• Proposed
  • Under Assessment
  • 3Preliminary Assessed
  • 4Assessed
  • 5Published

Mobergia calculiformis (W.A. Weber) H. Mayrhofer & Sheard

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Scientific name
Mobergia calculiformis
(W.A. Weber) H. Mayrhofer & Sheard
Common names
Coastal Popcorn Lichen
Palomitas Costeras
IUCN Specialist Group
Assessment status
Under Assessment
Proposed by
Jessica Allen
Frank Bungartz
Frank Bungartz, Manuela Dal Forno, María de los Angekes Herrera Campos, Christian Parrinello, Daniel Ramos, Reinaldo Vargas
Jessica Allen, Jason Hollinger, Daphne Stone

Assessment Notes


A2a,c - we estimate at least a 50% overall population reduction based on:
50% of the extant subpopulations are in protected areas, one of those is impacted by tourism, the other one might be affected in the future by the Escalera Nautica and is even threatened by currently ongoing infrastructure projects; all US subpopulations are already extirpated, the other 50% extant subpopulations are either minute (Sierra La Giganta) and/or threatened by urbanization (Sierra La Giganta and south of San Quintín).

Although the EOO is large, the AOO is less than 70km2 and we have severe fragmentation of the subpopulations, plus a continuing decline in extent of occurrence, area of occupancy, and at least projected decline of the number of locations and subpopulations.

Taxonomic notes

Mobergia is an unusual genus in the Physciaceae with only two species. The unusual conspicous “popcorn” morphology makes this species extremely easy to recognize.

Why suggested for a Global Red List Assessment?

The historic reports from the US are now all extirpated. In Baja California and Baja California Sur several viable subpopulations exist along the Pacific coast, the most northern one below San Quinitin is heavily impacted and in part eradicated by agriculture and urbanization. The one on the islands is a popular tourist site. The one near the fishermen town Santa Rosaliíta is in danger from the Escalera Nautica (a road building project). The one in Baja Sur is very small at the western flanks of the Sierra de la Giganta.

Geographic range

Mobergia calculiformis was originally reported from coastal California (USA) and both Baja California and Baja California Sur (Mexico) (Mayrhofer & Sheard 2004, Mayrhofer et al. 1992, Spjut 1995). All US locations have been revisited by K. Knudsen (personal communication) who confirmed that these subpopulations are now extirpated. The Mexican sites (almost all in Baja California) as the only surviving subpopulations. The only one subpopulation from Baja California Sur has not recently been confirmed. The species also occurs on Guadalupe Island, Baja California.
Using the known extant sites from the Baja peninsula the EEO is 108,000 km2 and the AOO as 72 km2. The relatively large EEO is a result of the specimens from Guadalupe Island, much off the coast, almost 250 km away from the mainland peninsula.

Population and Trends

All US subpopulations are extirpated. In Mexico we can distinguish four locations that are still extant (see distribution map of historic, extirpated and extant subpopulations):
(1) subpopulation immediately south of San Quintín is very heavily urbanized and the habitat has drastically changed.
(2) subpopulation near Santa Rosaliíta is still in very good shape, the small fisherman village is not much frequented by tourism and the species relatively abundant according to an informal survey by F. Bungartz & R. Vargas in May 2018; but this location will be very drastically changed if the Mexican government approves the Escalera Náutica project which plans to crisscross the peninsula with a network of roads to allow tourists to move their sailing boats from the Pacific to the Sea of Cortés.
(3) subpopulation on Guadalupe Island recently became encompassed within a biosphere reserve; although in a protected area this subpopulation is today heavily impacted by tourism and its accompanying development.
(4) subpopulation on the western flanks of Sierra La Giganta is not well documented and the southernmost outlier, Ciudad Insurgentes further south is a huge, heavily urbanized area, at the Pacific coast near the port of Adolfo López Mateos a large seashore resort is being built.

Population Trend: Decreasing

Habitat and Ecology

The species is semi-vagrant, saxicolous and attached to pebbles and larger coastal rock, cliffs, and boulders. It occurs only along the Pacific coast in a heavily fog-induced desert of the Baja peninsula (when similar habitat had still not been replaced by urban and agricultural development in the US, the species presumably was common there too).

HotRocky ShorelineSea Cliffs and Rocky Offshore Islands


The northernmost extant subpopulation south of San Quintín is very heavily impacted by agricultural and urban development as well as by tourism (Vanderplank 2011). These populations are currently not protected. Specimens that belong to the subpopulation along the pacific coast between El Rosario and Santa Rosaliíta are still very abundant and currently may be considered the ones best preserved (Bungartz & Vargas, pers. com). These sites are at least in part located in and near the Parque Natural del Desierto Central de Baja California, but the sites are nevertheless projected to be heavily developed as part of the Escalera Náutica project (Álvarez Torres 2009; and websites cited). Like most of the Baja desert sites an additional threat are the various off-road races (e.g., Baja 1000 Race, http://score-international.com/).A single, isolated location with another subpopulation in the Sierra La Giganta in Baja California Sur is poorly known (has not been visited since 1989), but the site lies just north of the heavily urbanized Ciudad Insurgentes.  The site of the subpopulation inside the Guadalupe Island Biosphere Reserve is healthy, but nevertheless impacted by tourism (Comisión Nacional de Áreas Naturales Protegidas 2013).

