Conservation of exceptional stands of the giant cardon cactus in Baja California Sur, Mexico

The giant cardon cactus (Pachycereus pringlei) is the emblem of the Baja California peninsula. It is a majestic plant widely distributed over the entire peninsula and often occurring in dense stands. It is difficult to visit Baja California without being exposed to scenic views framed by this tree-shaped cactus. Because the peninsula is sparsely populated and many of its areas are remote and difficult to access, most populations of cardon have remained intact through five centuries of European settlement. The first description (1768) of cardon was by the founder of Mission San Javier, the Jesuit priest Miguel del Barco, near the town of Loreto.

The Problem

At least two factors threaten populations of cardon in Baja California Sur. First, to establish and expand agricultural fields, entire stands are clearcut and bulldozed. Second is a phenomenon of cardon decline, whose exact cause is yet unknown (Bashan et al., 1995).

Because cardon is so widely distributed throughout the Baja California peninsula, it is not considered endangered. Yet, clearly there is a need to preserve some of the most magnificent stands for future generations. Because the combination of scenic beauty and remarkable specimens of cardons makes some sites particularly attractive, they deserve to be preserved as local, national, and international treasures.

General view of destruction of cardon stands at location no. 4 in 1998 and 1999

Close up of the destruction at the same area.

Natural decline of cardons

The giant columnar cardon cactus (Pachycereus pringlei) appears to have an ailment(s) that is destroying a large number of plants. The causal agent(s). whether biotic or abiotic, has yet to be determined. Two forms of symptom development have been recorded. The first is a circular tissue decay on a branch leading to death of the growing tip. In this case, the dead portion detaches and forms a "flat top" on the living part (hence the proposed name for this phenomenon). Progressive degeneration and death of the plant ensue. The second form is an initial circular crack on the branch without decay. Later, the green branch above the crack detaches, creating the characteristic flat top. A third type of degeneration was also observed: fatal bleaching. The time period between symptoms is unknown. It primarily affects mature, more then 100-year-old plants, but relatively young plants are also affected. Thirty-six field surveys covering the entire state of Baja California Sur found five major and four smaller centers of flat top decay. We believe that flat top decay syndrome of the cardon cacti in Baja California is common and widespread.

Conservation proposal

We describe here four sites in Baja California Sur that we believe it is urgent to consider for preservation before irreversible damage causes their disappearance.

The marked areas on this map of the southern half of the Baja California Peninsula include proposed cardon reserve areas. Select an area to zoom in for more detail.

Area 4 Area2 Area 1

Proposed reserve areas 1 and 2

Notice the perfect shape of cardons at this site.

Close-up of healthy side branch in unnamed wash north of Loreto.

Proposed reserve area 3

Arrow on map points to proposed reserve area.

Southern Bahia Concepcion has the tallest stands of Cardon detected in the survey. Note grown man at base of this sample.

Proposed reserve area 4

Huge specimen near Los Planes.
This area is under threat from clearcutting.

Arrow points to proposed reserve area.

Some facts about cardon cactus

The cardon is one of the most massive of all cacti. An average mature cardon may reach a height of ten meters, but individuals as tall as eighteen meters are known (León de la Luz and Valiente 1994). It is a slow growing plant (Roberts, 1989) with a life span measured in hundreds of years, but growth can be significantly enhanced in its initial stages by inoculation with plant growth-promoting bacteria such as Azospirillum sp. (Bashan et al., 1999; Carrillo et al., 2000; Puente and Bashan, 1993). Most adult cardon have several side branches that may be as massive as the trunk. The resulting tree may attain a weight of 25 tons (Gibson and Nobel, 1986). Adult cardon is adapted to the harsh climate of Baja California, characterized by drought and high temperatures, but as a seedling and juvenile it depends for survival on nurse plants, such as mesquite (Prosopis articulata) (Carrillo-García et al., 1999). In alluvial soils in southern Baja California, the cardons, and other cacti, occupy an extensive area.

Majestic cardon plant, the emblem of the Baja California peninsula. Note woman at base for size scale.

Some outstanding environmental features of cardon cactus:
  • The giant cardon stands out as possessing characteristics desirable for the stabilization of disturbed arid soils; a wide-spread, finally branched, shallow root system capable of responding to rare rainfall episodes by rapid regrowth (Bashan et al., 1999; Bravo-Hollis, 1978; Nobel, 1996).
  • The highly nutritious and succulent fruits of the cardon (Valencia et al., 1985), available in abundance during the desert dry season when other food sources are scarce, are a major source of nutrients to many desert birds and lesser long-nosed bats (Leptonycteris curasoae). The latter are the major pollinators of the night-blooming flowers of cardon and depend on them for survival (Tuttle,1991).

