Peebles Navajo Cactus (Pediocactus peeblesianus subsp. peeblesianus) is a small, solitary, globose cactus endemic to Navajo County, Arizona. It’s known from only two core populations and was listed as endangered in 1979.

Peebles Cactus grows in desert scrub on gravelly limestone/gravelly loam on Shinarump conglomerate of the Chinle Formation on low hills from 4,900-5,500 feet (1500-1700m) elevation.

Since 1986 three plots have been monitored. The total number of live plants in the monitoring plots fluctuates from 185 plants in 1986 up to a maximum count of 415 plants in 1995, and down to a minimum count of 42 plants in 2018. Threats to the species include: loss of habitat including gravel pit operations used for road construction, overutilization by cacti collectors, trampling from grazing cattle, lack of regulatory protection, limited distribution restricted to a specific soil type, rodent and lagomorph predation, and damage by off-highway vehicles and dust debris.

This project provides updated surveys and monitoring analyses to continue to track the success or decline of the cactus for the US Fish and Wildlife Status Review by:

1) continuing the long-term monitoring of Peebles Navajo Cactus in permanent plots established in 1985 and 1986;

2) statistically analyzing 3 additional years of demographic data of these populations;

3) surveying and mapping the distribution of the populations in the monitoring plot area and other BLM lands with GPS, in coordination with BLM personnel;

4) surveying for new populations of Peebles Navajo Cactus on public land to replace permanent plot on private land;

5) surveying for new populations of Peebles Navajo Cactus on Petrified National Forest; and

6) conducting pollination studies on plants within the greater population of the taxon.

If you would like to volunteer for this project, please contact Kirstin Phillips at kphillips@musnaz.org.

This project is funded through the University of Arizona with funds provided by the Arizona Department of Agriculture under the Research on Threatened and Endangered Plants Memorandum of Understanding developed to allocate United States Fish and Wildlife Service Endangered Species Act (Section 6) funding for plants in Arizona.