SECTION NO. 2
Fluminicola n. sp. 14, 15, 16, 17, 18
and Juga (Oreobasis)

Draft Management Recommendations
for
ROD Mollusk Species associated with cold-spring complexes
in the Sacramento River and Pit River systems:
Fluminicola new species 14, 15, 16, 17 and 18,
and Juga (Oreobasis) new species 3

v. 2.0

by

Joseph L. Furnish,
USDA Forest Service
San Francisco, California

and

Roger W. Monthey
USDI Bureau of Land Management
Salem, Oregon

December 1998

TABLE OF CONTENTS

Table 1
Figures
Distribution Maps

EXECUTIVE SUMMARY

Species: Mollusk species associated with cold-spring complexes (cold nasmodes) in the Sacramento River and Pit River systems, California. Designation of undescribed species follows that given in the Record of Decision (ROD) for Amendments to Forest Service and Bureau of Land Management Planning Documents within the Range of the Northern Spotted Owl (1994). Common names are taken from Frest and Johannes (1993b).

Taxonomic Group: Mollusks (Phylum Mollusca; Class Gastropoda; Families Hydrobiidae and Pleuroceridae)

ROD Components: All species in this document are Survey and Manage Strategies 1 & 2. Juga (Oreobasis) n. sp. 3 is also listed in the Standards and Guides for protection from grazing.

Other Management Status: None

Range: The distributions of all 6 species are based on recent surveys of 231 sites. All but 2 species are endemic (i.e., restricted) to the Upper Sacramento River system, California. The exceptions include: Fluminicola n. sp. 14, the Potem pebblesnail, and Fluminicola n. sp. 18, the Globular pebblesnail, both of which occur in the upper Sacramento River and the Pit River basins, California. These 2 species and Fluminicola n. sp. 16, the Shasta Springs pebblesnail, are the only ones in this group that are known to occur on federal land; all 3 occur within the Shasta National Forest.

Specific Habitat: Habitats associated with this species group are cold, perennial springs with substrate material ranging in size from mud, sand, and silt to gravel, cobble, boulders, and talus (Table 1). It is a cool water, periphyton feeder (i.e., feeds on the algal and microbial film on aquatic macrophytes), and likely on detritus. In addition to cold springs, the Cinnamon Juga sometimes occurs in the Sacramento River. Many occupied spring sites are characterized by the presence of macrophytes including such species as water cress (Rorippa), monkey flower (Mimulus), horsetail (Equisetum), pondweed (Potamogeton filiformis), bryophytes (mosses), and lichens. Occupied sites range from 439-1375 m (1440-4510 ft.) in elevation (Table 1).

Threats:

• Chemical spills and other forms of water pollution (e.g., livestock use of springs and channel bottoms) result in effects such as: 1. direct mortality of species as evidenced by the recent (1991) Cantara Spill on the Upper Sacramento River, and 2. deleterious habitat alterations resulting from factors such as eutrophication caused by excessive fertilization, reduced dissolved oxygen levels, or elevated water temperatures.
• Dam construction submerges cold springs, slows current velocities, lowers the availability of oxygen, and allows fine sediments to accumulate. Existing dams on the Sacramento River (e.g., Shasta Dam, and dams creating Whiskeytown Reservoir and Siskiyou Lake) and the Pit River by Pacific Gas and Electric have already caused extensive destruction of suitable habitat.
• Reductions in water flow by water diversions result in elimination or reduction of aquatic habitat for snails.
• Excessive sedimentation effects from a variety of activities such as logging, mining, road and railroad grade construction, and grazing may smother preferred substrates and may impair egg-laying or survivorship of eggs or young.

