Printer Friendly

The unionid mussels (mollusca: bivalvia: unionidae) of the Big Blue River Basin of northeastern Kansas and southeastern Nebraska.

ABSTRACT

A survey of 96 locales in the Big Blue River and its minor tributaries supplemented by museum vouchers documented the presence or former presence of 25 native unionid mollusk species and one introduced bivalve. Including the previously reported Little Blue Basin, the total documented unionid inventory of the Big Blue Basin consists of twenty-six species. Over a third of these species may have been extirpated from the basin, and many of the surviving species appear to have experienced significant range reductions. Habitat in the region is adversely impacted by surface and subsurface water withdrawals, erosion/siltation, and grazing. Chemicals and other pollutants from agricultural fields probably exert a further deleterious impact upon the fauna of the region. Despite these conditions, the Big Blue Basin continues to provide habitat for a number of species that are generally uncommon in northern Kansas and Nebraska.

**********

The Big Blue River originates in Hamilton County, Nebraska and flows east and then south for approximately 571 km to its juncture with the Kansas River near Manhattan, Kansas (Fig. 1). The total drainage basin encompasses some 25,550 [km.sup.2] in northeastern Kansas and southeastern Nebraska, with the greatest portion located in the later state. Major tributaries include the West Fork of the Big Blue in Nebraska; the Little Blue River in Kansas and Nebraska; and the Black Vermillion River in northern Kansas. The largest of these is the Little Blue River with a drainage of 9,158 [km.sup.2], or a little over one third of the total area in the Big Blue Basin.

The study area encompasses parts of two major geographical regions: the Central Lowlands and the Great Plains. In Nebraska, the course of the Big Blue River flows largely along the demarcation line between the two regions (Fenneman 1931), while the Kansas portion of the basin lies entirely within the Central Lowlands. The portion of the Big Blue Basin within the Central Lowlands was glaciated during the Pleistocene, while that in the Great Plains region was not subject to glaciation (Fenneman 1931, 1938). In both regions, the original native vegetation consisted primarily of grasses, with forested areas confined to corridors along streams.

Early references indicate the Big Blue River received its name due to the blue coloration of the water in some of the deeper holes (Andreas 1882, Dobbs 1918). The Big Blue cuts through limestone bedrock at a number of points in its course, and coupled with its former clarity, probably once provided good habitat for unionid mollusks. Coker (1919) reported 55 tons of shell were collected from the Big Blue for use in the production of buttons in the period 1914-1916.

By the early twentieth century, a large number of small dams had been constructed in the basin to harness the flow of the river and some of its tributaries for mills and the generation of electrical power. In Nebraska, Bouc (1983) notes the construction of "at least 35 dams across the Big Blue and its tributaries at one time or another, and at least 14 on the Little Blue." Other dams were also present in reaches of these rivers in Kansas. The Omaha World Herald (1929) reported the Big Blue River to be the most controlled river in the nation. Though most of these structures have since been removed, there are still a small number of extant power dams along both the Big Blue and the Little Blue. Following World War II, much of the lower portion of the Big Blue River was inundated with the creation of Tuttle Creek Lake.

The published references on the mussels of the Big Blue River have been based predominantly on limited collections at a handful of sites (Canfield and Weibe 1931, Hoke 1997b, Liechti and Huggins 1977, Murray and Leonard 1962, Popenoe 1885, Schuster and Dubois 1978, Tyron 1868, Walker 1906). Aughey (1877) published the only species list for the "Blue" (probably the Big Blue) river in Nebraska, and reported 35 currently recognized species for the Nebraska portion of the stream. Unfortunately, Aughey's scholarship has been questioned both recently (Bolick 1993) and by contemporary colleagues (Pound and Clements 1898), and there are significant problems with many of his identifications (Hoke 2000). Further, most of the related vouchers have been lost, and the surviving specimens document only four species. In an early study of the unionids of Kansas, Scammon (1906) mentions only two species specifically from the Big Blue River, and though he probably had evidence of a greater number of species from this system, he rarely gave specific collection site locales, and his species ranges are too broad (e.g. "all Kansas systems," "Kansas drainage," "most common in Kansas System," etc.) to be of much value as the basis for faunal inventories of specific streams. I have been unsuccessful in locating supporting vouchers, and it appears they have been lost or destroyed.

[FIGURE 1 OMITTED]

This study is an expansion of an initial project to document the freshwater mussels of Nebraska. Since four rivers in southern Nebraska flow either into or from northern Kansas, a region largely unstudied at the inception of the project, each of these rivers was surveyed in its entirety. The results of surveys of three rivers, the Big Nemaha, Republican, and Little Blue, have been previously published (Hoke 1996, 1997a, 2004). This paper will first present new data from the Big Blue River and its minor tributaries and then utilize the results of a survey of the Little Blue Basin (Hoke 2004) in presenting unionid distributions and species status for the entire Big Blue Basin

The goals of this study were to identify the species present and, to the extent possible, formerly present in the Big Blue River and its minor tributaries, to define their ranges and current status, and to identify factors influencing their survival and distribution in the region. In the absence of previous comprehensive basin studies, the survey was essentially an attempt to provide baseline data for the region.

METHODS

Initially, the survey relied extensively upon information supplied by other individuals for the locations of sites to be surveyed. In early 1976, a questionnaire was mailed to Nebraska conservation officers, on a statewide basis, requesting information on the locations of known freshwater mussel populations. Responses received provided the locations of a number of potential collection localities in the Nebraska portion of the Big Blue Basin, and in some instances information was also obtained regarding the locations of former populations as well. During the coarse of collections, comments were also actively sought from local residents of the region regarding both past and present unionid mollusk populations, as well as observations that might prove relevant to obtaining an understanding of these populations.

Specific site locations were determined primarily by the presence of bridge access to streams. Site selection was also influenced by a desire to obtain collections at intervals no greater than 18 km along the Big Blue and its larger tributaries, and by a goal of sampling all of the aquatic habitats in the region. The habitats identified for study were the Big Blue River, minor tributary rivers, creeks, and lakes, ponds and reservoirs. The collection effort focused on lotic habitats, but accessible lentic environments were also sampled. Because lentic habitats in the region are primarily private farm ponds, and were often not accessible for survey, it is probable their fauna is underrepresented in this study.

Though notes were made concerning the relative abundance of species recovered, the survey was qualitative and no attempt was made to record the number of specimens of each species examined at any site. Specimens were collected by hand, supplemented with the use of a garden rake. The sampling effort was thus limited to depths of 1.3 meters or less. The fact that a more rigorous collection method was not utilized was at least partially mitigated by confining collection activities to periods of low water, when visual and physical access to stream bottoms was at a maximum. In an effort to preserve the biological resources of the study area, recent shells were collected in preference to live specimens whenever possible. As a result, relatively few live individuals were retained. Live specimens not retained as vouchers were identified immediately upon extraction and then gently returned to their substrates. Collection locales were marked on USGS maps, and field notes were maintained for each site sampled denoting species recovered, environmental conditions, and any related interviews with local residents. In addition, a photographic record was usually taken at each collection locale.

In the absence of previous basin-wide surveys, significant efforts were made to identify components of the fauna no longer present in the basin. During collection activities, relict shells were examined in the hope of discovering former species since extirpated from the region. This effort was supplemented by visits to and examination of the collections at a number of museums.

Previous to preparation of this manuscript, officials of the Nebraska Game and Parks Commission and the Kansas Department of Wildlife and Parks were contacted in an effort to learn the results of any unpublished collection efforts in the basin. Information obtained from these sources is included in this paper as indicated in the text. The value of any studies discovered in this process was twofold: potentially serving as a further source of additional species, and as an independent means of measuring the completeness and quality of the collection effort in this study.

Most specimens were identified by the author; however, a number of specimens were identified by Dr. Harold Murray, Trinity University, and Dr. David H. Stansbery, Ohio State University Museum of Biological Diversity. All specimens collected prior to 1984 have been processed into the collections of the Museum of Biological Diversity at Ohio State University in Columbus, Ohio. Specimens collected after 1983 either have been donated to that facility and are awaiting processing into the collection or will be deposited at that facility at a later date.

The nomenclature utilized in this paper follows Turgeon, et al. (1998). Conversion of Aughey's (1877) nomenclature into current usage was accomplished with the use of Burch's (1975) synonymy, supplemented by the aid of Dr. David H. Stansbery, Ohio State University Museum of Biological Diversity.

[FIGURE 2 OMITTED]

RESULTS

A total of 96 sites are included in this study of the Big Blue River and its minor tributaries (Fig. 2). Six of these locales were sampled by Nebraska Game and Parks personnel, most between 1969 and 1970, and the related specimens and field notes relating to five of these locales were donated to the author. One site was collected by a local resident. Two additional sites pertain to recent collections at the University of Nebraska State Museum. The remaining 86 sites were collected solely by the author between 1973 and 2002, with most of the effort occurring in 1976, 1981, 1985, 1988, and 1995. Most sites were sampled only once, however, a number of locales in the Big Blue River and along the West Fork of the Big Blue were sampled on multiple occasions.

Unionid mollusks were recovered from 81 different locations or a little over 84 percent of all the sites collected from the Big Blue River and its minor tributaries. Twenty-four freshwater mussel species and the introduced bivalve Corbicula fluminea (Muller, 1744) were recovered during the survey. Table 1 shows the results of all collections, and gives the best condition of the shells of each species recovered from each location. The average number of species collected from productive sites in the study area was 4.48 and the richest locales (sites 26 and 38) produced 14 species each.

The total number of species occurrences, herein defined as the sum of the number of geographic locales at which each species was recovered, was 363, including six occurrences of unidentifiable specimens. Over half of all identifiable species occurrences (181) were of just five species. These relatively widespread mussels and the number of sites at which they were found (i.e. species occurrences) are as follows: Quadrula quadrula (Rafinesque, 1820)(49); Pyganodon grandis (Say, 1829) (40); Lasmigona c. complanata (Barnes, 1823) (33); Quadrula p. pustulosa (Lea, 1831) (33); and Lampsilis siliquoidea (Barnes, 1823) (26). In contrast, many unionids were quite uncommon in survey results. The remaining nineteen unionids produced a total of 176 species occurrences with the five least common mussels--Obovaria olivaria (Rafinesque, 1820), Potamilus purpuratus (Lamarck, 1819), Quadrula fragosa (Conrad, 1835), Truncilla donaciformis (Lea, 1828), and Utterbackia imbecillis (Say, 1829)--limited to a total of only eight species occurrences.

Nine unionids were collected live from at least one locale in the region, and six others plus the introduced bivalve C. fluminea were recovered as fresh dead, recent, or slightly to moderately weathered shells suggesting these species may still be present in the study area. The remaining nine unionids were collected only in greatly weathered or sub-fossil (chalky) condition and may have been extirpated from the basin. Included in this latter group are Anodontoides ferussacianus (Lea, 1834), Fusconaia flava (Rafinesque, 1820), Lampsilis teres (Rafinesque, 1820), Ligumia recta (Lamarck, 1819), Potamilus purpuratus, Quadrula fragosa, Strophitus undulatus (Say, 1817), Tritogonia verrucosa (Rafinexque, 1820), and Truncilla donaciformis.

Unionid species diversity was greatest in the lower part of the basin, in and below Indian Creek. This species-rich area corresponds generally with the Central Lowlands physiographic region.

