U.S. FISH AND WILDLIFE SERVICE SPECIES ASSESSMENT AND LISTING PRIORITY ASSIGNMENT FORM

SCIENTIFIC NAME: Helminthoglypta morroensis

COMMON NAME: Chorro shoulderband snail

LEAD REGION: Pacific Southwest Region, Region 8

DATE INFORMATION CURRENT AS OF: June 2018

STATUS/ACTION

X Species assessment – determined either we do not have sufficient information on threats or the information on the threats does not support a proposal to list the species and, therefore, it was not elevated to Candidate status

___ Listed species petitioned for uplisting for which we have made a warranted-but-precluded finding for uplisting (this is part of the annual resubmitted petition finding)

___ Candidate that received funding for a proposed listing determination; assessment not updated

___ New candidate

___ Continuing candidate

___ Listing priority number change Former LPN: ___ New LPN: ___

___ Candidate removal: Former LPN: ______A – Taxon is more abundant or widespread than previously believed or not subject to the degree of threats sufficient to warrant issuance of a proposed listing or continuance of candidate status. U – Taxon not subject to the degree of threats sufficient to warrant issuance of a proposed listing or continuance of candidate status due, in part or totally, to conservation efforts that remove or reduce the threats to the species. ___ F – Range is no longer a U.S. territory. I – Insufficient information exists on taxonomy, or biological vulnerability and threats, to support listing. ___ M – Taxon mistakenly included in past notice of review. ___ N – Taxon does not meet the Act’s definition of “species.” ___ X – Taxon believed to be extinct.

Date when the species first became a Candidate (as currently defined): n/a

Petition Information: _X_ Non-petitioned ___ Petitioned; Date petition received: 90-day substantial finding FR publication date: 12-month warranted but precluded finding FR publication date:

PREVIOUS FEDERAL ACTIONS: In 1994, we listed Helminthoglypta walkeriana as endangered (59 FR 64613). This taxon contained to two subspecific entities: H. walkeriana and H. walkeriana morroensis. At the time of listing, we thought the subspecific entity morroensis was extinct, and also speculated that there may have been as few as several hundred individuals of Helminthoglypta walkeriana remaining (59 FR 64615). In 1997, the subspecific entity morroensis was rediscovered at North Point Natural Area near the northern limit of Morro Bay (Roth and Tupen 2004, p. 3). In subsequent years it was found in other areas as well. In 1998 we completed a Recovery Plan for the Morro Shoulderband Snail and Four Plants from Western San Luis Obispo County (Service 1998, entire) and in 2001 designated critical habitat (66 FR 9233). Both the recovery plan and critical habitat addressed only Helminthoglypta walkeriana and not the subspecific entity morroensis, as we did not consider the morroensis subspecies to be part of the listed entity. In 2004, a taxonomic analysis was completed that elevated these subspecific taxa to full species: Helminthoglypta walkeriana and H. morroensis (Roth and Tupen 2004, entire). After 2004, H. walkeriana and H. morroensis were associated with the common names Morro shoulderband snail and Chorro shoulderband snail, respectively. Also in 2004, the Ventura Fish and Wildlife Office issued a “Dear Stakeholders and Interested Parties” letter stating we would no longer be regulating the Chorro shoulderband snail (Service 2004, entire). The final listing rule does not clarify whether or not the morroensis subspecies was included in the listing. In moving forward, the Service did not consider the morroensis subspecies to be part of the listed entity, and thus the 1998 Recovery plan and the 2001 critical habitat designation did not address morroensis. However, we do recognize that in 2006, the Service completed a 5- Year Review for both the Morro and Chorro shoulderband snail and recommended downlisting Morro shoulderband snail from endangered to threatened and delisting of Chorro shoulderband snail (Service 2006, entire). Since then, we have considered that only the scientific name Helminthoglypta walkeriana was added to the list of endangered and threatened wildlife, and H. morroensis was not added to the list. Because the entity Helminthoglypta morroensis was never added to the endangered species list, we have determined that it is most appropriate to now complete a listing assessment to determine whether or not the Chorro shoulderband snail meets the definition of threatened or endangered.

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ANIMAL/PLANT GROUP AND FAMILY: Animalia Mollusca Gastropoda Helminthoglyptidae Helminthoglypta morroensis

HISTORICAL STATES/TERRITORIES/COUNTRIES OF OCCURRENCE: San Luis Obispo County, California

CURRENT STATES/COUNTIES/TERRITORIES/COUNTRIES OF OCCURRENCE: San Luis Obispo County, California

LAND OWNERSHIP Within the estimated 28,600-hectare (ha) (70,650-acre (ac)) range of the Chorro shoulderband snail, the majority of lands (~84 percent) are within private ownership under the jurisdiction of the City of San Luis Obispo or County of San Luis Obispo. Approximately 7 percent of the range is part of the California Army National Guard at Camp San Luis Obispo, with the remaining non- private lands being under the ownership of the State of California (~5 percent), City of San Luis Obispo (~3 percent), and County of San Luis Obispo (~1 percent).

LEAD REGION CONTACT Sabrina West, Pacific Southwest Region

LEAD FIELD OFFICE CONTACT Julie Vanderwier, Ventura Fish and Wildlife Office

BIOLOGICAL INFORMATION The Species Status Assessment (SSA) for the Morro Shoulderband Snail (Helminthoglypta walkeriana) and Chorro Shoulderband Snail (Helminthoglypta morroensis)) is a summary of the information assembled and reviewed by us and incorporates the best scientific and commercial information available for the Chorro shoulderband snail. In the SSA, in order to evaluate the biological status of the species both currently and into the future, we assessed a range of conditions to allow us to consider the species’ resiliency, redundancy, and representation. This species assessment represents a summary of the biological information provided in the SSA 3

Report. For more detailed information on the species' biology and natural history, as well as an assessment of demographic risks, stressors, and limiting factors in the context of determining the viability and risks of extinction for the species, please refer to the SSA Report (Service 2019, entire). In this species assessment, we focus on the status of the Chorro shoulderband snail. We will publish a separate document discussing the status of the Morro shoulderband snail. However, since there are limited data available on the biology of and threats impacting the Chorro shoulderband snail, in some places, we use information for the Morro shoulderband snail as a surrogate, as the two are closely related and, based on the best available information, have similar life history characteristics and habitat use.

