SECTION NO. 5
Lyogyrus n. sp. 2

Draft Management Recommendations
for
Masked Duskysnail (Lyogyrus n. sp. 2)

v. 2.0

by

Roger Monthey
USDI BLM
Salem, Oregon

December 1998

TABLE OF CONTENTS

EXECUTIVE SUMMARY

Species: Lyogyrus n. sp. 2- undescribed (Masked Duskysnail)

Taxonomic Group: Mollusk (Phylum Mollusca; Class Gastropoda; Subclass Prosobranchia; Family Hydrobiidae)

ROD Components: Survey and Manage Strategies 1 & 2

Other Management Status: State of Washington Monitoring Species; BLM Tracking Species in Washington.

Range: It is currently known from 4 sites in two kettle lakes, Curlew Lake in Ferry County, Washington, and Fish Lake, which is partially within Wenatchee National Forest, Chelan County, Washington. The Fish Lake site is in close proximity to LSR RW 135 (Chiwawa LSR).

Specific Habitat: Lyogyrus n. sp. 2 is a kettle lake inhabitant and riparian associate. It lives in lentic ecosystems on oxygenated mud substrates with aquatic macrophyte growth. It is a cool water, periphyton feeder (i.e., feeds on the algal and microbial film on aquatic macrophytes), and likely on detritus.

Threats: The major concern for this species is loss of populations due to alteration of the ecological conditions (e.g., dissolved oxygen, water clarity, water temperature, aquatic macrophyte, and algal growth patterns) that are apparently important for its sustainability. The major threat is urbanization resulting in impacts such as water pollution from herbicides, pesticides and petroleum products, and eutrophication related to septic tank leakage and runoff of fertilizers and sediments. A potential threat is application of chemicals to control fish, insects, or aquatic plants. Other potential threats include water diversions for irrigation purposes and alteration of water temperature regime, although they may be less serious due to the large size of the lakes.

Management Recommendations: Manage the ecological conditions (i.e., maintenance or enhancement of clean, clear water conditions) at known sites. For example, modify human activities resulting in the introduction of septic tank leachate, sediments, oils, herbicides, and/or pesticides; and prohibit chemical applications to control fish, insects, or aquatic plants that could adversely affect these conditions.

Information Needs: Conduct surveys to locate populations of Lyogyrus n. sp. 2 in areas identified as potential suitable habitat. Prioritize surveys in areas where management treatments or projects are scheduled or proposed.

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I. NATURAL HISTORY

A. Taxonomic/Nomenclatural History

This species has not been formally described in the science literature, and there is no taxonomic/nomenclatural history for it. Lyogyrus n. sp. 2 is an undescribed, quite rare aquatic snail belonging to the family Hydrobiidae.

B. Species Description

1. Morphology

The following description of the genus Lyogyrus was taken from Burke (1994). As discussed by Burke (1994), Burch (1982) keys Lyogyrus as a subgenus of Amnicola with the following differences: 1. nuclear whorl of the shell small (0.29-0.36 mm diameter, as compared to 0.38-0.48 mm for subgenus Amnicola); 2. mantle diffusely shaded with pigment compared to heavily mottled with black in Amnicola; and 3. widely distributed in North America compared to widely distributed in eastern North America for Amnicola. Burch does not show consistencies in aperture shape or operculum either between or within the genera in his illustrations. Clarke (1981) described the operculum of Lyogyrus granum as ". . . brown, circular and multispiral as in Valvata." Of 2 Amnicola in his findings, he described the aperture of A. limosa as "ovate, narrower at the top, and with a thin callus on the parietal wall", but he neglected to describe the operculum. For A. walkeri, he said, "Aperture nearly round and attached to the penultimate whorl at the top and over only a short distance. . . Operculum thin, pale, and paucispiral." Pennak (1978) separated Lyogyrus from Amnicola in his key with "Operculum multispiral . . ." for Lyogyrus vs. "Operculum paucispiral . . ." for Amnicola. In his illustrations, (Fig. 502, E & O), he shows Amnicola with a teardrop shaped aperture and Lyogyrus with a round aperture.