Table 2 presents collection statistics from the Big Blue and its minor tributaries by habitat. The four major habitats sampled during the survey, the Big Blue River, minor rivers (Black Vermillion and West Fork Big Blue), creeks, and lentic areas all produced unionids. Not surprisingly, lotic sites supported a greater historic species diversity, 24 species, than lentic sites with only 10 species. Site diversity was greatest in the Big Blue River with an average of 5.26 species recovered at productive sites. The Big Blue was also historically the richest of the four habitats sampled, with 21 unionid species recovered as well as the introduced bivalve C. fluminea. Included in this total were four unionids not recorded for any other habitat: Obovaria olivaria, Potamilus purpuratus, Quadrula fragosa, and Truncilla donaciformis, as well as the introduced bivalve C. fluminea. Unfortunately, the Big Blue River also showed the greatest potential loss of diversity of the four habitats with only 47.62% of its historical fauna represented by shells in relatively good condition. Included among those species represented only by shells in poor condition are three of the four unionids reported only for the Big Blue River.

The minor rivers habitat was the most consistently productive of the lotic environments, with seventeen of eighteen sites (94.44%) producing shells, and average species diversity was high at 4.65 species per productive site. Historically this habitat supported eighteen species, and based upon the condition of shells collected, it is probable that at least eleven species (61.11%) still survive in these streams. This probable retention rate was the highest of the three lotic habitats.

Creek habitats were the least productive, with only 76.92% of locales yielding unionid mollusks, and the average diversity of productive sites was 3.80 species, the lowest of the four habitats surveyed. Nineteen unionid species were documented for creek habitats in the region, however, based upon the poor condition of shell material recovered, it is possible as few as ten species survive in these streams at present.

Lentic sites were the most consistently productive habitat and unionid mollusks were collected from every site sampled. The average number of species recovered was 4.00 species per site. The historic species richness of lentic habitats was low, with only ten species recovered; however, all but one of these were represented by shells in good condition suggesting that as much as 90 percent of the historic fauna supported by this habitat remains intact.

A number of the museums contacted during this study hold voucher specimens from the Big Blue River or its minor tributaries; however, most of these records are not specific concerning collection locations (usually giving only the river and state), and are of species recovered in the current survey. A single exception, a voucher of Pleurobema sintoxia (Rafinesque, 1820), collected from the Black Vermillion River prior to 1900, is in the collection of the University of Michigan Museum of Zoology (No. 153,994) and documents a species not recovered in the current survey.

Subsequent to the conclusion of fieldwork in the Big Blue River and its minor tributaries, it was learned that a mussel survey had been conducted by the Kansas Department ofFish and Game (KDF&G) at 32 sites in the southern portion of the basin, almost entirely in the Horseshoe Creek, and Black Vermillion River drainages. The results from that effort did not increase the number of species documented for the Big Blue River and its minor tributaries; however, it did provide valuable information on the distribution and status of species within the areas surveyed.

The historic mussel distributions of the Big Blue Basin

The physical location of species recovered in this survey of the Big Blue River and minor tributaries combined with that of a companion survey of the Little Blue River (Hoke 2004) provides baseline data to delineate the historic distributions of unionids in the Big Blue Basin. These distributions are discussed below and illustrated on Figs. 3 through 29. For these figures, filled circles indicate productive sites collected by or the location of specimens given to the author, with numbered circles indicating locales from the Big Blue or one of its minor tributaries, while unnumbered circles represent sites within the Little Blue drainage previously reported by Hoke (2004). Filled diamonds indicate sites collected by Nebraska Game and Parks Commission or Kansas Department of Wildlife and Parks personnel, and filled triangles denote sites documented by recent (i.e. post 1964) museum collections of the University of Nebraska State Museum, the Biology Department at the University of Nebraska at Kearney, and the Kansas Biological Survey. Filled squares indicate the location of pre-1900 museum vouchers. In Nebraska squares reference the work of Aughey (1877) as attested by surviving vouchers at the University of Nebraska State Museum, while in Kansas the single square denotes the locale of a voucher from the University of Michigan Museum of Zoology. The maps show all collections from the Little Blue Basin (Hoke 2004), and all collections from the Big Blue River and its minor tributaries included in Table 1 of this paper but include other relevant Kansas collection results only when they add to the distributions documented in this survey.

Twelve unionid species were collected as live records or fresh or recent empty shells, indicating their presence in the Big Blue Basin at the time of collection. All of these were collected within the Big Blue River or its minor tributaries, while only nine species were recovered in similar condition from the Little Blue Basin (Hoke 2004). These mussels are discussed in alphabetical order in the paragraphs below.

Lampsilis cardium Rafiniesque 1820 was widespread in the Big Blue System (Fig. 6), but was only infrequently observed live. The only live records are from the West Fork of the Big Blue and the upper portion of the Big Blue River in Nebraska. Specimens were collected in mud, and sand and mud substrates in 0.3 to 1.0 meter of water in slow current. The only shells in good condition from the Little Blue Basin were collected in 1967 (Hoke 2004). No evidence of recruitment was observed and the few live specimens recovered were old individuals.

Lampsilis siliquoidea was relatively common in the Big Blue Basin (Fig. 7), and specimens were present at 29 percent of all sites collected. Unfortunately, in most instances the best specimens recovered were heavily weathered unpaired valves, suggesting the mussel is in decline. Live specimens were obtained from the West Fork of the Big Blue River and also from a hole in the Big Blue River in Nebraska. These individuals were recovered from mud, mud and rock, and mud and sand substrates in 0.5 to 1.2 meters of water respectively. There was no evidence of recruitment. The only shells in good condition from the Little Blue Basin were collected in 1967 (Hoke 2004). The Kansas Department of Wildlife and Parks lists L. siliquoidea as a species in need of conservation (SINC species), and this survey is consistent with that categorization for both the Nebraska and Kansas portions of the survey region.

Lasmigona c. complanata was found to be one of the few unionids that appears to be holding its own and on occasion even thriving in parts of the Big Blue Basin (Fig. 9). Live specimens were collected from creeks, and rivers as well as from Tuttle Creek Lake. In 1976 hundreds of fresh dead specimens were observed stranded at site 36 due to low water conditions during a local draught. This mussel was most frequently collected in slow current from mud or sand and mud substrates in 0.3 to 0.7 meters of water.

Leptodea fragilis (Rafinesque, 1820) (Fig. 10) and Potamilus ohiensis (Rafinesque, 1820) (Fig. 16) were common in the Big and Little Blue (Hoke 2004) rivers and in some of the larger creeks near and below the Nebraska-Kansas border. They were especially abundant in Tuttle Creek Lake and below the Turtle Creek dam. These mussels were recovered live or as shells in good condition throughout the ranges documented in this study for the Big Blue and its minor tributaries and a similar pattern was noted for the Little Blue Basin as well (Hoke 2004), suggesting these mussels are currently holding their own or possibly even expanding their ranges in the Big Blue Basin. Both species were recovered from mud, sand, and mud and sand substrates.

Potamilus alatus (Say, 1817) was represented in the lower (Kansas) reaches of the Big Blue Basin by occasional specimens in relatively good condition (Fig. 15). The mussel appears to be a part of the extant unionid fauna of Tuttle Creek Lake where specimens in good condition were frequently encountered. Potamilus alatus was also documented for the Big Blue River in Nebraska as well as for the lower reach of Indian Creek in Gage County; however, the vouchers for these regions were older unpaired valves and may indicate the extirpation of the mussel from those areas. The recovery of specimens from Tuttle Creek Lake suggests that lentic areas behind several small dams along the Big Blue River in Nebraska may provide habitat for this mussel, however these areas were not investigated during this survey. Potamilus alatus was recovered from sand and mud substrates in water greater than 0.8 meters in depth.

Pyganodon grandis was found to be common in the Big Blue Basin (Fig. 18), with a presence in virtually every environment collected. It was found in lakes, creeks, and quiet reaches of rivers, and was present though (surprisingly) not abundant at collection sites in Tuttle Creek Lake. Specimens were usually obtained from mud or mud and sand substrates in slow currents or in quiet water ranging in depth from a few centimeters to over one meter.

Quadrula p. pustulosa (Fig. 20) was relatively common in the Nebraska portion of the Big Blue Basin, and present but rare in creeks in the eastern Nebraska reaches of the Little Blue Basin (Hoke 2004). Specimens collected in the Kansas portion of the Big Blue Basin were generally in poor condition, and only one live specimen was collected. On gravel bars below the Tuttle Creek Dam, Quadrula p. pustulosa was the most common bivalve represented, however the specimens were all chalky unpaired valves. Live specimens were collected in water from 0.2 to 0.8 meters in depth in quiet to moderate flow. Substrates varied from sand, to soft mud, and combinations of both. The mussel has disappeared from much of its former range in Nebraska (Hoke 1996). The Big Blue River and some of its minor tributaries in Nebraska provide the best remaining habitat for the species in that state.

The most common mussel collected in the Big Blue basin was Quadrula quadrula (Fig. 21). It was recovered from all habitat types sampled in the Big Blue River and its minor tributaries and was the most common mussel recovered from the Little Blue Basin as well (Hoke 2004). This mussel was not only widespread but usually also quite numerous when collected. Specimens were found in most substrates in water varying from a few centimeters to over a meter in depth. It was among the most numerous species encountered in the sheltered coves of Tuttle Creek Lake, and very large populations were noted in a lentic area southeast of the Tuttle Creek Dam.

Toxolasma parvus (Barnes, 1823) was relatively uncommon in the Nebraska portion of the study area, but shells were more widely distributed in basin creeks in Kansas (Fig. 23). The species may be more common in the region than is indicated from survey results, since it is easy to overlook specimens due to their small size.

Uniomerus tetralasmus (Say, 1831) was relatively widespread in the survey region (Fig. 27), but live populations were generally restricted to creeks, ponds, and headwater reaches of larger rivers. Uniomerus tetralasmus was usually collected in less than 0.5 meters of water from soft mud substrates in quiet water.

Utterbackia imbecillis was very rare in collection results from the Big Blue Basin (Fig. 28). In part its infrequency may be the product of the relatively minimal collection effort expended in lentic environments and thus possibly an artifact of sampling bias toward lotic localities. However, since this unionid was also present at only one of the 32 productive sites surveyed by the Kansas Department of Wildlife and Parks between 1996 and 2000, its near absence from collection results may reflect a real scarcity in the Big Blue Basin. The mussel was collected from soft mud in quiet waters of a pond-like area below and southeast of the Tuttle Creek Dam in this survey and from a small tributary of the Black Vermillion River by the Kansas Department of Wildlife and Parks.

The unionids Amblema plicata (Say, 1817), Ligumia subrostrata (Say, 1831), Obovaria olivaria, and Strophitus undulatus as well as the introduced bivalve Corbicula fluminea were collected in slightly to moderately weathered condition from at least one site in the Big Blue Basin, and it is possible that at least some populations of these species still reside in the system. These bivalves are briefly discussed below.

Amblema plicata was primarily restricted to the Kansas portion of the Big Blue Basin, and was recovered at only one site north of the Kansas-Nebraska border (Fig. 3). If populations still remain they are likely to be found in some of the deeper holes in the Big Blue River and its larger tributaries, habitats that were not examined in the current survey.

Specimens of Ligumia subrostrata were widely distributed in the Big Blue Basin (Fig. 12), but most specimens recovered were in poor condition. A thorough search in smaller tributaries and the upper reaches of some larger streams might prove productive. This species was one of the most common mussels found in the adjacent Big Nemaha Basin (Hoke 1996), where it was almost always found in a heavily weathered condition.

Obovaria olivaria (Fig. 13) was collected in chalky condition as an unpaired valve from two sites on the Big Blue River and a third site along the Little Blue River (Hoke 2004). A complete, slightly to moderately weathered specimen was recovered by the Nebraska Game and Parks Commission prior to 1998 and viewed by the author after completion of survey work in the Nebraska portion of the study area. This specimen may indicate the presence of surviving populations along the Big Blue River between Crete, Nebraska, and the Kansas border. Since live specimens of this species have not been observed in the Kansas drainage since Scammon (1906) recovered some near Topeka, Kansas, it is important that any live populations be located and protected.