Species Description Like other species in the genus Helminthoglypta, the shells of both the Morro shoulderband snail and the Chorro shoulderband snail are heliciform (shaped like a spiral), umbilicate (having a depression in the center), and reddish brown to chestnut in color. They have a single characteristic, narrow, dark spiral band on the “shoulder” with thin light yellowish margins above and below (Hemphill 1911, p. 102; Roth 1985, p. 5). Shell characteristics form the basis of all historic descriptions of the Morro and Chorro shoulderband snails, with no reference to or descriptions of the soft anatomy (Roth and Tupen 2004, p. 2). The shells of the Chorro shoulderband snail is more depressed (lesser shell height/shell width ratio) than the shells of the Morro shoulderband snail and have a larger, less occluded umbilicus (Tupen and Roth 2005, p. 10). The sculpture of the shell is profusely granular or intensely papillose (covered with small, round protrusions), with weak to absent incised spiral grooves on the body whorl. Incised spiral grooves, a key sculptural feature of the shell/body whorl of Morro shoulderband snails, are generally overridden by intense papillation on the shell of the Chorro Figure 1. Chorro Shoulderband Snail. Dan shoulderband snail (Roth 1973, p. 151; Walgren Dugan, EcoVision Partners 2003a, p. 10). In addition to the extreme papillation, Roth (1973, p. 151) indicated decreased whorl number for the Chorro shoulderband snail and Walgren (2003a, p. 93) suggested an overall smaller size at maturation. Roth and Tupen (2004, Figure 2) show no significant difference in size between Morro and Chorro shoulderband snails or among populations of the Chorro shoulderband snail. Based upon this research, Tupen (2018, pers. comm.) postulates that observed size differences are likely more a site-specific phenotypic response to some environmental factor(s).

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Taxonomy The Chorro shoulderband snail belongs to the land snail genus, Helminthoglypta (Ancey 1887), which contains three subgenera that comprise more than 100 species and subspecies. Helminthoglypta is a large genus primarily found throughout California but also ranging north into southern Oregon and south into Baja California, Mexico inclusive of its offshore islands. The banded dune snail was first described as Helix walkeriana by Hemphill (1911, entire) based on collections made in San Luis Obispo County near “Morro, California.” Hemphill also described a subspecific taxon of Helix walkeriana, variety morroensis, from near “San Luis Obispo City” based on sculptural features of the shell (Roth and Tupen 2004, p. 2). Both forms of the species were reassigned to the genus Helminthoglypta from the genus Helix in 1930 (Roth and Tupen 2004, p. 2). At the time of listing of Helminthoglypta walkeriana (59 FR 64613), the banded dune snail included Helminthoglypta walkeriana and a more inland subspecific taxon referred to as H. w. “morroensis.” Since then, the status of these two taxa has been re-examined (Roth and Tupen 2004, entire; Tupen and Roth 2005, pp. 9–10; Walgren 2003a p. 4). Roth (1985, p. 2) acknowledged that the taxonomic status of the banded dune snail remained “unsettled” and recognized both subspecific taxa as subspecies. Walgren later stated that both subspecific taxa were valid subspecies “…based on unique shell morphology, ecology, and geographically isolated ranges” (Walgren 2003b, p. 98). He also recommended that “…further research should focus on…soft tissue anatomy and DNA to address the taxonomic status of [the] various types.” Roth and Tupen (2004, p. 6) analyzed variations in the shell forms and soft tissue anatomy (genitalia) of the two taxa. They determined that variations in shell shape, shell sculpture, and soft tissue anatomy between the two taxa were consistent with reproductive isolation. Based on these data, Roth and Tupen elevated both subspecific taxa to full species status resulting in the following combinations: Helminthoglypta walkeriana (Morro shoulderband snail) and H. morroensis (Chorro shoulderband snail) (Roth and Tupen 2004, entire). Therefore, we regard both the Morro shoulderband snail and the Chorro shoulderband snail as full species (Service 2019, p. 9).

Habitat/Life History Historic information on the habitat associations of the Chorro shoulderband snail is brief and lacking in detail. Walgren (2003a, p. 65) described habitat for this species as vegetation and/or plant community associations including “sand verbena-beach bursage, coyote brush, coast live oak woodland, nodding needlegrass, European beachgrass, California annual grassland, iceplant, and dune lupine-goldenbush series communities.” Roth and Tupen (2004, p. 6) reported the primary plant associates for the Chorro shoulderband snail include sweet fennel (Foeniculum vulgare), coyotebush (Baccharis pilularis), poison hemlock (Conium maculatum), and native bunch grasses of the genus Stipa. Chorro shoulderband snails are also commonly associated with stands of mission fig cactus (Opuntia ficus-indica) where it occurs in and around the City of San Luis Obispo (EcoVision Partners 2017, p. 27; Tenera 2003b, pp. 6–8). EcoVision 5

Partners (2017, p. 3) reported the Chorro shoulderband snail within the leaf litter of coyotebush and California sagebrush. Individuals also occur in the interface of rock outcrops and grasslands, rock piles, and individual rocks (Ballantyne 2018, pers. comm.; Sloan 2018 pers. comm.; EcoVision 2017, p. 3). It appears that the use of refugia is diverse and opportunistic. Many species of Helminthoglypta occur in Mediterranean climate regions of California and have adapted to changing environmental conditions by having a two-part life cycle. While feeding, reproduction, and most individual growth occurs during the rainy season (Roth 1985, p. 13), the majority of the year can be spent in aestivation to survive the drier portions of the year (Belt 2018, pers. comm.). Refugia used for the aestivation phase of the life cycle for both the Morro and Chorro shoulderband snail appear to be opportunistic in nature. They can include native and nonnative plant species; accumulations of litter and grass; dense clumps of native and nonnative grasses, young patches of iceplant (Carpobrotus spp.), cactus (Opuntia spp.); and anthropogenic features and debris (stockpiled construction materials, wood, cement, plastic) (Roth and Tupen 2004, p. 17; SWCA 2013–2018, entire; Dugan 2018, pers. comm.). As previously stated, most activity among species of Helminthoglypta living in California occurs during the rainy season (Roth 1985, p. 13). In coastal San Luis Obispo County, the period of greatest activity generally extends from October through April but can vary each year depending on the frequency and duration of seasonal rainfall and heavy fog/dew. During this period, individuals may be particularly active during the evening, night, and early morning hours when humidity is higher. Helminthoglypta species are also active during overcast and rainy days (van der Laan 1980, pp. 49, 52; USDA 1999, p. 3; Tupen 2018, pers. comm.). The Chorro shoulderband snail likely emerges from aestivation during and following periods of rainfall in search of food resources and for mating and egg-laying activities. Precipitation and humidity requirements for the Chorro shoulderband snail are very likely similar to those of the Morro shoulderband snail, although the Chorro shoulderband snail occur in more xeric habitats further removed from the direct coastal influence experienced by the Morro shoulderband snail. Terrestrial snails become inactive during prolonged dry periods and enter a state of aestivation where individuals produce an epiphragm (a seal of dried mucus) across the shell aperture to greatly reduce water/weight loss (van der Laan 1975, p. 361). Helminthoglypta frequently aestivate sealed to the lower outer branches of shrubs (van der Laan 1975, p. 365; Roth 1985, p. 13). Attachment to a substrate may provide additional protection from desiccation by forming a more complete seal of the aperture (van der Laan 1975, p. 365). In response to increasingly desiccating conditions, snails withdraw further into their shells and may secrete multiple epiphragms, (van der Laan 1975, pp. 363, 367). Smaller snails tended to experience higher mortality rates during aestivation, possibly due to their thinner shells and higher surface to volume ratios (van der Laan 1975, p. 364). Helminthoglypta come out of aestivation after rain events that thoroughly wet the environment and may regain as much as 50 percent of their body weight back within 24 hours (van der Laan 1975, p. 364). Like other terrestrial snails, we expect the Chorro shoulderband snail to have a patchy distribution coincident with the presence of suitable refugia and food sources. 6