Management Recommendations: All sites occupied by these snails should be protected and monitored. Specific recommendations include:

1. Maintain water temperatures below 18^oC (65^oF) to avoid thermal stress and ensure adequate availability of oxygen. (18 represents the critical threshold for trout that reside in the Upper Sacramento and Pit River systems.)
2. Maintain dissolved oxygen levels at or near saturation levels.
3. Maintain and/or restore native riparian plant communities that aid in maintaining cool water temperatures (i.e., below 18^oC) by providing shade, reducing sedimentation impacts, and providing litter fall nutrients to energy pathways in the stream ecosystem.
4. Avoid or mitigate for activities (e.g., logging, grazing, mining, construction) that could significantly increase sedimentation or potential for eutrophication of occupied sites.
5. Avoid water diversions, pollution, pumping, or other activities that may reduce water flow below levels necessary to sustain viable populations. This level must be determined on a site-specific basis but these species generally need flowing water.
6. Avoid or mitigate for the construction of dams that could have the following negative impacts: submersion of cold springs, slowing of current velocities, lowering of dissolved oxygen, and increased sedimentation.

Information Needs: Additional surveys should be conducted to locate populations in areas with potential suitable habitat. More monitoring or research is needed on habitat requirements of these species. Develop a collection of voucher specimens for appropriate administrative units within the range of these species. Provide additional training opportunities for identifying mollusk species and conducting surveys within the appropriate administrative units. Monitor water temperatures and other environmental parameters (e.g., sedimentation, dissolved oxygen) that potentially affect these species.

Determine the minimum instream flow requirements necessary to maintain environmental conditions within physiological limits.

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I. NATURAL HISTORY

A. Taxonomic/Nomenclatural History

None of these species have been formally described in the science literature, and there is no taxonomic/nomenclatural history for specific species. However, Frest and Johannes (1993a, 1993b, 1995) recognized them as distinct, and their reports account for much of the following information. The Fluminicola species are within the family Hydrobiidae, the "spring snails," and subfamily Lithoglyphinae. North American snails within this subfamily closely resemble some foreign groups. Similarities in the male reproductive system and shell led Taylor (1966, 1981) to consider these snails as representatives of the European genus Lithoglyphus. However, Thompson (1984), after detailed studies, concluded that Fluminicola is likely distinct, but there is still a need for detailed anatomical and conchological examination.

Juga (Oreobasis) n. sp. 3 is a member of the family Pleuriceridae or the "river snails". This family differs from the family Hydrobiidae in that the males lack a verge (male copulatory organ). Juga is a genus that is distinct from eastern pleruocerid snails based on reproductive anatomy and egg mass characters (Taylor 1966). Juga species have been previously assigned to Goniobasis, Oreobasis, Oxytrema, and Melania.

B. Species Descriptions

1. Common Characteristics

Species are grouped because of their mutual affinity for cold-spring complexes.

2. Morphology

The following descriptions are taken from Frest and Johannes (1995): Fluminicola n. sp. 14 (Potem pebblesnail) - This species has a medium-high conic spire, ranging to about 4 mm in height; adults have about 4.5 whorls. The shell is thick and green; the protochonch is small and flattened; the shell apex is blunt; later whorls are even and moderately convex. The aperture is bluntly ovate; the entire margin is thickened more or less evenly (except possibly the base), but the columellar callus is rather narrow. There is a narrow umbilical chink and small funicle (basal crescent) that does not extend to the base of the columella.

Fluminicola n. sp. 15 (Flat-top pebblesnail) - This species has a tall conic spire with rather flattened, even adult whorls and a large, flat protoconch. The shell is comparatively thin (translucent) and yellow; adults have about 4 whorls and a height of 2.5 mm. There is a moderate columellar callus that thins across the parietal wall; the rest of the subcircular apertural margin is very thin. The umbilicus is barely but consistently perforate; there is no, or just a trace of, a funicle. The body is colorless, as is the mantle.

Fluminicola n. sp. 16 (Shasta Springs pebblesnail) - This species has an adult height of about 3.5 mm and a low conic spire of about 4 whorls with a blunt protoconch, and even, moderately convex adult whorls. The shell is green and moderately thick; there is a distinct though quite small basal crescent that does not reach the base of the columella; the umbilicus is closed. The aperture margin is subcircular and moderately thickened almost completely around. The body is dark gray except on the base of the foot, and the mantle is similarly colored. The operculum is dark orange-brown.

