About Harvesting and Regrowth project

A scene from our long-term regrowth study.

A long-term field study of peyote harvesting and regrowth performed within its natural habitat.

Cactus Conservation Institute’s signature study on the impact of peyote harvesting is the only longitudinal study ever conducted on the species Lophophora williamsii.

Thanks to the generous support of a cactus conservationist this 10-year project became a published reality. The results appeared in print in a peer reviewed journal in 2011 and 2012 with a 2014 follow-up. Our sincere thanks and deepest appreciation goes to Libbie Winston Mize for graciously supporting this important and timely study.

We are continuing to monitor this population every two years.

This study is ongoing and new data will be reported as CCI has resources and as long as the plants themselves remain in the field to study. Sadly, as viewed in image files, the impact that harvesting has had is very clearly visible to even a casual observer. Take a look at the plants that were harvested (Plants 101-150) versus those that were not (Control plants, 151-200).

Please read on — All of our raw data, images, and complete study findings are available for download. For scientists and others who are data-driven, all of our data are accessible. If there is something you are missing and cannot find, please contact us and we will try to assist you.

Please check back! We will be adding images and data for later years (2018 and 2019) shortly. Currently, some of our photos of the plant tags are missing and will be added in. For those who want a more immersive experience, our older site is still accessible.

Regrowth study site showing typical Tamaulipan thornscrub vegetation.

Among other objectives, the Regrowth study investigated effects of harvesting where best practices were observed, both in terms of a single harvesting event and repeated harvesting; as well as the mescaline content of regrowth as compared to other cacti. Impact on survival rates, number of crowns, and above-ground volume were among the reported findings.

While our study highlights far more findings than just one, an inescapable conclusion is that greenhouse production of peyote that is intended for sacramental use is a logical suggestion. With the cooperative effort of the regulators at the DEA – whose legal responsibility would be to promulgate a regulatory framework that would allow the Native American Church (NAC) to supply its own peyote in a mode which would prevent harvesting in the wild – such production of the sacrament for the NAC could be undertaken by any tribe that wanted to control their own supply of peyote. If this practice were generally adopted by NAC chapters in the U.S., that would relieve the harvesting pressure on the wild populations of peyote in South Texas and allow them to recover.

“If a person performs his duties as a keeper of the living medicine with the same care and reverence that he would bring to a peyote meeting – the same care and reverence with which he might tend the fire – then the medicine will reflect that care and that reverence to those who use it as the sacrament.”

Ted Herrera 
Spiritual Leader 
Rio Grande Native American Church

Peer-reviewed articles

Terry et al. (2011). Limitations to natural production of Lophophora williamsii (Cactaceae) I. Regrowth and survivorship two years post harvest in a South Texas population.

JOURNAL ARTICLE

Limitations to natural production of Lophophora williamsii (Cactaceae) I. Regrowth and survivorship two years post harvest in a South Texas population.

Martin Terry, Keeper Trout, Bennie Williams, Teodoso Herrera and Norma Fowler

Journal of the Botanical Research Institute of Texas

Vol. 5, No. 2 (7 DECEMBER 2011), pp. 661-675 (15 pages)

PDF DOI

Abstract

Lophophora williamsii (peyote) is a cactus whose crowns are commercially harvested for religious use as an ingested psychoactive sacrament by members of the Native American Church. Over the past quarter century peyote has become progressively less available, due in part to improper harvesting techniques and excessive harvesting. Since anatomical aspects of the regrowth of peyote and best harvesting practices were explicated in a previous study (Terry & Mauseth 2006), the principal focus in the present study was to determine the effects of harvesting where only best practices were employed. We assessed the effects of (1) harvesting per se (a single harvesting event evaluated after two years), (2) repeated harvesting (two harvesting events two years apart), and (3) not harvesting at all. After two years, the once-harvested group had a 90% survival rate and the unharvested control group had a 98% survival rate, a difference that was not statistically significant. The above-ground volume of the unharvested plants was significantly larger than that of the regrown harvested plants. While the regrown harvested plants had on average more crowns, their crowns were significantly smaller, in comparison to those of the unharvested plants. After two years, the surviving plants in the harvested group were divided into two subgroups, one of which was harvested for a second time. The other subgroup consisted of plants that had been harvested only once (at the start of the study) and were not reharvested. The weights of the crowns obtained in the second harvest were significantly lower than the weights of the crowns obtained in the first harvest from the same plants two years earlier. The net effect of a single harvesting was a reduction of plant above-ground volume by almost 80% after two years of regrowth. These data reflect what is occurring on a massive scale in habitat where peyote is commercially harvested. The annual numbers of crowns being harvested have not yet decreased drastically, due to the increased number of crowns produced as regrowth in response to harvesting. But the average size of the crowns in the regulated peyote market has decreased markedly due to too-early harvesting of immature regrowth crowns. These results—with emphasis on the conspicuous reduction in mean size of individuals—are typical of overharvested populations of wild-collected species, such as ginseng. The conclusion for conservation management is that reducing the frequency of harvesting of wild peyote would allow regrowth crowns to mature in size—thus reducing the number of crowns per dose required for sacramental consumption. It would also allow regrowth crowns to mature sexually, which would effectively de-suppress the production of seed for the next generation.

Terry et al. (2012). Limitations to natural production of Lophophora williamsii (Cactaceae) II. Effects of repeated harvesting at two-year intervals in a South Texas population.

