Funded by a BCSS Research Grant to:
Zlatko Janeba, Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague, Czech Republic; email: .
Cecilia Elizondo, El Colegio de la Frontera Sur, San Cristóbal de las Casas, Chiapas, Mexico; .
The BCSS Research Grant supported botanical explorations of the Yucatán Peninsula with the goal to study cacti, with a special emphasis on the genus Mammillaria Haw. Two species of the genus Mammillaria Haw. are the only globular cacti belonging to the family Cactaceae that have been reported from the Yucatán Peninsula, occurring only in the northernmost coastal areas of the Mexican state of Yucatán. While Mammillaria heyderi subsp. gaumeri (Britton & Rose) D.R.Hunt is a relatively common cactus inhabiting various types of biotopes (from stabilized coastal sand dunes to dry tropical deciduous forests), Mammillaria columbiana subsp. yucatanensis (Britton & Rose) D.R.Hunt has been re-discovered in its habitat near Progreso (type locality) only very recently and only a few specimens have been reported. Thus, although recorded from other parts of Mesoamerica, M. columbiana subsp. yucatanensis should be considered as a very endangered plant in the Yucatán Peninsula, deserving the special protection status. The biggest threat to both mammillarias is the destruction of their habitats due to the urbanization of the coastal areas.
Figure 1. Cultivated specimen of Mammillaria heyderi subsp. gaumeri (originating from south of Progreso).
The aim of the study was monitoring the distribution range and habitats of Mammillaria heyderi subsp. gaumeri, attempts to rediscover Mammillaria columbiana subsp. yucatanensis in its habitat, and evaluation of potential threats to both mammillaria species at the Yucatán Peninsula.
Figure 2. The cultivated specimen of Mammillaria columbiana subsp. yucatanensis in the Centro de Investigación Científica de Yucatán, A.C. (CICY), 15 Dec 2011.
Figure 3. Two plants of Mammillaria heyderi subsp. gaumeri hiding under a low bush in Chelem, municipality of Progreso, Yucatán, Mexico.
Figure 4. Mammillaria heyderi subsp. gaumeri growing in the shade of a bush in Chelem, municipality of Progreso, Yucatán, Mexico.
To conlude, only two globular cacti have been so far reported and described from the Yucatán peninsula (Mexico) and only from the northernmost coastal portion of the state of Yucatán. Both species belong to the genus Mammillaria Haw. While Mammillaria heyderi subsp. gaumeri is quite common in diverse biotopes and its distribution range extends some 200 km along the Yucatecan coast, Mammillaria columbiana subsp. yucatanensis has been only recently rediscovered and it is extremely rare in its habitat (so far only a handful of verified records exists). Moreover, it seems to be localized, within the Yucatán peninsula, only to the Progreso area. Although more studies are needed to verify the real distribution range and abundance of M. columbiana subsp. yucatanensis in the habitat, this cactus clearly deserves the highest degree of local protection.