Historical Range/Distribution The final 1994 listing rule states that the banded dune snail “formerly occupied primarily coastal dune scrub habitat along approximately 8 km (5 mi) of dunes extending onto the Morro sand spit, at Baywood Park, San Luis Obispo, sites between Morro Bay and Cayucos, and probably along Morro Bay in the vicinity of Cuesta-by-the-Sea.” Additionally, it notes individuals from San Luis Obispo (type locality for “morroensis”) and 4.8 km (3 mi) south of Cayucos (Roth 1973, p. 153). In 1994, we thought Helminthoglypta walkeriana “morroensis” (the Chorro shoulderband snail today) was extinct; however, in 1997, a population of snails with form “morroensis” shell morphology was identified at North Point Natural Area near the northern limit of Morro Bay (Roth and Tupen 2004, p. 3, Figure 1; Tupen 2018, pers. comm.). Since that time, living Chorro shoulderband snails have been found at other locations from north of Morro Bay inland through the City of San Luis Obispo (Walgren 2003a, p. 90; Tenera 2003a, p. 14; Tenera 2003b, pp. 6–8; EcoAnalysts 2004, entire; EcoVision Partners 2017, p. 23).

Current Range/Distribution The geographic range of the Chorro shoulderband snail is described in Roth and Tupen (2004, p. 17) as extending “from Cayucos southward to Morro Bay, and inland from Morro Bay through the Chorro and Los Osos valleys to San Luis Obispo City.” The projected, plausible range for the taxon, based on similarities in topography, soils, and vegetation with known sites, included areas eastward from the coast into the Morro and Toro valleys, habitats along the south-facing aspects of the Santa Lucia Range north of the Chorro Valley, San Luis Obispo City, and Edna Valley, within the floor of Edna Valley, and in the upper watershed of San Luis Obispo Creek and its tributaries, including State University lands (Roth and Tupen 2004, p. 17). The former description, based on known locations for the Chorro shoulderband snail, is supported by the results of the EcoVision Partners (2017, entire) survey efforts. The Chorro shoulderband snail was found within 2.4 kilometers (1.5 miles) east of the coast in the Morro Valley and likely occurs farther inland in both the Morro Valley and Toro Valley, but higher value habitat features in these areas were on privately-owned property and could not be accessed for surveys (EcoVision Partners 2017, p. 32). The Chorro shoulderband snail was not found in areas southeast of the City of San Luis Obispo, including the floor of the Edna Valley and locations near the southern extent of the projected range from Roth and Tupen (2004, p. 4) (EcoVision Partners 2017, p, 32). EcoVision Partners (2017, Figure 5) revised the range for H. morroensis to exclude the areas southeast of the City of San Luis Obispo (EcoVision Partners 2017, p. 33). Chorro shoulderband snails are more generalized in their habitat associations than Morro shoulderband snails, providing them with greater available habitat throughout their range. Chorro shoulderband snails are found on a diversity of general soil types, including alluvial clay 7 soils, serpentine rock outcrops, talus slopes, and weathered serpentine derived clays (Roth and Tupen (2004, p. 17; Walgren 2003a, p. 64; EcoVision Partners 2017, p. 32). Associated plant communities where Chorro shoulderband snails occur include oak woodland, chaparral, coastal sage scrub, and grassland. California sagebrush, coyote brush, and black sage are often present (EcoVision 2017, p. 29). During the 2017 survey, EcoVision Partners identified live individuals, shells, or shell fragments on 17 different soil series, which were predominantly clay or clay loams soils (14 soil types from 6 series) (EcoVision Partners 2017, p. 27). Due to the high diversity of soil series present and larger overall species distribution (see Figure 2), we used level 12 USGS watersheds (https://water.usgs.gov/GIS/huc.html) to delineate 10 Population Areas for analysis purposes (Figure 2): • Cayucos Creek (299 ha (740 ac)): This region represents the north and westernmost location where Chorro shoulderband snails occur. With the exception of Cayucos State Beach, owned and managed by the California Department of Parks and Recreation, we do not consider any lands in this region protected. Most of the region is in private ownership either as part of the developed community of Cayucos or as ranchlands used for active agriculture or grazing. Information on distribution for Chorro shoulderband snails is very limited and based largely on anecdotal observations made by State Parks biologists (Walgren and Andreano 2018, pers. comm.; Roth and Tupen 2004, p. 4). Surveys in 2017 identified shells that may be within this population area (or very close) (EcoVision Partners 2017, p. 23). • Old Creek (635 ha (1,570 ac)): This area includes Whale Rock Reservoir and its immediate surrounding watershed. The reservoir and its watershed are open space under the ownership and management of the City of San Luis Obispo. This area is fenced and allows only passive uses (e.g., hiking, fishing, bird watching). As such it is protected at least in the near-term. Chorro shoulderband snails have been documented in this area; however, information on distribution is very limited and based largely on past anecdotal observations and the results of the 2016–2017 survey effort (Roth and Tupen 2004, p. 4; EcoVision Partners 2017, p. 23). Abundance data are limited to the two occurrences from the 2017 survey effort; relative abundance was very low (1–2 individuals) for each. • Willow Creek (1,639 ha (4,050 ac)): Very little, if any, of this area is under formal protection. Residential development and urban uses in the community of Cayucos and northern City of Morro Bay occur in the westernmost portions of this area. Remaining acreage is in private ownership. Chorro shoulderband snails have been documented in this area; however, information on distribution is very limited and based largely on past anecdotal observations and the results of the 2016–2017 survey effort (EcoVision Partners 2017, p. 23). Abundance data are limited to the three occurrences from the 2017 survey effort where the relative abundance was medium (7–15 individuals) at two locations and high (16–25) at a single location.

