MANAGEMENT RECOMMENDATIONS FOR TERRESTRIAL MOLLUSK SPECIES Prophysaon coeruleum, Blue-Gray Taildropper & Prophysaon dubium, Papillose Taildropper V. 2.0 by Thomas E. Burke Wenatchee National Forest Entiat Ranger District with contributions by Nancy Duncan, Roseburg District BLM and Paul Jeske, Salem District BLM TABLE OF CONTENTS EXECUTIVE SUMMARY ..................................................... 1 MANAGEMENT RECOMMENDATIONS ...................................... 3 Prophysaon coeruleum (Blue-gray Taildropper) I. NATURAL HISTORY .................................................. 4 A. Taxonomic/Nomenclatural History ..................................... 4 B. Species Description ................................................ 4 1. Morphology ................................................ 4 2. Reproductive Biology ......................................... 5 3. Ecology ................................................... 5 C. Range, Known Sites ................................................ 6 D. Habitat Characteristics and Species Abundance ........................... 7 1. Habitat .................................................... 7 2. Abundance ................................................ 8 II. CURRENT SPECIES SITUATION ....................................... 9 A. Why Species is Listed Under Survey and Manage Standard and Guideline ....... 9 B. Major Habitat and Viability Considerations .............................. 9 C. Threats to the Species ............................................. 10 D. Distribution Relative to Land Allocations ................................ 11 Prophysaon dubium (Papillose Taildropper) I. NATURAL HISTORY ................................................. 12 A. Taxonomic/Nomenclatural History .................................... 12 B. Species Description ............................................... 12 1. Morphology ............................................... 12 2. Reproductive Biology ........................................ 13 3. Ecology .................................................. 13 C. Range, Known Sites ............................................... 14 D. Habitat Characteristics and Species Abundance .......................... 15 1. Habitat ................................................... 15 2. Abundance ............................................... 16 II. CURRENT SPECIES SITUATION ...................................... 17 A. Why Species is Listed Under Survey and Manage Standard and Guideline ...... 17 B. Major Habitat and Viability Considerations .............................. 17 C. Threats to the Species ............................................. 18 Prophysaon coeruleum and Prophysaon dubium - i D. Distribution Relative to Land Allocations ................................ 19 Prophysaon coeruleum and Prophysaon dubium III. MANAGEMENT GOALS AND OBJECTIVES ............................ 20 A. Management Goals for the Taxon ..................................... 20 B. Specific Objectives ............................................... 20 IV. HABITAT MANAGEMENT ............................................ 21 A. Lessons from History .............................................. 21 B. Identification of Habitat Areas for Management ........................... 22 C. Management Within Habitat Areas .................................... 27 D. Other Management Issues and Considerations ........................... 34 V. RESEARCH, INVENTORY AND MONITORING NEEDS .................. 35 A. Data Gaps and Information Needs .................................... 35 B. Research Questions ............................................... 36 C. Monitoring Needs and Recommendations ............................... 37 VI. REFERENCES ....................................................... 38 VII. APPENDIX - FIGURES .................................................41 Prophysaon coeruleum and Prophysaon dubium - ii EXECUTIVE SUMMARY Species: Prophysaon coeruleum Cockerell, 1890 (Blue-gray Taildropper) Prophysaon dubium Cockerell, 1890 (Papillose Taildropper) Taxonomic Group: Mollusks (Phylum Mollusca: Class Gastropoda) ROD Components: Survey and Manage Strategies 1 and 2. Other Management Status: Prophysaon coeruleum is on the Oregon Natural Heritage Program List 2 and Washington State Monitoring List. Prophysaon dubium is on the Oregon Natural Heritage Program List 2, Washington State Monitoring List, BLM Assessment species for Oregon, and BLM Tracking species for Washington. Range: Prophysaon coeruleum - Western Cascades and Puget Trough of Washington, western Oregon, south to northern California. It occurs on both sides of the Cascades in southern Oregon and is suspected on the east slopes of the Cascades in Washington. Prophysaon dubium - Washington Cascades (east and west) and