Basic Information
Common Name: San Diego Mesa Mint
Scientific Name: Pogogyne abramsii
Species Code: POGABR
Management Category: VF (species with limited distribution in the MSPA or needing specific vegetation characteristics requiring management)
Occurrence Map
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 POGABR-1

Management units: 6

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).

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.

Current Distribution Rangewide

California and San Diego endemic restricted to vernal pools on mesas of western San Diego County, CA [1]. Confusion exists regarding the historical range.

Known Populations in San Diego County

Within MSPA it is found in MU2: Kearny Mesa, at Montgomery-Gibbs Executive Airport (Mongomery Field), Murphy Canyon, Marine Corps Air Station Miramar which supports the majority of occurrences, MU6: Del Mar Mesa, Carroll Canyon, Lopez Ridge/Peñasquitos Canyon, City of Mira Mesa [2].

List Status

FE/CE [3].

Habitat Affinities

Found exclusively in vernal pools with Redding soils and a clay subsoil perched on a hardpan [4]. Found 90-200 m in elevation [1]. San Diego Mesa mint is considered an obligate wetland species (found almost always in wetland areas), but is more tolerant of the seasonal inundation of vernal pool habitats [5].

Taxonomy and Genetics

Mint family (Lamiaceae) [6]. One of 8 recognized species of Pogogyne [4]. John Thomas Howell (1931) separated Pogogyne nudiscula into two species: P. nudiscula and P. abrasmii based on hairs on the calyx, thinner bracts, and geographic distribution [7]. He considered populations north of Mission Valley P.abramsii and all populations on Otay Mesa P. nudiscula. Current work supports this separation and distinction based on the above characteristics and a different number of flowers per node [6].

Life History Demography

An annual herb with flowers arranged in whorls [8]. The plants usually give off a strong, sweet mint odor [9]. Stems thread like, wiry-erect to spreading 5-20cm, generally 0.5- 0.8 mm diameter at inflorescence base; bracts are purple-tinged with acuminate tips; inflorescence 8-10 mm wide; calyx densely white-hairy; bell shaped corolla 10–12 mm, sparsely hairy; style hairy 2-4 mm below stigma lobes. Fruit ± 1.5 mm [6].

Seasonal Phenology

Blooms from May or June through early July when water is absent from the vernal pool completing its life cycle in the spring rather than in the summer through winter months [5, 9]. The sparsely hairy, small bell-shaped purple flowers have a yellow or white throat and diagnostic hairy style [4]. It has two flowers per node on the stem [6]. Vegetation gives off a reddish tinge as plant matures [8]. The link between the onset of germination, the temporal conditions needed for vernal pool inundation, temperature, and moisture are critical to the germination, maturation, flowering, and fruiting [2].

Pollination Seed Dispersal

The Eurasian honey bee (Apis mellifera) and two anthophorid bees (Exomalopsis nitens and E. torticornis) are the most common and likely pollinators of P. abramsii [10]. Potential pollinators in nearby chaparral were also found visiting vernal pool flora [11]. Self-fertile, but greater seed set when cross-pollinated [10]. Seeds float, which may result in dispersal opportunities when pools interconnect [12]. Waterfowl visit pools and are presumed to dispersal agents [13]. Small animal movement may be a potential vector for seed dispersal and gene flow between vernal pool obligate species [14].

Threats

Threatened by OHV use, military activities, alteration of watershed, habitat fragmentation and isolation of vernal pool systems and complexes, degradation due to filling, grading, discing, and leveling, invasion from weedy nonnative plants, human access and disturbance, trampling, small population size, soil compaction, erosion, drought and climate change, and fire control activities [15]. Destruction of watersheds and disruption of hydrological systems can create further impacts by creating barriers to dispersal, such that pollination and reproductive output may be inhibited [11,12].

Special Considerations:

Examination of occurrence data from the time of listing suggests that the distribution of Pogogyne abramsii has decreased since its listing in 1978 [5]. Rainfall and temperature both affect the germination rate and successful reproduction [12]. Soil moisture late in the season is probably as important as is actual duration of standing water for this species therefore drought may play an important role in restricting the species to pool basins where soils are saturated longer and retain water in the spring [15]. Modifications to the uplands associated with a vernal pool complex can impact the pool’s hydrology, even if they occur outside the pool’s surface area [4].

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

[3] U.S. Fish and Wildlife Service. 1978. Endangered and Threatened WIldlife and Plants: Endangered and threatened wildlife and plants: Final Rule; Determination of Endangered Status for Five Plants as Endangered Species. Federal Register 43: 44810.

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

[5] U.S. Fish and Wildlife Service. 2010. Pogogyne abramsii San Diego Mesa Mint 5-Year Review: Summary and Evaluation. Carlsbad, CA.

[6] Silveira, M., M.G. Simpson, and J.D. Jokerst. 2016.  Pogogyne nudiuscula, in Jepson Flora Project (eds.) Jepson eFlora. Available: http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=38938. Accessed on December 20, 2016.

[7] Howell, J. T. 1931. The Genus Pogogyne. Proceedings of the California Academy of Sciences 20: 105–128.

[8] Jokerst, J.D. 1993. The Jepson Manual: Higher Plants of California, Pogogyne In J.C. Hickman (editor), Berkeley: University of California Press.

[9] Munz, P.A. 1974. A Flora of Southern California. Berkeley: University of California Press.

[10] Schiller, J. R., P. H. Zedier, and C. H. Black. 2000. The Effect of Density Dependent Insect Visits, Flowering Phenology, and Plant Size on Seed Set of the Endangered Vernal Pool Plant Pogogyne abramsii (Lamiaceae) in Natural Compared to Created Vernal Pools. Wetlands 20: 386– 396.

[11] Scioli, J.A. 2014. Pollinator Specificity and Pollen Limitation in the San Diego Mesa Mint, Pogogyne abramsii, A Vernal Pool Endemic. University of California, San Diego.

[12] Schleidlinger, C.R. 1981. Population Dynamics of Pogogyne abramsii on the Clairemont Mesa, San Diego County, California. M.S. Thesis, San Diego State University, San Diego California.

[13] Zedler, P.H. 1987. The Ecology of Southern California Vernal Pools: A Community Profile. Biological Report 85 (7.11). U.S. Fish and Wildlife Service, Washington, DC.

[14] Zedler, P.H. and C. Black. 1992. Seed Dispersal by a Generalized Herbivore: Rabbits as Dispersal Vectors in a Semiarid California Vernal Pool Landscape. American Midland Naturalist 128:1– 10.

[15] Bauder, E.T. 1987. Threats to San Diego Vernal Pools and Case Study in Altered Pool Hydrology, ed. T.S. Elias, 209-213, Conservation and Management of Rare and Endangered Plants. Proceedings from a conference of the California Native Plant Society.