Fluminicola n. sp. 17 (Disjunct pebblesnail) - This is one of the most spectacular of the new Upper Sacramento system Fluminicola species. The spire is flat-topped and then normally coiled for about 1-1.5 additional whorls. The remaining 2 whorls are distinctly disjunct, and the final whorl is strongly descending also. All whorls except the initial are strongly convex. The round aperture is reinforced around the whole margin, but rather thinly; there is a well-developed basal crescent that begins at the columellar base and is exaggerated by the disjunct coiling; and a moderately wide, open umbilicus. This species' shell is dark green, sometimes with whitish streaks, and thin except for the final whorl. The body is dusted with gray and there is pigment on the base of the foot as well; the mantle is black; the operculum is light horn. The species is moderate in size, only 3.3 mm in length despite the disjunct coiling.

Fluminicola n. sp. 18 (Globular pebblesnail) - Fluminicola n. sp. 18 is a small form, adult at about 4 whorls that are even and convex after the protoconch. Average height of adults is 2.5 mm. The subglobular shell has a low, slanted protoconch and is thin, yellow, and semi-translucent. The subcircular aperture has a weakly and relatively evenly reinforced margin all around, except that the parietal callus is slightly thinner than the columellar. The shell is narrowly umbilicate and has a distinct though narrow basal crescent that extends to the columellar base. The body lacks pigment, as does the mantle, and appears similar to that of Fluminicola n. sp. 15, except that the eye spots in this taxon are much larger.

Juga (Oreobasis) n. sp. 3. (Cinnamon Juga) - Juga (Oreobasis) from 8 sites in the Shasta Springs complex and perhaps elsewhere differs considerably from Juga nigrina (s.l.) and constitutes a new species. The spire is short and stout throughout ontogeny; the juvenile is completely smooth; the adult whorls have channeled sutures and are rather flat-sided, and the color is deep cinnamon red (the shell appears black in the field). Nacre of adults is purplish brown. No described Oreobasis is similar. There is a somewhat comparable undescribed taxon in the Deschutes drainage in Oregon, but it has a shorter spire, flatter whorls, thicker shell, and royal purple nacre in adults.

3. Reproductive Biology

Information on life history is very sparse, but Fluminicola n. spp. 14-18 are probably similar to other Fluminicola species that have been better studied. Typically, members of the genus are dioecious (i.e., have separate sexes) and semelparous (i.e., breed only once in their lifetime and then die). Individuals have a life span of one year, with 90 percent or more of the population turning over annually. Surviving individuals are generally those that do not breed during their first year. Eggs are laid in the spring and hatch in approximately 2-4 weeks. Sexual maturity is reached by late summer after a few months of growth. Individuals overwinter as adults and do not disperse widely, so populations remain very localized in their distribution.

The reproductive biology of Juga n. sp. 3 is unknown. However, based on the assumption that the biology of this species is similar to other species of Juga in the Pacific Northwest that have been better studied, the following generalities may be made. According to Hawkins and Furnish (1987) and Furnish (1990), Juga silicula (Gould) is an abundant species in creeks, streams, and small rivers of the Willamette Valley and Coast Range north to Puget Sound. In a small stream in the Oregon Coast Range, it reached sexual maturity in 3 years and adults usually lived 5-7 years. The species is dioecious and appears to be iteroparous (i.e., breeds several times after reaching sexual maturity). In late spring, egg masses containing about 150 individuals are layed on the undersides of cobble-sized substrates in shaded, running water. Young snails hatch in about one month.

4. Ecology

All of the 5 Fluminicola species are rare aquatic snails belonging to the family Hydrobiidae. The common name for this family is "spring snails," which is an allusion to the type of habitat where they are primarily found. All hydrobiid snails (i.e., of the family Hydrobiidae) have gills that make them dependent upon dissolved oxygen in the water in which they live. Like most hydrobiid snails, the snails of this group are highly sensitive to water pollution, oxygen deficits, elevated water temperatures, and sedimentation. Major predators include waterfowl, amphibians, turtles, sculpins, and trout. Typically, many individuals are infected with trematode parasites.

