ITIS Basic Information
Common Name: Spreading Navarretia
Scientific Name: Navarretia fossalis
Species Code: NAVFOS
Management Category: VF (species with limited distribution in the MSPA or needing specific vegetation characteristics requiring management)
Occurrence Map

Historically present
Between 2000 and
Last 10 years
Table of Occurrences

Goals and Objectives

Goal: Protect, enhance, and restore vernal pool habitat on Conserved Lands in the MSPA that supports or has the potential to support VF and SL species (i.e., California Orcutt grass, Otay mesa mint, San Diego button-celery, San Diego mesa mint, spreading navarretia, Riverside fairy shrimp, San Diego fairy shrimp, and western spadefoot) so that the vegetation community has high ecological integrity, and these species are resilient to environmental stochasticity and threats, such as altered hydrology, climate change and invasive plants, and will be likely to persist over the long term (>100 years).

Regional and/or Local NFO 2018, 2019, 2020, 2021 VF
MON-IMP-MONPL NAVFOS-1

Management units: 2, 3, 6

Beginning in 2018, conduct annual surveys for spreading navarretia in occupied, historically occupied and potentially suitable vernal pools to determine cover clases in each basin and cover of each nonnative species using a standardize protocol as defined in the VPMMP (City of San Diego 2015). Nonnative cover classes will be combined to determine if management triggers for Level 1, 2 or 3 management are met. Management recommendations will be made, noting individual nonnative species that pose a threat to direct specific management actions. Management actions will be implemented annually as part of the general vernal pool habitat management objectives for different management levels (ML1, ML2, ML3).