Strophitus undulatus(Fig. 22) was relatively common in the Kansas portion of the Big Blue Basin; however, most specimens were in badly weathered or chalky condition. This species was also common to the east in the adjacent Big Nemaha Basin (Hoke 1995), where it was almost always represented by shells in a similar condition. This mussel is listed by the Kansas Department of Game and Fish as a SINC species, and the results of this study are in accord with that categorization. It is possible some scattered populations of this mussel continue to exist in the basin.

Many specimens of the introduced bivalve Corbicula fluminea (Fig. 29) were recovered from site 1, several kilometers above the confluence of the Big Blue and Kansas rivers, and it is likely that live populations are also present though none were observed at that site. This bivalve was not collected above the Tuttle Creek Dam, though it is present in the Kansas River and in reservoirs in the tributary Republican, Solomon, Saline and Smoky Hill basins to the west (Hoke 1997a). It is possible Tuttle Creek Dam is currently acting as a faunal barrier for this species.

Nine of the unionids recovered from the Big Blue Basin were represented only by specimens in poor condition (i.e., badly weathered to chalky condition), and one additional species was found through an examination of museum collections. It is likely many or all of these species have been extirpated from the survey area. A brief summarization follows.

Potamilus purpuratus (Fig. 17) and Quadrula fragosa (Fig. 19) were collected only in sub-fossil or chalky condition, and they have almost certainly been extirpated from the study area. Potamilus purpuratus is very rare in the Missouri River Basin, where it has only been reported from the Kansas Basin in Kansas (Scammon 1906, Schuster and Dubois 1978), and the Elkhorn Basin in Nebraska (Hoke 1994). Quadrula fragosa is a federally endangered species. The occurrence of this species in the Big and Little Blue rivers was previously reported by Hoke (1997b). Given the chalky condition of the specimens recovered, and the collection locales, two environmentally stressed rivers at the western edge of the species' range, it seems unlikely that populations continue to survive in the region.

The status of the remaining species, represented in survey results only by greatly weathered or sub-fossil shells, is less clear, though it is probable that many of them have also been extirpated from the Big Blue Basin. Most of the species in this category are listed by the Kansas Department of Wildlife and Parks as Species in Need of Conservation (SINC). These include Anodontoides ferussacianus (Fig. 4), Fusconaia tiara (Fig. 5), Lampsilis teres (Fig. 8), Truncilla donaciformis (Fig. 25), and Truncilla truncata Rafinesque, 1820 (Fig. 26). Anodontoides ferussacianus, and F. tiara were once relatively common in the lower (Kansas) portion of the survey area. The fact that these animals were not represented at any locale by shells in better condition may suggest their current absence from the region. Some species were not only recovered in poor condition but were also extremely rare. Truncilla donaciformis and T. truncata were represented solely by one greatly weathered or sub-fossil valve each.

[FIGURE 3 OMITTED]

[FIGURE 4 OMITTED]

[FIGURE 5 OMITTED]

[FIGURE 6 OMITTED]

[FIGURE 7 OMITTED]

[FIGURE 8 OMITTED]

[FIGURE 9 OMITTED]

[FIGURE 10 OMITTED]

[FIGURE 11 OMITTED]

[FIGURE 12 OMITTED]

[FIGURE 13 OMITTED]

[FIGURE 14 OMITTED]

[FIGURE 15 OMITTED]

[FIGURE 16 OMITTED]

[FIGURE 17 OMITTED]

[FIGURE 18 OMITTED]

[FIGURE 19 OMITTED]

[FIGURE 20 OMITTED]

[FIGURE 21 OMITTED]

[FIGURE 22 OMITTED]

[FIGURE 23 OMITTED]

[FIGURE 24 OMITTED]

[FIGURE 25 OMITTED]

[FIGURE 26 OMITTED]

[FIGURE 27 OMITTED]

[FIGURE 28 OMITTED]

[FIGURE 29 OMITTED]

Though not listed as a SINC species, Ligumia recta and Tritogonia verrucosa are probably in serious decline or possibly extinct in the Big Blue Basin. Ligumia recta (Fig. 11), though not abundant at any site, was widely distributed; however, it was usually collected as an unpaired valve and always in greatly weathered or subfossil condition. Tritogonia verrucosa (Fig. 24) was less frequently represented in survey results but was also always collected in a similar condition, and again usually as an unpaired valve.

Pleurobema sintoxia (Fig. 14) appears to be historically quite rare in the Kansas drainage, and other than the museum record previously noted, there is only a single record from the Delaware River, a tributary of the Kansas River located east of the study area (Liechti and Huggins 1977). Pleurobema sintoxia has not been recovered from the Big Blue Basin for more than a century, and in view of the greatly deteriorated conditions in the region since that point in time, it seems likely this animal may be extirpated from the basin.

ANALYSIS

All of the freshwater mussels reported for the Big Blue Basin from all published sources [except Aughey (1877)] and recent unpublished surveys are given in Table 3. The current survey coupled with the previously published Little Blue Basin survey (Hoke 2004) recovered a total of 25 unionid species for the Big Blue Basin with one additional species discovered in museum records, more than in any report except for the 35 species reported by Aughey (1877).

Given the questions concerning Aughey's (1877) identifications and scholarship previously discussed, there may well be no way of reconciling the two works; however, Table 4 summarizes the differences. Seventeen species reported by Aughey (1877) for the Big Blue Basin were recovered in the current survey, and four others have been reported for other streams in Nebraska by various authors. Four species, though otherwise unreported for the state, have been recovered in regions contiguous to Nebraska and could have been present in the state when streams were more pristine. In contrast, nine of Aughey's (1877) reported mussels have never been reported elsewhere from any stream within the Missouri River Basin. One additional species, Elliptio crassidens, is highly doubtful, having only been recovered prior to 1920 in the Missouri Basin from one site near the mouth of the Osage River in east-central Missouri (Oesch 1995). If these ten species can be judged to be incorrect identifications, then the minimum error rate for Aughey's species list for the Big Blue system is almost 29 percent. A further known error is the exclusion of Ligumia recta, one of only four species from the Big Blue River that is supported by vouchers from the handful of surviving specimens relating to Aughey's work. It is unknown whether this species was inadvertently omitted from Aughey's list, or if it was misidentified and included on the list as another species. In short, there is little reason to place reliance on Aughey's (1877) list, and there is justifiable cause to question the species listed.

The absence of reliable early system-wide studies precludes any attempt to identify changes in the fauna of the Big Blue Basin from a comparison of historic results; however, a method was devised to determine the general status of each species based upon the condition of the specimens collected from the study area. For each species recovered at each location, the conditions of all specimens retained were categorized as follows: live, fresh dead, recent shell, slightly to moderately weathered shell, heavily weathered shell, and chalky (sub-fossil) shell. The best specimen of each species at each site was noted and compared to the best specimens of the same species from every other locale in the study area to arrive at a determination of the current status of the animal. It is the contention of this paper that a general absence of shells in good condition (herein defined as specimens in live, fresh dead, recent, or slightly to moderately weathered condition) for any unionid constitutes evidence of a significant decline or possible extirpation of the species within the region. Though the condition of the shells of any species at a single site cannot by itself be utilized to suggest the current status of a species at that site, since it may be true that live individuals were overlooked at a particular locale, it is likely that a failure to locate shells of a given species in good condition after collections at many sites probably indicates the decline or extirpation of that species within the region.

The above method can produce valid results only to the extent that the samples at individual collection sites are more or less reflective of the fauna at those locales. There are no other collections with which to compare the current results on a site by site basis, but it is possible to compare the best condition of the specimens obtained from the Kansas portion of the study area in this survey to those recovered by the Kansas Department of Fish and Game in their 1996-2000 surveys in the Big Blue Basin. A comparative analysis is presented in Table 5. Examination of Table 5 reveals little difference in the condition of species recovered in both studies and supports the quality of the data obtained in the current study.

Table 6 summarizes the condition of the best specimens of each species collected from the Big Blue River and its minor tributaries in this study and from the Little Blue Basin as presented in Hoke (2004). The single most significant aspect of this summary is the generally poor condition of the specimens recovered, with 62% of all best conditions of shells collected represented by specimens in heavily weathered or chalky condition. In the Little Blue Basin, 72% of the best species occurrences were in poor condition. These figures indicate a significant deterioration of the unionid fauna in the Big Blue Basin.

The last column of Table 6 computes the maximum range reduction of each species, based upon the number of best condition shells recovered in poor condition during the survey. The figures presented assume all collections at all sites completely reflected the current composition of the unionid fauna present at the time of collection. Since it is likely that at least some collections were incomplete, and because areas deeper than 1.3 meters were not tested, these range reductions are probably overly pessimistic. The degree of bias is unknown; however, it is the author's opinion that they fairly present the magnitude of the actual decline in the region.

The fifteen unionids that were found exclusively in lotic environments were on average recovered in the worst condition and exhibited the greatest range reductions. Lotic species that appear to have been rare in the basin were recovered in the worst conditions, and, with the possible exception of Obovaria olivaria, have probably been eliminated from the Big Blue Basin. Even formerly widespread and common lotic or primarily lotic species such as Lampsilis cardium, L. siliquoidea, and Quadrula p. pustulosa have disappeared from much of their former ranges. In contrast, nine of the ten unionids found in this survey to inhabit lentic environments exclusively or in part were recovered from at least one locale in good condition, though their ranges too appear to be in decline.

DISCUSSION

The unionid distributions discussed above are the product of the original native populations of the region and the environmental alterations brought about by the settlement and agricultural development of the area. Today the streams of the Big Blue Basin are much changed from their original state. The Big Blue River from the confluence of the Little Blue to the Kansas River is almost entirely impounded behind Tuttle Creek Lake. In addition, numerous small power dams still exist along the Big Blue and Little Blue rivers in northern Kansas and Nebraska. Creation of these impoundments eliminated significant habitat for lotic species.

Erosion is a problem throughout the Big Blue System. In Nebraska portions of the Big and Little Blue rivers, turbidity affects 79 percent of the stream mileage in the Big Blue basin (Bliss and Schainost 1973a), and 91 percent of the stream mileage in the Little Blue basin (Bliss and Schainost 1973b). The waters of the Big Blue are often brown in color reflecting the amount of silt in suspension. In 1976, a Sechi disk reading of 1.5 cm was obtained at one collection site along the West Fork of the Big Blue River near Dorchester, Nebraska. Crops are sometimes planted to the very edge of stream banks, resulting in severe losses of topsoil during heavy rains. At a site along the Little Blue River, Hoke (2004) noted a large expanse of eroded soil along the stream bottom adjacent to a large plowed field. The eroded topsoil was as much as six feet in depth and covered a significant portion of the stream bottom at this site. The upper third of Tuttle Creek Lake is now almost entirely filled with sediment. Silt is known to be detrimental to unionids, and has been reported to be responsible for severe decreases in many freshwater mussel populations (Ellis 1936). Excessive silt decreases the biological productivity of streams by blocking sunlight and thus limiting photosynthesis and fills up the deeper holes in stream bottoms, thus decreasing the food and degrading or eliminating the habitat for many fish. Since unionids are parasitic upon species specific host fish, decreases in fish diversity and abundance resulting from excessive silt directly impacts the unionid reproductive cycle and can lower recruitment or eliminate successful reproduction entirely.

The most significant threat to bivalve mollusks in the Big Blue System at present is probably extensive surface and subsurface water withdrawals. Groundwater levels in some Nebraska reaches of the Big and Little Blue river basins have declined as much as 30 feet from pre-settlement levels (Mack et al. 1996a). These declines appear to be the product of the extensive drilling of the locale aquifers for irrigation wells usually associated with center pivot systems (Mack et al. 1996b). Lowered water tables result in the dewatering of reaches of creeks that once supported unionids. Dewatering is most significant in the Little Blue Basin, and in upper reaches of the Big Blue Basin. Anecdotal reports from a number of sources indicate the former presence of populations of mussels along now dry or nearly dry reaches of Big Sandy Creek in the Little Blue Basin (Hoke 2004) and Lincoln Creek in the upper Big Blue Basin.

