Argemone pleiacantha ssp. pinnatisecta

A genetic study by Cervantes et al. (2010) concluded the taxon should be treated as a species, Argemone pinnatisecta.

This taxon is a perennial herb in xeric to mesic, disturbed sites, canyon bottoms and slopes endemic to the western slope of the Sacramento Mountains in Otero County, New Mexico in the southwestern United States. There are approximately 20 occurrences, though population size is difficult to estimate due to annual fluctuations with moisture availability. Plants require at least two years between germination and establishing as mature individuals. In combination with low population recruitment, small population sizes and low genetic divergence among populations increase the possibility of extirpations, making this taxon moderately vulnerable. It also has narrow environmental specificity, requiring sufficient moisture and habitat stability in a xeric landscape with multi-use threats, including water pipeline maintenance and water extraction, grazing and trampling by livestock, road construction and maintenance, and off-road vehicles. Additional threats include erosion, flooding, drought, competition from non-native plants, and Alternaria, a species of fungal mold. Additional measures to protect the taxon should be enacted, including the enforcement of rotation dates for cattle, livestock exclusion fences, and investigating acquisition of water rights.

This taxon is endemic to the western slope of the Sacramento Mountains in Otero County, New Mexico in the southwestern United States (FNA 1997, McDonald 2010). Range extent was estimated to be 304 square kilometers using NatureServe Network occurrence data documented between 1994 and 2025 (RARECAT 2024, NatureServe 2025).

By applying a 1 km separation distance to NatureServe Network occurrence data documented between 1994 and 2025, it is estimated that there are twenty populations which may be considered six occurrences based on shared watersheds (RARECAT 2024, NatureServe 2025).

Detailed descriptions of threats can be found in five-year reviews (USFWS 2013, USFWS 2022). Threats include ongoing water pipeline maintenance and water extraction, grazing and trampling by livestock, erosion, flooding, drought, road construction and maintenance, off-road vehicles, competition from non-native plants, and Alternaria, a species of fungal mold.

Municipal water use and water extraction of springs predate the creation of the National Forest. Water extraction has altered natural hydrology, likely reducing poppy habitat by decreasing water availability in the canyons. Additionally, repair, replacement, and maintenance of the pipelines further impacts the taxon's habitat (USFWS 2013).

Livestock grazing directly impacts plants and alters their preferred habitat. Cattle congregate in the mesic microsites where the poppy persists during drought periods, leading to increased trampling of plants. "Healthy mature plants appear to be capable of re-sprouting after livestock tread on them, but mortality appears likely to occur in young plants or in stressed mature plants suffering from drought or disease. Damage to seedlings by livestock has long been suspected and occasionally reported, but was rarely documented. Direct evidence of cattle dislodging poppy seedlings was observed in 2006 (Tonne 2008)" (USFWS 2013). Perhaps more importantly, cattle can severely alter the habitat to a point where it no longer supports the poppy by removing vegetation through grazing and increased erosion from loss of stabilizing vegetation and compaction from hooves, leading to increases in erosion, increases in channel incision, and decreasing bank stability (USFWS 2013).

"In healthy riparian areas, moderate levels of flooding appear to benefit the poppy by contributing additional water, silt, and nutrients for increased germination and establishment;" however, the alteration of habitat from cattle in combination with severe rains and flooding cause increasing damage to habitat and threaten the loss of plants (USFWS 2013). In severe floods, plants can be uprooted, leading to direct loss of plants. Additionally, plants may be buried and unable to resprout. The preferred soil composition may be washed away with a deposition of suboptimal habitat for the species, also loosing co-associated vegetation that provides soil stabilization. These severe floods also further alter the stream channels, removing structure in the bars, banks, and terraces and the distribution of water through the system.

Conversely, droughts can cause plants to fail to produce seed, cause catastrophic loss of seedlings, and increase disease prevalence. In drought years, when plants may have additional stresses, prevalence of a disease appears to increase leading to necrotic tissues. This disease appears to be a mold in the genus Alternaria. "Plant mortality due to the fungus is suspected, but is not well-documented (Sivinski 1999). Alternaria may only kill plants that are already quite stressed, or is possibly restricted to the aerial portion of the plant and does not affect the roots. It is unclear whether plants that die back are able to re-sprout" (USFWS 2013).

Populations along roadside face threats from roadside maintenance activities. At least three adult plants were killed with herbicide spraying in 2007, so an agreement has been made to not treat roadsides with this taxon with herbicide (USFWS 2013). City road maintenance also destroyed many mature poppies through clearing a maintenance road; "blading along drainage ditches and the shoulders of unpaved roads has destroyed some poppy plants.... Invasive plants such as Russian thistle, tamarisk, spotted knapweed, and Russian knapweed occur in poppy habitat. At present, the Forest Service and New Mexico State Highway and Transportation Department coordinate efforts at weed control and implement spraying of infested sites along the highways. Because plant competition may be a limiting factor to the distribution of the poppy based on the poppy’s preference for sites that are more open and less densely vegetated, eliminating invasive plants may be beneficial for the poppy (U.S. Fish and Wildlife Service 1994). However, any spraying performed near poppy individuals still may pose a threat to the survival of this species" (USFWS 2013).

Roads through poppy habitat introduce additional threats from off-highway vehicles. "Unauthorized off-highway vehicles can crush individual poppy plants and threaten the health of poppy habitat. Off-highway vehicles can destabilize or compact soils, which affect seed germination and plant growth....Off-highway vehicles can crush or disturb poppy individuals and may modify the soils, local hydrology, and microclimates associated with seed germination and plant growth (U.S. Forest Service 2004). Furthermore, the creation of trails through poppy habitat can promote the spread of noxious weeds already present in the area" and threaten seedling establishment through competition (USFWS 2013).