Juga (Oreobasis) n. sp. 3 is a member of the family Pleuroceridae or "river snails." Not much is known about the ecology of this species. It occurs in large cold springs and spring runs, with sand-cobble substrate, in forested areas, along with one or more endemic Fluminicola species. This species is dependent upon dissolved oxygen in the water column and, like the Fluminicola species, is sensitive to water pollution, oxygen deficits, elevated water temperatures, and sedimentation.

C. Range, Known Sites

The distributions of all 6 species are based on recent surveys of 231 sites. All but 2 species are endemic (i.e., restricted) to the Upper Sacramento River system, California. The exceptions include: Fluminicola n. sp. 14, Potem pebblesnail, and Fluminicola n. sp. 18, Globular pebblesnail, both of which occur in the upper Sacramento River and the Pit River basins, California. Fluminicola n. sp. 14, Fluminicola n. sp. 18, and Fluminicola n. sp. 16, the Shasta Springs pebblesnail, are the only ones in this group that are known to occur on federal land; all 3 occur within the Shasta National Forest.

Fluminicola n. sp. 14, Potem pebblesnail, is an Upper Sacramento endemic and appears to be restricted to small, perennial, cold, shallow spring runs in the upper Sacramento system (Frest and Johannes 1993a, 1995). The species has been collected from a total of 11 sites out of the 231 surveyed by Frest and Johannes (1995, Map 1), only one of which is on federal land in the Shasta National Forest (see Table 1).

Fluminicola n. sp. 15, Flat-top pebblesnail, is an Upper Sacramento endemic. It is known to occur at only 4 spring sites on both sides of the Sacramento River at Shasta Springs and Mossbrae Falls (Frest and Johannes 1993a, 1995, Map 2, Table 1). There are no known sites on federal land.

Fluminicola n. sp. 16, Shasta Springs pebblesnail, is an Upper Sacramento River endemic and is only found in the Shasta Springs area. Frest and Johannes (1993a, 1995) collected it from 19 sites, none of which are on federal land (Map 3, Table 1).

Fluminicola n. sp. 17, Disjunct pebblesnail, is an Upper Sacramento River endemic and is found only in the Shasta Springs area. Frest and Johannes (1993a, 1995) collected it from 3 sites, none of which are on federal land (Map 4, Table 1).

Fluminicola n. sp. 18, Globular pebblesnail, is in the upper Sacramento River and Pit River basins in small, perennial springs and spring headwaters. Frest and Johannes (1993a, 1995) collected it from 3 sites, none of which are on federal land (Map 5, Table 1).

Juga (Oreobasis) n. sp. 3, Cinnamon Juga, is an upper Sacramento River endemic and a crenophile (i.e., prefers spring environments). There are 8 records of occurrence at Shasta Springs, Cantara Bend on the Sacramento River, Upper Soda Springs and below McBride Springs on Willow Creek (Map 6, Table 1). Thus far it has mostly been collected from spring complexes, with one record from the Sacramento River. Further collections may demonstrate that it occurs more widely in the Upper Sacramento River, which represents a habitat-type commonly occupied by congeneric (i.e., Juga) species in western California, Oregon, and Washington.

D. Habitat Characteristics and Species Abundances

Frest and Johannes (1993a) provided the following general description of the habitat for this species group in the Upper Sacramento system. The terrain is steep, moist, and comparatively well vegetated. Rivers and creeks are perennial, have relatively large discharges, and flow through deep, incised, shaded canyons. Vegetation is primarily coniferous and soils are thin and nutrient poor. Aquatic environments generally have clear, cold, well oxygenated, flowing waters that have relatively low concentrations of dissolved nitrogen and phosphorus. Macrophytes such as Mimulus, Potamogeton and/or Rorippa occur in patches at some occupied sites (see Table 1). Substrates range from mud, sand, and silt to gravel, cobble, boulders, and talus, mostly derived from metamorphic and igneous parent material with some sedimentary lithologies.