The impact of lowered water tables on freshwater mussels is exacerbated by surface water withdrawals from the rivers for irrigation. The author observed only a two-meter wide flow remaining along portions of the upper Big Blue River immediately below some of these siphons. The extensive surface water withdrawals are followed by large return flows from the irrigated fields adjacent to area streams. The return flows are warm and laden with chemicals and nutrients from adjacent agricultural fields and often create sustained high water conditions in area streams during the runoff period. Since many unionids move into shallow water to reproduce in the summer, the effect of alternately abnormally low flow followed by abnormally high flow conditions is probably highly disruptive to recruitment.

Access of domestic livestock to stream bottoms also impacts unionids. Site 77 along the West Fork of the Big Blue was surveyed both before and after the reach was opened up to direct access by cattle. Mussels were noticeably less abundant several weeks after the introduction of cattle to the river bottom. The cattle compacted the formerly soft mud substrates at that site and damaged the mussels inhabiting that reach of the river. Domestic livestock also impact unionids through pollution of surface water (Prophet 1967, Prophet and Edwards 1973).

These detrimental factors can work together to destroy both the extant unionid fauna and the relict shells that evidence the fauna as well. As stream flows lesson due to lowering of water tables, livestock gain access to stream bottoms from which they were formerly restricted and over time crush and eventually totally destroy relict shells. This process was documented for a site on the Little Blue River by Hoke (2004).

The relative absence of early collection activities in the region, coupled with destruction of relict specimens due to grazing activities and the inundation of the lower portion of the Big Blue River, probably preclude a complete inventory of all the unionids once present and a thorough documentation of the complete extent of their historic ranges.

ACKNOWLEDGEMENTS

A number of individuals and organizations contributed to this study. The late Bob Thomas, formerly Fisheries Chief, Nebraska Game and Parks Commission, donated specimens from a number of sites in the region and also provided the names and addresses utilized in a mail survey of Nebraska conservation officers. Dr. David H. Stansbery, Ohio State Museum of Biological Diversity, identified or corroborated identifications of numerous specimens from the region and also gave his support to the project. Dr. G. Thomas Watters, Ohio State Museum of Biological Diversity, reviewed the initial version of the manuscript and provided useful comments. Conservation officers of the Nebraska Game and Parks Commission provided much useful information in their responses to my questionnaire on Nebraska mussels.

Special thanks are extended to the Kansas Department of Wildlife and Parks for providing the extremely valuable results of their recent (1996-2000) collections from the Big Blue Basin and to the organizations that funded this effort. These organizations and the years funded are as follows: Kansas Department of Wildlife and Fish (1996-2000), Kansas Water Office (1996-2000), the United States Environmental Protection Agency (1999-2000), and the United States Fish and Wildlife Service (1996-1998).

The author is indebted to the following institutions for physical access to unionid collections and for courtesies extended during these visits: Field Museum of Natural History, Chicago, Illinois; U. S. National Museum, Washington D. C.; Philadelphia Academy of Science, Philadelphia, Pennsylvania; Museum of Biological Diversity, Ohio State University, Columbus, Ohio; University of Michigan Museum of Zoology, Ann Arbor, Michigan; Nebraska State Museum, Lincoln, Nebraska; Department of Biology, University of Nebraska at Kearney, Nebraska; Kansas Biological Survey, Lawrence, Kansas; and the University of Colorado Museum of Natural History, Boulder, Colorado.

LITERATURE CITED

Andreas, A. T. 1882. History of the State of Nebraska, Vol. 1. Chicago, The Western Historical Company: 1-930.

Aughey, S. 1877. Catalogue of the land and freshwater shells of Nebraska. Bulletin of the U. S. Geological and Geographical Survey of the Territories 3(3): 697-704.

Bliss, Q. P., and S. Schainost, 1973a. Big Blue Basin Stream Inventory Report. Lincoln, Nebraska Game and Parks Commission, Bureau of Wildlife Services, Aquatic Wildlife Division: 13 pp. + appendices A, B, and C.

--, and--. 1973b. Little Blue Basin Stream Inventory Report. Lincoln, Nebraska Game and Parks Commission, Bureau of Wildlife Services, Aquatic Wildlife Division: 12 pp. + appendices A, B, and C.

Bolick, M. R. 1993. Samuel Aughey, Jr.: The controversial first director of the University of Nebraska State Museum. Museum Notes 84: 1-4.

Bouc, K. 1983. River portraits: The Blues. Nebraskaland Magazine's Nebraska Rivers. Nebraskaland Magazine 61(1): 82-89.

Burch, J. B. 1975. Freshwater Unionacean clams (Mollusca: Pelecypoda) of North America. Malacological Publications: 1-204.

Canfield, H. L., and A. H. Weibe. 1931. A cursory survey of the Blue River system of Nebraska. U.S. Department of Commerce, Bureau of Fisheries, Circular 73: 1-10.

Coker, R. E. 1919. Fresh-water mussels and mussel industries of the United States. Bulletin of the U. S. Bureau of Fisheries 36 (1917-1918): 11-89, 42 pls. (Issued separately as U. S. Bureau of Fisheries Document 865.)

Dobbs, H. J. 1918. History of Gage County Nebraska. Western Publishing and Engraving Company, pp. 1-1100.

Ellis. M. M. 1936. Erosion silt as a factor in aquatic environments. Ecology 17(1): 29-42.

Fennemen, Nevin M. 1931. Physiography of Western United States. New York and London, McGrawHill Book Company: xiii + 1-534.

--. 1938. Physiography of Eastern United States. New York and London, McGraw-Hill Book Company: xiii + 1-714.

Frest, Terrance J. 1987. Final Report on Federal Aid Projects Se-1-3 And Se-1-4 Mussel Survey of Selected Interior Iowa Streams. Funded Under Section 6, Endangered Species Act. U. S. Fish and Wildlife Service, Iowa Department of Natural Resources, under contract to the University of Northern Iowa: 1-215.

Hoke, E. 1994. A survey and analysis of the unionid mollusks of the Elkhorn River basin, Nebraska. Transactions of the Nebraska Academy of Sciences 21: 31-54.

--. 1996. The unionid mollusks of the Big and Little Nemaha river basins of southeastern Nebraska and northeastern Kansas. Transactions of the Nebraska Academy of Sciences 23: 37-57.

--. 1997a. The unionid mollusks of the upper Kansas Basin of northwestern Kansas and southwestern Nebraska. Transactions of the Nebraska Academy of Sciences 24: 35-62.

--. 1997b. Confirmation of the former occurrence of the federally endangered unionid Quadrula fragosa (Conrad, 1835) in Kansas. Triannual Unionid Report 13: 42.

--. 2000. A critical review of the unionoid mollusks reported for Nebraska by Samuel Aughey (1877). Central Plains Archeology 8(1): 35-47.

--. 2004. The freshwater mussels (Mollusca: Bivalvia: Unionidae) of the Little Blue River of northeastern Kansas and southeastern Nebraska. Transactions of the Nebraska Academy of Sciences 29: 7-24.

Liechti, P. M., and D. G. Huggins. 1977. Unionacean mussels of Kansas. Technical Publications of the State Biological Survey of Kansas 4: 17-30.

Mack, A., J. Weir, and J. Sharpe. 1996a. Groundwater-level Changes in Nebraska, Predevelopment to Spring 1994 [Map]. Lincoln, Conservation and Survey Division, Institute of Agriculture and Natural Resources, University of Nebraska.

--,--, and--. 1996b. Registered Irrigation Wells in Nebraska--Summer 1995 [Map]. Lincoln, Conservation and Survey Division, Institute of Agriculture and Natural Resources, University of Nebraska.

Murray, H. D., and A. Byron Leonard. 1962. Handbook of unionid mussels in Kansas. University of Kansas Museum of Natural History, Miscellaneous Publications 28: 1-184.

Oesch, R. D. 1995. Missouri Naiades: A Guide To The Mussels of Missouri. Jefferson City, Missouri Department of Conservation: vii + 1-271.

Omaha World Herald. 1929. Blue River claimed to be most completely harnessed in nation. July 17, 1929 issue, page 2, column 1.

Pound R., and F. E. Clements. 1898. The Phytogeography of Nebraska: I. General survey. Lincoln., J. North & Company.

Popenoe, A. E. 1885. List of unionidae, collected in Kansas rivers, with localities. Transactions of the Kansas Academy of Sciences 9: 78-79.

Prophet, C. W. 1967. River pollution by feedlot runoff. Proceedings of the Oklahoma Academy of Sciences 48: 207-209.

--, and N. L. Edwards. 1973. Benthic macroinvertebrate community structure in a Great Plains stream receiving feedlot runoff. American Water Resources Association, Water Resources Bulletin 9: 583-589.

Scammon, R. E. 1906. The Unionidae of Kansas, part I. University of Kansas Scientific Bulletin 3: 279-373, pls. 52-86.

Schuster, G. A., and M. B. Dubois. 1978. Additional new records of freshwater mussels (Bivalvia: Unionidae) from Kansas. Technical Publications of the State Biological Survey of Kansas 8: 1-11.

Tryon, G. W., Jr. 1868. Notes on Mollusca collected by Dr. F. V. Hayden in Nebraska. American Journal of Conchology. New Series 4(3): 150-151.

Turgeon, D. D., A. E. Bogan, E. V. Coan, W. K. Emerson, W. G. Lyons, W. L. Pratt, C. F. E. Roper, A. Scheltema, F. G. Thompson, and J. D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. American Fisheries Society Special Publication 16: viii + 1-248.

Walker, B. 1906. A list of shells from Nebraska. The Nautilus 20(6): 81-83.

Ellet Hoke

Midwest Malacology, Inc.

1878 Ridgeview Circle Drive

Manchester, Missouri 63021
Table 1. Best condition of unionids collected from the Big Blue River
and minor tributaries in northeastern Kansas and southeastern Nebraska:
L = live, R = recent, F = fresh dead, D = slightly to moderately
weathered, WD = heavily weathered, S = sub-fossil or chalky condition.
Nomenclatural citations may be found in Tables 4, 5, and 6.

