Assessment Notes

Justification

Alectoria fallacina is endemic to the Appalachian Mountains of eastern North America. It is known from a small number of scattered occurrences in remnant old-growth forests. The majority of the extant population occurs in Great Smoky Mountains National Park in the eastern United States. The species is large and conspicuous, and has been searched for extensively in suitable habitat throughout the entire range of the taxon. In addition to being restricted to old-growth forests, the species occurs on mature trees of specific conifer host species. The rarity and spatial dispersion of the population make the species particularly susceptible to stochastic events including wildfires and storms. These events are increasing in the area where it occurs, particularly in the region that hosts the largest subpopulation. Host trees have been impacted previously by invasive species and air pollution, and continue to be impacted directly by invasive species. The southern Appalachian spruce-fir forests where much of the population occurs are considered endangered and likely to be greatly impacted by climate change in the near-term future. The species has a very restricted distribution and there are inferred continuing declines in EOO, AOO, habitat quality, and number of mature individuals. Therefore, it is assessed as Endangered under criteria A2ce and B2ab(i,ii,iii,v).

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Taxonomic notes

Alectoria fallacina is a chemically and morphologically distinct species that has been recognized for nearly 100 years and considered endemic to the Appalachian Mountains of eastern North America. A detailed treatment and comparison to the allopatric and widespread A. sarmentosa, with which it has been confused, was published by Lendemer and McMullin (2022).

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Geographic range

Alectoria fallacina is endemic to the Appalachian Mountains of eastern North America where it occurs on mature conifers in remnant old-growth forest stands (Lendemer and McMullin 2022). There are five locations at which the species is currently known to be extant, and one location hosts the majority of individuals in the population.

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Population and Trends

The population is distributed across three spatially restricted and separated subpopulations that are strongly disjunct. The majority of extant individuals are concentrated in a single subpopulation located in Great Smoky Mountains National Park (GSMNP), in the eastern United States.  Historical occurrences from New York and Virginia, U.S.A. suggest the species was more widespread and that there have been past declines in EOO, AOO, number of mature individuals, number of locations and number of subpopulations.

Population Trend: decreasing

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Habitat and Ecology

Alectoria fallacina occurs on the bark and branches of mature individuals of specific conifer species (Balsam Fir, Abies balsamea; Fraser's Fir, Abies fraseri; Red Spruce, Picea rubens; Eastern Hemlock, Tsuga canadensis) in remnant old-growth forests (Lendemer and McMullin 2022). It primarily occurs in the canopies of mature trees, with fragments of thalli falling and becoming established on lower branches closer to ground level.

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Threats

This species was historically impacted by large-scale logging throughout its range in the Appalachian Mountains as is now restricted to remnant old-growth conifer forests. Old-growth forest habitats have been greatly reduced from their historical extent throughout the Appalachian Mountains where the species occurs and the habitat is now highly fragmented. The population is currently being impacted by an invasive species that causes mortality of several host tree there (e.g. Hemlock Wooly Adelgid, Adelges tsugae and Eastern hemlock, Tsuga canadensis; Ellison et al. 2018). The population has also likely been impacted by air pollution, including acid rain and fog in the past (Noss et al. 2015).

Now, the spruce and spruce-fir ecosystems where the species occurs is also imperilled by invasive species and climate change (Noss 2015, Allen and Lendemer 2016, Lendemer et al. 2017). All of the subpopluations are subject to minor impacts from recreation and maintenance of recreation infrastructure, as well as ongoing maintenance of roads and utility corridors. The majority of the population, occurs in Great Smoky Mountains National Park, U.S.A. and occurrences within this subpopulation were likely extirpated thorough direct and indirect effects of the 2016 Gatlinburg wildfire.

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Conservation Actions

The entire location in Great Smoky Mountains National Park is well-protected, and this represents the majority of the entire population (>90%).

Monitoring of all extant sites is required to determine the degree, rate and time-frame of decline. Detailed surveys and increased protections for suitable habitat is also needed. The species is not currently included on lists of threatened taxa. A species-based management plan needs to be developed, and the species needs to be incorporated into existing management plans for suitable habitat and extant sites. Study of the potential reintroduction into formerly occupied areas should be considered. Increased education about the species, its ecology, and how it could be conserved would also be highly beneficial.

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Use and Trade

This species is collected for scientific research.

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Source and Citation

Lendemer, J. & McMullin, T. 2022. Alectoria fallacina. The IUCN Red List of Threatened Species 2022: e.T194660207A194678104. https://dx.doi.org/10.2305/IUCN.UK.2022-1.RLTS.T194660207A194678104.en .Accessed on 1 August 2023

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• Country occurrence