Habitats of individual species are described below (see summary in Table 1). An estimate of abundance is not available for any of the species; however, populations of similar Fluminicola species may be quite dense. For example, F. seminalis reaches densities of 2000-3000 per m² in the same vicinity. Under such circumstances it may constitute the major invertebrate biomass at a site.

Fluminicola n. sp. 14, Potem pebblesnail - This species is a crenophile (i.e., it prefers spring habitats). Substrate types at occupied sites are usually mud, silt, and sand with scattered gravel, cobbles, and boulders. The species has been found at sites ranging from 439-963 m (1440-3160 ft.) in elevation. It has not yet been found to co-occur with other Fluminicola spp.; however, at a few of the sites, it co-occurred with Juga spp., and it occurred together once with Vorticifex effusa.

Fluminicola n. sp. 15, Flat-top pebblesnail - This species is a crenophile. It occurs in small, perennial, cold springs or spring sources on gravel substrates. The species has been found at sites ranging from 756-841 m (2480-2520 ft.) in elevation. It sometimes co-occurs with the Shasta Springs and Globular pebblesnails, and occurs on both sides of the Sacramento River, at the Shasta Springs and Mossbrae Falls spring complexes.

Fluminicola n. sp. 16, Shasta Springs pebblesnail - This species is a crenocole (i.e., it only occurs in springs). It occurs in the lower portions of larger springs, amid water cress (Rorippa), and mostly on pebbles and cobbles. The species has been found at sites ranging from 744-890 m (2440-2920 ft.) in elevation. It has 3 co-occurrences with the Disjunct pebblesnail at Shasta Springs and Rock Spring. It has 3 co-occurrences with Juga (O.) n. sp. 3; 2 at springs near Cantara Bend and one at Shasta Springs.

Fluminicola n. sp. 17, Disjunct pebblesnail - This species is a crenocole, and it usually occurs in the lower portions of larger springs, commonly on Rorippa. It is only known to occur at 3 sites ranging from 756-768 m (2480-2520 ft.) in elevation.

Fluminicola n. sp. 18, Globular pebblesnail - This species is a crenocole. It occurs in small springs and spring headwaters on the sides and undersides of stones in shaded areas. It may be photophobic. Occupied sites range from 750-853 m (2460-2800 ft.) in elevation. It co-occurs with the Flat-top pebble snail at Shasta Springs.

Juga (Oreobasis) n. sp. 3, Cinnamon Juga - This species is quite rare. It generally occurs in large, cold, perennial springs at elevations ranging from 707-1375 m (2320-4510 ft.). There is one record from the Sacramento River, and it is possible that further collections will reveal more frequent occurrences there. Substrates at occupied sites ranged from mud and sand (rarely) to cobbles and gravel (more commonly); macrophytes including water cress (Rorippa), monkey flower (Mimulus), horsetail (Equisetum), and pondweed (Potamogeton) were usually present. It co-occurs with Fluminicola n. sp. 15 in the Mossbrae Falls spring complex on the east side of the Upper Sacramento River on a west-facing forested slope, and with Fluminicola n. sp. 16 at Shasta Springs on the west side of the river and in springs near Cantara Bend.

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II. CURRENT SPECIES SITUATION

A. Why Species is Listed Under Survey and Manage Standards and Guidelines

Partially because of the high degree of endemism associated with these species, the FEMAT analysis (USDA, Forest Service, and USDI, Bureau of Land Management 1994) concluded that these species have low likelihood of attaining stable, well distributed populations. All of the species in this group are considered to be rare since they occur at a few, highly localized sites in restricted habitats. Five of the species are endemic to the Upper Sacramento River system. Historically all species in this group have suffered from habitat degradation so it is appropriate to protect surviving populations.