JOURNAL ARTICLE

Limitations to natural production of Lophophora williamsii (Cactaceae) II. Effects of repeated harvesting at two-year intervals in a South Texas population.

Martin Terry, Keeper Trout, Bennie Williams, Teodoso Herrera and Norma Fowler

Journal of the Botanical Research Institute of Texas,

Vol. 6, No. 2 (23 NOVEMBER 2012), pp. 567-577 (11 pages)

PDF DOI

Abstract

In 2008 we began a long-term study of the effects of harvesting on a wild population of the cactus Lophophora williamsii (peyote), including harvesting treatments similar to those used to harvest it for legally protected religious use by members of the Native American Church. Here we assess the effects of harvesting in three different treatments: (1) plants that were harvested once, (2) plants that were harvested every two years (typical of commercial harvesting rates), and (3) control plants that were never harvested. After four years, the survival rate was significantly greater in the unharvested control plants (94%) than in the harvested plants (73%). Average harvested mass of fresh tissue per plant decreased significantly (by 44%) between the first and second harvests, and then further decreased significantly (by 32%) between the second and third harvests. The average number of crowns per plant, which increased after the first harvest, decreased after the second harvest. Estimated total volume of the above-ground crown(s) of each plant, which was closely related to harvested plant mass, was used to compare growth rates between treatments. The average growth rate of the multiple-harvest plants was significantly lower than the average growth rates of plants in the other two treatments. Growth rates in the control and single-harvest treatments did not differ significantly in 2012, but because the single-harvest plants were so much smaller than the control plants in 2010, they remained smaller than the control plants in 2012. The annual number of crowns harvested and sold commercially as "buttons" by licensed peyote distributors continued its slow decrease in 2011, while the price per unit continued to rise. These trends and the results of this study all indicate that present rates of peyote harvest are unsustainable.

Terry et al. (2014). Limitations to natural production of Lophophora williamsii (Cactaceae) III. Effects of repeated harvesting at two-year intervals for six years in a South Texas (USA) population.

JOURNAL ARTICLE

Limitations to natural production of Lophophora williamsii (Cactaceae) III. Effects of repeated harvesting at two-year intervals for six years in a South Texas (USA) population.

Martin Terry, Keeper Trout, Bennie Williams, Teodoso Herrera and Norma Fowler

Journal of the Botanical Research Institute of Texas,

Vol. 8, No. 2 (2014), pp. 541-550

PDF DOI

Abstract

Here we report the 6-year results of a long-term study of the effects of harvesting on a wild population of the cactus Lophophora williamsii (peyote). Harvesting was performed using the best known technique: removing only the crown from the top of the plant. The two-year interval between harvests was chosen because it was similar to that observed by persons who harvest peyote for legally protected religious use by members of the Native American Church. Plants in the study were divided into three treatment groups: (1) control plants that were never harvested, (2) plants that were harvested only once, at the beginning of the study, and (3) plants that were harvested at the beginning of the study and every two years thereafter. Over the last two years of the study (2012‒2014), the survival rate was significantly lower (77%) in the plants harvested every two years than in the once-harvested plants (100%) and the unharvested control plants (98%). At the end of the 6th year of the study, average volume of living crown tissue per plant was significantly and substantially lower in the plants harvested every two years than in the once-harvested plants and the unharvested controls. The average volume of once-harvested plants was 27% lower than that of the controls, although this latter difference was not statistically significant. The modal number of crowns per plant varied with treatment and over time; in the plants harvested every two years it underwent a progression from 1 to 2 to 3 to 1 in response to successive harvests. The results of this study indicate that a six-year recovery period, following the harvesting of peyote in natural habitats, is probably not long enough to ensure long-term sustainability. key words: cactus conservation, peyote harvest, cactus overharvesting, Native American Church, peyote conservation status.

Illustrative images

These images below are just a teaser of what sort of data we’ve been collecting on this longitudinal, 2008-2019 study. All our raw data, including measurements and photographs for each of more than hundred fifty study plants is available below.

This plant was not one of our subjects but is showing regrowth following an earlier harvest.

Regrowth on a Lophophora williamsii in 2018.

Notice that one of the crowns was harvested and replaced with a rock.

 

2010 regrowth on the same Lophophora williamsii that was shown above.

 

Regrowth on the same Lophophora williamsii in 2012.

Regrowth on the same Lophophora williamsii in 2014.

Regrowth on the same Lophophora williamsii in 2016.

Those are not yellow flowers but are floral remnants after the petals were eaten by something.

Regrowth on same Lophophora williamsii in 2016.

 

This was one of our study ‘participants’.

Regrowth on the same Lophophora williamsii in 2010.

Regrowth on same Lophophora williamsii in 2011.

Regrowth on the same Lophophora williamsii in 2012.

Regrowth on same Lophophora williamsii in 2014.

This was one of our study ‘control participants’.

The same plant had been harvested by someone when we visited in 2018.

 

Spreadsheets, tables and reports available for download here.

Please note that both file types offer raw data content.We recommend Word file for more casual readers and the Excel file for those who may want to work with the data.

COMING SOON

Images of plant tags (no plant images shown; images of tags were taken with date stamps to validate that plants were visited each year).

Despite the well-established history of successful greenhouse production of peyote for ornamental purposes in Europe and elsewhere, there is a great need for studies to determine optimal horticultural practices to maximize production of peyote biomass in a controlled greenhouse environment.  This will be the next phase of Cactus Conservation’s longitudinal research initiatives.  You can help ensure the research continues by your donations, large or small, to Cactus Conservation Institute.