U.S. Joint Fire Science Program


Date of this Version


Document Type



Final report to the Joint Fire Science Program, Project: 01C-3-3-12


US government work.


Kuenzler’s cactus (Echinocereus fendleri var. kuenzleri [Castetter, Pierce and Schwerin] L. Benson]) is a federally- and state-listed endangered species that is known to occur in pinyon-juniper habitat in the mountains of south central New Mexico in Lincoln, Otero, Chaves and Eddy counties. Presence of this species affects the management of its habitat with prescribed burning. However, there has been no research that has documented the response of Kuenzler’s cactus to fire. This project was initiated in 2002 to provide information on habitat characteristics of Kuenzler’s cacti and to investigate its response to fire. Because of the protected status of the species, this report provides thorough documentation of correspondence with the U.S. Fish and Wildlife Service (USFWS) to acquire “take permits” to conduct our research. Research was designed with two complementary components of study. Field work in Lincoln and Eddy Counties, New Mexico involved the location and marking of plants for study. These plants were described with respect to morphological characteristics and habitat features. Prescribed burning was conducted by exposing a 12- m2 area surrounding plants to hand-ignited fire (n=13 burned plants in Eddy Co. and n=96 burned plants in Lincoln Co.). First- and second-year results indicated that burning did not affect frequency of flowering, number of flowers produced, or plant mortality. Nursery-purchased plants were grown under greenhouse conditions for 2 years prior to use in a controlled-burning experiment that involved burning plants either with excelsior as a fine fuel source (at 600 or 1,200 lbs/acre, fuel loads that represent average and high fuel amounts in the plant’s habitat in New Mexico) or in a burn barrel with durations of flame of 5, 10 or 15 seconds. All plants burned in the burn barrel showed apparent mortality 3-months post burning. Plants burned with the equivalent of 1,200 lbs/acre of excelsior had higher mortality than plants burned with 600 lbs/acre of fuel or control plants, and there was no difference in mortality between control plants and plants burned with 600 lbs/acre of excelsior. There was a negative relationship between plant size and mortality of plants burned with the equivalent of 600 lbs/acre of fuel: smaller plants had a higher probability of mortality than larger plants. There was no relationship between mortality and plant size for plants burned with the equivalent of 1,200 lbs/acre of fuel. Results of our field surveys provide strong indications that this plant is not as rare as previously thought. This information was used by the U.S. Fish and Wildlife Service in its 2005 “Five-Year Review” of this species. Under the conditions of our field burning in New Mexico, we found no evidence that the species is negatively affected by burning. Early (3-month post burning) indications from plants burned under conditions of known and controlled fuel amounts and spatial distribution also suggest that under average fine fuel conditions, this species is not negatively affected by fire. However, smaller plants have a higher probability of mortality than larger plants. Our results also show that plants burned under conditions of high fuel loads experience increased mortality, and this is not related to plant size. Therefore, use of prescribed fire in habitats that include Kuenzler’s cacti must be based on burn plans that take into account the amount of fuel.