 Big Blue River and Minor Tributaries

 Big Blue River

Year(s) Collected: 1988
 2002 1988 1985 2002 2002

Taxa Map Reference: 1 2 (a) 3 (e) 4 (a) 6 (a)

 1. Amblema plicata -- -- -- -- --
 2. Anodontoides -- -- -- -- --
 ferussacianus
 3. Fusconaia flava -- -- -- -- --
 4. Lampsilis cardium S -- -- -- --
 5. Lampsilis siliquoidea -- -- -- -- --
 6. Lampsilis teres -- -- -- -- --
 7. Lasmigona c. complanata L F F F F
 8. Leptodea fragilis R -- F F F
 9. Ligumia recta S -- -- -- --
10. Ligumia subrostrata -- -- WD -- --
11. Obovaria olivaria S -- -- -- --
12. Potamilus alatus WD S -- R R
13. Potamilus ohiensis WD R F R R
14. Potamilus purpuratus -- -- -- -- --
15. Pyganodon grandis -- R F F F
16. Quadrula fragosa -- -- -- -- --
17. Quadrula p. pustulosa S -- WD -- --
18. Quadrula quadrula F R F L F
19. Strophitus undulatus -- -- -- -- --
20. Toxolasma parvus -- R WD -- --
21. Tritogonia verrucosa -- -- -- -- --
22. Truncilla donaciformis -- -- -- -- --
23. Uniomerus tetralasmus -- -- WD -- --
24. Utterbackia imbecillis -- F -- -- --
25. Corbicula fluminea D -- -- -- --
26. Unidentifiable unionid -- -- -- -- --
 Total Species: 10 7 9 6 6

 Big Blue River and Minor Tributaries

 Big Blue River

 1983
Year(s) Collected: 1995 1995
 2002 2002 1988 1988 1988 1981

Taxa Map Reference: 7 (a) 26 27 29 32 35

 1. Amblema plicata -- -- -- -- -- --
 2. Anodontoides -- -- -- -- -- --
 ferussacianus
 3. Fusconaia flava -- S -- -- -- --
 4. Lampsilis cardium -- S S S S --
 5. Lampsilis siliquoidea -- S -- -- -- --
 6. Lampsilis teres -- S S -- -- --
 7. Lasmigona c. complanata F -- -- WD -- --
 8. Leptodea fragilis F F WD R F --
 9. Ligumia recta -- S S -- S --
10. Ligumia subrostrata -- -- -- -- -- --
11. Obovaria olivaria -- S -- -- -- --
12. Potamilus alatus -- -- WD R R --
13. Potamilus ohiensis R R -- R L --
14. Potamilus purpuratus -- S -- -- -- --
15. Pyganodon grandis -- -- -- -- -- --
16. Quadrula fragosa -- S -- -- -- --
17. Quadrula p. pustulosa -- S S -- S S
18. Quadrula quadrula L D S R L --
19. Strophitus undulatus -- -- -- -- -- --
20. Toxolasma parvus -- -- -- -- -- --
21. Tritogonia verrucosa -- S S S S --
22. Truncilla donaciformis -- WD -- -- -- --
23. Uniomerus tetralasmus -- -- -- WD -- --
24. Utterbackia imbecillis -- -- -- -- -- --
25. Corbicula fluminea -- -- -- -- -- --
26. Unidentifiable unionid -- -- -- -- -- --
 Total Species: 4 14 S S 8 1

 Big Blue River and Minor Tributaries

 Big Blue River

Year(s) Collected: 1976 1981 1976
 1981 1976 1988 (d) 1988 1988

Taxa Map Reference: 36 40 42 43 46 47

 1. Amblema plicata -- -- -- -- -- --
 2. Anodontoides -- -- -- -- -- --
 ferussacianus
 3. Fusconaia flava -- -- -- -- -- --
 4. Lampsilis cardium S -- S -- -- S
 5. Lampsilis siliquoidea L -- S -- -- S
 6. Lampsilis teres S -- -- -- -- --
 7. Lasmigona c. complanata D -- -- -- -- L
 8. Leptodea fragilis -- -- -- -- -- --
 9. Ligumia recta S -- S -- -- --
10. Ligumia subrostrata -- -- -- -- -- --
11. Obovaria olivaria -- -- -- D -- --
12. Potamilus alatus -- -- -- -- -- --
13. Potamilus ohiensis L -- -- -- -- L
14. Potamilus purpuratus S -- -- -- -- --
15. Pyganodon grandis D -- -- -- -- S
16. Quadrula fragosa -- -- -- -- -- --
17. Quadrula p. pustulosa D -- S -- -- L
18. Quadrula quadrula D -- S -- F L
19. Strophitus undulatus -- -- -- -- -- --
20. Toxolasma parvus -- -- -- -- -- --
21. Tritogonia verrucosa WD S -- -- -- --
22. Truncilla donaciformis -- -- -- -- -- --
23. Uniomerus tetralasmus -- -- -- -- -- --
24. Utterbackia imbecillis -- -- -- -- -- --
25. Corbicula fluminea -- -- -- -- -- --
26. Unidentifiable unionid -- -- -- -- -- --
 Total Species: 11 1 5 1 1 7

 Big Blue River and Minor Tributaries

 Big Blue River

Year(s) Collected: 1976
 1976 1995 1988 1988 (c) 1988

Taxa Map Reference: 59 60 61 62 63 64

 1. Amblema plicata -- -- -- -- -- --
 2. Anodontoides -- -- -- -- -- --
 ferussacianus
 3. Fusconaia flava -- -- -- -- -- --
 4. Lampsilis cardium -- -- S -- S WD
 5. Lampsilis siliquoidea -- -- S -- WD WD
 6. Lampsilis teres -- -- -- -- -- --
 7. Lasmigona c. complanata WD -- D -- -- --
 8. Leptodea fragilis -- -- -- -- -- --
 9. Ligumia recta -- -- -- -- S S
10. Ligumia subrostrata -- -- -- -- -- --
11. Obovaria olivaria -- -- -- -- -- --
12. Potamilus alatus -- -- -- -- S --
13. Potamilus ohiensis -- R -- -- -- --
14. Potamilus purpuratus -- -- -- -- -- --
15. Pyganodon grandis WD WD -- -- -- S
16. Quadrula fragosa -- -- -- -- -- --
17. Quadrula p. pustulosa L -- -- -- S S
18. Quadrula quadrula L R L S D R
19. Strophitus undulatus -- -- -- -- -- --
20. Toxolasma parvus -- -- -- -- -- --
21. Tritogonia verrucosa -- -- -- -- -- --
22. Truncilla donaciformis -- -- -- -- -- --
23. Uniomerus tetralasmus -- -- -- -- -- --
24. Utterbackia imbecillis -- -- -- -- -- --
25. Corbicula fluminea -- -- -- -- -- --
26. Unidentifiable unionid -- -- -- -- -- --
 Total Species: 4 3 4 1 6 6

 Big Blue River and Minor Tributaries

 Big Blue River

 1970 (b)
Year(s) Collected: 1974
 1981 1974 1981 1970 (b)

Taxa Map Reference: 80 81 82 83 84 (a)

 1. Amblema plicata -- -- -- -- --
 2. Anodontoides -- -- -- -- --
 ferussacianus
 3. Fusconaia flava WD -- -- -- --
 4. Lampsilis cardium WD S S -- --
 5. Lampsilis siliquoidea WD S L -- WD
 6. Lampsilis teres -- -- -- -- --
 7. Lasmigona c. complanata WD D D WD --
 8. Leptodea fragilis -- -- -- -- --
 9. Ligumia recta S S S -- --
10. Ligumia subrostrata WD -- -- -- --
11. Obovaria olivaria -- -- -- -- --
12. Potamilus alatus -- -- -- -- --
13. Potamilus ohiensis -- -- -- -- --
14. Potamilus purpuratus -- -- -- -- --
15. Pyganodon grandis WD D WD -- D
16. Quadrula fragosa -- -- -- -- --
17. Quadrula p. pustulosa WD WD WD -- --
18. Quadrula quadrula WD WD D -- WD
19. Strophitus undulatus WD -- S -- --
20. Toxolasma parvus -- -- WD -- --
21. Tritogonia verrucosa -- -- -- -- --
22. Truncilla donaciformis -- -- -- -- --
23. Uniomerus tetralasmus -- -- -- -- --
24. Utterbackia imbecillis -- -- -- -- --
25. Corbicula fluminea -- -- -- -- --
26. Unidentifiable unionid -- -- -- -- --
 Total Species: 10 7 9 1 3

 Big Blue River and Minor Tributaries

 Big Mill
 Big Blue River Blue R. Creek

Year(s) Collected: 1970 (b) 1995 1976 1981 1995

Taxa Map Reference: 85 90 91 93 5

 1. Amblema plicata -- -- -- -- --
 2. Anodontoides -- -- -- -- --
 ferussacianus
 3. Fusconaia flava -- -- -- -- --
 4. Lampsilis cardium -- -- -- -- --
 5. Lampsilis siliquoidea -- -- -- -- --
 6. Lampsilis teres -- -- -- -- --
 7. Lasmigona c. complanata -- -- -- -- --
 8. Leptodea fragilis -- -- -- -- --
 9. Ligumia recta -- -- -- -- --
10. Ligumia subrostrata -- -- -- -- S
11. Obovaria olivaria -- -- -- -- --
12. Potamilus alatus -- -- -- -- --
13. Potamilus ohiensis -- -- -- -- --
14. Potamilus purpuratus -- -- -- -- --
15. Pyganodon grandis D L D L --
16. Quadrula fragosa -- -- -- -- --
17. Quadrula p. pustulosa -- -- -- -- --
18. Quadrula quadrula -- L -- -- --
19. Strophitus undulatus -- -- -- -- --
20. Toxolasma parvus -- -- -- -- --
21. Tritogonia verrucosa -- -- -- -- --
22. Truncilla donaciformis -- -- -- -- --
23. Uniomerus tetralasmus -- L -- WD D
24. Utterbackia imbecillis -- -- -- -- --
25. Corbicula fluminea -- -- -- -- --
26. Unidentifiable unionid -- -- -- -- S
 Total Species: 1 3 1 2 3

 Big Blue River and Minor Tributaries

 Fancy Creek Vermillion River

Year(s) Collected: 1995 1995 1995 1988 1988 1988

Taxa Map Reference: 8 9 10 11 13 14

 1. Amblema plicata -- S -- -- -- WD
 2. Anodontoides -- -- -- -- -- --
 ferussacianus
 3. Fusconaia flava S S WD -- -- WD
 4. Lampsilis cardium -- -- -- -- -- WD
 5. Lampsilis siliquoidea -- S -- -- S WD
 6. Lampsilis teres -- -- -- -- -- --
 7. Lasmigona c. complanata -- WD -- -- -- R
 8. Leptodea fragilis -- -- -- R F R
 9. Ligumia recta -- -- -- -- -- WD
10. Ligumia subrostrata S S WD -- S --
11. Obovaria olivaria -- -- -- -- -- --
12. Potamilus alatus -- -- -- -- -- R
13. Potamilus ohiensis -- WD R -- F R
14. Potamilus purpuratus -- -- -- -- -- --
15. Pyganodon grandis R S S WD S WD
16. Quadrula fragosa -- -- -- -- -- --
17. Quadrula p. pustulosa -- S -- -- -- R
18. Quadrula quadrula -- -- -- -- -- R,
19. Strophitus undulatus S S S S -- --
20. Toxolasma parvus S -- -- -- -- --
21. Tritogonia verrucosa -- S -- -- -- WD
22. Truncilla donaciformis -- -- -- -- -- --
23. Uniomerus tetralasmus D -- S -- -- --
24. Utterbackia imbecillis -- -- -- -- -- --
25. Corbicula fluminea -- -- -- -- -- --
26. Unidentifiable unionid -- -- -- S -- --
 Total Species: 6 10 6 4 5 13

 Big Blue River and Minor Tributaries

 Vermillion River

Year(s) Collected: 1985 1985 1985 1985 1985 1985

Taxa Map Reference: 17 18 22 23 24 25

 1. Amblema plicata -- WD -- -- -- --
 2. Anodontoides -- -- -- -- S --
 ferussacianus
 3. Fusconaia flava -- -- -- -- -- --
 4. Lampsilis cardium -- -- S -- -- --
 5. Lampsilis siliquoidea -- WD S -- -- --
 6. Lampsilis teres -- -- -- -- -- --
 7. Lasmigona c. complanata -- WD L -- -- --
 8. Leptodea fragilis -- L R -- -- --
 9. Ligumia recta -- WD -- -- -- --
10. Ligumia subrostrata -- WD WD -- S --
11. Obovaria olivaria -- -- -- -- -- --
12. Potamilus alatus -- S -- -- -- --
13. Potamilus ohiensis -- -- R -- -- --
14. Potamilus purpuratus -- -- -- -- -- --
15. Pyganodon grandis D S L -- S --
16. Quadrula fragosa -- -- -- -- -- --
17. Quadrula p. pustulosa -- WD D -- -- --
18. Quadrula quadrula -- D L -- -- --
19. Strophitus undulatus -- -- -- -- -- --
20. Toxolasma parvus -- D -- -- -- --
21. Tritogonia verrucosa -- -- -- -- -- --
22. Truncilla donaciformis -- -- -- -- -- --
23. Uniomerus tetralasmus R -- -- L L R
24. Utterbackia imbecillis -- -- -- -- -- --
25. Corbicula fluminea -- -- -- -- -- --
26. Unidentifiable unionid -- -- -- -- S --
 Total Species: 2 11 9 1 5 1