The Cardon as Ambience

Sunset over the desert

The cardon is an omnipresent facet of life in the Baja Peninsula. It surrounds us and permeates the very atmosphere with its presence.

Cardon over the Sea of Cortes

Although difficult to evaluate objectively the impact on the local society and such commercial aspects as tourism, it is undeniable that the disappearance of the cardon from the Baja Peninsula would forever change the face of this land, leaving a hole in the fabric of the world.

Reference for extra reading on cardon

First description of cardons from the 17th century
In poetic prose, the Jesuit priest Don Miguel del Barco of mission San Javier wrote: "This tree, although full of moisture, is found only on dry lands, on level and sloped ground alike, provided that there is no moisture nearby, for this it shuns.... Whence then does it draw that moisture and the sap with which it is replete? Not from the rains, since these are very scant in California, and therefore, where there is no permanent spring and one must rely on rainwater alone, nothing can be sown or planted...The cardon, however, even though years may pass without rain, shows no sign of distress: it perseveres serenely, with the same fresh green color and the same abundant sap, as ever....".

Mission San Javier, 34 km east of Loreto, established by the Jesuit priest Miguel del Barco in the 17th century and preserved intact to this day.

Additional reading on cardons

  • Bashan, Y., Rojas, A., and Puente, M.E. 1999. Improved establishment and development of three cactus species inoculated with Azospirillum brasilense transplanted into disturbed urban desert soil. Canadian Journal of Microbiology 45; 441-451.
  • Bashan, Y., Toledo, G., and Holguin, G. 1995. Flat top decay syndrome of the giant cardon cactus (Pachycereus pringlei): description and distribution in Baja California Sur, Mexico. Canadian Journal of Botany. 73; 693-692.
  • Bravo-Hollis, H. 1978. Las cactáceas de México (The cactaceae of Mexico). Vol. 1. Universidad Autónoma de México. Mexico.
  • Carrillo-Garcia, A., Leon de la Luz, J.L., Bashan, Y., and Bethlenfalvay, G.J. 1999. Nurse plants, mycorrhizae, and plant establishment in a disturbed area of the Sonoran desert. Restoration Ecology 7: 321-335.
  • Carrillo, A., Bashan, Y., Diaz-Rivera, E., and Bethlenfalvay, G.J., 2000. Effect of resource island soils, competition and inoculation with Azospirillum on survival and growth of Pachycereus pringlei, the giant cactus of the Sonoran desert. Restoration Ecology 8:(in press).
  • Del Barco, M. 1768. Correcciones y adiciones a la historia o noticia de la California en su primera edición de Madrid, año de 1757. Re edited by M. León-Portilla (1988) by the title: "Historia Natural y Crónica de la antigua California". Universidad Nacional Autónoma de México, Instituto de Investigaciones Históricas. México.
  • Gibson, A.C., and Nobel, P.S. 1986. The cactus primer. Harvard University Press, Cambridge, Mass.
  • León de la Luz, J. L., and Valiente-Banuet, A. 1994. Las Cactáceas revisitadas: Un recurso natural diverso y predominantemente Mexicano. Ciencia y Desarrollo. 20 (no. 117); 58-65.
  • Nobel, P.S. 1996. Ecophysiolgy of roots of desert plants, with special emphasis on agaves and cacti. Pages 823-844. In: Y. Waisel, A., Eshel, and U. Kafkafi (eds). Plant roots, the hidden half. 2nd Ed. Marcel Dekker. N.Y.
  • Puente, M.-E., and Bashan, Y. 1993. Effect of inoculation with Azospirillum brasilense strains on the germination and seedling growth of the giant columnar cardon cactus. Symbiosis. 15; 49-60. Roberts, N.C. 1989. Baja California plant field guide. Natural History Publishing Co. La Jolla, CA.
  • Tuttle, M.D. 1991. Bats the cactus connection. National Geographic 179 (6) :131-140. Valencia, M.E., Atondo, J.L., and Hernandez, G. 1985. Nutritive value of Zostera marina and cardon (Pachycereus pringlei) as consumed by the Seri indians in Sonora Mexico. Ecology of Food and Nutrition. 17;165-174.