Nolina cismontana

Nolina cismontana published as the name for this taxon by Hess and Dice (1995). Accepted by Kartesz (1999). Apparently formerly included in Nolina parryi as "ssp. parryi", for example by Munz, but in a sense excluding its type. Accepted by Baldwin et al. (2012).

Found only in the cismontane region of southern California (Western Transverse Ranges and northern and western Peninsular Ranges), in Ventura, Orange, Riverside, and San Diego Counties. Approximately 49 occurrences are believed extant. Many are highly threatened by development. Potential indirect effects from development include changes in the frequency and timing of wildfires; fire regime alteration is likely the primary threat to the species in protected areas. Believed to be declining throughout its range (on both protected and unprotected lands) due to habitat loss and degradation.

Endemic to southern California. Found only in the cismontane region of southern California, in the Western Transverse Ranges and northern and western Peninsular Ranges. Scattered populations range from the Ojai Valley area/foothills of Santa Ynez Mountains (western Ventura Co.) south to the Simi Hills and Santa Monica Mountains (southeastern Ventura Co.), Santa Ana Mountains (Orange, Riverside, and San Diego Cos.), foothills west of the Palomar and Cuyamaca Mountains (San Deigo Co.), and the vicinity of Viejas Mountain (San Deigo Co.). Apparently, no locations in Los Angeles County have been documented (USFWS 2007). There are no element occurrences from Riverside County, but the species has been reported from that county in the Cleveland National Forest near Corona (USFWS 2007).

There are approximately 49 extant occurrences (CNDDB 2015).

Threats include development, agriculture, roads, recreation, inappropriate burning regime (CNDDB 2015). Occurrences not on protected land are highly threatened by habitat loss to development, including urban development, conversion to agriculture (e.g. orchards), and road construction (Reiser 1994, USFWS 2007, Ingram 2008, CNPS 2009). Remaining habitat is also becoming more fragmented as a result of these activities. Potential indirect effects from development include changes in the frequency and timing of wildfires due to increased human-caused ignitions associated with new urban areas and increased access to open spaces (Stephenson and Calcarone 1999); fire regime alteration is likely the primary threat to this species in protected areas (USFWS 2007). Altered fire regimes may also prompt increases in fire suppression activities, which could further disturb habitat (Stephenson and Calcarone 1999). Another potential indirect effect of development is increases in non-native species as a result of new roads, urban areas, and other ground-disturbing activities (Stephenson and Calcarone 1999). Recreational activities have also been cited as a threat to this species (CNPS 2009).