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Figure 2. Chorro shoulderband snail Distribution and Ten Population Areas (outlined and labeled in white)

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• Toro Creek (1,529 ha (3,780 ac)): None of the lands in this area are considered protected as most of the area is in private ownership as large-parcel ranchlands zoned for agriculture (e.g., grazing). An adult shell was identified in this population area by Dwayne Oberhoff in 2015 (Dugan 2018, pers. comm.) and Tupen (2018, pers. comm.) recalls individuals in the area as well. As such, we believe the population area is occupied by Chorro shoulderband snails; however, have no information on their distribution or abundance. • Morro Creek (2,563 ha (6,335 ac)): This area is located to the north and south of State Highway 41 that runs between the Cities of Morro Bay and Atascadero. Similar to the Toro Creek population area, we are not aware that any of these lands are under formal protection. Most are in private ownership as large-parcel ranchlands zoned for agriculture (e.g., grazing, avocado orchards). Chorro shoulderband snails have been documented in this area; however, information on distribution is very limited and based largely on past anecdotal observations and the results of the 2016–2017 survey effort (EcoVision Partners 2017, p. 23). Abundance data are limited to one occurrence with a low (3–6 individuals) relative abundance. • Chorro Creek (8,837 ha (21,835 ac)): This is the largest of the population area polygons within the estimated distribution of Chorro shoulderband snails. Developed areas within this area include the California Men’s Colony, Dairy Creek Golf Course, Cuesta College, and Camp San Luis Obispo (California Army National Guard). With the exception of Chorro Creek Ecological Reserve (CCER) and portions of Chorro Creek Regional Park and the San Luis Obispo Wildlife Area, we believe that much of this area is unprotected. The majority of this area is large-parcel ranchlands zoned for agriculture (e.g., grazing, avocado orchards) in private ownership or part of Camp San Luis Obispo. Chorro shoulderband snails have been documented in this area as part of surveys conducted at Camp San Luis Obispo prior to 2004 (e.g., Walgren in litt. 2002; Morro Group 2004, Figure 4). Information on distribution within this population area is largely limited to anecdotal observations; however, the species likely occurs on CCER as it has been detected in grasslands within the right-of- way for Highway 1 near CCER (Stafford 2018, pers. comm.) and as part of the 2016–2017 survey effort (EcoVision Partners 2017, p. 23). Abundance data are limited to the seven occurrences identified in the 2017 survey effort: two occurrences with a relative abundance of very low (1–2 individuals), one occurrence at low (3–6 individuals), one at medium (7–15 individuals), and three at high (16–25 individuals). • Morro Bay (364 ha (900 ac)): This area is protected as part of Morro Bay State Park owned and managed by CDPR. Information on distribution for Chorro shoulderband snails is very limited and based largely on anecdotal observations made by State Parks biologists and includes one of the few observations of sympatry between Morro shoulderband snails and Chorro shoulderband snail individuals (Walgren and Andreano 2018, pers. comm.). Chorro shoulderband snails were not found in this area during the 2017 survey effort (EcoVision Partners 2017, p. 23); therefore, abundance data are lacking.

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• Los Osos Creek (2,693 ha (6,655 ac)): The majority of this area is in private ownership as large-parcels zoned for agriculture (e.g., grazing, row crops) and, therefore, not considered protected. Chorro shoulderband snails have been documented in this area, but information on distribution is very limited and based largely on past anecdotal observations and results of the 2016–2017 survey effort (EcoVision Partners 2017, p. 23). Abundance data are limited. The County observed Chorro shoulderband snail shells in association with drainage areas on the Giacommazi and Andre parcels in Los Osos Valley near the site of the current wastewater facility (Ballantyne 2018, pers. comm.); 3.2 ha (8 ac) of the former site is deed-restricted to protect habitat values. Two occurrences were also identified in the 2017 EcoVision Partners survey effort: one with a relative abundance of very low (1–2 individuals) and the other of low (3–6 individuals). • Upper San Luis Obispo Creek (3,632 ha (8,795 ac)): Some of this area is protected from development activities as City of San Luis Obispo open space. Much of the central portion of the City of San Luis Obispo is within in this area as is the campus and outlying lands of California Polytechnic State University, San Luis Obispo. Chorro shoulderband snails are known from this area from surveys conducted at Bishop Peak (Tenera 2003a, p. 14, A4), California Polytechnic State University SLO (Walgren in litt. 2002), and development projects prior to 2004 (Tenera 2003b, p. 6–8). Information on distribution is limited and based largely on past anecdotal observations and results of the 2016– 2017 survey effort (EcoVision Partners 2017, p. 23). Abundance data are limited to the four occurrences found during the 2017 survey effort: three occurrences with a relative abundance at very low (1–2 individuals) and the fourth estimated at low (3–6 individuals). • Lower San Luis Obispo Creek (6,400 ha (15,815 ac)): This area is the second largest within the distribution of Chorro shoulderband snails and contains lands protected as open space (e.g., Laguna Lake, Ferrini Ranch, Irish Hills Natural Reserve). Chorro shoulderband snails are known to occur in this area from surveys conducted on Bishop Peak (City of San Luis Obispo 2004, pp. 4, 16; Figures 6, 22), the Unocal (now Chevron) Tank Farm (EcoAnalysts 2004, p. entire), and the 2016–2017 survey effort (EcoVision Partners 2017, p. 23); however, information on distribution is otherwise limited. Abundance data are limited to the six occurrences found during the 2017 survey effort, three of which had a relative abundance of very low (1–2 individuals), two of which were low (3–6 individuals), and one was very high (>25 individuals).

Population Estimates/Status The level of survey effort throughout the distribution of the Chorro shoulderband snail is extremely limited. As noted, formal surveys were not conducted between 2004 and 2016. Information on species presence until 2017 is largely from presence-absence surveys conducted prior to July 2004 and incidental observations thereafter. In 2017, EcoVision Partners conducted surveys at 60 sites within west-central San Luis Obispo

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County. Live Chorro shoulderband snail and/or shells/shell fragments were present at 26 of the survey locations, including 14 of the historic sites and 12 new locations (EcoVision Partners 2017, p. 20, Figure 4). Use of a consistent, time-constrained search effort between all sites provided a general indication of the relative abundance of Chorro shoulderband snails at the surveyed sites. Demonstration of abundance used a range of very low (1–2 observations) to very high (>25 observations) (EcoVision Partners 2017, p. 26). Relative abundance was highest at sites within public open space areas and military reservations and lower at highly disturbed sites, such as roadside rights-of-way. Of the occupied sites, 1 was at very high abundance, 5 were at high abundance, 5 were at medium abundance, 5 at low abundance, and 10 at very low abundance.