The following description of this species was taken from Frest and Johannes (1993) and from Burke (1994) after Frest (pers. comm.). The snail is very high-spired, about 4 mm tall, slightly brownish, with evenly convex whorls; it has a round, unreinforced aperture margin, with up to 8 whorls as an adult. The operculum has an orangish spot near its middle. The operculum is large for the genus, up to 2 millimeters in length. The mantle color is light yellow, with black pigmentation forming a mask on the neck and around and between the eyes. The tentacles are light, with single distinct yellow bands when alive. The shell shape and pigment pattern are distinctive as compared to previously described forms. This species more closely resembles eastern U.S. species than do most of the recently discovered western species.

2. Reproductive Biology

Information on life history is very sparse, but the reproductive biology of Lyogyrus n. sp. 2 is probably similar to other Hydrobiid species that have been better studied. Typically, members of the family are dioecious (i.e., have separate sexes) and semelparous (i.e., breed only once in their life time and then die), and 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.

3. Ecology

Since this undescribed species has not been studied, there is little information available on the ecology of the species. All hydrobiid snails have gills that makes them dependent upon dissolved oxygen in the water in which they live. It is a cool water, periphyton feeder (i.e., feeds on the algal and microbial film on aquatic macrophytes), and likely on detritus. Burke (pers. comm.) indicated that both lakes inhabited by this species are highly eutrophic with an abundant growth of aquatic macrophytes and algae. Burke (pers. comm.) speculated this may be an unhealthy situation for the species, but further studies on the basic ecology of the species are necessary. Individuals overwinter as adults and do not disperse widely, so populations remain very localized in their distribution. Major predators are probably amphibians, turtles, sculpins, and trout. Typically, many individuals may be infected with trematode parasites.

C. Range, Known Sites

The type locality has not been designated until the formal description is published. This species is rare and locally endemic to 2 kettle lakes on the periphery of the Columbia drainage in Washington State, in areas heavily affected by Late Pleistocene glaciation. Curlew Lake is in Ferry County and Fish Lake is partially within the Wenatchee National Forest, Chelan County, Washington. The Fish Lake site is in close proximity to LSR RW 135 (Chiwawa LSR).

Frest and Johannes (1993) also noted the 1970s surveys by Clarke, who examined a number of Washington kettle lakes while finding only one site with this species; and earlier surveys by Henderson in the 1920s and 1930s, who examined many more kettle lakes without finding this taxon. Frest and Johannes (1993) reported they have recently begun surveying additional kettle lakes in Washington, Montana, and Idaho, with very limited success in finding this species to date.

The original distribution of this undescribed species was likely northern and central Washington on the east side of the Cascades east to the Rockies, in heavily glaciated valleys, in Pend d'Oreille, Stevens, Ferry, Okanogan, and Chelan counties. This taxon was also found in adjacent parts of the Idaho Panhandle and northwestern Montana with similar geologic history (Frest and Johannes 1993).

D. Habitat Characteristics and Species Abundance

Information on life history is very sparse. Lyogyrus n. sp. 2 is a kettle lake and riparian associate. It lives in lentic ecosystems on oxygenated mud substrates with aquatic macrophyte growth. It prefers cool water and is a periphyton feeder (i.e., feeds on the algal and microbial film on aquatic macrophytes), and may feed on detritus as well. It is found in association with aquatic macrophytes such as Potamogeton crispus, Elodea, Myriophyllum spicatum, Ceratophylum densum, and Chara. Sizable numbers of waterlogged deciduous leaves (especially Alnus and Populus) are always present. This species occurs with another rare endemic (Amnicola n. sp. 1) at one site. There is little information on species abundance. However, Clarke (see Burke 1994) reported in the 1970s that "an apparently new species of Lyogyrus was collected at Fish Lake about 10 miles north of Winston, Washington, but the population is dense and the lake appears to be in no danger of being damaged."

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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 this species, the FEMAT analysis (USDA, Forest Service and USDI, Bureau of Land Management 1994) concluded this species has a low likelihood of attaining stable, well distributed populations. Lyogyrus n. sp. 2 is currently restricted to 2 kettle lakes in eastern Washington. It is considered rare and locally endemic. Potentially, this species is at risk from urbanization, and other human activities that may adversely affect the ecological conditions necessary for self-sustaining populations of this species.

B. Major Habitat and Viability Considerations

Relatively little is known about this species. The major viability considerations for this species are loss of populations due to management activities (see Threats section) that impact the water quality.