B. Major Habitat and Viability Considerations

Fluminicola species, like most hydrobiid snails, are highly sensitive to oxygen deficits (i.e., less than saturation levels), elevated water temperatures (above 18^oC or 65^oF), and sedimentation (i.e., smothering layers of fine sediment). These 5 Fluminicola species are only found in pristine springs that have cold, well oxygenated, clear water, generally with cobble and/or boulder substrates. Any activities that degrade these water quality parameters will adversely impact these Fluminicola species.

The life history traits of Fluminicola species also put them at risk. All species appear to breed only once in their lifetime and then die. Usually 90 percent of the population turns over annually so any condition (e.g., excessive sedimentation, elevated water temperature) that impairs egg laying, or survivorship of eggs or young, may result in extirpation.

Juga (Oreobasis) n. sp. 3 is also a gilled snail that is sensitive to alterations in water chemistry, oxygen deficits, and fine sediments. It is believed to be relatively long-lived, with many individuals reaching an age of 5 to 7 years. Declining population trends may not become apparent for a few years unless recruitment into the population is monitored by looking for the appearance of young individuals.

C. Threats to the Species

Some of the major threats to these species include:

• Chemical spills and other forms of water pollution (e.g., livestock use of springs and channel bottoms) resulting in effects such as: 1. direct mortality of species as evidenced by the recent (1991) Cantara Spill on the Upper Sacramento River, and 2. deleterious habitat alterations resulting from factors such as eutrophication caused by excessive fertilization, reduced dissolved oxygen levels, or elevated water temperatures.

• Dam construction that submerges cold springs, slows current velocities, lowers the availability of oxygen, and allows fine sediments to accumulate. Existing dams on the Sacramento River (e.g., Shasta Dam, Whiskeytown Reservoir, and Siskiyou Lake) and the Pit River have already caused extensive destruction of potentially suitable habitat.

• Reductions in water flow by water diversions, road construction, or pumping of aquifers resulting in elimination or reduction of aquatic habitat for snails.

• Excessive sedimentation from a variety of activities such as logging, mining, road and railroad grade construction, and grazing may smother substrates preferred by these species and may impair egg-laying or survivorship of eggs or young.

D. Distribution Relative to Land Allocations

Populations in the Upper Sacramento River and Pit River basins are located in areas allocated as Late-Successional Reserves or Managed Late-Successional Reserves. Field offices should refer to the Survey and Manage Database as well as maps of Late- Successional Reserves and other allocations in their administrative area to determine site locations in relation to specific land allocations.

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III. MANAGEMENT GOALS AND OBJECTIVES

A. Management Goal for the Taxon

The management goal for these species is to assist in maintaining species viability.

B. Specific Objectives

• Maintain water quantity (as determined on a site-specific basis) and water quality [e.g., high dissolved oxygen, stream temperatures below 18^oC or (65^o F)] at levels suitable for sustainability of these species.

• Maintain and/or restore native riparian plant communities by maintaining cool water temperatures (i.e., below 18^oC) by providing shade, reducing sedimentation impacts, and providing litter fall nutrients to energy pathways in cold-spring complexes.

• Maintain integrity of streambed substrates by minimizing sedimentation, and preventing physical alteration of the site caused by grazing or road construction.

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IV. HABITAT MANAGEMENT

A. Lessons from History

Historically, species in this group and their habitats have suffered significant negative impacts from mining, logging, road and railroad grade construction, grazing, water pollution, and water manipulations over the last century. For example, hydraulic mining in the 1800s caused extensive damage by removal of riparian vegetation and by bank destruction, resulting in elevated water temperatures and excessive sedimentation of aquatic habitats. In addition, the need for lumber to sustain mining operations increased logging activities resulting in similar effects. Road and railroad grade construction in riparian areas also added to these effects. Grazing operations have impacted aquatic habitat by diverting, channelizing, or damming spring flow, thus affecting the quantity and quality of habitat, and livestock trampling of springs resulting in sedimentation and water pollution.