THREATS We define “threat” as any action or condition that is known to or is reasonably likely to negatively affect individuals of a species. This includes those actions or conditions that have a direct impact on individuals, as well as those that affect individuals through alteration of their habitat or required resources. The mere identification of “threats” is not sufficient to compel a finding that listing is warranted. Describing the negative effects of the action or condition (i.e., “threats”) in light of the exposure, timing, and scale at the individual, population, and species levels provides a clear basis upon which to make our determination. In determining whether a species meets the definition of an “endangered species” or a “threatened species,” we have considered the factors under section 4(a)(1) and assessed the cumulative effect that the threats identified within the factors—as ameliorated or exacerbated by any existing regulatory mechanisms or conservation efforts—will have on the species now and in the foreseeable future. At the time of listing, we identified urban development and other anthropogenic activities such as recreation, grazing, and utility construction as threats to the banded dune snail (59 FR 64613); however, no threats specifically impacting the portion of the species now considered to be the Chorro shoulderband snail were identified, given that the species was thought to be extinct (Service 2006). In the SSA Report (Service 2019, pp. 21–66) and this assessment, we review six potential threats that could be affecting the Chorro shoulderband snail now and in the future. In this assessment, we discuss in detail only those factors that could affect the species at a population or species-level. Currently, the primary threat to the Chorro shoulderband snail is the implementation of land use practices that eliminate, reduce, fragment, and/or modify habitat used by the species, including development (Factor A) and agriculture (Factor A). We expect that climate change (Factor E) will likely exacerbate the severity of threats. Additional threats to the species include vegetation management (Factor A), and predation (Factor C); however, our analysis shows that these threats have little to no impact on species viability (Service 2019, pp. 21–64). We also analyzed the threat of collection (Factor B). In 1994, we stated that the taxonomic distinctiveness of the banded dune snail made it vulnerable to recreational or scientific collectors. Since then, however, we are not aware of specific collection activities for recreational or scientific purposes of the Chorro shoulderband 12 snail. Finally, we also considered the effect of existing regulatory mechanisms (Factor D) on the magnitude of existing threats; there are few or no regulatory mechanisms addressing the threats impacting the species. We discuss identified likely threats to the species below. • Development. Human development consists of converting the landscape into residential, commercial, industrial, and recreational features, with associated infrastructure such as roads. Converting the landscape into development not only removes individuals of the Chorro shoulderband snail, but also removes their habitat, thereby reducing the space available for the species to inhabit. In addition, development results in indirect effects by fragmenting the habitat and creating edge effects, such as increased vulnerability to desiccation, fire, and predation. Overall, development can degrade and remove habitat that supports the Chorro shoulderband snail; however, changes are occurring at a small scale and much available habitat remains. There are no regulatory mechanisms addressing impacts from development on the Chorro shoulderband snail. • Agriculture. Agriculture, especially change from grazing lands to more intensive uses (e.g., avocado orchards, row crops, or vineyards) has the potential to impact habitat that supports the Chorro shoulderband snail. Land used for agriculture and grazing occurs in 5 of the 10 Chorro shoulderband snail Population Areas (Cayucos Creek, Toro Creek, Morro Creek, Chorro Creek, and Los Osos Creek) (Service 2019, pp. 33–36). Observed agricultural uses in the species range include row crops, vineyards, hay fields, and orchards (EcoVision Partners 2017, p. 28). Local jurisdictions do not typically regulate agricultural uses in those areas zoned for agriculture. The large-scale mechanical disturbance of soils and vegetation associated with the planting, maintenance, and harvest of crops eliminates habitat and likely results in injury and mortality to individual snails within these areas. Individuals remaining in these areas occupy fragmented, often low value, habitat along drainage swales, fence lines, roadside rights-of-way, and un-tillable features. Lands under cultivation occur on relatively level soils throughout the range of the Chorro shoulderband snail but agricultural activity appears most intensive along the floor of Los Osos Valley and the Edna region south of the City of San Luis Obispo. Overall, agriculture is continuing to degrade and remove habitat that supports the Chorro shoulderband snail on a small scale; however, much available habitat remains. There are no regulatory mechanisms addressing impacts from agriculture on the Chorro shoulderband snail. • Climate Change. California is becoming hotter and drier. The 3-year period from 2012 to 2014 was the hottest and driest in California in the 100-year timeframe considered (Mann and Gleick 2015, p. 3858), and it was the most severe drought in California in the past 1,200 years (Griffin and Anchukaitis 2014, p. 9017). This trend of hotter, drier years appears likely to continue (Thorne et al. 2017, entire). Considering data up to 2015, Brown et al. (2016, entire) reported that most of the warming occurred in the past 35 years, with 15 of the 16 warmest years occurring since 2001. The summer of 2016 was determined to be the warmest in California since record keeping began in the late 13

1800s, only to be surpassed in this regard by the summer of 2017 (NOAA National Centers for Environmental Information 2018). Furthermore, the frequency of years with rainfall 20 percent or more below normal has greatly increased in the past century (NOAA 2018). Climate change is likely to affect many terrestrial gastropod populations in California, including the Chorro shoulderband snail. Species with small geographic ranges, such as the Chorro shoulderband snail, are particularly vulnerable to extinction by climate change (Allan et al. 2005, p. 284). The increased frequency of protracted drought events is likely to result in higher mortality during prolonged periods of seasonal aestivation, particularly among smaller individuals in the population (van der Laan 1975, p. 364). Higher levels of egg mortality from desiccation are expected. Warmer temperatures and greatly reduced wet season precipitation during prolonged multi-year drought events also increase stress on vegetation (Coates et al. 2015, p. 14277) and may limit time for feeding and breeding in terrestrial snails in California. Coastal sage scrub communities had the highest seasonal variability in terms of the relative amount of ground covered by green vegetation during the drought years of 2013–2014 (Coates et al. 2015, p. 14283). Coastal sage scrub plant species also had the highest land surface temperature values of the communities analyzed, likely resulting from lower vegetation cover, lower evapotranspiration, and south-facing slopes typical of coastal sage scrub communities (Coates et al. 2015, p. 14284). These effects of prolonged drought could reduce the value and quality of sheltering habitat as well as food availability within the primary plant community association for the Chorro shoulderband snail. Climate change may affect individual snails, but the largest impacts are expected to be on habitat. Still, the species has persisted through several extended drought periods since it was rediscovered in the 1990s, indicating that it may be able to find refugia even in hotter, drier, years suggesting that despite its narrow range, the species is sufficiently resilient to potential changes in climate. There are no regulatory mechanisms addressing impacts from climate change on the Chorro shoulderband snail.

CONSERVATION MEASURES PLANNED OR IMPLEMENTED We are not aware of any conservation actions being implemented specifically for the Chorro shoulderband snail; however, areas conserved as open space by the City and/or County of San Luis Obispo, as well as those acquired and/or managed by the Land Conservancy of San Luis Obispo, benefit the species through habitat preservation.

SUMMARY OF THREATS We examined the effects of threats affecting the Chorro shoulderband snail and its habitat; we now summarize these threats and their cumulative effects on the species. While past and ongoing effects of development, agriculture, and climate change may have some negative

14 effects on the Chorro shoulderband snail, our analyses indicate that despite these ongoing threats, the species has maintained a similar distribution since they were rediscovered in 1997. As mentioned above, though the species was considered extinct in 1994, that was likely due to lack of surveys in appropriate areas. Its viability is projected to stay the same or decrease slightly, depending on future land use change, particularly an increase in agricultural development, in San Luis Obispo County. Still, even considering a reduced potential condition in some areas, Population Areas of Chorro shoulderband snails are substantial in size, and contain substantial amounts of suitable habitat. Though few or no regulatory mechanisms exist that afford protection to the Chorro shoulderband snails, the species has persisted despite the lack of protections, and we do not expect that to change in the foreseeable future. Additionally, we consider whether any threats might be acting in concert, resulting in increased impacts to the species. Along with a decrease in habitat quality due to increased temperatures and increased frequency of droughts, the effects of climate change may also exacerbate low population size and fragmented habitats, resulting in some increased risk of extirpation. However, we do not think these effects will be sufficient to extirpate any Population Areas, as substantial suitable habitat area remains, and the species has much available refugia to persist through increased hot and dry weather. Aside from these potential effects, we are not aware of any other cumulative impacts of threats that are currently impacting the species.