C. Threats to the Species

The major concern for this species is loss of populations due to alteration of the ecological conditions that are apparently important for its survival (e.g., dissolved oxygen, water clarity, cool water temperatures, aquatic macrophyte and algal growth patterns). The major threats are urbanization, resulting in impacts such as water pollution from herbicides, pesticides and petroleum products, and eutrophication related to septic tank leakage and runoff of fertilizers and sediments. A potential threat is application of chemicals to control fish, insects, or aquatic plants. Another potential threat is water diversion for irrigation purposes, although this is unlikely due to the large size of the lakes. Alteration of water temperature regime is also unlikely due to the large size of these lakes.

D. Distribution Relative to Land Allocations

One site is on private land (Curlew Lake) and the other site (Fish Lake) is partially within the Wenatchee National Forest, Chelan County, Washington. The Fish Lake site is in close proximity to LSR RW 135 (Chiwawa LSR). Forest Service lands that directly border Fish Lake are within a Riparian Reserve as specified by the Northwest Forest Plan.

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III. MANAGEMENT GOALS AND OBJECTIVES

A. Management Goals for the Taxon

The goal for the management of Lyogyrus n. sp. 2 is to assist in maintaining species viability.

B. Specific Objectives

• Maintain appropriate water quantity (as determined on a site specific basis) and water quality (e.g., high dissolved oxygen at or near saturation levels, stream temperatures below 18^oC or 65^oF) at levels suitable for sustainability of these species.
• 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 lake ecosystem.
• Maintain integrity of lakebed substrates by minimizing sedimentation (i.e., avoid smothering of suitable substrates).

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IV. HABITAT MANAGEMENT

A. Lessons from History

Most large kettle lakes in northern Washington, Idaho, and northwestern Montana have been modified by human activity to some extent. According to Frest and Johannes (1993), these lakes have been heavily poisoned and stocked with fish, serve as preferred sites for human habitation, or have been used for irrigation, with resultant eutrophication and extirpation or reduction of the native mollusk fauna. Many such lakes now lack mollusk faunas or have very reduced, low-diversity, generalized faunas, even though numerous dead shells of other taxa in lake sediments indicate diverse faunas in the past. Eutrophication problems have resulted in citizen complaints and initiation of cleanup programs in both lakes where this species occurs.

B. Identification of Habitat Areas for Management

Manage all known sites on BLM and Forest Service land. Fish Lake within Wenatchee National Forest is the only currently identified site on federal lands where management could be implemented to maintain viability of the species.

Identify the habitat areas around known site locations, including the body of water in which the site is located and 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

The following management activity is recommended at this time:

Avoid or reduce the effects of human activities that result in water pollution, sedimentation, and eutrophication. Prohibit chemical applications to control fish, insects, or aquatic plants; and prohibit water diversions that could adversely affect ecological conditions necessary for continued sustainability of this species.

D. Other Management Issues and Considerations

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

• Conduct surveys to locate populations of Lyogyrus n. sp. 2 in areas identified as potential suitable habitat. Prioritize surveys in areas where management treatments or projects are scheduled or proposed.
• Develop keys and descriptions that allow field offices to accurately identify this species.

B. Research Questions

• What are the dispersal mechanisms for this species?
• What are the specific habitat requirements of this species?
• How does this species respond to changes in water quality conditions?

C. Monitoring Needs and Recommendations

The 2 kettle lake populations should be monitored to measure the responses of these populations to continued threats.

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VI. REFERENCES

Burch, J. B. 1982. North American Freshwater Snails, Identification Keys, Generic Synonymy, Supplemental Notes, Glossary, References, Index. Walkerana, No. 4:217-365

Burke, T. E. 1994. Mollusk Species From the Record of Decision (ROD) President's Forest Plan Supplement Table C-3 Survey and Manage. Notes on Molluscan Species from Washington. Unpublished manuscript.

Clarke, A. H. 1981. The Freshwater Molluscs of Canada. National Museums of Natural Sciences, National Museums of Canada, Ottawa.

Frest, Terrence J. and Edward J. Johannes. 1993. 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.

Pennak, R. W. 1978. Freshwater Invertebrates of the United States. John Wiley & Sons, New York.

USDA, Forest Service and Department of the 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.