Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. Prescott National Forest Rare Invertebrates Final Report 2/23/2011 Rare Species of Prescott National Forest: Invertebrates Final Report 2/28/2011 Prepared for National Forest Service By Lawrence E. Stevens and Jeri D. Ledbetter Museum of Northern Arizona 3101 N. Fort Valley Road Flagstaff, AZ 86001 1 Prescott National Forest Rare Invertebrates Final Report 2/23/2011 AN INTRODUCTION TO THE HYDROBIIDAE SPRINGSNAILS OF THE PRESCOTT NATIONAL FOREST REGION (http://en.wikipedia.org/wiki/Hydrobiidae) Hydrobiidae are known as the mudsnails and springsnails, and are a large cosmopolitan family of very small freshwater and brackish water snails. These snails have an operculum, and are in the aquatic gastropod mollusks in the clade Littorinimorpha. The fossil record of this family extends back to the Early Carboniferous Period. Hydrobiidae is the largest family within the superfamily Rissooidea. Nearly 400 genera have been assigned to this family, and probably more than 1,000 species. This family was originally named by Troschel in 1857, as the group Hydrobiae. Troschel was not certain of their rank, and he placed them in the Taenioglossata: Ctenobranchiata between the Lithoglyphi and Ancyloti. Over the years there have been numerous attempts to give an adequate and more finely divided classification. The North American Hydrobiidae springsnails are generally small to minute snails, with a shell height often less than 3 mm. The dextrally (right)-coiled shells are smooth (except for growth lines conforming to the shape of the outer lip) and are usually rather nondescript. The shell offers few clear characteristics to taxonomists trying to classify species within this family. This difficulty is compounded by a high degree of intraspecific variation. Species descriptions often have to be based on the characteristics of the operculum, radula and penis. Within the family, the springsnails (Pyrgulopsis and Trionia) are particularly diverse and prone to endemism in springs in the Basin and Range geologic province of western North America. The ctenidium (a comblike respiratory apparatus) exists along most of the length of the pallial cavity and this gill consists of 10 to 200 triangular filaments. The osphradium is an olfactory organ linked with the respiration organ, and is usually relatively small. The taenioglossate radula consists of more than fifty rows of teeth. The central tooth is trapezoidal. The lateral teeth have few to numerous cusps. The marginal teeth are usually with numerous cusps. Most species in this family live in freshwater (lakes, ponds, rivers, streams), but some are found in brackish water or at the borders between freshwater and brackish water. A few species occur in marine settings on sandy or muddy bottoms between algae and sea grass. Hydrobiid snails usually have both male and female individuals, but very rarely reproduction may be parthenogenic or caused by internal fertilization. Females lay eggs in single capsules on the leaves or stems of water plants, but sometimes they produce eggs that are hatched within the pallial gonoduct of the body. In such species the young are born 2 Prescott National Forest Rare Invertebrates Final Report 2/23/2011 alive. Species that inhabit estuaries sometimes produce veliger larvae. These small snails feed on algae, diatoms and detritus. Hydrobiid snails in the American Southwest are often found in great abundance at the sources of springs. Feeding on biofilm and algae, these species often play important micro- ecological roles in springs ecosystem function. The high level of hydrobiid endemism at springs, coupled with threats of groundwater pumping that reduce or eliminate springs, has elicited conservation attention in this family. 3 Prescott National Forest Rare Invertebrates Final Report 2/23/2011 VERDE RIM SPRINGSNAIL Pyrgulopsis glandulosa Hershler and Landye 1988 Figure 1: Verde Rim Springsnail (Pyrgulopsis glandulosa), Nelson Place Spring, Yavapai County, Arizona, with mm marks (photo by L.E. Stevens). 4 Prescott National Forest Rare Invertebrates Final Report 2/23/2011 Taxonomy Mollusca Gastropoda Neotaenioglossa Hydrobiidae Pyrgulopsis P. glandulosa Hershler and Landye 1988 Description General Description: A small aquatic snail with a dextral (right-upwards) curving conical shell. The shell is amber colored when the snail is alive, and is transparent or bleached white after death. The periostracum is a thin chitin layer that covers the shell, and is light brown. The shell length slightly exceeds its width. VRS shell whorls vary from 3.5 to 4.0 and are convex, with impressed sutures. Mature snail shells are 1/8 in (2.0-2.8 mm) long. The snout is thick, relatively wide, with terminal fleshy lips. VRS have narrow cephalic tentacles that are less than twice as long as the snout and are expanded at the tips. Upon dissection, the ventral penial surface has two accessory crests and the dorsal surface has at least two elongated ridges. The posterior end of the foot is rounded. Egg capsules are likely hemispherical to spherical, as with other Pyrgulopsis. Similar Species: All Pyrgulopsis snails in Arizona are indistinguishable in the field, and must be carefully preserved and dissected for proper identification. “Based on penial morphology, this species is most similar to P. montezumensis, which also occurs in Verde River drainage, but differs in having a larger penis.