 Big Blue River and Minor Tributaries

 Clear Unnamed
 Creek Robidoux Creek Creek

Year(s) Collected: 1985 1985 1985 1985 1995

Taxa Map Reference: 15 19 20 21 28

 1. Amblema plicata S -- D -- S
 2. Anodontoides -- -- -- -- --
 ferussacianus
 3. Fusconaia flava S -- S -- --
 4. Lampsilis cardium -- -- -- -- --
 5. Lampsilis siliquoidea S -- -- -- --
 6. Lampsilis teres -- -- -- -- --
 7. Lasmigona c. complanata -- D D -- WD
 8. Leptodea fragilis -- -- -- -- --
 9. Ligumia recta -- -- -- -- --
10. Ligumia subrostrata S D WD S --
11. Obovaria olivaria -- -- -- -- --
12. Potamilus alatus -- -- -- -- --
13. Potamilus ohiensis -- -- -- -- --
14. Potamilus purpuratus -- -- -- -- --
15. Pyganodon grandis -- D D -- --
16. Quadrula fragosa -- -- -- -- --
17. Quadrula p. pustulosa -- -- -- -- --
18. Quadrula quadrula -- -- WD -- --
19. Strophitus undulatus -- -- WD -- --
20. Toxolasma parvus -- D -- -- --
21. Tritogonia verrucosa -- -- -- -- --
22. Truncilla donaciformis -- -- -- -- --
23. Uniomerus tetralasmus -- -- WD -- S
24. Utterbackia imbecillis -- -- -- -- --
25. Corbicula fluminea -- -- -- -- --
26. Unidentifiable unionid -- -- -- -- S
 Total Species: 4 4 8 1 4

 Big Blue River and Minor Tributaries

 Horseshoe Mission
 Creek Creek Pond

Year(s) Collected: 1988 1985 1989 (c) 1980

Taxa Map Reference: 30 31 33 34 (a)

 1. Amblema plicata -- -- -- --
 2. Anodontoides -- -- -- --
 ferussacianus
 3. Fusconaia flava -- -- -- --
 4. Lampsilis cardium -- -- -- --
 5. Lampsilis siliquoidea S -- S --
 6. Lampsilis teres -- -- -- --
 7. Lasmigona c. complanata -- -- F --
 8. Leptodea fragilis -- -- -- --
 9. Ligumia recta -- -- -- --
10. Ligumia subrostrata S S -- --
11. Obovaria olivaria -- -- -- --
12. Potamilus alatus -- -- -- --
13. Potamilus ohiensis -- -- F --
14. Potamilus purpuratus -- -- -- --
15. Pyganodon grandis -- WD -- --
16. Quadrula fragosa -- -- -- --
17. Quadrula p. pustulosa -- -- -- --
18. Quadrula quadrula -- -- F --
19. Strophitus undulatus -- -- -- --
20. Toxolasma parvus -- -- -- --
21. Tritogonia verrucosa -- -- -- --
22. Truncilla donaciformis -- -- -- --
23. Uniomerus tetralasmus -- S -- L
24. Utterbackia imbecillis -- -- -- --
25. Corbicula fluminea -- -- -- --
26. Unidentifiable unionid S S -- --
 Total Species: 3 4 4 1

 Big Blue River and Minor Tributaries

 Rockford Indian
 Indian Creek Lake Creek

 1976
Year(s) Collected: 1981 1981 1995 1988 1988

Taxa Map Reference: 37 38 39 41 (a) 44

 1. Amblema plicata S -- -- -- --
 2. Anodontoides -- WD -- -- --
 ferussacianus
 3. Fusconaia flava -- S -- -- --
 4. Lampsilis cardium -- S -- -- --
 5. Lampsilis siliquoidea WD WD -- -- --
 6. Lampsilis teres WD WD -- -- --
 7. Lasmigona c. complanata D WD -- -- --
 8. Leptodea fragilis -- -- -- -- --
 9. Ligumia recta S S -- -- --
10. Ligumia subrostrata S WD -- -- --
11. Obovaria olivaria -- -- -- -- --
12. Potamilus alatus WD -- -- -- --
13. Potamilus ohiensis -- -- -- -- --
14. Potamilus purpuratus -- -- -- -- --
15. Pyganodon grandis WD D -- -- --
16. Quadrula fragosa -- -- -- F --
17. Quadrula p. pustulosa -- WD -- -- --
18. Quadrula quadrula D D L -- --
19. Strophitus undulatus S WD -- -- --
20. Toxolasma parvus -- D -- -- --
21. Tritogonia verrucosa S -- -- -- --
22. Truncilla donaciformis -- -- -- -- --
23. Uniomerus tetralasmus -- D -- -- WD
24. Utterbackia imbecillis -- -- -- -- --
25. Corbicula fluminea -- -- -- -- --
26. Unidentifiable unionid -- -- -- -- --
 Total Species: 11 14 1 1 1

 Big Blue River and Minor Tributaries

 Cub
 Creek Turkey Creek

Year(s) Collected: 1980 1980 1980 1980 1995 1995

Taxa Map Reference: 45 48 49 50 51 52

 1. Amblema plicata -- -- -- -- -- --
 2. Anodontoides -- -- -- -- -- --
 ferussacianus
 3. Fusconaia flava -- -- -- -- -- --
 4. Lampsilis cardium -- -- S -- -- --
 5. Lampsilis siliquoidea -- -- S -- -- --
 6. Lampsilis teres -- -- -- -- -- --
 7. Lasmigona c. complanata -- WD WD -- -- --
 8. Leptodea fragilis -- -- -- -- -- --
 9. Ligumia recta -- -- -- -- -- --
10. Ligumia subrostrata -- -- -- -- -- --
11. Obovaria olivaria -- -- -- -- -- --
12. Potamilus alatus -- -- -- -- -- --
13. Potamilus ohiensis -- -- -- -- -- --
14. Potamilus purpuratus -- -- -- -- -- --
15. Pyganodon grandis -- -- -- -- -- --
16. Quadrula fragosa -- -- -- WD -- --
17. Quadrula p. pustulosa -- WD WD WD S R
18. Quadrula quadrula -- WD WD WD -- R
19. Strophitus undulatus -- -- -- -- -- --
20. Toxolasma parvus -- -- -- -- -- --
21. Tritogonia verrucosa -- -- -- -- -- --
22. Truncilla donaciformis -- -- -- -- -- --
23. Uniomerus tetralasmus WD -- -- -- -- --
24. Utterbackia imbecillis -- -- -- -- -- --
25. Corbicula fluminea -- -- -- -- -- --
26. Unidentifiable unionid -- -- -- -- -- --
 Total Species: 1 3 5 3 1 2

 Big Blue River and Minor Tributaries

 West Fork
 Big Blue
 Turkey Creek River

Year(s) Collected: 1995 1995 1995 1995 1974

Taxa Map Reference: 53 54 55 57 65

 1. Amblema plicata -- -- -- -- --
 2. Anodontoides -- -- -- -- --
 ferussacianus
 3. Fusconaia flava -- -- -- -- --
 4. Lampsilis cardium -- -- -- -- S
 5. Lampsilis siliquoidea -- -- -- -- S
 6. Lampsilis teres -- -- -- -- --
 7. Lasmigona c. complanata -- -- -- -- S
 8. Leptodea fragilis -- -- -- -- --
 9. Ligumia recta -- -- -- -- --
10. Ligumia subrostrata -- -- -- -- --
11. Obovaria olivaria -- -- -- -- --
12. Potamilus alatus -- -- -- -- --
13. Potamilus ohiensis -- -- -- -- --
14. Potamilus purpuratus -- -- -- -- --
15. Pyganodon grandis -- -- -- -- --
16. Quadrula fragosa -- -- -- -- --
17. Quadrula p. pustulosa -- D -- -- --
18. Quadrula quadrula WD L WD -- --
19. Strophitus undulatus -- -- -- -- --
20. Toxolasma parvus -- -- -- -- --
21. Tritogonia verrucosa -- -- -- -- --
22. Truncilla donaciformis -- -- -- -- --
23. Uniomerus tetralasmus -- -- -- D --
24. Utterbackia imbecillis -- -- -- -- --
25. Corbicula fluminea -- -- -- -- --
26. Unidentifiable unionid -- -- -- -- --
 Total Species: 1 2 1 1 3

 Big Blue River and Minor Tributaries

 West Fork Big Blue River

 1970 (b)
Year(s) Collected: 1974 1973 1976 1991 1991

Taxa Map Reference: 66 67 70 75 76

 1. Amblema plicata -- -- -- -- --
 2. Anodontoides -- -- -- -- --
 ferussacianus
 3. Fusconaia flava -- -- -- -- --
 4. Lampsilis cardium -- -- -- -- S
 5. Lampsilis siliquoidea L -- -- S --
 6. Lampsilis teres -- -- -- -- --
 7. Lasmigona c. complanata L D L -- WD
 8. Leptodea fragilis -- -- -- -- --
 9. Ligumia recta -- -- -- -- S
10. Ligumia subrostrata -- -- -- -- --
11. Obovaria olivaria -- -- -- -- --
12. Potamilus alatus -- -- -- -- --
13. Potamilus ohiensis -- -- -- -- --
14. Potamilus purpuratus -- -- -- -- --
15. Pyganodon grandis L -- -- -- S
16. Quadrula fragosa -- -- -- -- --
17. Quadrula p. pustulosa L -- L WD D
18. Quadrula quadrula L D L R L
19. Strophitus undulatus -- -- -- -- --
20. Toxolasma parvus -- -- -- -- --
21. Tritogonia verrucosa -- -- -- -- --
22. Truncilla donaciformis -- -- -- -- --
23. Uniomerus tetralasmus -- -- L -- --
24. Utterbackia imbecillis -- -- -- -- --
25. Corbicula fluminea -- -- -- -- --
26. Unidentifiable unionid -- -- -- -- --
 Total Species: 5 2 4 3 6

 Big Blue River and Minor Tributaries

 West Fork Big Blue Lincoln Keysor
 River Creek Creek

Year(s) Collected: 1976 1991 1995 1995 1995 1981

Taxa Map Reference: 77 78 79 86 87 92

 1. Amblema plicata -- -- -- -- -- --
 2. Anodontoides -- -- -- -- -- --
 ferussacianus
 3. Fusconaia flava -- -- -- -- -- --
 4. Lampsilis cardium L -- -- -- -- --
 5. Lampsilis siliquoidea L -- -- -- -- --
 6. Lampsilis teres -- -- -- -- -- --
 7. Lasmigona c. complanata L -- -- -- -- --
 8. Leptodea fragilis -- -- -- -- -- --
 9. Ligumia recta -- -- -- -- -- --
10. Ligumia subrostrata -- -- -- -- -- --
11. Obovaria olivaria -- -- -- -- -- --
12. Potamilus alatus -- -- -- -- -- --
13. Potamilus ohiensis -- -- -- -- -- --
14. Potamilus purpuratus -- -- -- -- -- --
15. Pyganodon grandis L -- WD L -- D
16. Quadrula fragosa -- -- -- -- -- --
17. Quadrula p. pustulosa L S -- L -- --
18. Quadrula quadrula L D -- L F --
19. Strophitus undulatus -- -- -- -- -- --
20. Toxolasma parvus -- -- -- -- -- --
21. Tritogonia verrucosa -- -- -- -- -- --
22. Truncilla donaciformis -- -- -- -- -- --
23. Uniomerus tetralasmus -- -- -- -- -- D
24. Utterbackia imbecillis -- -- -- -- -- --
25. Corbicula fluminea -- -- -- -- -- --
26. Unidentifiable unionid -- -- -- -- -- --
 Total Species: 6 2 1 3 1 2

 Big Blue River and
 Minor Tributaries

 Total

Taxa Map Reference: Study

 1. Amblema plicata 7
 2. Anodontoides 2
 ferussacianus
 3. Fusconaia flava 9
 4. Lampsilis cardium 21
 5. Lampsilis siliquoidea 26
 6. Lampsilis teres 5
 7. Lasmigona c. complanata 33
 8. Leptodea fragilis 14
 9. Ligumia recta 16
10. Ligumia subrostrata 18
11. Obovaria olivaria 3
12. Potamilus alatus 11
13. Potamilus ohiensis 18
14. Potamilus purpuratus 2
15. Pyganodon grandis 40
16. Quadrula fragosa 1
17. Quadrula p. pustulosa 33
18. Quadrula quadrula 49
19. Strophitus undulatus 9
20. Toxolasma parvus 7
21. Tritogonia verrucosa 9
22. Truncilla donaciformis 1
23. Uniomerus tetralasmus 21
24. Utterbackia imbecillis 1
25. Corbicula fluminea 1
26. Unidentifiable unionid 9
 Total Species: 363

(a) Denotes lentic habitat.

