As I mentioned in a previous entry, Botany Photo of the Day series in 2010 will tie in to the monthly educational themes here at UBC Botanical Garden celebrating the International Year of Biodiversity. For January, our educational theme is "Resolutions for Biodiversity", so we're going to be highlighting stories this week where people have resolved to conserve rare plants.
Lindsay Bourque is responsible for today's write-up. Lindsay writes:
The pima pineapple cactus is a small hemispherical cactus (10-18 cm in height). It is native to the Sonoran Desert of southern Arizona and northern Mexico. Coryphantha scheeri var. robustispina is a rather uncommon lower elevation cactus with prominently grooved, thick tubercles. Older tubercles toward the bottom of plants can differentiate to form new plants if the parent plant dies. Silky, pale yellow flowers burst into bloom in July with the onset of the monsoon season in the Sonoran Desert. The flowers are quickly followed by sweet, green fruits, which are an important food source for desert fauna.
Added to the United States Endangered Plant Species List in 1993*, threats to this taxon include loss of habitat due to urban development, off-road vehicle use, road construction, livestock grazing, and agriculture & mining. Nonnative grasses are also altering its habitat, preventing establishment of new individuals. Buenos Aires National Wildlife Refuge has a prescribed burn management regime to control these nonnative grass species. Illegal collecting is also a problem, despite state protection laws. Approximately only 21 populations of pima pineapple cactus remain*.
In 1998, on behalf of a coalition of 31 environmental groups, the Center for Biological Diversity drafted the Sonoran Desert Conservation Plan. Encompassing nearly 6 million acres, this large-scale, regional habitat conservation plan is intended to end uncontrolled development in Pima County by establishing a process to conserve large areas of desert. It manages development and open space in southern Arizona to protect the pima pineapple cactus and 22 other endangered taxa.
*Daniel adds: This story highlights the importance of taxonomists in conservation decisions. The Flora of North America account for this taxon lumps it into Coryphantha robustispina -- a broad, inclusive species that ranges from Arizona to Texas and includes some of northern Mexico. If one follows that interpretation, then one could question the endangered status. However, if one follows the interpretation of the US Fish & Wildlife Service and its contracted taxonomists (PDF), the narrower interpretation as Coryphantha scheeri var. robustispina yields a threatened plant taxon (more about their analysis and reviews here: Coryphantha scheeri var. robustispina).