“ (AGFD 2003). Range Overall Range: Nelson Place Spring is the only known locality for this species (Landye 1981; Fig. 2). The Arizona Game and Fish Department (2003) reports that the locality consists of “…two springs, separated by 150 meters, that form the headwaters of Sycamore Creek, Yavapai County, central Arizona.” Nelson Place Springs lies at about 1605-1610 m and consists of 3 springs complexes, each separated by a few tens of meters. Neither the upper nor the small lowermost springs appear to support VRS; however, a site visit in September 2010 revealed a large, healthy population of VRS at the main (middle) springs complex. Nelson Place Springs was once a popular stopping place for travelers between Phoenix and the high plateaus of northern Arizona. The site appears to have been restored, with the removal of housing structures and roads, and the overall site has been fenced. The only remaining signs of human presence are catalpa and Lombardy poplar trees, and a water drain structure, none of which appear to negatively affect the snail habitat at the middle springs source. Known Localities and Distribution of Specimens: Prior to our visit in September 2010, VRS had not, to our knowledge been observed since its original collection in the 1970s by 5 Prescott National Forest Rare Invertebrates Final Report 2/23/2011 Landye (J. Landye, retired USFWS, personal communication 2010). The specimens collected by Landye are housed in the Smithsonian Institution in Washington, DC. Figure 2: Verde Rim Springsnail distribution in Arizona. Roads, Forest Service and Wilderness boundary data from Prescott National Forest geodatabase. Raster layers provided by USGS. Projection NAD83. Habitat Requirements As with many Pyrgulopsis species, VRS is narrowly endemic to the source of the main Nelson Place Springs (Fig. 3). At that site the snail occurs in association with rocks, logs, and other firm substrata in the uppermost 20 m of the spring outflow, which lies on the Prescott National Forest. Also, like other Pyrgulopsis, it appears to prefer the roots of non- native watercress (Nasturtium officinale). Water temperature of the spring during the site visit was 68oF (20oC). 6 Prescott National Forest Rare Invertebrates Final Report 2/23/2011 Figure 3: Nelson Place main spring, September 2010 (photo by L. E. Stevens). Ecology and Life History Details of the ecology and life history of this Pyrgulopsis are likely similar to other members of the genus that are springs source-specialists; however, no specific information is available on VRS ecology and life history. “Most hydrobioids are oviparous, with females depositing small egg capsules, either singly or (rarely) in strings, on the substrate. A small number of hydrobioids are ovoviviparous, in which female’s brood of shelled young hatch in the pallial gonoduct. Copulation in hydrobioids is usually via an anterior opening to the glandular oviduct. The ventral channel may be traversed at least in part by the penis, but it is more likely that the penis only enters the anterior-most section. (Hershler and Ponder, 1998)” (AGFD 2003). Behavior Likely similar to other Pyrgulopsis, VRS is tightly tied to the spring source and firm substrata and aquatic vegetation. It is primarily nocturnal, and stays beneath rocks or in 7 Prescott National Forest Rare Invertebrates Final Report 2/23/2011 the shallow hyporheic zone and substratum during the day. There is some evidence of negative phototaxy in P. glandulosa, as they appear to move away from light. The attraction of this species to non-native watercress has not been studied. Although individuals are commonly found in watercress roots, it is uncertain whether the roots are used as a food source. Conservation Status VRS is listed by NatureServe as a G1 (globally imperiled) species, and is listed by the State of Arizona as an S1 species (imperiled in the state; NatureServe 2007). In addition, it is listed as a USDA Forest Service Region 3 Regional Forester’s sensitive species, and the USFWS is concerned about this springsnail. Threats General threats: Ungulate grazing, planned and wild fires, recreation impacts, and global climate changes are the primary threats to this snail. A monitoring program that includes a periodic check on the abundance of the snail appears warranted. National Forest Service habitat modifying activities: The primary Forest Service management activities that may influence the VRS habitat at Nelson Place Springs are listed in Table 1. VRS habitat stewardship issues include non-native species and recreation management issues. Although several non-native trees and other plants occur at the site, removal of non-native trees may negatively affect the VRS population. Crayfish exist in the nearby creek, and occasional monitoring may reveal incursions into the springs area, which may be somewhat protected by the placement of the drainpipe. Increased recreational use intensity may introduce additional disturbance and non-native species, and monitoring also can provide management with information on present use levels and new non-native species introductions. Table 1: Common general and specific Forest Service management practices, potential impacts, and mitigation actions for use on non-wilderness lands. General Activity Management Action Impacts Mitigation Actions Brush control Mechanical cutting of Wood chip cover of Designate stream buffer juniper with lop and riparian habitats zone; avoid chipping near scatter to 18 to 24 spring or riparian habitats inches from the ground Brush control Mechanical removal of Exposure of aquatic Designate stream buffer oaks, manzanita, and habitats, heating water zone; avoid concentrating other brushy during daytime slash near spring or riparian vegetation as a fuel habitats reduction project near WUI 8