(b) Collection by official of the Nebraska Game and Parks Commission
with specimens donated to the author.

(c) Specimens in the collection of the University of Nebraska State
Museum.

(d) Specimen of the Nebraska Game and Parks Commission, Lincoln,
Nebraska.

(e) Collected by local resident.

Table 2. Collection statistics from the Big Blue River
and its minor tributaries.

 Lotic Habitats

 Big Blue (a) Minor
 River Rivers Creeks
Study productivity
 Productive sites 27 17 30
 Total sites collected 32 18 39
 Study productivity by
 habitat and in total 84.38% 94.44% 76.92%

Average productive site
 diversity
 Species occurrences 142 79 114
 Average site diversity by
 habitat and in total 5.26 4.65 3.80

Status of habitat viability
 for mussels
 Probable extant species
 (live, fresh, recent, &
 slightly to moderately
 weathered shell
 conditions only) 10 11 10
 Historic species (all
 shell conditions) 21 18 (b) 19
 Surviving percentage of
 historic fauna 47.62% 61.11% 52.63%

 Lentic Habitats

 Impoundments, Total
 Lakes & Ponds Region
Study productivity
 Productive sites 7 81
 Total sites collected 7 96
 Study productivity by
 habitat and in total 100.00% 84.38%

Average productive site
 diversity
 Species occurrences 28 363
 Average site diversity by
 habitat and in total 4.00 4.48

Status of habitat viability
 for mussels
 Probable extant species
 (live, fresh, recent, &
 slightly to moderately
 weathered shell
 conditions only) 9 15
 Historic species (all
 shell conditions) 10 25 (b)
 Surviving percentage of
 historic fauna 90.00% 60.00%

(a) Black Vermillion and West Fork Big Blue rivers

(b) Includes Pleurobema sintoxia (museum specimens)

Table 3. Published and unpublished reports on the unionid fauna of
the Big Blue Basin (excludes Aughey 1877): L = live, F = fresh dead,
R = recent shell, D = slightly to moderately weathered shell,
WD = heavily weathered shell, S = sub-fossil or chalky shell,
X = reported, P = probable record. Nomenclatural citations may be
found in Tables 4, 5, and 6.

 Reference

 Kansas (g) Kansas
Species Current DW&P Biol.
 Study & 1996-2000 Survey
 Hoke (2004) 1976-80

Amblema plicata D WD --
Anodontoides ferussacianus WD (f) WD --
Ellipsaria lineolata -- -- --
Fusconaia flava WD WD X
Lampsilis cardium L WD --
Lampsilis siliquoidea L WD --
Lampsilis teres WD (f) WD --
Lasmigona c. complanata L L X
Leptodea fragilis L L X
Ligumia recta WD WD X
Ligumia subrostrata D R --
Obovaria olivaria S -- --
Pleurobema sintoxia M -- --
Potamilus alatus L (f) R X
Potamilus ohiensis L L X
Potamilus purpuratus S -- --
Pyganodon grandis L R X
Quadrula fragosa S -- --
Quadrula p. pustulosa L L X
Quadrula quadrula L L X
Strophitus undulatus D (f) WD X
Toxolasma parvus R R X
Tritogonia verrucosa WD WD X
Truncilla donaciformis WD -- --
Truncilla truncata S (f) -- --
Uniomerus tetralasmus L L X
Utterbackia imbecillis F WD --
Total Species Reported 26 20 13

 Reference

 Murray & Canfield Walker
Species Leonard & Weibe (1906) (c)
 (1962) (1931)

Amblema plicata -- -- --
Anodontoides ferussacianus -- -- --
Ellipsaria lineolata -- X (b) (?) --
Fusconaia flava -- -- --
Lampsilis cardium -- -- --
Lampsilis siliquoidea -- -- X
Lampsilis teres -- -- --
Lasmigona c. complanata -- -- --
Leptodea fragilis -- -- --
Ligumia recta -- -- --
Ligumia subrostrata -- -- --
Obovaria olivaria -- -- --
Pleurobema sintoxia -- -- --
Potamilus alatus -- -- --
Potamilus ohiensis X (a) -- --
Potamilus purpuratus -- -- --
Pyganodon grandis -- -- --
Quadrula fragosa -- -- --
Quadrula p. pustulosa -- -- --
Quadrula quadrula -- -- --
Strophitus undulatus -- -- --
Toxolasma parvus -- -- --
Tritogonia uerrucosa -- -- --
Truncilla donaciformis -- -- --
Truncilla truncata -- -- --
Uniomerus tetralasmus -- -- --
Utterbackia imbecillis -- -- --
Total Species Reported 1 1 1

Reference

 Scammon Popenoe Tryon
Species (1906) (1885) (d) (1868) (e)

Amblema plicata -- -- --
Anodontoides ferussacianus -- -- --
Ellipsaria lineolata -- -- --
Fusconaia flava -- -- --
Lampsilis cardium -- X X
Lampsilis siliquoidea X -- --
Lampsilis teres -- -- X
Lasmigona c. complanata P -- --
Leptodea fragilis P X --
Ligumia recta P X X
Ligumia subrostrata -- -- --
Obovaria olivaria P X? --
Pleurobema sintoxia -- -- --
Potamilus alatus P X X
Potamilus ohiensis -- X --
Potamilus purpuratus X -- --
Pyganodon grandis -- X --
Quadrula fragosa -- -- --
Quadrula p. pustulosa -- X --
Quadrula quadrula -- X --
Strophitus undulatus -- -- --
Toxolasma parvus -- -- --
Tritogonia uerrucosa -- -- --
Truncilla donaciformis P X --
Truncilla truncata -- X --
Uniomerus tetralasmus P -- --
Utterbackia imbecillis P -- --
Total Species Reported 2 + ? 11 4

(a) References unidentified literature source.

(b) Big Blue River at Crete, Nebraska, "butterfly" mussel.

(c) Big Blue River at Crete, Nebraska.

(d) Big Blue River at Manhattan, Nebraska.

(e) Big Blue River, Gage County, Nebraska.

(f) Best condition taken from Little Blue River Basin study
(Hoke 2004).

(g) Includes records published by Liechti and Huggins (1977) and
Schuster and Dubois (1978).

Table 4. Analysis of unionid mollusks reported for the
"Blue River" by Aughey (1877).

 Recovered
 from
 Big Blue other
 Aughey this rivers in
Species (1877) study Nebraska

Actinonaias ligamentina (Lamarck, 1819) X -- X (a)
Actinonaias pectorosa (Conrad, 1834) X -- --
Anodonta suborbiculata Say, 1831 X -- X (b)
Elliptio complanata (Lightfoot, 1786) X -- --
Elliptio crassidens (Lamarck, 1819) X -- --
Elliptio dilatata (Rafinesque, 1820) X -- --
Epioblasma flexuosa (Rafinesque, 1820) X -- --
Epioblasma personata (Say, 1829) X -- --
Epioblasma triquetra (Rafinesque, 1820) X -- --
Fusconaia (lava (Rafinesque, 1820) X X --
Lampsilis cardium Rafinesque, 1820 X X --
Lampsilis fasciola Rafinesque, 1820 X -- --
Lampsilis ovata (Say, 1817) X -- --
Lampsilis siliquoidea (Barnes, 1823) X X --
Lampsilis teres (Rafinesque, 1820) X X --
Leptodea fragilis (Rafinesque, 1820) X X --
Leptodea ochracea (Say, 1817) X -- --
Ligumia subrostrata (Say, 1831) X X --
Megalonaias nervosa (Rafinesque, 1820) X -- --
Obliquaria reflexa Rafinesque, 1820 X -- --
Pleurobema clava (Lamarck, 1819) X -- X (c)
Pleurobema sintoxia (Rafinesque, 1820) X X --
Potamilus alatus (Say, 1817) X X --
Potamilus capax (Green, 1832) X -- --
Potamilus ohiensis (Rafinesque, 1820) X X --
Pyganodon grandis (Say, 1829) X X --
Quadrula c. cylindrica (Say, 1817) X -- --
Quadrula fragosa (Conrad, 1835) X X --
Quadrula p. pustulosa (Lea, 1831) X X --
Quadrula quadrula (Rafinesque, 1820) X X --
Strophitus undulates (Say, 1817) X X --
Toxolasma parvus (Barnes, 1823) X X --
Tritogonia verrucosa (Rafinesque, 1820) X X --
Truncilla donaciformis (Lea, 1828) X X --
Villosa lienosa (Conrad, 1834) X -- X (d)
Total Species Reported 35 17 4

 Confirmed for a state
 bordering Nebraska
 Native to Nebraska?

Species Possible Doubtful

Actinonaias ligamentina (Lamarck, 1819) -- --
Actinonaias pectorosa (Conrad, 1834) -- --
Anodonta suborbiculata Say, 1831 -- --
Elliptio complanata (Lightfoot, 1786) -- --
Elliptio crassidens (Lamarck, 1819) -- X (i)
Elliptio dilatata (Rafinesque, 1820) X (e) --
Epioblasma flexuosa (Rafinesque, 1820) -- --
Epioblasma personata (Say, 1829) -- --
Epioblasma triquetra (Rafinesque, 1820) X (f) --
Fusconaia (lava (Rafinesque, 1820) -- --
Lampsilis cardium Rafinesque, 1820 -- --
Lampsilis fasciola Rafinesque, 1820 -- --
Lampsilis ovata (Say, 1817) -- --
Lampsilis siliquoidea (Barnes, 1823) -- --
Lampsilis teres (Rafinesque, 1820) -- --
Leptodea fragilis (Rafinesque, 1820) -- --
Leptodea ochracea (Say, 1817) -- --
Ligumia subrostrata (Say, 1831) -- --
Megalonaias nervosa (Rafinesque, 1820) X (g) --
Obliquaria reflexa Rafinesque, 1820 X (h) --
Pleurobema clava (Lamarck, 1819) -- --
Pleurobema sintoxia (Rafinesque, 1820) -- --
Potamilus alatus (Say, 1817) -- --
Potamilus capax (Green, 1832) -- --
Potamilus ohiensis (Rafinesque, 1820) -- --
Pyganodon grandis (Say, 1829) -- --
Quadrula c. cylindrica (Say, 1817) -- --
Quadrula fragosa (Conrad, 1835) -- --
Quadrula p. pustulosa (Lea, 1831) -- --
Quadrula quadrula (Rafinesque, 1820) -- --
Strophitus undulates (Say, 1817) -- --
Toxolasma parvus (Barnes, 1823) -- --
Tritogonia verrucosa (Rafinesque, 1820) -- --
Truncilla donaciformis (Lea, 1828) -- --
Villosa lienosa (Conrad, 1834) -- --
Total Species Reported 4 1