Housing & urban areasCommercial & industrial areasTourism & recreation areasShifting agricultureSmall-holder grazing, ranching or farmingScale Unknown/UnrecordedMining & quarryingRenewable energyRoads & railroadsUtility & service linesShipping lanesFlight pathsRecreational activitiesRun-offSoil erosion, sedimentationHabitat shifting & alteration

Conservation Actions

Most current conservation actions are focusing on the preservation of plant habitat and habitat for birds and small mammals (e.g., Aguirre-Muñoz et al. 2018, Harper et al. 2011, Lovich et al. 2009, Rodríguez-Estrella 2005, Vanderplank 2011), but lichens are still largely ignored. The Comisión Nacional de Áreas Naturales Protegidas (2013) in its management program for the Isla Guadalupe Biosphere Reserve highlights the necessity to preserve the enormous lichen diversity on the island, citing Moran (1996), who emphasized that on the Baja mainland and in southern California (USA) comparable ecosystems have largely been destroyed (Comisión Nacional de Áreas Naturales Protegidas (2013, p. 32): “...Esta flora es remanente de la que hubo alguna vez en gran parte del Sur de California y del Norte de Baja California. Prácticamente este ecosistema ha sido destruido por el desarrollo y cambio de uso de suelo en Estados Unidos…”).
Raising public awareness for the very unique lichen biota of the Baja peninsula is thus critically important and particularly on the Pacific site the sensitive fog desert habitat needs to be better protected from a broad range of destructive impact: tourism, off-road driving (e.g., Baja 1000 race, http://score-international.com/), urbanization, infrastructure (Aguirre-Muñoz et al. 2018), agriculture (Vanderplank 2011), etc.

Site/area protectionSite/area managementNational level

Research needed

The current size and extent of the different subpopulations are insufficiently known. Some sites (e.g. Sierra La Giganta, Baja California Sur) have not recently been visited and need to be surveyed whether the species there still persists. Others, like Guadalupe Biosphere Reserve are formally protected by law, but no actual species management plans focusing on lichen preservation have been developed. Species Action/Recovery Plans need to be developed urgently for the locations close to population centers/urban and agricultural areas (e.g., south of San Quintín).

The species is one of two unique ones in the genus and taxonomically easily recognized, large and conspicuous, but its population trends are virtually completely unknown.

Population size, distribution & trendsLife history & ecologyThreatsActionsSpecies Action/Recovery PlanArea-based Management PlanPopulation trendsHabitat trends

Use and Trade



Aguirre-Muñoz, A., Bedolla-Guzmán, Y., Hernández-Montoya, J., Latofski-Robles, M., Luna-Mendoza, L., Méndez-Sánchez, F., Ortiz-Alcaraz, A., Rojas-Mayoral, A. & Samaniego-Herrera, A. (2018) The Conservation and Restoration of the Mexican Islands, a successful Comprehensive and Collaborative Approach Relevant for Global Biodiversity. In: A. Ortega-Rubio (ed.), Mexican Natural Resources Management and Biodiversity Conservation, https://doi.org/10.1007/978-3-319-90584-6_9
Álvarez Torres, E.M. (2009) Escala Náutica del Mar de Cortés: Puerto Libertad. Liberty Cove: el Desarrollo Turístico, la sustentabilidad urbana o la tradición y modernidad en los conglomerados rurales. Revista de Arquitectura, Urbanismo y Ciencias Sociales 1(3): 1-28
Comisión Nacional de Áreas Naturales Protegidas (2013) Programa de Manejo Reserva de la Biosfera Isla Guadalupe. Secretaría de Medio Ambiente y Recursos Naturales, Distrito Federal de México, pp. 1-230.
Harper, A.B.; Vanderplank, S., Dodero, M., Mata, S. & Ochoa, J. (2011) Plants of the Colonet Region, Baja California, Mexico, and a Vegetation Map of Colonet Mesa Aliso: A Journal of Systematic and Evolutionary Botany 29(1): 25–42. Available at: http://scholarship.claremont.edu/aliso/vol29/iss1/4
Lovich, R.E., Grismer, L.L. & Danemann, G. (2009) Conservation status of the herpetofauna of Baja California, México and associated islands in the Sea of Cortez and Pacific Ocean. Herpetological Conservation and Biology 4(3):358-378.
Mayrhofer, H. & Sheard, J.W. (2004) Mobergia. In: Nash III, T.H., Ryan, B.D., Diederich, P., Gries, C. & Bungartz, F. (eds.): Lichen Flora of the Greater Sonoran Desert Region, Vol. 2. Lichens Unlimited, Arizona State University, Tempe, Arizona, pp. 364-365.
Mayrhofer, H., Sheard, J.W. & Matzer, M. (1992) Mobergia (Physciaceae, lichenized Ascomycetes), a new genus endemic to western North America. The Bryologist 95(4): 436-442.
Rodríguez-Estrella, R. (2005) Terrestrial Birds and Conservation Priorities in Baja California Peninsula. USDA Forest Service General Technical Report PSW-GTR-191: 115-120.
Spjut, R.W. (1995) Occurrence of Mobergia calculiformis (Physciaceae, Lecanorales) in the northern Vizcaino Desert of Baja California, Mexico. In: Daniëls, F.J.A., Schulz, M. & Peine, J. (eds.): Flechten Follmann. Contributions to lichenology in Honour of Gerhard Follmann. Geobotanical and Phytotaxonomical Study Group, Botanical Institute, University of Cologne, Cologne, pp. 475-482.
Vanderplank, S.E. (2011) The Flora of Greater San Quintín, Baja California, Mexico (2005–2010). Aliso: A Journal of Systematic and Evolutionary Botany 29(2): 65–103. Available at: http://scholarship.claremont.edu/aliso/vol29/iss2/2

Relevant Internet Resources about the Escalera Náutica Project:

Baja 1000 Race: http://score-international.com/

Known distribution - countries

Regional Population and Trends

Country Trend Redlisted