Work initiated as part of the Central Valley Project (after 1937) and the California Water Project (in 1960) resulted in major habitat modifications. Dam construction on the Sacramento River (e.g., Shasta Dam, and dams creating Whiskeytown Reservoir and Siskiyou Lake) and Pit River caused extensive destruction of suitable habitat. Dam construction generally submerges cold springs, slows current velocities, lowers the availability of oxygen, and allows fine sediments to accumulate. Existing populations have been decimated and, as a result, they have become fragmented and isolated.

In July 1991 any remaining populations in the Upper Sacramento River were apparently destroyed or greatly diminished when railroad cars carrying the herbicide metam sodium (Vapam) derailed at Cantara Bend and spilled into the river. This resulted in major impacts in the lower 40 miles of the river, with only the upper 3 miles unaffected by the spill.

B. Identification of Habitat Areas for Management

Identify the habitat areas around known site locations, including all habitat features that contribute to the environmental conditions important to the species at the known site.

In most cases, the Riparian Reserve standards and guides for buffer widths and meeting Aquatic Conservation Strategy objectives will be sufficient for management within these areas. In situations where RRS and ACS do not apply or are not considered sufficient (e.g., wetlands less than 1 acre, springs and seeps) apply the standards and guides for perennial stream widths to determine the size of the area. Where wind firmness is a problem, habitat area widths may need to be increased to protect species habitat conditions.

C. Management Within Habitat Areas

All sites occupied by these snails should be protected. Specific recommendations include:

1. Maintain water temperatures below 18^oC (65^oF) to avoid thermal stress and ensure adequate availability of oxygen. (18^oC represents the critical threshold for trout.)

2. Maintain dissolved oxygen levels at or near saturation levels.

3. Maintain and/or restore native riparian plant communities that aids in maintaining cool water temperatures (i.e., below 18C) by providing shade, reducing sedimentation impacts, and providing litter fall nutrients to energy pathways in the stream ecosystem.

4. Avoid or mitigate for activities that could significantly increase sedimentation, pollution, or potential for eutrophication of occupied sites (e.g., logging, grazing, mining, construction activities, fertilizing, herbicides).

5. Avoid water diversions or other activities that may reduce water flow below levels necessary to sustain viable populations. This level must be determined on a site-specific basis, but these species generally need flowing water.

6. Avoid or mitigate for the construction of dams that could have the following negative impacts: submersion of cold springs, slowing of current velocities, lowering of dissolved oxygen, and increased sedimentation.

D. Other Management Issues and Considerations

If reestablishment is considered for some of these species, Frest and Johannes (1993a, 1995) advised for a similar species (F. seminalis) that relatively pure colonies should be reintroduced using fairly large numbers (i.e., in the range of several hundred to several thousand individuals per reintroduction site). Formerly occupied sites may be identified by consulting museum records. No other management issues and considerations are identified at this time.

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V. RESEARCH, INVENTORY, AND MONITORING NEEDS

The objective of this section is to identify opportunities for additional information that could contribute to more effective species management. The content of this section has not been prioritized or reviewed as to how important the particular items are for species management. While the research, inventory, and monitoring information is not required, these recommendations should be addressed by a coordinating body at the Northwest Forest Plan level.

A. Data Gaps and Information Needs

• Develop keys and descriptions that allow field offices to accurately identify these species.

• Conduct surveys to locate populations in areas identified as potential suitable habitat. Prioritize surveys in areas where management treatments or projects are scheduled or proposed. Surveys to reliably establish patterns of distribution have only recently been initiated (Frest and Johannes 1993a, 1995), so it is appropriate to conduct additional surveys in suitable habitats of the Sacramento River and Pit River basins prior to undertaking activities that may adversely impact these species.

• Conduct monitoring or research on habitat requirements of these species.

• Develop a collection of voucher specimens for appropriate administrative units within the range of these species.

• Monitor water temperatures at or in the vicinity of occupied sites using continuous reading thermometers, or at least maximum-minimum thermometers, to assure compliance.

