PNF – Plant not found.
    TNF – Tag not found.
     NP   – Not present.
       –    – Missing data.


Concerning data on regrowth involving multiple pups:
    1) There is not necessarily a direct 1:1 correspondence between sequential figures for individual pups within a single plant.
    2) It was not uncommon for some or all pups to be partly or entirely covered with soil so some photos may reflect the pre-uncovery state.

    Images of the tags can be viewed via the links for the tag numbers and images of the actual plants can be viewed using the links in the columns headed "Regrowth as number of pups" or "Number of crowns".

The plants being surveyed are part of a larger population occurring on private land in South Texas. The area of the survey site itself is defined with a transect of 17-gauge electric fence wire secured with steel stakes the locations of which are recorded with a high resolution GPS. The transect zigzags through the study site with all plants in the study being located within approximately one-half meter of the wire. The area of the study site has not yet been accurately measured but we estimate it to be around half a hectare.

    Above are the data from the first eight months and the first twelve months of our study on the effect of harvesting on regrowth and mortality of peyote plants in habitat, with starting data on 50 plants (harvested 13 MAR 2008) and follow-up data collected eight months later (22-23 NOV 2008) and twelve months later (7 MAR 09). Diameters of original plants are given as the mean average of the widest and narrowest diameters whenever they were not symmetrical.
    At this point we are inferring mortality of a harvested plant if it produced no regrowth of buttons (zero in the "Regrowth as number of pups" column) up to the present.
    The percentage of multiple regrowth buttons per harvested plant (up to 6 new buttons per plant) is gratifying, and shows the benefit of the good harvesting practice of cutting high (at or above the junction of green aerial stem and the beige subterranean stem) and relatively level. The rather large size (up to about 2.5 cm in diameter) attained by some of these new buttons in only eight months was also gratifying, but the contribution of soil moisture from the hurricane in the summer of 2008 probably made this a better-than-average year for the growth of new buttons from old rootstocks.
    An unexpected problem that arose in the first study monitoring at the 8-month time point was the fact that we were unable to locate 11 out of the original 50 numbered tags and the plants to which they referred. The tags had been tied with 17-gauge wire to very large nails driven into the ground next to each plant in the study. Some lost tags were probably covered over with soil that washed down the slopes with the rains associated with the hurricane during the summer of 2008. Other tags and plants may have been dug up and buried by feral hogs, which are numerous on the property. Large holes (made by animals, not humans) were evident under many of the nurse shrubs where most of the peyote plants grow. We encountered a similar picture in Spring of 2009.
    This inability to locate these tags and the corresponding plants effectively reduced the number of plants in the study from 50 to 39 (a 22% loss). It also poses a question of interpretation, as the loss of such plants could be considered "natural" mortality if it is due to the digging of feral hogs.
    At present, we are simply eliminating from the study those plants whose tags were not found — where the plants themselves were likewise not found.
    We harvested, measured and tagged 20 more plants on 23 NOV 2008, to bring the total number of plants in the "harvested" group up to 59. {The results from our March 2009 visit concerning those twenty individuals can be found farther below.}

    The preliminary figure for mortality that may be attributable to harvesting, then, is 5/39, or about 13%. 

    2010 data


    We also tagged and measured a control group of 50 plants on 23 NOV 2008, which in future monitoring will give us an idea of the magnitude of natural mortality not associated with harvesting.

7 March 2009 update:
    Interestingly we found the same number of harvested study plants (with their tags) but as can be seen in the table above these were not entirely the same plants & tags as had been located on 23 November 2008.
    On this visit we used a Trimble high-resolution GPS instrument to record the location of all tags and/or plants located.
    Complete or partial burial of plants and their tags was sometimes encountered. To aid in future visits we added a rebar stake near each tagged plant.
    We did photograph additional plants that appeared to be previously harvested plants showing regrowth. One of which was lacking a photograph of the tag and, based on its location in the sequence of images, appeared likely to match #134 – which was recorded as being both found and measured. There were two additional images that also had no accompanying tag photos.
    These are referred to here as TNF 1 (possibly #134), TNF 2 & TNF 3.
    All of the 50 members of our control group were located but photographic data is not available for one of them.
    Images and data concerning the control group can be found below.

Control #154