California Brackish Water Snail
Tryonia imitator
Introduction
Status
Ecological Requirements
Monterey County Regions: Coastal Strand
Monterey County Natural Communities: Saline Emergent Wetland (CDFW 2020)
Inhabits coastal lagoons, estuaries, sloughs, and Salicornia-dominated marshes with areas of permanent water harboring stands of immergent native vegetation and algae (CDFW 2020, Kellogg 1985)
Rare species found only in permanently submerged areas in a variety of sediment types; able to withstand a wide range of salinities (4-44 parts per trillion) (CDFW 2020, Kellogg 1985)
Sensitive and desiccation in habitats subjected to seasonal or occasional drying (Kellogg 1985)
Full species account available: California Natural Diversity Database, RareFind 5 (CDFW 2020)
RCIS Conservation Priority: Moderate (non-listed, limited distribution in the RCIS area, representative of brackish marshes)
Range and Modeled Habitat
Climate Change Vulnerability Assessment
In the RCIS area, occurrences of the California brackish water snail (CBWS) are primarily in Elkhorn Slough, and modeled suitable habitat also occurs at the mouth of the Carmel River. Fifty-year predictions of Elkhorn Slough estuarine habitat trends include a significant decrease in the extent of salt marsh and conversion to mudflats and tidal creeks (Elkhorn Slough Tidal Wetland Project Team 2007). The erosion rate is expected to increase, causing significant marsh losses (Elkhorn Slough Tidal Wetland Project Team 2007). By mid-century, large portions of Elkhorn Slough’s low-lying salt marshes are projected to be flooded. By the end-of-century, flooded areas are projected to expand and cover a larger region (NOAA 2015). See the PDF for this species for a summary of the climate change exposure, spatial distribution, and vulnerability of saline emergent wetland communities statewide, which could experience a 75 to 100 percent reduction in habitat suitability.
Conservation Strategies
California Brackish Water Snail Goals, Objectives, and Actions
There are 33 proposed actions. For complete goals, objectives and actions explanations see the complete table of conservation strategies in the RCIS PDF.
Species Goals, Objectives, and Actions
Goal CBWS 1
Promote persistence of California brackish water snail populations in the RCIS area through protection, restoration, and enhancement of habitat.Objective CBWS 1.2
Enhance or restore occupied, suitable, and potentially suitable California brackish water snail habitat in the RCIS area. Measure progress towards achieving this objective in acres of habitat and adjacent/equivalent acres enhanced or restored and occupied by California brackish water snail.Action CBWS 1.2.1
Survey known occupied and potentially suitable habitats to enhance knowledge about population size and population trends. Include correlating water quality data (e.g., nutrients, herbicides, pesticides) with species presence/absence.
Action CBWS 1.2.2
Remove non-native plant species and non-native New Zealand mudsnail (Potamopyrgus antipodarum) in suitable brackish habitats throughout the RCIS area.
Action CBWS 1.2.3
Enhance or restore native submerged vegetation in suitable or potentially suitable habitat.
Action CBWS 1.2.4
Restore tidal regimes in suitable or potentially suitable habitat.
Regional Goals, Objectives, and Actions
Goal RC 1
Sustain resilient, connected natural communities for the full range of native species, habitats, and ecological functions in the RCIS area through the protection of large blocks of continuous habitat supporting sensitive species.Objective RC 1.1
Protect and preserve existing intact non-marine habitats and resources and allow for expansion of habitat by protecting suitable or occupied habitat. Measure progress towards achieving this objective by the number of acres of habitat and adjacent/associated acres protected.Action RC 1.1.1
Acquire parcels with suitable habitat through fee title purchase or conservation easement.
Action RC 1.1.2
Conduct surveys using eDNA and/or traditional survey methods in suitable or potentially suitable habitat to locate undocumented occurrences of focal species and other conservation elements and opportunities for habitat protection, enhancement, restoration, and creation (USFWS 2008).
Action RC 1.1.3
Create and sustain long-term funding for protected areas maintenance.
Action RC 1.1.4
Establish an incentive program for private landowners to protect occurrences and manage habitat.
Action RC 1.1.5
Protect populations from impacts from construction, vegetation management, and/or activities, including by surveying areas such as roads/trails and implementing species protection measures.
Objective RC 1.2
Enhance occupied and suitable habitat. Measure progress towards achieving this objective by number of acres of habitat enhanced and/or occupied.Action RC 1.2.1
Manage current and future recreation access including off-road vehicles, biking, equestrian, foot traffic, and unleashed pets to reduce impacts and disturbance to sensitive species and habitats. Ensure recreation is compatible with suitable and future potentially suitable habitat and adjacent areas, and areas of known occurrences. Enforcement and fencing may be used to prevent illegal off-road vehicle use (USFWS 2010).
Action RC 1.2.10
Work with private landowners and stakeholders to research species biology, threats, populations, densities, and/or ranges.