Action Statement Action status Projects
IMP-1 Submit project metadata, monitoring datasets and management recommendations to the MSP Web Portal. On hold
Criteria Deadline year
Annual Surveys Completed with Management Recommendations 2021
Threat Name Threat Code
Altered hydrologyALTHYD
Climate changeCLICHN
Human uses of the PreservesHUMUSE
Invasive plantsINVPLA
Urban developmentURBDEV
Code Obj. code Statement
NAVFOS-1 MON-IMP-MONPL Beginning in 2018, conduct annual surveys for spreading navarretia in occupied, historically occupied and potentially suitable vernal pools to determine cover clases in each basin and cover of each nonnative species using a standardize protocol as defined in the VPMMP (City of San Diego 2015). Nonnative cover classes will be combined to determine if management triggers for Level 1, 2 or 3 management are met. Management recommendations will be made, noting individual nonnative species that pose a threat to direct specific management actions. Management actions will be implemented annually as part of the general vernal pool habitat management objectives for different management levels (ML1, ML2, ML3).
ORCCAL-1 MON-IMP-MONPL Beginning in 2018, conduct annual surveys for California Orcutt grass in occupied, historically occupied and potentially suitable vernal pools to determine cover clases in each basin and cover of each nonnative species using a standardize protocol as defined in the VPMMP (City of San Diego 2015). Nonnative cover classes will be combined to determine if management triggers for Level 1, 2 or 3 management are met. Management recommendations will be made, noting individual nonnative species that pose a threat to direct specific management actions. Management actions will be implemented annually as part of the general vernal pool habitat management objectives for different management levels (ML1, ML2, ML3).
POGABR-1 MON-IMP-MONPL Beginning in 2018, conduct annual surveys for San Diego mesa mint in occupied, historically occupied and potentially suitable vernal pools to determine cover clases in each basin and cover of each nonnative species using a standardize protocol as defined in the VPMMP (City of San Diego 2015). Nonnative cover classes will be combined to determine if management triggers for Level 1, 2 or 3 management are met. Management recommendations will be made, noting individual nonnative species that pose a threat to direct specific management actions. Management actions will be implemented annually as part of the general vernal pool habitat management objectives for different management levels (ML1, ML2, ML3).
POGNUD-1 MON-IMP-MONPL Beginning in 2018, conduct annual surveys for Otay mesa mint in occupied, historically occupied and potentially suitable vernal pools to determine cover clases in each basin and cover of each nonnative species using a standardize protocol as defined in the VPMMP (City of San Diego 2015). Nonnative cover classes will be combined to determine if management triggers for Level 1, 2 or 3 management are met. Management recommendations will be made, noting individual nonnative species that pose a threat to direct specific management actions. Management actions will be implemented annually as part of the general vernal pool habitat management objectives for different management levels (ML1, ML2, ML3).
VERPOO-1 MON-SURV-VEG Beginning in 2018, conduct annual qualitative monitoring of all vernal pools on Conserved Lands in the MSPA to document threats such as trampling, dumping and invasive plants, and as defined in the City of San Diego's Vernal Pool Managment and Monitoring Plan (VPMMP; City of San Diego 2015). Qualitative surveys should be conducted during the wet season using standardized protocols and should assess threats, whether pools are inundated, and verify fairy shrimp viability and reproduction. Three visits should be made during the wet season to determine pool inundation. The monitoring results should be used to determine the overall disturbance category (i.e., Levels 1-3), formulate management recommendations and to determine whether more comprehensive threats monitoring is required.
VERPOO-2 MON-SURV-VEG Beginning in 2018, conduct baseline hydrological surveys of vernal pools on Conserved Lands in the MSPA to characterize the hydrology of each basin within a vernal pool complex and prepare a report with survey results for each pool complex. Use a standardized methodology and protocol to determine maximum pool depth, define pool inlet and outlets, and geomorphic setting of the complex, as described in the VPMMP (City of San Diego 2015).
VERPOO-3 MON-EVAL-DIST Starting in 2018, conduct a topographic disturbance assessment if annual qualitiative monitoring indicates there is topographical and/or hydrological disturbance at a vernal pool (see City of San Diego VPMMP). Measure maximum pool depth for each basin, determine inlet and outlet locations. These data can be compared against baseline hydrological survey data to inform management recommendations. If there is a need to reconstruct a basin because of disturbance, then monitoring should be repeated to determine if the restored pool has achieved hydrological function.
VERPOO-4 MGT-IMP-VPML1 Beginning in 2018, conduct annual routine stewardship management to maintain vernal pool habitat and existing MSP species populations as defined in the VPMMP (City of San Diego 2015). Level 1 pools are those where little maintenance is needed, other than routine access patrols and enforcement, removal of trash and debris, edge effects maintenance (e.g., offsite erosion control and irrigation management), maintaining fencing and signage, reparing trespass damage, repairing minor topographic disturbances, and controlling invasive plants for MSP species and general habitat maintenance (2 visits per spring).
VERPOO-5 MGT-IMP-VPML2 Beginning in 2018, conduct Level 2 management to enhance and stabilize vernal pool habitat and MSP species that monitoring has shown to be in decline based on VPMMP (City of San Diego 2015) management triggers. Level 2 management includes implementing all Level 1 actions in addition to other more intensive management. This more intensive management includes mechanized and hand repair to baseline conditions those moderate topographic disturbances that affect pool integrity, ponding potential and overall size as defined in the VPMMP (City of San Diego 2015). Vernal pools with MSP species should be dethatched as needed to clear thatch from vernal pool basins and in = 20-foot surrounding site-specific management buffers followed up with invasive plant control 2 times in the spring. General invasive plant control should be conducted in other vernal pool basins and/or associated upland watersheds, with the number of visits increased to 3 per year. For Level 2 management, seed banking, bulking and redistribution may be needed to enhance declining populations of MSP plant species. For declining MSP fairy shrimp populations, additional monitoring is required to determine what is causing the decline followed by management to mitigate the threat. Shrimp cysts may need to be collected from other pools in the complex and redistributed into the impacted pool, although with no collection from pools containing Lindahl's fairy shrimp. Off-site cyst collection may be implemented if there is no on-site cyst bank or it is too depauperate.
VERPOO-6 MGT-IMP-VPML3 Beginning in 2018, conduct Level 3 management to restore vernal pool habitat and MSP species that monitoring has shown to be in decline or in very poor condition based on VPMMP (City of San Diego 2015) management triggers. Level 3 management includes implementing all Level 1 actions in addition to other more intensive management. This more intensive management includes restoring existing pools to increase populaitons of MSP species, mechanized and hand repair to baseline conditions those extensive topographic disturbances that affect pool integrity, ponding potential and overall size as defined in the VPMMP (City of San Diego 2015). Vernal pools with MSP species should be dethatched as needed to clear thatch from vernal pool basins and in a 35-foot watershed management buffer followed up with invasive plant control 4 times in the spring. General invasive plant control should be conducted in other vernal pool basins and/or associated upland watersheds, with the number of visits increased to 4 per year. For Level 3 management, some MSP species may be absent from the seed bank, requiring off-site collection from genetically appropriate populations, bulking and redistribution to restore the MSP species seed bank. Container plantings may also be needed to restore MSP species. For declining MSP fairy shrimp populations, additional monitoring is required to determine what is causing the decline followed by management to mitigate the threat. Shrimp cysts may need to be collected from other pools in the complex and redistributed into the impacted pool, although with no collection from pools containing Lindahl's fairy shrimp. Off-site cyst collection may be implemented if there is no on-site cyst bank or it is too depauperate.
Proctor Valley Vernal Pools and Uplands Habitat Restoration Project
The Proctor Valley Vernal Pool and Uplands Habitat Restoration Project will complete restoration of 19 acres of vernal pools and coastal sage scrub in Proctor Valley on the City of San Diego's Otay Lakes Cornerstone Lands, a biological core area under the San Diego MSCP. The Project includes restoration of vernal pools and coastal sage scrub habitat and establishment of occurrences of two high-priority Management Strategic Plan (MSP) plants with seed collection, seed bulking, propagation, planting and seeding, and maintenance. The Project also includes restoration of habitat specific to the needs of several MSP animal species through seeding and planting of host and nest plants, construction of artificial burrows, and other measures. Project partially funded by SANDAG TransNet EMP Land Management Grant #5001972 and #5004955.