CURRENT CONDITION Resiliency Factors influencing the ability of the Chorro shoulderband snail to withstand stochastic events include abundance, habitat quality defined as presence of suitable habitat in a relatively intact landscape, and protected habitat as the likelihood that this habitat will persist into the future. For details on how we calculated condition categories, see the SSA Report (Service 2019, pp. 41–42; Table 3).

Table 1. Current resiliency of Chorro shoulderband snail (CSS) Population Areas CSS Population Relative Habitat Protected Overall Area Abundance quality habitat

Cayucos Creek Unknown Moderate Low Moderate

Old Creek Low Moderate High Moderate

Willow Creek High Moderate Low Moderate Toro Creek Unknown High Low Moderate Morro Creek Low High Low Moderate

Chorro Creek High High Low Moderate

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Morro Bay Unknown Moderate High High Los Osos Creek Low High Low Moderate Upper San Luis Moderate Moderate Low Moderate Obispo Creek Lower San Luis High Moderate Low Moderate Obispo Creek

Representation Maintaining representation of healthy populations across the diversity of Chorro shoulderband snail habitats or ecological gradients is expected to conserve the relevant diversity associated with species persistence across these habitat types and maintain its limited distribution to reduce risk associated with catastrophic events. While abundance information is not available for the Cayucos Creek and Morro Bay Population Areas, individuals are present at some level in these areas such that the species is considered represented in all Population Areas and habitat types within its historic distribution (Table 1).

Redundancy The Population Areas for the Chorro shoulderband snail are substantial in size, contain suitable habitat, and occupied such that we do not anticipate the effects of catastrophic events, such as prolonged and/or more intensive drought, increased wildfire frequency and/or intensity, and/or localized flooding, to reduce redundancy for the species as compared to historical levels. Overall, though catastrophic events may likely occur, the Chorro shoulderband snail has enough redundancy to withstand those events.

Current Condition Summary The resiliency analysis of the Chorro shoulderband snail Population Areas reveals a single population area at high resiliency and nine areas at moderate resiliency. While abundance information is not available for the Cayucos Creek, Toro Creek and Morro Bay Population Areas, individuals are present at some level in these areas such that the species is considered represented in all Population Areas within its historic distribution. Because of its narrow range, the species will always be vulnerable to catastrophic events. Still, though the species has a very narrow range, it has maintained a similar distribution since it was rediscovered in 1997. Therefore, we do not anticipate the effects of catastrophic events, such as prolonged and/or more intensive drought, increased wildfire frequency and/or intensity, and/or localized flooding, to reduce redundancy for the species as compared to historical levels.

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FUTURE CONDITION The future scenarios attempt to encompass the range of plausible possibilities for each population area over the next 30 years. While the recovery plan states a persistence time frame of 50 years (Service 1998, p. 40), we selected a timeframe of 30 years for foreseeable future due to Scenario 2 in our SSA Report, which envisions full implementation of a regional conservation strategy expected to take 25 years to complete. First, we forecasted the condition of each population area under the status quo, with continued climate change effects and habitat conservation proceeding in a fashion similar to how it has over the past 30 years in accordance with implementation of City of San Luis Obispo and County of San Luis Obispo general plans (Status Quo). Second, we forecasted the condition of each population area under status quo, but with the additional effects of intensification of agriculture in those areas zoned for agricultural uses (Ag Intensification). We consider both scenarios to be plausible.

Table 2. Summary of Chorro shoulderband snail Resiliency: Current and Future Condition by Population Area

Future Scenario Future Scenario CSS Population Area Current Condition Status Quo Ag Intensification

Cayucos Creek Moderate Moderate Low

Old Creek Moderate Moderate Moderate

Willow Creek Moderate Moderate Moderate

Toro Creek Moderate Moderate Moderate Morro Creek Moderate Moderate Low

Chorro Creek Moderate Moderate Moderate

Morro Bay High High High Los Osos Creek Moderate Moderate Low Upper San Luis Obispo Moderate Moderate Moderate Creek Lower San Luis Obispo Moderate Moderate Moderate Creek

Representation Maintaining representation across the north-south and east-west gradients within the distribution of the Chorro shoulderband snail is likely to conserve the relevant genetic diversity 17 and associated adaptive capacity for the species. Currently, we believe all Population Areas are extant, which demonstrates representation. Currently, nine out of 10 Population Areas exhibit moderate resiliencies, and one exhibits high resiliency. Into the future under the status quo, no loss of species representation is expected. If habitat conversion increases due to agricultural intensification, three of the 10 Population Areas scattered throughout the range could be at risk of extirpation, but representation would likely remain across the rest of the range.

Redundancy Chorro shoulderband snails need multiple resilient Population Areas distributed throughout its limited (but not as limited as Morro shoulderband snails) distribution to provide for redundancy. With the exception of the southern portion of the range, most of the Chorro shoulderband snail's distribution is within a connected, intact landscape. Even considering a potential reduction in resiliency over the current condition, we do not anticipate the effects of potential catastrophic events to result in a loss in redundancy for the species. This is because the Population Areas appear to be sufficiently large, contain a substantial amounts of habitat likely suitable for the species, and are occupied by the species, albeit likely at varying levels.