 Not Report-
 ed from the
 Mo. Basin by
 any other
Species source

Actinonaias ligamentina (Lamarck, 1819) --
Actinonaias pectorosa (Conrad, 1834) X
Anodonta suborbiculata Say, 1831 --
Elliptio complanata (Lightfoot, 1786) X
Elliptio crassidens (Lamarck, 1819) --
Elliptio dilatata (Rafinesque, 1820) --
Epioblasma flexuosa (Rafinesque, 1820) X
Epioblasma personata (Say, 1829) X
Epioblasma triquetra (Rafinesque, 1820) --
Fusconaia (lava (Rafinesque, 1820) --
Lampsilis cardium Rafinesque, 1820 --
Lampsilis fasciola Rafinesque, 1820 X
Lampsilis ouata (Say, 1817) X
Lampsilis siliquoidea (Barnes, 1823) --
Lampsilis teces (Rafinesque, 1820) --
Leptodea fragilis (Rafinesque, 1820) --
Leptodea ochracea (Say, 1817) X
Ligumia subrostrata (Say, 1831) --
Megalonaias nervosa (Rafinesque, 1820) --
Obliquaria reflexa Rafinesque, 1820 --
Pleurobema clava (Lamarck, 1819) --
Pleurobema sintoxia (Rafinesque, 1820) --
Potamilus alatus (Say, 1817) --
Potamilus capax (Green, 1832) X
Potamilus ohiensis (Rafinesque, 1820) --
Pyganodon grandis (Say, 1829) --
Quadrula c. cylindrica (Say, 1817) X
Quadrula fragosa (Conrad, 1835) --
Quadrula p. pustulosa (Lea, 1831) --
Quadrula quadrula (Rafinesque, 1820) --
Strophitus undulates (Say, 1817) --
Toxolasma parvus (Barnes, 1823) --
Tritogonia verrucosa (Rafinesque, 1820) --
Truncilla donaciformis (Lea, 1828) --
Villosa lienosa (Conrad, 1834) --
Total Species Reported 9

(a) Big Nemaha River (Hoke 1996), Elkhorn River (Hoke 1994).

(b) Missouri River (Hoke 1983).

(c) Big Nemaha River Basin--collected by author, paper submitted
for publication.

(d) Big Nemaha River (Tryon 1868).

(e-i) Location and citation for species collection nearest to
Nebraska:

(e) Boyer River western Iowa (Frest 1987).

(f) Wakarusa River, eastern Kansas Scammon (1906), cited by
Murray and Leonard (1962).

(g) Osage River Basin, southeastern Kansas (Murray and Leonard
1962), and Platte River in northwestern Missouri (Oesch 1995).

(h) Osage River Basin, southeastern Kansas (Murray and Leonard 1962),
and Platte River in northwestern Missouri (Oesch 1995).

(i) Near mouth of the Osage River in central Missouri prior to
1920 (Oesch 1995).

Table 5. Comparison of best shell condition in current survey
and Hoke (2004) for Kansas sites only to KDW&P survey for the
Big Blue Basin: L = live, F = fresh shell, R = recent shell, D =
slightly to moderately weathered shell, WD = heavily weathered
shell, and S = chalky shell.

 Shell condition (a)

 Current KDW&P
Species Study (c) 1998-2000 (d)

Amblema plicata (Say, 1817) D WD
Anodontoides ferussacianus (Lea, 1834) WD WD
Fusconaia (lava (Rafinesque, 1820) WD WD
Lampsilis cardium Rafinesque, 1820 WD WD
Lampsilis siliquoidea (Barnes, 1823) WD WD
Lampsilis teres (Rafinesque, 1820) WD WD
Lasmigona c. complanata (Barnes, 1823) L L
Leptodea fragilis (Rafinesque, 1820) L L
Ligumia recta (Lamarck, 1819) WD WD
Ligumia subrostrata (Say, 1831) D R
Obovaria olivaria (Rafinesque, 1820) S --
Potamilus alatus (Say, 1817) L R
Potamilus ohiensis (Rafinesque, 1820) L L
Potamilus purpuratus (Lamarck, 1819) S --
Pyganodon grandis (Say, 1829) L L
Quadrula fragosa (Conrad, 1835) S --
Quadrula p. pustulosa (Lea, 1831) R L
Quadrula quadrula (Rafinesque, 1820) L L
Strophitus undulatus (Say, 1817) D WD
Toxolasma parvus (Barnes, 1823) R R
Tritogonia verrucosa (Rafinesque, 1820) WD WD
Truncilla donaciformis (Lea, 1828) WD --
Truncilla truncates Rafinesque, 1820 S --
Uniomerus tetralasmus (Say, 1831) L L
Utterbackia imbecillis (Say, 1829) F WD
Corbicula fluminea (Muller, 1774) D --
Total Taxa Represented 26 20

 Difference (b)

 Study vs.
Species KDW&P

Amblema plicata (Say, 1817) +
Anodontoides ferussacianus (Lea, 1834) s
Fusconaia (lava (Rafinesque, 1820) s
Lampsilis cardium Rafinesque, 1820 s
Lampsilis siliquoidea (Barnes, 1823) s
Lampsilis teres (Rafinesque, 1820) s
Lasmigona c. complanata (Barnes, 1823) s
Leptodea fragilis (Rafinesque, 1820) s
Ligumia recta (Lamarck, 1819) s
Ligumia subrostrata (Say, 1831) (-)
Obovaria olivaria (Rafinesque, 1820) nc
Potamilus alatus (Say, 1817) +
Potamilus ohiensis (Rafinesque, 1820) s
Potamilus purpuratus (Lamarck, 1819) nc
Pyganodon grandis (Say, 1829) s
Quadrula fragosa (Conrad, 1835) nc
Quadrula p. pustulosa (Lea, 1831) (-)
Quadrula quadrula (Rafinesque, 1820) s
Strophitus undulatus (Say, 1817) +
Toxolasma parvus (Barnes, 1823) s
Tritogonia verrucosa (Rafinesque, 1820) s
Truncilla donaciformis (Lea, 1828) nc
Truncilla truncates Rafinesque, 1820 nc
Uniomerus tetralasmus (Say, 1831) s
Utterbackia imbecillis (Say, 1829) +
Corbicula fluminea (Muller, 1774) nc
Total Taxa Represented +

(a) KDW&P utilized only three categorizations for shell condition:
L = live; R = Recent; and WD = weathered. For comparative
purposes it is assumed that the conditions of F, R, & D in the
current study equate to KDW&P's R, and the conditions of
WD and S in the current study equate to KDW&P's WD condition.

(b) + = better; s = same; (-) = worse; and nc = not comparable.

(c) Includes Kansas locales from Hoke (2004).

(d) For 39 sites in Kansas: 7 in Little Blue Basin, 32 in Big
Blue River and minor tributaries.

Table 6. Condition of fauna as indicated by number of species
occurrences and best condition of shells: L = live, F = fresh shell,
R = recent shell, D = slightly to moderately weathered shell,
WD = heavily weathered shell, and S = sub-fossil or chalky shell.

 Shell Condition

 Good Poor
Species L, F, R, D WD & S

Amblema plicata (Say, 1817) 1 9
Anodontoides ferussacianus (Lea, 1834) -- 4
Fusconaia flava (Rafinesque, 1820) -- 10
Lampsilis cardium Rafinesque, 1820 2 35
Lampsilis siliquoidea (Barnes, 1823) 7 33
Lampsilis teres (Rafinesque, 1820) -- 7
Lasmigona c. complanata (Barnes, 1823) 24 18
Leptodea fragilis (Rafinesque, 1820) 21 3
Ligumia recta (Lamarck, 1819) -- 24
Ligumia subrostrata (Say, 1831) 1 22
Obovaria olivaria (Rafinesque, 1820) 1 3
Potamilus alatus (Say, 1817) 6 9
Potamilus ohiensis (Rafinesque, 1820) 23 4
Potamilus purpuratus (Lamarck, 1819) -- 2
Pyganodon grandis (Say, 1829) 25 26
Quadrula fragosa (Conrad, 1835) -- 3
Quadrula p. pustulosa (Lea, 1831) 15 35
Quadrula quadrula (Rafinesque, 1820) 49 20
Strophitus undulates (Say, 1817) 1 14
Toxolasma parvus (Barnes, 1823) 4 4
Tritogonia uerrucosa (Rafinesque, 1820) -- 11
Truncilla donaciformis (Lea, 1828) -- 1
Truncilla truncates Rafinesque, 1820 -- 1
Uniomerus tetralasmus (Say, 1831) 14 13
Utterbackia imbecillis (Say, 1829) 1 --
Corbicula fluminea (Muller, 1774) 1 --
Unidentifiable unionid -- 11
 Total Species Occurrences 196 322
Breakdown by Component
 Big Blue and minor tributaries 152 211
 Little Blue Basin 44 111
 Total Species Occurrences 196 322

 Shell
 Condition
 Maximum %
 All Shell Decrease in
Species Conditions Range *

Amblema plicata (Say, 1817) 10 (90)
Anodontoides ferussacianus (Lea, 1834) 4 (100)
Fusconaia flava (Rafinesque, 1820) 10 (100)
Lampsilis cardium Rafinesque, 1820 37 (95)
Lampsilis siliquoidea (Barnes, 1823) 40 (83)
Lampsilis teres (Rafinesque, 1820) 7 (100)
Lasmigona c. complanata (Barnes, 1823) 42 (43)
Leptodea fragilis (Rafinesque, 1820) 24 (13)
Ligumia recta (Lamarck, 1819) 24 (100)
Ligumia subrostrata (Say, 1831) 23 (96)
Obovaria olivaria (Rafinesque, 1820) 4 (75)
Potamilus alatus (Say, 1817) 15 (60)
Potamilus ohiensis (Rafinesque, 1820) 27 (15)
Potamilus purpuratus (Lamarck, 1819) 2 (100)
Pyganodon grandis (Say, 1829) 51 (51)
Quadrula fragosa (Conrad, 1835) 3 (100)
Quadrula p. pustulosa (Lea, 1831) 50 (70)
Quadrula quadrula (Rafinesque, 1820) 69 (29)
Strophitus undulates (Say, 1817) 15 (93)
Toxolasma parvus (Barnes, 1823) 8 (50)
Tritogonia uerrucosa (Rafinesque, 1820) 11 (100)
Truncilla donaciformis (Lea, 1828) 1 (100)
Truncilla truncates Rafinesque, 1820 1 (100)
Uniomerus tetralasmus (Say, 1831) 27 (48)
Utterbackia imbecillis (Say, 1829) 1 0
Corbicula fluminea (Muller, 1774) 1 0
Unidentifiable unionid 11 (100)
 Total Species Occurrences 518 (62)
Breakdown by Component
 Big Blue and minor tributaries 363 (58)
 Little Blue Basin 155 (72)
 Total Species Occurrences 518 (62)

* Best species occurrences in heavily weathered and sub-fossil or
chalky condition divided by total of all species occurrences for
that unionid.
COPYRIGHT 2005 Nebraska Academy of Sciences
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2005 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:Hoke, Ellet
Publication:Transactions of the Nebraska Academy of Sciences
Date:Sep 1, 2005
Words:13056
Previous Article:A survey of infectious diseases and parasites in Wild Turkeys from Nebraska.
Next Article:The degree of chimpanzee theory of mind and the evolution of modularity.
Topics:

Terms of use | Privacy policy | Copyright © 2019 Farlex, Inc. | Feedback | For webmasters