Current Distribution Rangewide

Northwestern Los Angeles County to western Riverside County, and coastal San Diego County in California, to San Quintin in northwestern Baja California, Mexico [1]. Fewer than 30 populations are known to exist in the U.S. and nearly 60 percent are concentrated in three locations in southern California: Otay Mesa in southern San Diego County, along the San Jacinto River, and in Hemet, Riverside County [2].

Known Populations in San Diego County

Within the MSPA it is known from MU3 (Otay Mesa), MU4 (MCAS Miramar), MU5 (Ramona), MU6 (San Marcos), MU7 (Del Mar), and MU8 (Marine Corps Base Camp Pendleton) [4].

List Status

FT [5].

Habitat Affinities

Vernal pools in San Diego, in man-made depressions and ditches that have the same hydrological dynamics as vernal pools; alkali playa habitat elsewhere in range (Riverside County) [5].

Taxonomy and Genetics

Polemoniaceae (Phlox family) [6]. First described by Reid Moran in 1977 based on collection made in 1969 in northwestern Baja California, Mexico [7]. The similar Navarretia prostrata can occur in similar habitats but is distinguished by flower and calyx differences, and pollen grain surfaces. Chromosomes: 2n=18 [8].

Life History Demography

Low, spreading or ascending, annual herb 4-6 inches tall [6]. The lower portions of stems are mostly hairless (glabrous), leaves are 1 to 5 cm long and finely divided into linear segments and slender spine-tipped lobes [8].

Seasonal Phenology

Blooms April- June when vernal pools are devoid of standing water [1]. The small flowers are white to pale lavender with linear petals, and borne in small, flat-topped, leafy clusters [8].

Pollination Seed Dispersal

Germinates from seeds left in the seed bank, produces fruit, dries out, and senesces in the hot, dry summer months [2]. The fruit is an ovoid, two-chambered capsule covered by a viscous layer that becomes sticky when moistened [7]. The seed can stick to an animal or bird visiting the vernal pool [9]. There is evidence that there is a low pollen to ovule ratio suggesting frequent self-pollination however, it is not considered an obligate self-pollinator because this species can also outcross to other plants [10]. Hypothetically, insects would be the main pollinators of the flowers [11]. The Hymenopteran insect Perdita navarretiae (a type of mining bee in the Andrenidae family) has been documented to make repeated visits to N. fossalis, possibly for pollination.

