Hypotrachyna riparia is known from nine locations in Oregon state in the United States of America. Large wildfires pose a serious threat to this species, and in 2020 one of the largest subpopulations was likely extirpated, and at minimum led to a 25% decline in the total population size. The invasion of the Emerald Ash Borer poses an additional threat to the species as it expands its range into Oregon in the coming years. Based on the species' ongoing decline, limited extent of occurrence and area of occupancy, and the ongoing decline of its habitat, it is assessed as Vulnerable (A4ce; B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)).
Assessor/s: Stone, D., Villella, J. & Root, H.; Reviewer/s: Allen, J.; Contributor/s: Loring, S.; Facilitator(s) and Compiler(s): Lymbery, C. & Allen, J.
Bibliography:
Alig, R.J. (2003) Land use changes involving forestry in the United States, 1952 to 1997, with projections to 2050. Pacific Northwest Research Station587: 92.
IUCN (2022) The IUCN Red List of Threatened Species. Version 2022-1. Available at: www.iucnredlist.org. (Accessed: 21 July 2022).
McCune, B. (1998) Hypotrachyna riparia, a new lichen from western North America. The Bryologist101(3): 448-450.
Miller, J.E., Root, H.T. & Safford, H.D. (2018) Altered fire regimes cause longāterm lichen diversity losses. Global Change Biology24(10): 4909-4918.
Nisbet, D., Kreutzweiser, D., Sibley, P. & Scarr, T. (2015) Ecological risks posed by emerald ash borer to riparian forest habitats: A review and problem formulation with management implications. Forest Ecology and Management358: 165-173.
Find out more about the IUCN Red List Categories and Criteriahere.