• 1Proposed
  • 2Under Assessment
  • 3Preliminary Assessed
  • 4Assessed
  • 5Published

Peltigera aquatica Miadl. & Lendemer

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Scientific name
Peltigera aquatica
Miadl. & Lendemer
Common names
Western Water Fan
IUCN Specialist Group
Assessment status
Proposed by
James Lendemer
James Lendemer
Comments etc.
Anders Dahlberg

Assessment Notes

Taxonomic notes

Why suggested for a Global Red List Assessment?

Peltigera aquatica (Common name: Western Water Fan) is endemic to mountainous regions of western North America where it is restricted to aquatic habitats in high quality mountain streams. It is endangered by multiple factors including habitat destruction/degradation and climate change.

Geographic range

Peltigera aquatica is endemic to mountainous regions of the western United States, ranging from California north to Washington.

Population and Trends

Demographic studies are needed to assess and monitor populations sizes. Many populations are known only from historical occurrences and there has been documented declines of some populations in long-term observational studies in California.

Population Trend: Decreasing

Habitat and Ecology

This species is restricted to slow moving, relatively small, cold mountain streams with high water quality and low turbidity.

Temperate Forest


The threats to this aquatic species are diverse. The major threats stem from 1) changes in habitat (macro- and micro- scales) resulting from deposition of pollutants and ecosystem alterations, 2) changes in habitat (macro- and micro- scales) that are likely to result from climate change, 3) changes in habitat (macro- and micro- scales) resulting from conversion and deterioration of natural habitats both historically and ongoing.

Residential & commercial developmentHousing & urban areasCommercial & industrial areasTourism & recreation areasLivestock farming & ranchingEnergy production & miningOil & gas drillingMining & quarryingRenewable energyTransportation & service corridorsRoads & railroadsUtility & service linesLogging & wood harvestingUnintentional effects: large scale (species being assessed is not the target) [harvest]Natural system modificationsFire & fire suppressionDams & water management/useInvasive non-native/alien species/diseasesPollutionDomestic & urban waste waterSewageRun-offIndustrial & military effluentsSeepage from miningAgricultural & forestry effluentsNutrient loadsSoil erosion, sedimentationHerbicides and pesticidesGarbage & solid wasteAir-borne pollutantsClimate change & severe weatherHabitat shifting & alterationDroughtsTemperature extremesStorms & flooding

Conservation Actions

There are many conservation actions that can be taken including educating and training land managers and local botanists to identify the species so we can monitor its health, federally listing the species as endangered in the United States, improving numerous regulations and policies that would safeguard the aquatic habitats where the species occurs, and providing increased protection for buffer forest stands along riparian areas where the species occurs and could occur in the future.

Land/water protectionSite/area protectionResource & habitat protectionLand/water managementSite/area managementHabitat & natural process restorationSpecies recoveryEducation & awarenessFormal educationTrainingAwareness & communicationsLaw & policyLegislationPolicies and regulationsNational level

Research needed

The overall distribution of this species is well understood. Further research that will aid in the conservation of this species includes population assessments and monitoring, population genetics studies, and ecological studies that incorporate threats to the species. Additionally, a species recovery plan needs to be written.

ResearchPopulation size, distribution & trendsLife history & ecologyThreatsActionsConservation PlanningSpecies Action/Recovery PlanArea-based Management PlanMonitoringPopulation trends

Use and Trade


Miadlikowska, J./ D. Richardson/ N. Magain/ B. Ball/ F. Anderson/ R. Cameron/ J. C. Lendemer/ C. Truong/ F. Lutzoni 2014: Phylogenetic placement, species delimitation, and cyanobiont identity of endangered aquatic peltigera species (lichen-forming Ascomycota, Lecanoromycetes). . - American journal of botany 101(7): 1141-1156.

Country occurrence

Regional Population and Trends

Country Trend Redlisted