The following Participating Institutions are custodians for this species in the CPC National Collection:
Rancho Santa Ana Botanic Garden
The conservation of Arenaria ursina is fully sponsored.
Naomi Fraga contributed to this Plant Profile.
Arenaria ursina (Bear Valley sandwort) is a low tufted perennial in the pink family (Caryophyllaceae) endemic to the northeastern San Bernardino Mountains, San Bernardino County, California. This species occurs in a unique habitat called pebble plains (also known as pavement plains). Pebble plain habitat is of limited distribution (occurring only in the San Bernardino Mountains) and supports a biologically rich but highly threatened plant community that consists of small cushion forming plants, minute annuals, grasses, and succulents. Arenaria ursina was listed as threatened by the federal government in 1998.
Distribution & Occurrence
Arenaria ursina occurs on pebble plains and is often associated with Eriogonum kennedeyi var. austromontanum (also a pebble plain endemic). This species prefers mesic rocky sites with accumulated leaf litter within pebble plains and occurs at elevations of 6,720-9,475 ft (2,050-2,890 m) (USDA FS 2007a, USFWS 1998). Pebble plains are open treeless areas that consist of clay soil (up to 53%) mixed with a pavement of quartzite pebbles and gravel that are pushed to the surface through frost action (USDA FS 2007a). The combination of clay soil, frost heaving, extreme temperature fluctuations, high light intensity, and desiccating winds is thought to prevent the establishment of tree species on pebble plains (USDA FS 2007b).
|The California Natural Diversity Database reports 25 occurrences, 17 of these are on the San Bernardino National Forest. The number of individuals at each occurrence ranges from thousands of plants to hundred of plants, and the number of plants at most occurrences is unknown (CNDDB 2007).|
Conservation, Ecology & Research
existing roads and trails bisecting habitat
Implement strategies within the Pebble Plain Habitat Management Guide to the greatest extent practicable.
Utilize the habitat suitability criteria and detection protocols developed for this taxon and apply to surveys at the project level.
Survey all new occurrences of Arenaria ursina and any occurrences that have not been visited in the past ten years, and record occurrence status, habitat condition, and threats.
Collect a herbarium voucher specimen of Arenaria ursina to document new occurrences or to verify a historical occurrence if the occurrence is not known to have been documented in at least ten years prior.
Map known and new occurrences of Arenaria ursina in the plan area using NRIS data collection standards, and incorporate these occurrences into the GIS corporate database.