January 6, 2014
Las Cruces, NM
Hello and happy New Year! Today is my first day back in the office after a relaxing holiday vacation, and it sure feels great to be back. Chicago, where I am from, is currently experiencing record low temperatures with a high of -12 and a low of -16. Let me repeat that. Today’s HIGH in Chicago is predicted to be -12. Las Cruces, on the other hand, is still experiencing highs in the upper 50’s and lower 60’s. Like I said, I am very happy to be back.
Before the holidays, Kate and I were busy monitoring the rare plant Peniocereus greggii var. greggii (Night-Blooming Cereus or Queen of the Night cactus), which is a cacti found exclusively in southern New Mexico, northern Mexico, and west Texas. This species has high ornamental value, and has been extirpated from several regions due to overcollection for commercial and private distribution. For more information about this species, see the New Mexico Rare Plants web site.
Night-Blooming Cereus (Peniocereus greggii var. greggii). Photo Credit: Mike Howard
For three weeks, Kate and I travelled to several populations scattered around the bootheel region of New Mexico to gather data on the species’ health and scout the region for new individuals. Currently, there is very limited data on Peniocereus greggii var. greggii, and its habitat preferences are poorly understood. One thing that is known about the species, however, is that it typically grows within a nurse plant, such as Creosotebush (Larrea tridentata). This relationship is beneficial to the Night-Blooming Cereus for several reasons: (1) the shrub overstory provides physical protection from herbivory, trampling, high winds, or other potential sources of damage, (2) the shrub canopy also provides shade, which may prevent damage from excess solar radiation, (3) the nurse plant also increases nutrient and water availability.
Kate and I were assigned to monitor this species because BLM New Mexico has an ongoing project that may threaten the relationship between the Night-Blooming Cereus and its nurse plant. Restore New Mexico is a nine-year-old project whose mission is to restore New Mexico’s land to its former species composition. This includes promoting the spread of native grasses in the Chihuahuan Desert region of the southern portion of the state. Shrubs, such as Creosotebush (Larrea tridentata) and Mesquite (Prosopis glandulosa) have come to dominate the Chihuahuan Desert due to a combination of climate change and overgrazing. In order to facilitate the establishment of native grasses, BLM New Mexico applies herbicide to large portions of its land to kill off the dominant shrub cover. This approach, however, may be problematic for the Night-Blooming Cereus since the herbicide kills off its nurse plants.
One of the Peniocereus greggii populations that Kate and I monitored was divided evenly between treated and untreated parcels of land. Therefore, Our Peniocereus greggii var. greggii monitoring work will hopefully be the beginning of a long term project to assess the affects of herbicide application on Night-Blooming Cereus health. While the data we collected this year have not yet been analyzed, we were surprised to find a significant number of healthy Night-Blooming Cereus individuals within the treated parcels of land. However, long term monitoring is still needed to determine whether it is safe to apply herbicide to areas occupied by rare plants, such as the Night-Blooming Cereus.
-Elisabeth Ward