FINDING Section 4 of the Act (16 U.S.C. 1533) and its implementing regulations (50 CFR part 424) set forth the procedures for determining whether a species meets the definition of an endangered species or a threatened species. The Act defines “endangered species” as a species “in danger of extinction throughout all or a significant portion of its range,” and “threatened species” as a species “likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.” The Act requires that we determine whether a species meets the definition of “endangered species” or “threatened species” because of any of the following factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) Overutilization for commercial, recreational, scientific, or educational purposes; (C) Disease or predation; (D) The inadequacy of existing regulatory mechanisms; or (E) Other natural or manmade factors affecting its continued existence. In the SSA Report and this assessment (Service 2019, pp. 21–66), we reviewed six potential threats that could be affecting the Chorro shoulderband snail now and in the future. Currently, the primary threat to the Chorro shoulderband snail is the implementation of land use practices that eliminate, reduce, fragment, and/or modify habitat used by the species, including development (Factor A) and agriculture (Factor A). We expect that climate change (Factor E) could exacerbate the severity of threats. We discuss likely threats to the species below. We also considered the effect of existing regulatory mechanisms (Factor D) on the magnitude of existing threats; however, there are few or no regulatory mechanisms addressing the threats impacting the species. Additional threats to the species include vegetation management (Factor A), collection (Factor B), and predation (Factor C); however, our analysis shows that these threats have little to no impact on species viability. While past and ongoing effects of habitat modification by development and agriculture, and 18 potential impacts to individuals and habitat from climate change may have some negative effects on the Chorro shoulderband snail, our analyses indicate that despite these ongoing threats, the species has maintained a similar distribution since it was rediscovered. As mentioned above, though the species was considered extinct, that was likely due to lack of surveys in appropriate areas. Its viability is projected to stay the same or decrease slightly, depending on future land use change, particularly an increase in agricultural development, in San Luis Obispo County. Still, even considering a potential reduced condition in some areas, Population Areas of Chorro shoulderband snails are substantial in size, and contain substantial amounts of suitable habitat. Though few or no regulatory mechanisms exist that afford protection to the Chorro shoulderband snails, the species has persisted despite the lack of protections, and we do not expect that to change in the foreseeable future. Additionally, we considered whether any threats might be acting in concert, resulting in increased impacts to the species. Along with a decrease in habitat quality due to increased temperatures and increased frequency of droughts, the effects of climate change may also exacerbate low population size and fragmented habitats, resulting in some increased risk of extirpation. However, we do not think these effects will be sufficient to extirpate any Population Areas, as substantial suitable habitat area remains, and the species has much available refugia to persist through increased hot and dry weather. Status Throughout All of Its Range After evaluating threats to the species and assessing the cumulative effect of the threats under the section 4(a)(1) factors, we do not think that identified stressors have caused or are causing population-level declines such that we would consider them threats to the Chorro shoulderband snail now or in the future. Thus, after assessing the best available information, we determine that the Chorro shoulderband snail is not in danger of extinction now or likely to become so in the foreseeable future throughout all of its range.

Significant Portion of the Range Analysis Under the Act and our implementing regulations, a species may warrant listing if it is in danger of extinction or likely to become so in the foreseeable future throughout all or a significant portion of its range. Having determined that the Chorro shoulderband snail is not in danger of extinction or likely to become so in the foreseeable future throughout all of its range, we now consider whether it may be in danger of extinction or likely to become so in the foreseeable future in a significant portion of its range—that is, whether there is any portion of the species’ range for which it is true that both (1) the portion is significant; and, (2) the species is in danger of extinction now or likely to become so in the foreseeable future in that portion. Depending on the case, it might be more efficient for us to address the “significance” question or the “status” question first. We can choose to address either question first. Regardless of which question we address first, if we reach a negative answer with respect to the first question that we address, we do not need to evaluate the other question for that portion of the species’ range. In undertaking this analysis for the Chorro shoulderband snail, we choose to address the status question first—we consider information pertaining to the geographic distribution of both the 19 species and the threats that the species faces to identify any portions of the range where the species is endangered or threatened. For the Chorro shoulderband snail, we considered whether the threats are geographically concentrated in any portion of the species’ range at a biologically meaningful scale. We examined the following threats: land use practices that eliminate, reduce, fragment, and/or modify habitat used by the species, including development (Factor A) and agriculture (Factor A); vegetation management (Factor A); collection (Factor B); predation (Factor C); and climate change (Factor E), including cumulative effects. Threats do occur at different magnitudes across the range of the Chorro shoulderband snail. For example, there is a higher level of threat from agriculture on the floor of Los Osos Valley and the Edna region south of the City of San Luis Obispo. However, the magnitude of agriculture in those areas is not such that the species is likely to become endangered in the foreseeable future, as much available habitat remains in those areas and across the species’ range. Other threats, such as climate change, are at a uniform magnitude across the species’ range. We found no concentration of threats in any portion of the Chorro shoulderband snail’s range at a biologically meaningful scale. Therefore, no portion of the species’ range can provide a basis for determining that the species is in danger of extinction now or likely to become so in the foreseeable future in a significant portion of its range, and we find the species is not in danger of extinction now or likely to become so in the foreseeable future in any significant portion of its range. This is consistent with the courts’ holdings in Desert Survivors v. Department of the Interior, No. 16-cv-01165-JCS, 2018 WL 4053447 (N.D. Cal. Aug. 24, 2018), and Center for Biological Diversity v. Jewell, 248 F. Supp. 3d , 946, 959 (D. Ariz. 2017). Determination of Status Our review of the best available scientific and commercial information indicates that the Chorro shoulderband snail does not meet the definition of an endangered species or a threatened species in accordance with sections 3(6) and 3(20) of the Act. Therefore, we find that listing the Chorro shoulderband snail as an endangered or threatened species under the Act is not warranted at this time.

COORDINATION WITH STATES California Department of Fish and Wildlife provided information and comments on the species status assessment (Service 2019, entire).

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LITERATURE CITED Ancey, C.F., 1887. Description of new genera or sub-genera of Helicidae. Conchologists' Exchange 2: 22–23.

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Allan J.D., M. Palmer, and N.L. Poff. 2005. Chapter 17. Climate change and freshwater ecosystems. P. 274–290. In: Climate change and biodiversity. T.E. Lovejoy, and L.J. Hannah, eds. Yale University Press, New Haven, Connecticut. 418 pages. Ballantyne, K. 2018. In Litt. Environmental Programs Manager, Department of Public Works, County of San Luis Obispo. Peer review comments on draft Morro shoulderband snail and Chorro shoulderband snail SSA report. May 18. Belt, T. 2018. In Litt. Senior Biologist, SWCA Consultants. Peer review comments on draft Morro shoulderband snail and Chorro shoulderband snail SSA report. May 18. Brown D., M. Cabbage, and L. McCarthy. 2016. NASA, NOAA analyses reveal record-shattering global warm temperatures in 2015. Press release (available on the internet at http://www.nasa.gov/press-release/nasa-noaa-analyses-reveal-record-shattering- global-warm-temperatures-in-2015). Accessed 23 January 2016. 4 pages. City of San Luis Obispo. 2004. Bishop Peak Natural Reserve. Natural Resources Protection Program. July. Coates, E. R., P. E. Dennison, D. A. Roberts, and K. L. Roth. 2015. Monitoring the Impacts of Severe Drought on Southern California Chaparral Species using Hyperspectral and Thermal Infrared Imagery. Remote Sensing, 7, 14276–14291. Dugan, D. 2018. In Litt. Principal Biologist, EcoVision Partners. Peer review comments on draft Morro shoulderband snail and Chorro shoulderband snail SSA report. May 21. EcoAnalysts. 2004. Surveys for the Federally Endangered Morro Shoulderband Snail (Helminthoglypta walkeriana) at Unocal’s Tank farm site in San Luis Obispo, San Luis Obispo County, California. 4 pp. EcoVision Partners. 2017. Chorro shoulderband snail (Helminthoglypta morroensis): An assessment of range & habitat associations. Report prepared for the U.S. Fish and Wildlife Service. September. Griffin D, and K.J. Anchukaitis. 2014. How unusual is the 2012–2014 California drought? Geophysical Research Letters 41:9017–9023. .Hemphill, H. 1911. Descriptions of some varieties of shells with short notes on the geographical range and means of distribution of land shells. Transactions of the San Diego Society of Natural History (1): 99–108. Mann M.E., and P.H. Gleick. 2015. Climate change and California drought in the 21st century. Proceedings of the National Academy of Sciences 112:3858–3859. Morro Group. 2004. 2004 Annual Report for Endangered Species Permit (TE-824123-3). NOAA National Centers for Environmental Information. 2018. Climate at a glance: U.S. time series, average temperature. Available (Feb. 2018): https/www.ncdc.noaa.gov/cag/time-series/us.

