Regularity: Regularly occurring
Global Range: It occurs in Arizona, New Mexico, Oklahoma, Texas and Mexico.
Habitat and Ecology
Comments: It occurs on gravelly limestone soils in desert and grasslands from near sea level, deeper soils of valley and plains, and on mountain hillsides.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 81 to >300
Comments: 100 EO's (Benson 1982).
It often grows under the partial shade of trees, shrubs, or tall grass (Weniger 1970).
Thomas (2006) found that long-term survival after fire in Arizona populations was severely diminished with all plants dead after 16 years. Although new cacti did eventually establish on the study areas and by the end were of a similar size to the dead cohort, fire more rapidly removed the breeding populations, reducing seed availability in the occasional years favorable for establishment, and increasing the risk of local extinction.
Life History and Behavior
Mammillaria is dispersed by a wide array of vertebrate animals (van Rheede van Ousdtshorn and van Rooyen 1999). It is suspected that M. heyderi fruit are eaten by birds and rodents (Boke 1953).
IUCN Red List Assessment
Red List Category
Red List Criteria
Mammillaria heyderi has a very large extent of occurrence, is abundant, and there are no known major threats. Hence, it is listed as Least Concern.
National NatureServe Conservation Status
Rounded National Status Rank: NNR - Unranked
NatureServe Conservation Status
Rounded Global Status Rank: G4 - Apparently Secure
Reasons: Reported from the southwestern United States, abundance unknown.
Comments: Most cacti subject to horticultural collecting.