Action RC 1.2.11
Create/enhance connections between ecologically required habitat types, such as between aquatic breeding and upland dispersal habitats.
Action RC 1.2.2
Control non-native invasive species from occupied and/or suitable habitat, and areas designated by the U.S. Fish and Wildlife Service as critical habitat throughout the RCIS area.
Action RC 1.2.3
Reduce/eliminate pesticide, rodenticide (especially first- and second-generation anticoagulant rodenticides), and herbicide use, including for roadside vegetation removal projects as part of integrated pest management efforts in identified suitable habitat, and sensitive natural communities. Promote alternative pest reduction methods, such as promoting natural predator populations (Ventura County Public Works Agency 2017).
Action RC 1.2.4
Minimize impacts from native and non-native predator populations that have increased due to anthropogenic factors, including through educational outreach and trainings on how to safely coexist with native predators and predator removal programs where appropriate.
Action RC 1.2.5
Reduce anthropogenic impacts on habitat, including infrastructure construction and maintenance, inappropriate grazing, uncontrolled grazing, or overgrazing, off-road vehicles, foot traffic, fire suppression, recreational development and activities, non-native plants, and sand mining
Action RC 1.2.6
Manage infrastructure construction and maintenance projects, including transportation, solar energy facilities and projects on military properties, to be compatible for sensitive species.
Action RC 1.2.7
Manage grazing, including the installation of wildlife-friendly fencing, to ensure it is compatible with suitable and future potentially suitable habitat and adjacent areas, and areas of known occurrences. Grazing in sensitive natural communities, public lands should be reduced.
Action RC 1.2.8
Reduce trash dumping in areas with suitable and future potentially suitable habitat and adjacent areas, and areas of known occurrences.
Action RC 1.2.9
Enhance and restore native vegetation in occupied habitat and suitable but unoccupied habitat.
Goal RC 2
Promote persistence of species and important natural communities through the establishment and improvement of habitat connectivity in the RCIS area.Objective RC 2.1
Establish and improve habitat connectivity between large blocks of suitable habitat. Measure progress towards achieving this objective by the number of improved connectivity corridors used by sensitive species.Action RC 2.1.1
Install, repair, and improve infrastructure, such as adding large culverts, under crossings, overcrossings, bridges, directional fencing, scuppers, barrier breaks, roadside animal detection systems, sound barriers, limiting lighting at constructed or natural linkages and remove existing barriers to promote wildlife movement and reduce road mortality (Yap and Rose 2019). Focus on areas with high numbers of vehicle-related mortality, areas with high Area of Conservation Emphasis Terrestrial Connectivity rankings and include areas to create corridor redundancy.
Action RC 2.1.2
Enhance habitat on either side of crossing structures, including protecting adjacent areas, restricting human activity nearby, etc.
Action RC 2.1.3
Create and sustain long-term funding for long-term management of crossings, including acquisition and maintenance of adjacent habitat where suitable.
Action RC 2.1.4
Work with transportation districts or others to collect and analyze roadkill data to identify hotspots where mortality occurs to inform the design of wildlife crossing infrastructure improvements (Yap and Rose 2019).
Water Goals, Objectives, and Actions
Goal Water 1
Improve conditions of water resources, aquatic and riparian habitats, and connectivity throughout the RCIS area through enhancement and restoration.Objective Water 1.2
Improve appropriate hydrology and hydrological functions to support sensitive species and habitats. Measure progress towards achieving this objective by the improvement of hydrological indicators such as water depth, stream flow, water temperature and chemical composition.Action Water 1.2.1
Moderate extreme water temperature fluctuations by controlling water flow regimes downstream of impoundments, water diversions, and residential or industrial developments.
Action Water 1.2.2
Ensure releases from water storage and diversion facilities maintain surface flows necessary for all life history stages of sensitive species (NMFS 2013).
Action Water 1.2.3
Maintain appropriate management of flood-control activities (both routine and emergency) to be compatible with sensitive species (NMFS 2013).
Action Water 1.2.4
Restore hydrological functions of waterways to mimic natural flow, temperature regimes, and sediment loads where feasible (Hayes et al. 2016).
Action Water 1.2.5
Develop and implement operating criteria to ensure the pattern and magnitude of groundwater extractions and water releases provide essential ecological functions.
Objective Water 1.3
Improve estuarine and marine aquatic conditions in areas with sensitive species and habitats. Measure progress towards achieving this objective by the improvement of aquatic conditions (water chemical composition, habitat structure, native species diversity) water quality, and connectivity of water resources.Action Water 1.3.1
Minimize impacts to estuary water quality and tidal regimes from coastal transportation, military activities, and agricultural practices upstream, and other development projects.
Action Water 1.3.2
Enhance water quality in occupied and suitable estuary and lagoon habitats.
Action Water 1.3.3
Manage negative impacts of upstream and estuarine channelization and water quality (USFWS 2005a).
Action Water 1.3.4
Develop and implement strategies for managing freshwater inflow to estuary and lagoon habitats (USFWS 2005a).