Threats

Threatened by loss of habitat through development, urbanization, habitat fragmentation, grazing, agriculture, watershed alteration (drainage pattern), and invasive nonnative plants [12]. Detrimental edge effects including recreational activities, foot traffic, and off-road vehicles.

Special Considerations:

As an obligate wetland species, Navarretia fossalis depends on compatible, seasonal inundation and is vulnerable to changes in water levels and periods of inundation [2]. Abundance varies year to year depending on precipitation and the inundation/drying time of the vernal pool. This makes it difficult to obtain an accurate count of the number of individuals in a population because the ratio of standing plants to remaining seeds in the seed bank that makes up the population cannot be visually measured. Modifications to the uplands surrounding a vernal pool can negatively affect the pool’s hydrology, even if such modifications occur outside the pool’s surface watershed. Disturbance may also allow invasive plants or non-vernal pool species to occupy the pools and compete with vernal pool plant species and may also alter the composition of native species of a vernal pool [3].

Literature Sources

[1] California Native Plant Society Rare Plant Program. 2016. Inventory of Rare and Endangered Plants (online edition, v8-02). California Native Plant Society, Sacramento, CA. Available: http://www.rareplants.cnps.org. Accessed November 8, 2016.

[2] U.S. Fish and Wildlife Service. 2009. Navarretia fossalis (Spreading navarretia) 5-Year Review: Summary and Evaluation. Carlsbad, CA.

[3] Bauder, E.T., and S. McMillian. 1998. Current Distribution and Historical Extent of Vernal Pools in Southern California. Pages 56-70 in C.W. Witham, E.T. Bauder, D. Belk, W. Ferren and R. Ornduff (editors), Ecology, conservation, and management of vernal pool ecosystems: proceedings from a 1996 conference. California Native Plant Society, Sacramento, CA.

[4] MSP-MOM. 2014. Management Strategic Plan Master Occurrence Matrix. San Diego, CA. Available: http://sdmmp.com/reports_and_products/Reports_Products_MainPage.aspx

[5] U.S. Fish and Wildlife Service. 1998. Determination of Endangered Status for Four Southwestern California Plants from Vernal Pool Wetlands and Clay Soils . Federal Register 63: 54975-54994.

[6] Day, A.G. 1993. The Jepson Manual: Higher Plants of California, Navarretia, ed. J.C. Hickman, 844-851. Berkeley: University of California Press.

[7] U.S. Fish and Wildlife Service. 1998. Recovery Plan for Vernal Pools of Southern California. Portland, OR.

[8] Leigh A. Johnson 2017. Navarretia fossalis, in Jepson Flora Project (eds.) Jepson eFlora. Available: http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=34450. Accessed on November 08, 2016.

[9] Sorensen, A. E. 1986. Seed Dispersal by Adhesion. Annual Review of Ecological Systems 17: 443-463.

[10] Spencer, S.C. and L.H. Rieseberg. 1998. Evolution of Amphibious Vernal Pool Specialist Annuals: Putative Vernal Pool Adaptive Traits in Navarretia (Polemoniaceae). ed. C. W. Witham et al., 76-85, Ecology, conservation and management of vernal pool ecosystems – proceedings from a 1996 conference. California Native Plant Society, Sacramento, CA.

[11] Thorp, R.W. and J.M. Leong. 1998. Specialist Bee Pollinators of Showy Vernal Pool Flowers. ed. C.W. Witham, E.T. Bauder, D. Belk, W.R. Ferren Jr., and R. Ornduff, 169-179, Ecology, conservation and management of vernal pool ecosystems – proceedings from a 1996 conference. California Native Plant Society, Sacramento, CA.

[12] Bauder, E.T. 1986. San Diego Vernal Pools: Recent and Projected Losses, Their Condition, and Threats to Their Existence. Prepared for Endangered Plant Project, California Department of Fish and Game, Sacramento, CA.