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Roth, B. 1973. The systematic position of Helminthoglypta traskii fieldi Pilsbry, 1930 (Gastropoda: Stylommatophora). Bulletin of the Sothern California Academy of Sciences 72(3): 148–155. Roth, B. 1985. Status survey of the banded dune snail Helminthoglypta walkeriana. Prepared for the U.S. Fish and Wildlife Service, Sacramento Endangered Species Office, Sacramento, California. Roth, B. and J. Tupen, 2004. Revision of the Systematic Status of Helminthoglypta walkeriana morroensis (Hemphill, 1911) (Gastropoda; Pulmonata). Zootaxa 616:1–23. Sloan, R. 2018. In Litt. Biologist. Peer review comments on draft Morro shoulderband snail and Chorro shoulderband snail SSA report. May 18. Stafford, B. 2018. In Litt. Senior Environmental Scientist, California Department of Fish and Wildlife. Peer review comments on draft Morro shoulderband snail and Chorro shoulderband snail SSA report. May 17. SWCA Environmental Consultants. 2013. 2012 annual construction monitoring report for the Los Osos wastewater project, San Luis Obispo, California. Prepared for the County of San Luis Obispo, Department of Public Works. January. SWCA Environmental Consultants. 2014. 2013 annual construction monitoring report for the Los Osos wastewater project, San Luis Obispo, California. Prepared for the County of San Luis Obispo, Department of Public Works. January. SWCA Environmental Consultants. 2015. 2014 annual construction monitoring report for the Los Osos wastewater project, San Luis Obispo, California. Prepared for the County of San Luis Obispo, Department of Public Works. January. SWCA Environmental Consultants. 2016. 2015 annual construction monitoring report for the Los Osos wastewater project, San Luis Obispo, California. Prepared for the County of San Luis Obispo, Department of Public Works. January. SWCA Environmental Consultants. 2017. 2016 annual construction monitoring report for the Los Osos wastewater project, San Luis Obispo, California. Prepared for the County of San Luis Obispo, Department of Public Works. January. SWCA Environmental Consultants. 2018. 2017 annual construction monitoring report for the Los Osos wastewater project, San Luis Obispo, California. Prepared for the County of San Luis Obispo, Department of Public Works. January. Tenera Environmental. 2003a. Wildlife Resources of the Bishop Peak Natural Reserve. Prepared for the City of San Luis Obispo. July. Tenera Environmental. 2003b. Bowden Ranch Estates: Morro Shoulderband Snail (Helminthoglypta walkeriana) Survey Report. Prepared for Oasis Partners and Bowden Ranch Estates JV.

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Thorne, J.H. et al. 2017. The impact of climate change uncertainty on California’s vegetation and adaptation management. Ecosphere 8(12): 1–14. Tupen J. and B. Roth, 2005. New study confirms restricted status of endangered California land snail. Tentacle. 13: 9–10. Tupen, J. 2018. Senior Biologist, ECORP Consulting. Peer review comments on draft Morro shoulderband snail and Chorro shoulderband snail SSA report. May 17. van der Laan, K. L. 1975. Aestivation in the land snail Helminthoglypta arrosa (Binney) (Pulmonata: Helicidae). The Veliger, volume 17, number 4, pages 360–368. van der Laan, K. L. 1980. Terrestrial pulmonate reproduction: seasonal and annual variation and environmental factors in Helminthoglypta arrosa (Binney) (Pulmonata: Helicidae). The Veliger, volume 23, number 1, pages 48–54, July 1. [USDA] U.S. Department of Agriculture. 1999. Management Recommendations for Survey and Manage Terrestrial Mollusks. Version 2.0. Region 6, Portland, OR. 305 pp. [Service] U.S. Fish and Wildlife Service. 1998. Recovery plan for the Morro shoulderband snail and four plants from western San Luis Obispo County, California. Portland, Oregon. [Service] U.S. Fish and Wildlife Service. 2004. Letter to Stakeholders and Interested Parties regarding the regulatory status of the Morro shoulderband snail. U. S. Department of the Interior, Fish and Wildlife Service, Ventura Field Office, Ventura, California. June 7. [Service] U.S. Fish and Wildlife Service. 2006. Banded Dune Snail (Helminthoglypta walkeriana) [=Morro shoulderband snail (Helminthoglypta walkeriana) and Chorro shoulderband snail (Helminthoglypta morroensis)] Five Year Review; September 11. [Service] U.S. Fish and Wildlife Service. 2019. Species status assessment report for the Morro Shoulderband Snail (Helminthoglypta walkeriana) and the Chorro Shoulderband Snail (Helminthoglypta morroensis), Version 1.1. February 2019. Ventura, California. Walgren, M. 2002. Environmental Scientist, California Department of Parks and Recreation. Correspondence with Steve Kirkland, Fish and Wildlife Biologist, regarding submittals to the California Natural Diversity Data Base. April 14. Walgren, M. 2003a. The current status of the Morro Shoulderband snail (Helminthoglypta walkeriana), California Polytechnic State University, San Luis Obispo, California. Unpublished MS Thesis. Walgren, M. 2003b. Distribution and morphotypes of the federally endangered land snail Helminthoglypta (Charodotes) walkeriana (Hemphill, 1911). Bulletin of the Southern California Academy of Sciences, 102(2), pp. 96–99. Walgren, M.J. and L.E. Andreano. 2018. Staff Environmental Scientists, California Department of Parks and Recreation (State Parks). Personal communication with Service biologist Julie Vanderwier regarding new acquisition in Los Osos. January 2.

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Federal Register Documents 59 FR 64613; December 15, 1994. Endangered and Threatened Wildlife and Plants; Endangered or Threatened Status for Five Plants and the Morro Shoulderband Snail From Western San Luis Obispo County, California. Final rule. 66 FR 9233; February 7, 2001. Endangered and Threatened Wildlife and Plants; Final Determination of Critical Habitat for the Morro Shoulderband Snail (Helminthoglypta walkeriana). Final Rule.

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APPROVAL/CONCURRENCE: Lead Regions must obtain written concurrence from all other Regions within the range of the species before recommending changes, including elevations or removals from candidate status and listing priority changes; the Regional Director must approve all such recommendations. The Director must concur on all resubmitted 12-month petition findings, additions, or removal of species from candidate status, and listing priority changes.

Approve:

Regional Director, Fish and Wildlife Service Date

Concur: Director, Fish and Wildlife Service Date

Do not concur: Director, Fish and Wildlife Service Date

Director's Remarks:

Date of annual review: Conducted by:

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