5 mi SE Colfax, T24N, R6E, sec. 7 McLean ___X X

4 Mackinaw River, 1 mi W Colfax, T24N, R5E, sec. 4 McLean X X X X

5 Mackinaw River, 3 mi W Colfax, T24N, R5E, sec. 6 McLean X X X X

6 Mackinaw River, 1 mi SW Lexington, T25N, R4E, sec. 21/26-8/35-6 McLean X __

7 Mackinaw River, 1 mi SW Pleasant Hill, T25N, R4E, sec. 21 McLean X X

8 Mackinaw River, 4 mi W Lexington, T25N, R3E, sec. 10 McLean X X

9 Mackinaw River, 1 mi W Clarksville, T25N, R3E, sec. 3 McLean X

10 Mackinaw River, 6.5 mi WNW Lexington, T25N, R3E, sec. 5 McLean X X

11 Mackinaw River, 4.5 mi WSW Gridley, T26N, R2E, sec. 36 McLean X X X

12 Mackinaw River, 0.8 mi S Kappa, T25N, R2E, sec. 4-5 McLean X X

13 Mackinaw River, 2.5 mi WSW Kappa, T25N, R1E, sec. 1 Woodford X X

14 Mackinaw River, 4 mi W Kappa, T25N, RIE, sec. 3 Woodford X __

15 Mackinaw River, 2.5 mi NE Congerville, T25N, R1E, sec. 7 Woodford __ X X

16 Mackinaw River, 3 mi N Congerville, T25N, R1W, sec. 3 Woodford__ X

UPPER MACKINAW RIVER TRIBUTARIES

Ul* trib. Mackinaw River, 3 mi ESE Anchor, T24N, R6E, sec. 2 McLean X

U2* trib. Mackinaw River, 2 mi SW Anchor, T24N, R6E, sec. 8 McLean X

U3* trib. Mackinaw River, 1.5 mi S Colfax, T24N, R5E, sec. 10 McLean X

U4* trib. Mackinaw River, 1.2 mi WSW Colfax, T24N, R5E, sec. 4 McLean ___ X

U5 Henline Creek, 4 mi NNW Colfax, T25N, R5E, sec. 20 McLean ___ X

U6* Henline Creek, 4 mi NW Colfax, T25N, R5E, sec. 30 McLean __ _ X X

U7 Crooked Creek, 2.5 mi SSE Lexington, T25N, R4E, sec. 29 McLean _ X X

U8 Turkey Creek, 1 mi NNW Lexington, T25N, R4E, sec. 6 McLean __ X

U9 Buck Creek, 1 mi NW Clarksville, T25N, R3E, sec. 3 McLean_ _ X X

U10 Money Creek, 2.5 mi N Towanda, T25N, R3E, sec. 29 McLean X X X

U11 Lake Bloomington, Lake Bloomington, T25N, R3E, sec. 7 McLean _ X

U12 Six Mile Creek, 6 mi N Normal, T25N, R2E, sec. 28 McLean X

U13 Six Mile Creek, 9.5 km SSW El Paso, below dam, T25N, R1E, sec. 1 Woodford X

PANTHER CREEK

P1 Panther Creek, 2.3 km N Panola, T27N, R2E, sec. 17 Woodford X X

P2 Panther Creek, 3.5 mi SW Panola, T27N, R1E, sec. 26 Woodford ___ X

P3 Panther Creek, 7.5 km WNW El Paso, T27N, R1E, sec. 34 Woodford X

P4 Panther Creek, 1.5 mi S Secor, T26N, R1E, sec. 17 Woodford _ _ X X

P5 Panther Creek, 3.5 mi SSW Secor, T26N, R1E, sec. 30 Woodford __ X

P6 East Branch Panther Creek, 2.7 km SSE Panola, T27N, R2E, sec. 31-2 Woodford X X X

P7 East Branch Panther Creek, 6.2 km NW El Paso, T27N, R1E, sec. 26 Woodford_ X

P8 West Branch Panther Creek, Roanoke, T27N, R1W, sec. 14 Woodford X ___ X

WALNUT CREEK

W1 Walnut Creek, 2.5 mi NW Eureka, T26N, R2W, sec. 3 Woodford X

W2 Walnut Creek, 2 mi NW Eureka, T26N, R2W, sec. 2 Woodford X

W3 Walnut Creek, 3 mi SSE Eureka, T26N, R1W, sec. 31-2 Woodford X X

W4 Walnut Creek, 2 mi E Goodfield, T25N, R1W, sec. 4 Woodford X X

13

Table 1. Mackinaw River drainage study sites, continued.

LOWER MACKINAW RIVER

17 Mackinaw River, 1.9 mi E Goodfield, T25N, R1W, sec. 17 Woodford X X X

18 Mackinaw River, 1.5 mi SE Goodfield, T25N, R1W, sec. 19 Woodford X

19 Mackinaw River, 2 mi S Goodfield, T25N, R2W, sec. 36 Tazewell X

20 Mackinaw River, Mackinaw R. State F&W Area, T24N, R2W, sec. 3 Tazewell X X

21 Mackinaw River, Mackinaw R.r F&W Area to 1 mi N Mackinaw, Tazewell XT24N, R2W, sec. 4

22 Mackinaw River, 1 mi N Mackinaw, T24N, R2W, sec. 8 Tazewell X X X

23 ickinaw River, 1 mi N Mackinaw to CR 1435N, T24N, R2W, sec. 7 Tazewell X

24 Mackinaw River, 2 mi SW Mackinaw, T24N, R3W, sec. 24 Tazewell X

25 Mackinaw River, 4 mi SW Mackinaw, T24N, R3W, sec. 27 Tazewell X X X

26 Mackinaw River, 3.5 mi SE Tremont, T24N, R3W, sec. 34 Tazewell X

27 Mackinaw River, 3 mi NNE Hopedale, T23N, R3W, sec. 9 Tazewell X X

28 Mackinaw River, 3 mi NW Hopedale, T23N, R3W, sec. 17 Tazewell X X X X

29 Mackinaw River, 6 mi NNW Delavan, T23N, R4W, sec. 7 Tazewell X X X

30 Mackinaw River, 2.5 mi N Green Valley, T23N, R5W, sec. 15 Tazewell X X X X

31 Mackinaw River, 3 mi NW Green Valley, T23N, R5W, sec. 17 Tazewell X

32 Mackinaw River, 4 mi WSW South Pekin, T23N, R6W, sec. 1 Tazewell X

33 Mackinaw River, 3.5 mi SW Crescent, T24N, R6W, sec. 24 Tazewell X X X

34 Mackinaw River, 3 mi NE Talbot, T24N, R6W, sec. 13 Tazewell X

LOWER MACKINAW TRIBUTARIES

MU1 Mud Creek, 1 mi W Allentown, T24N, R3W, sec. 2 Tazewell X X

MU2 Mud Creek, 3 mi WSW Mackinaw, T24N, R3W, sec. 23 Tazewell X

PR1 Prairie Creek, 3 mi NW Hopedale, T23N, R3W, sec. 9 Tazewell X

L1 Little Mackinaw River, 2 mi N Hopedale, T23N, R3W, sec. 14 Tazewell X

*sampled in 1998, 1999, and 2000

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