0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Millimeters/Centimeters usda forest service -rocky mtnresearchstation usda forestservice idaho governor’sofficeofspeciesconservation This handy field guide will help citizen-scientists, researchers, researchers, This fieldguidewillhelpcitizen-scientists, handy and natural resource professionals learn aboutthe professionals more resource and natural orma j.smithmuseumof naturalhistory a guidetosouthernidaho’s Freshwater Mollusks Freshwater u.s. fish and wildlife service u.s.fishandwildlifeservice u.s. bureauofreclamation mollusks of southern Idaho. the collegeofidaho produced by: steve lysne, us fish and wildlife service a guidetosouthernidaho’s Freshwater Mollusks Freshwater usda forest service -idahogovernor’s officeofspeciesconservation usda forestservice the collegeof idaho,ormaj.smithmuseum ofnaturalhistory u.s. fish and wildlife service -u.s.bureauofreclamation u.s. fishandwildlifeservice 2009 a guide to southern idaho’s Freshwater Mollusks author: steve lysne produced by: u.s. fish and wildlife service u.s. bureau of reclamation usda forest service - rocky mtn research station idaho governor’s office of species conservation the college of idaho orma j. smith museum of natural history Table of Contents Introduction...................................................................... 1 How to Use This Guide.................................................... 3 Mollusk Anatomy.............................................................. 5 Freshwater Habitats.......................................................... 6 Springs Tributary Streams Large Rivers Lakes and Reservoirs Freshwater Mollusks.......................................................... 10 List of Mollusks in this Guide................................10 Part I: Elongated or pointed shells....................... 11 Part II: Round or wide shells................................ 21 Part III: Clams...................................................... 33 Invasive Species in Idaho..................................................39 Reporting Element Occurrences...................................... 40 Collecting Mollusks/Who to Contact Data Collection Forms (Back of Guide) Mollusk Literature............................................................ 42 Acknowledgments............................................................ 43 Introduction reshwater mollusks have a long American history. Years ago,F they served as a dietary staple for Native Americans, and by the late 19th century, shells were commonly used in the button industry at home and abroad. Although often quite small in size, mollusks have played a large part in both the social and economic history of humans. Today, there is growing interest in the role these animals play in biological mohawk tribe diversity and ecoystem health. The focus has turned to conserving freshwater mollusks, as Native Americans used bead-clamshell necklaces, called research now shows that “wampum,” for barter, gifts and cultural rights. they are the most imperiled group of animals in North America: greater than 60% of the 842 named species are considered imperiled, critically imperiled, or extinct. Much can be learned from these creatures and their habitats if efforts continue to understand our molluscan diversity. Molluscan research over the past 20 years has resulted in an ambitious program to survey and catalog the distribution of all North American freshwater mollusks. The information gathered will be of great use not only to researchers, but to natural resource managers and citizens. As more is learned about the distribution of mollusks, we will be able to better manage these species and the habitats upon which they depend. 1 Introduction How to Use This Guide A Guide to Southern Idaho’s Freshwater Mollusks contributes to the understanding of the diversity and distribution of mollusks his Guide is designed to be used by in southern Idaho. Tcitizen-scientists, researchers, and natural This Guide is a collaborative effort of several Idaho entities, resource professionals. Take this handy Guide including the U.S. Fish and Wildlife Service; U.S. Bureau of with you in the field to help identify the Reclamation; USDA Forest Service - Rocky Mountain Research freshwater snails or clams you find. Station; Idaho Governor’s Office of Species Conservation; The This book is organized by three simplified dan gustafson, College of Idaho’s Orma J. Smith Museum of Natural History/ montana state university shell types: William H. Clark, Museum Director; Dr. Jack B. Burch and Ethan • Elongated or pointed shells Nedeau for illustrations. Photography in this Guide is a collabora- • Round or wide shells tive effort by many individuals and agencies; see credits at back • Clams