Congrats to Oswaldo Valdez on graduating with a bachelor’s degree in biology from the Universidad de la Sierra, where he presented the results of his internship report on the efficacy of manual control for the invasive species Mimosa aculeaticarpa in grasslands at Rancho Agua de Enmedio, Cananea, Sonora. He was advised by Zach Palma, SIA’s program director for the southern Sky Islands.
By Oswaldo Valdez
My research was conducted at Rancho Agua de Enmedio, in Cananea, Sonora, where I addressed a problem that exists in the region: the expansion of the invasive plant Mimosa aculeaticarpa, known as catclaw. This plant is a thorny shrub that has been reproducing and spreading, taking up space in native grasslands, and forming dense patches that reduce ecosystem productivity and promote erosion.
My objective through this study was to evaluate the efficacy of manual control (extraction with a pickaxe and shovel) of this invasive species and to determine whether it truly works as a strategy to reduce catclaw presence and promote grassland recovery. To do so, I compared a treated plot with an untreated one, measuring density, coverage, and resprouting capacity.
The results showed that manual control of catclaw was effective, achieving a reduction of nearly 65% in individual plant density in the treated plot. A reduction in average coverage was also observed, which promoted the recovery of grass cover in the treated area. 28.9% of the catclaw individuals evaluated in the treated plot showed resprouting, associated with the recorded root/height ratio, which also confirmed something important: Catclaw is a resilient species. It has a high resprouting capacity and tolerance to disturbance, which demonstrates that manual control, while effective at reducing its abundance and coverage, should be complemented with continuous monitoring and ecological restoration strategies to ensure the sustainable recovery of grasslands.
In conclusion, this research shows that, although manual removal of catclaw does not completely eliminate the risk of resprouting, it does significantly reduce the density and vigor of remaining individuals, making it a useful technique to integrate into management, restoration, and conservation programs in semi-arid landscapes in northern Sonora.