Characterization of the geographic distribution, reproductive phenology and fruits of Stenocereus martinezii, a threatened columnar cactus

Stenocereus martinezii is a columnar cactus that produces fruits with commercial relevance (pitayas) and is classified as an Endangered (En) species on the IUCN Red List. It is currently considered endemic to the state of Sinaloa, Mexico; however, it could have a wider geographic distribution that has not been detected due to low collection efforts. It is also one of the least known Stenocereus species in terms of its biology, ecology, ethnobotany and nutritional composition. The objective of this work was to update the geographic distribution of S. martinezii, locate sites where it is used commercially, describe its reproductive phenology, and describe the physical and chemical composition of its fruits. For its distribution, field explorations were carried out in areas of western Durango and eastern Sinaloa from 2013 through 2024 and a data base was built and compared to previous reports in biological collections. Phenology was monitored in three localities in 2017 and fruit composition was quantified from fruits collected in the Arroyo Grande community. The newly detected distribution area of S. martinezii was considerably larger than previously reported from literature and scientific collections, and this is the first report of this species in the state of Durango. At the edge of its range, Stenocereus martinezii is displaced by the other two commercially important pitaya cactus species in Sinaloa: Stenocereus montanus in the east and Stenocerus thurberi in the west. Reproductive phenology was unimodal, and productivity was higher in populations where fruits are harvested. Its reproductive stage occurs later than more southern species and earlier than more northern species, making it a food bridge for migratory bird and bat species. Stenocereus martinezii fruits are smaller but with a similar chemical composition with other fruits of this genera with commercial value.