POSSIBLY DD ??
Proper assessment cannot proceed until taxonomy of pink-colored Leptonia in the west is resolved.
CS, 3 April 2017. I forgot to mention - as for Lepiota subrubinea, I think we have to settle for Data Deficient.
The taxonomy, range, habitat associations, are all much blurrier than for the other species.
The pink colors of the fruitbodies usually draw enough attention that photos and collections are made and widely distributed/shared.
However, there are a number of forms (= putative species) of pink Leptonia species in this western United States, spanning a broad range from southern Calfornia to British Columbia. Until the taxonomy of this group is resolved, proper assessment cannot proceed.
Known from less than 10 localities, most collections are from a single mycelium in Humboldt County.
Associated with Coast Redwood (Sequoia sempervirens), an IUCN Endangered species, which is threatened by significant changes in seasonal precipitation (less winter rain and less summer fog) in recent decades. Not collected from the type locality in over three decades.
Although Leptonia subrubinea is not familiar to most collectors, the pink colors of the fruitbodies are striking (nearly diagnostic among members of the genus on the Pacific Coast), and likely to draw attention from even casual mycologists. Confusion possible with Leptonia rosea var. marginata and a number of putative undescribed species.
Described from a handful of collections from the same mycelium in Humboldt County (northern California), collected also at Salt Point (Mushroom Observer 225619) and Mendocino County (Desjardin SFSU-F-023481). Perhaps distributed along a narrow area of the Pacific coast. A collection from British Columbia does not seem to pertain to this species (Mushroom Observer 82089 = UBC28380). A collection from Idaho is suspect due to lack of notes “... identification questionable…”(Largent 1994).
Population size unknown, status and current trends unknown.
Although perhaps undersurveyed, the conspicuous nature of this species suggests that potential number of sites is not tremendously greater.
Litter decayer. Found on soil, moss, and needle-litter duff and humus; primarily (exclusinvely?) under Coast Redwoods.
Primarily associated with Coast Redwood forests. This tree is listed as Endangered by the IUCN due to a number of anthropogenic threats, both direct and indirect.
Climate change threatens this species by increasing fire frequency and intensity, increasing average yearly temperatures, increasing incidence and severity of drought conditions, and decrease of summer fog conditions upon which this species is dependent (especially in the southern areas of its distribution). The southernmost areas of Redwoods seem likely to experience local extirpations as climate continues to warm and dry and summer fog regimes dissipate.
From IUCN page on Sequoia sempervirens: “AOO is thus likely to fall below 2,000 km², the threshold for Vulnerable.
Past decline ... almost certainly in excess of 50% over three generations… Continuing decline is inferred from the fact that the proportion of redwood in commercially exploited forests containing this species is still declining, due to deliberate or accidental replacement by more competitive species in the early phases of succession after clear-felling, especially Pseudotsuga menziesii [5.3.3].”
Outreach to land managers in charge of suitable habitat in hopes of increased total area of protection. (IUCN 1.1 - Site/Area protection)
Recommend to land managers that fungal surveys should always incorporated into planning and research when long term land use and protection plans are being developed.
(IUCN 4.3 - Awareness and Communication)
Systematic surveys of Entolomataceae in Coast Redwood habitats, especially in areas near type locality, to determine whether known populations are still extant, and whether other populations exist. (1.2 Population size, distribution, & trends). Repeat surveys to determine long-term patterns. (3.1 Monitoring Population Trends).
Largent, D.L.; Thompson, B.L. 1985. Two new species in the Entolomataceae (Agaricales) from California. Mycologia. 77(6):984-987