• Monitor other environmental parameters (e.g., sedimentation, dissolved oxygen) that potentially affect these species.

• Determine the minimum instream flow requirements necessary to maintain environmental conditions within physiological limits.

B. Research Questions

• Where did viable populations of these species occur prior to the Cantara spill? Can these species be reestablished at sites occupied prior to the spill?

• Are survey and manage provisions effective? If not, why? What should be done differently?

• What is the condition of existing populations with regard to absolute size and density?

• What are the dispersal mechanisms of these species?

• What are the specific habitat requirements of these species?

• How do these species respond to changes in water quality conditions and other disturbances?

• What implications, if any, does management for these species have on other species?

C. Monitoring Needs and Recommendations

Recommend protocols for monitoring presently known populations and conducting surveys. At a minimum, variables that should be monitored to track habitat quality include: (1) water temperature, (2) dissolved oxygen, (3) sedimentation, and (4) discharge at springs and creeks, or current velocity at river sites.

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VI. REFERENCES

Frest, Terrence J. and Edward J. Johannes. 1993a. Freshwater Molluscs of the Upper

Sacramento System, California with Particular Reference to the Cantara Spill. Deixis Consultants, 1992 Yearly Report. Unpublished report prepared for the State of California, Department of Fish and Game, Contract #FG2016R1. 101 pp. and 2 Appendices.

___________. 1993b. Mollusc Species of Special Concern within the Range of the Northern

Spotted Owl. Deixis Consultants, Final Report. Unpublished report prepared for the Forest Ecosystem Management Working Group, U.S.D.A. Forest Service; Pacific Northwest Region; Portland, OR. 98 pp. and 1 addendum.

___________. 1995. Freshwater Molluscs of the Upper Sacramento System, California with

Particular Reference to the Cantara Spill. Deixis Consultants, 1994 Yearly Report. Unpublished report prepared for the State of California, Department of Fish and Game, Contract #FG2016R1. 88 pp. and 4 Appendices.

Furnish, J. L. 1990. Factors Affecting the Growth, Production and Distribution of the

Stream Snail Juga silicula (Gould). Unpublished Ph.D. thesis, Oregon State University, 205 pp.

Hawkins, C. P. and J. L. Furnish. 1987. Are Snails Important Competitors in Streams?

Oikos 49:209-220.

ROD. 1994. Record of Decision for Amendments to Forest Service and Bureau of Land

Management Planning Documents within the Range of the Northern Spotted Owl. Standards and Guidelines for Management of Habitat for Late-Successional and Old-Growth Forest Related Species Within the Range of the Northern Spotted Owl. U.S. Department of Agriculture, Forest Service, Portland, OR. ii + 74 pp.; vii + 143 pp.

Taylor, D. W. 1966. Summary of North American Blancan Nonmarine Mollusks.

Malacologia 4:1-172.

___________. 1981. Freshwater Mollusks of California: A Distributional Checklist.

California Fish and Game 67(3):140-163.

Thompson, F. G. 1984. North American Freshwater Snail Genera of the Hydrobiid Subfamily

Lithoglyphinae. Malacologia 25:109-141.

USDA, Forest Service, and Department of Interior, Bureau of Land Management. 1994. Final

Supplemental Environmental Impact Statement on Management of Habitat for Late-Successional and Old-Growth Forest Related species within the Range of the Northern Spotted Owl, Appendix A, Forest Ecosystem Management: An Ecological, Economic, and Social Assessment. Portland, OR.

Table 1. Attributes of collection localities for Fluminicola and Juga species
in the upper Sacramento and Pit River systems.
(Collection site numbers and data are taken from Frest and Johannes (1993a, 1995). x=occurrence at site.)

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Table 1 (continued) - Attributes of collection localities for Fluminicola and Juga species in the upper Sacramento and Pit River systems.
(Collection site numbers and data are taken from Frest and Johannes (1993a, 1995). x = occurrence at site.)

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