Conservancy Fairy Shrimp Habitat and Natural History Studies-Vollmar Consulting
BACKGROUND INFORMATION
The federally-listed endangered Conservancy fairy shrimp is among the rarest of California’s endemic fairy shrimp. It is also the largest of the endemic shrimp and requires the longest period to complete its breeding cycle (Helm 1996). The Conservancy fairy shrimp is currently known from fewer than 20 locations in widely scattered sites restricted to the northern and mid Central Valley and Delta regions of California. Most known occurrences are within large clay-bottom vernal pools, generally larger than 3-4 acres in total area, with highly turbid waters. Though no specific research has been conducted, it is generally thought that Conservancy fairy shrimp occupies these large, turbid-water pools because they remain ponded long enough to support successful breeding in most years and the turbid waters provide visual protection from foraging shorebirds and waterfowl. Prior to our recent new discovery, the only known occurrences of Conservancy fairy shrimp within Solano County were within large clay-bottom pools on the Jepson Prairie (Eriksen and Belk 1999).
Given the species’ fairly specific pool habitat preference, we were surprised to discover a robust population of Conservancy fairy shrimp in very different pools on the Montezuma Wetlands Vernal Pool Mitigation Preserve. This 400-acre preserve is situated on alluvial terraces bordering the historic tidal marsh boundary. The preserve was established to provide mitigation for incidental impacts to federally-listed vernal pool fairy shrimp (Branchinecta lynchi) and vernal pool tadpole shrimp (Lepidurus packardi) as part of a tidal marsh restoration project. The preserve incorporates ten small to medium sized natural vernal pools, most of which are hydrologically interconnected. They are underlain by silty soils and have mildly alkaline waters that are clear to moderately turbid. We discovered Conservancy fairy shrimp in seven of ten pools within the preserve including the smallest pool which is just over a tenth of an acre in maximum size. The maximum diameter of this pool is around 70 feet.
PROPOSED PROJECT
Given the occurrence of a robust population of Conservancy fairy shrimp in such an unusual setting, we believe there are likely more as yet undiscovered occurrences of the species elsewhere in eastern Solano County. Our proposed project is intended to provide a more comprehensive understanding of the species’ habitat preferences and natural history characteristics, to identify pools potentially occupied by the species in eastern Solano, and, where survey access is gained, to documented new occurrences of the species in the region. We will conduct this work through the four specific tasks discussed below.
Task 1: Gather and Analyze Ecological and Natural History Data
We will compile and analyze existing habitat and natural history data on the species including our monitoring data from the Montezuma Wetlands Vernal Pool Preserve as well as data from other sites in and out of Solano County to develop a more complete understanding of the species’ preferences and tolerances related to pool habitat characteristics. We will conduct sites visits to occupied pools to where no data have been collected or are available and GPS maximum pool ponding areas and collect soils for chemical and textural analysis. We will analyze all existing data and additional field data collected from the site visits to develop a more complete understanding of the pool habitat preferences and tolerances of the Conservancy fairy shrimp.
Task 2: Map Potential Conservancy Fairy Shrimp Pools in Eastern Solano County
We will remotely identify and map pools within eastern Solano County that have potential to support Conservancy fairy shrimp based on size and associated soils. All mapping will be conducted using GIS. Mapped pools will be stratified into two or three classes based on overall habitat suitability and potential to support Conservancy fairy shrimp. We will use recent aerial photography taken in mid winter to early spring that readily show inundated pools. We currently possess this aerial photography in house.
Task 3: Conduct Field Surveys
During winter 2006-2007, we will visit all known Conservancy fairy shrimp pools within Solano County and collect specific data on pool size and maximum ponding depth, water quality and soil characteristics, Conservancy shrimp presence and abundance, and diversity and abundance of associated aquatic invertebrates and amphibians. We will visit and sample some Conservancy fairy shrimp pools outside of Solano County focusing on pools that are atypical for the species. Where survey access can be obtained, we will also conduct surveys within pools mapped under Task 2 that provide potential habitat for Conservancy fairy shrimp. We will conduct three survey rounds within all sampled pools corresponding to early, mid and late inundation periods (roughly mid January, mid February and mid March).
Task 4: Develop Comprehensive Ecology and Natural History Profile and Prepare Report
We will analyzed all existing data and additional field data collected during 2006-2007 field season to develop a more complete understanding of the pool habitat preferences and tolerances of the Conservancy fairy shrimp. We will also develop a more comprehensive understanding of the species natural history cycles on a seasonal and annual basis. Much of this information will be developed from data gathered over the past four years at the Montezuma Wetlands Vernal Pool Preserve. During these years, we have noted dramatic fluctuations in the seasonal timing and abundance of Conservancy fairy shrimp within occupied pools including some years when the species did not appear at all in some of the occupied pools. This information will be useful for assessing adequacy of presence/absence surveys for Conservancy fairy shrimp based on seasonal rainfall and temperature characteristics.
Once we have completed our analyses, we will prepare a report summarizing the methods and results of our project. The report will include 11x17 color maps showing locations of mapped pools. The report and all GIS data will be provided to SCWA, USFWS, Solano County, City of Fairfield, other interested cities, Solano Land Trust, and The Nature Conservancy for improved conservation planning for Conservancy fairy shrimp.
LISTED SPECIES THAT WILL BENEFIT FROM THE PROJECT
Conservancy fairy shrimp will be the primary species that benefits from this project. However, several other federally-listed species that primarily occupy larger vernal pools will receive incidental benefits from this project through increased attention and conservation of medium to large vernal pools. These species include Colusa grass (Neostapfia colusana), Crampton’s tuctoria (Tuctoria mucronata), vernal pool tadpole shrimp (Lepidurus packardi), and California tiger salamander (Abystoma californiense).
PARTNERSHIPS
We will involve multiple partners in our project to insure that information we develop is used as widely and effectively as possible. During the course of the project, we will work with staff from Solano Land Trust, The Nature Conservancy, LSA (as the primary consultant for development of the regional HCP), and other entities involved in vernal pool and fairy shrimp conservation. These partners will provide guidance and review during the course of the project to ensure that our final products can be easily integrated into the conservation strategies/plans these organizations have developed for Solano County. We will also solicit partnerships with the San Francisco Estuary Institute and the Ulatis Resource Conservation District and make our project data available to these groups.