Olympic Mountains south through the western Oregon Cascades and Coast Range, into the Siskiyou and Trinity mountains of northern California. Specific Habitat: Prophysaon coeruleum is more closely associated with conifer forests and Prophysaon dubium is more closely associated with hardwood stands. Both species are found in some mixed conifer stands. Some specific microsite characteristics for the individual species include: Prophysaon coeruleum - Typical P. coeruleum is often found in late-successional forests where it is associated with conifer logs, ground litter, fungi and mosses. Prophysaon dubium - It is a generally found in late successional forest or riparian areas more closely associated with hardwood logs, leaf litter and fungi. Threats: Primary threats to these species are -Isolating or losing additional populations -Further loss of habitat to support the species across the landscape -Predation -Competition from exotic mollusks -High intensity fire Prophysaon coeruleum and Prophysaon dubium - Page 1 Management Recommendations: Three management strategies are recommended for Prophysaon coeruleum and P. dubium, depending on local distribution within the area under consideration. A primary concern in all strategies is to moderate fluctuations in temperature and humidity by maintaining favorable shade and limiting adverse impacts of fire. • Strategy 1 is the recommended option where the species is not locally common. The general prescription is to maintain or restore microsite conditions and best habitat features at the site. The Habitat Area is the area needed to generally maintain favorable microsite conditions at the single site. Habitat disturbance should be only to benefit the species. • Strategy 2 can be used when the species is locally common, and occurs in locally clustered sites that occupy a portion of the project area. The Habitat Area is an area or polygon around all sites. This approach allows limited disturbance, including thinning and other activities. • Strategy 3 can be used where the species is locally common and when it seems to occur throughout a proposed project area. The Habitat Area is the same as the survey or project area. This approach allows a higher level of disturbance, including openings, thinning and other activities, but connectivity within the Habitat Area remains. All known sites should be within a Habitat Area. In Strategy 1, known sites will be managed individually within Habitat Areas. In Strategies 2 and 3, known sites will be managed collectively as a population within Habitat Areas. In areas where these species are locally common, local managers have the option of using Strategies 1, 2, or 3. There can be a combination of Habitat Area types within a single project. Strategies 2 and 3 are intended to provide additional flexibility while successfully maintaining and/or improving habitat for populations and providing for continued occupation of the area by the species. Strategies 2 and 3 allow some of the individual sites to be temporarily degraded, while maintaining the population as a whole. They maintain contiguity throughout the occupied habitat and stipulate that any degradation should recover within twenty years. Information Needs: Some of the primary information needs are: • Are the recognized variants of P. coeruleum separate species or subspecies? • What is the range of habitat conditions tolerated by each species? What is the range of conditions (biological and physical attributes) required for populations to remain secure and viable? • What stand characteristics (canopy cover, age, large woody debris, litter and duff, etc.) are required to support the required conditions? • How do the required stand characteristics vary under different circumstances (elevation, slope, aspect, etc.)? • What stand size is required to provide sufficient area of suitable habitat? • How much time is required for recolonization of a site by species from adjacent populations? Prophysaon coeruleum and Prophysaon dubium - Page 2 MANAGEMENT RECOMMENDATIONS SPECIES Prophysaon coeruleum Cockerell, 1890 (Blue-gray Taildropper) Prophysaon dubium Cockerell, 1890 (Papillose Taildropper) INTRODUCTION The descriptive parts of sections I and II are arranged by species in the order listed above. However, the Management Recommendations for them, sections III through VI, are combined. In general, management for these species should be implemented as an ecosystem management approach, since these two species, other survey and manage species, as well as other species of concern are likely to be found in the same areas. These management recommendations are primarily based on information available from all sources in August 1998. Additional data and analysis collected since that time may lead to differing