of book. The Guide would not have been possible without the Some of the mollusks in this Guide can be identified to the diligence of author Steve Lysne, who led the project when he was species-level based on their physical appearance, geographic employed by the U.S. Fish and Wildlife Service in Boise, Idaho. distribution, or lack of similar-looking species. Others, however, It is our hope that this Guide will encourage greater numbers cannot be determined by appearance or distribution, and may be of people to learn more about Idaho’s mollusks, and to actively more difficult to identify. Those species are only described to the engage in looking for these species in Idaho’s freshwaters. When level of genus. For characteristics described in each species profile, appropriate, we encourage samples to be submitted for research. please refer to Mollusk Anatomy, page 5. Samples will be deposited in the Orma J. Smith Museum of Common habitat type and general range maps are also included Natural History. Information about responsible collecting is on each species page. included in this Guide. Data collection forms are in this booklet. Pick up the snail or clam and orient Species distribution data contributed by citizen-scientists, it toward you to determine its shape, researchers, and natural resource professionals will be compiled and then try to match the specimen in an electronic database and made available to the public and with those from this Guide. scientific community. The net product will be reflective of the collective energy that is placed into this project. Thank you for taking the time to use the A Guide to Southern Idaho’s Freshwater Mollusks. 2 3 How to Use This Guide Mollusk Anatomy part i snail shoulder protoconch Elongated or pointed shells spire suture parietal lip body whorl aperture Stagnicola spp part ii umbilicus plait or fold (not shown) Round or wide shape midline tentacle foot Radix auricularia snout foot part iii ethan nedeau Clams * Southern Idaho has few large clams, but limpet apex slightly convex there are many “fingernail” or “pea” clams. shape here concave shape These are very difficult to identify and are not here included in this Guide. posterior slope anterior slope Gonidea angulata If you don’t feel you can positively identify the mollusk, or if it appears to be a species described only to the generic level, consider collecting the individual for positive identification. midline (See Reporting Element Occurrences, ethan nedeau page 40) 4 5 Freshwater Habitats Freshwater Habitats springs tributary Southern Idaho has a streams tremendous concentration Tributary streams in southern Idaho of freshwater springs and are generally mid-sized, with predictable spring-fed creeks. flows, although they are known Most exist on to flash flood private land. following Amazingly, severe weather. these springs Driven by and spring-fed snowmelt, creeks contribute tributaries are greater than 5,000 cubic feet per second (cfs) to the base flow of much colder the Snake River, which greatly improves water clarity, quality and than large rivers or reservoir systems habitat availability for mollusks. that typically have warmer water The springs are characterized by relatively slow flows, stable, temperatures due to large surface cool temperatures and crystal-clear water. Substrates for these areas and volume. types of habitat range from fine sands to larger pebble/gravel or Tributary streams have moderate cobble/boulder areas with submerged vegetation. to swift currents and cobble to boulder- Springs and creeks are easily sized substrates. In some areas, waded, and are ideal for clear- fine sediments may also be found. botttom buckets or hand collections. Tributaries are accessible to collectors with waders, though caution must be exercised in high flow conditions, deep pools and rapids. 6 7 Freshwater Habitats Freshwater Habitats large rivers lakes and reservoirs Idaho’s largest river is the Reservoirs are more Snake River. Its free-flowing common than lakes reaches contain swift, in southern Idaho, powerful currents and but similar groups of numerous habitats, including mollusks can be found riffles, runs, counter-current in both. Lakes and eddies and still reservoirs have deep, backwaters. slow-moving water and The Snake River is fine sediments, often artist or photographer credit generally warmer with abundant than its contrib- submerged vegetation. uting streams. Reservoirs are warm in the Nearly every summer and may freeze in the winter. type of substrate Reservoirs are best sampled with a exists in this system, dip-net in the shallows or any of the from fine clay silts to bedrock, various grab-samplers in deeper waters. and mollusks use all of them. Most mollusks will be found in deeper The diversity of