Lamelloporus americanus is a saprophytic species that grows on dead trunks restricted to Cloud Forests in Central America and western South America, associated only with high altitude environments, above 1,000 m asl, being dependent on specific climatic conditions (temperature, humidity, etc.) of these areas. It is known from single sites in Colombia, Costa Rica, Mexico, Panama, Venezuela, Ecuador and Peru, and despite being a widespread species it is considered rare. The Cloud Forests associated with the Neotropical region are expected to face a decline of up to ca. 90% in the next 40 years (Helmer et al. 2019, Lutz et al. 2013, Ponce-Reyes et al. 2013). Additionally, intentional burning, hunting, and intensified agriculture are current threats to this species, also impacting its habitat quality requirements. Based on L. americanus restricted distribution to Cloud Forest areas and the critical reduction of these environments predicted in the Neotropical region, which will translate in a reduction of population size and habitat quality for the species, a conservative reduction of at least 50% in the next 40 years (reflecting three generations of the species) is suspected. The species is consequently assessed as Endangered (EN A3c).

Lamelloporus americanus Ryvarden, Mycotaxon 28(2): 529 (1987), from Mexico.

A very conspicuous and easily identifiable, neotropical, submontane-montane, moist forest polypore, yet with very few records from this threatened forest ecosystem.

Lamelloporus americanus is expected to be restricted to Cloud Forests throughout the Central America region and western South America, and thus associated only with high altitude environments, above 1,000 m asl (Ryvarden 1987, Mata et al. 2007, Romero-Bautista et al. 2010, Guzmán and Piepenbring 2011, Salvador-Montoya et al. 2015, Vandegrift et al. 2023). It is known from single sites in the countries of Colombia, Costa Rica, Mexico, Panama, Venezuela, Ecuador and Peru, and is apparently very rare within its distribution area. The species does not occur in all Cloud Forest areas within the Neotropical region, as despite the large sampling efforts in Southern Brazilian Cloud Forests since 2011, no specimen was found. Therefore, it is expected that the species requires specific conditions associated with Central America and western South America high altitude areas. It is expected that the species could also occur in other countries with cloud forests not yet recorded in Central America.

Lamelloporus americanus is a conspicuous and rare species occurring on dead trunks, with only seven records in Cloud Forests within Central America and western South America. The species is believed to be restricted to these high altitude areas (above 1,000 m asl) within its occurrence range (from Peru to Mexico, but could also occur in cloud forests of Central America countries where the species was not recorded), as several expeditions with significant sampling effort have been carried in other Cloud Forests areas in the Neotropical region, such as in Southern Brazil, and the species was never found. The Cloud Forests associated with the Neotropical region are expected to face a decline of 57% to 86% in the next 37 years, due to a reduction in cloud immersion, which is an essential condition for the existence of these formations (Helmer et al. 2019). Additionally, Cloud Forest areas from the countries where the species occurs are predicted to reduce by up to 96% (Lutz et al. 2013, Ponce-Reyes et al. 2013). Based on L. americanus restricted distribution to Cloud Forest areas and the critical reduction of these environments predicted for the Neotropical region, which will translate to a decrease in population size and habitat quality for the species, a reduction of at least 50% in the next 40 years (reflecting three generations of the species) is conservatively suspected.

Lamelloporus americanus is a saprophytic species that grows on dead trunks (Ryvarden 1987, Mata et al. 2007, Romero-Bautista et al. 2010, Guzmán and Piepenbring 2011, Salvador-Montoya et al. 2015, Vandegrift et al. 2023). The label of the type material mentions that it was found on the wood of Ulmus sp., and it does not specify whether the host was alive or decomposing. A generation length of 40 years is defined based on the substrate durability in which the species is found. With respect to habitat type, vegetation type, and altitude, Salvador-Montoya et al. (2015) infer that the species exhibits a distribution restricted to Cloud Forests in the Neotropics. Given the existing records of L. americanus, it presents a preference or adaptability to the climatic conditions (temperature, humidity, etc.) of these areas.

The threats that affect Lamelloporus americanus population and its habitat are climatic and anthropogenic effects, which have been varying over time (Young and León 2007, Valencia et al. 2010). For example, intentional burning leading to the promotion of grasslands from arson for grazing, hunting and intensified agriculture has reduced approximately 500 m from the forest line of mountain forests where no anthropogenic disturbance existed (Lægaard and Balslev 1992, Sarmeinto 1995, Sarmiento and Frolich 2002, Young and León 2007, Valencia et al. 2010). Despite these threats, currently, the main threats to L. americanus populations that will reach all populations simultaneously, are the climate change outcomes. Regarding the Cloud Forests of the countries where L. americanus was recorded, Peru’s Cloud Forests display the highest predicted loss of area, which would be reduced by up to 96% in the face of the drastic advance of climate warming in the 21st century (Lutz et al. 2013). Also, Ponce-Reyes et al. (2013) analyzed the decline of Cloud Forests in Mexico over the next 60 years, and estimated that the cover of these forests could be reduced by 20%. These estimates are somewhat in line with predictions for all Cloud Forests areas in the Neotropical region, in which a reduction in cloud immersion, a vital characteristic for Cloud Forests maintenance, of 57-86% will happen between 2041-2060, depending on the greenhouse gas emissions scenario (Helmer et al. 2019).

In addition to promoting the dissemination of the urgent need for Cloud Forest protection and climate change awareness in the media or social networks, it is seen that it is necessary to carry out in vitro cultures (ex situ conservation) of this taxon in order to preserve its genetic diversity. It is also important to recognize Cloud Forest areas as fragile and unique ecosystems and promote in situ conservation of these areas.

More clarification is needed regarding the species distribution in Cloud Forest areas in countries within its occurrence range (including those countries without records, but potential for it), as well as its exact habitat requirements. Also, it is necessary to verify the possibility to preserve the species genetic diversity using in-vitro approaches.

There are no known uses for this species.

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Guzmán, G. & Piepenbring, ,M. 2011. Hongos de Panamá. Introducción a la identificación de los macroscópicos. México D.F.: Instituto de Ecología, A.C. 372 p.
Læssøe, T. & Petersen, J.H. 2008. Svampelivet på ækvator. Svampe 58: 1-52.
Mata, M., Ruiz-Boyer, A., Carranza, J. & Ryvarden, L. 2007. Nuevos registros de hongos poliporoides (Basidiomycetes) para Costa Rica. Boletín de Sociedad Micologica de Madrid 31: 123-129.
Ponce-Reyes, R.,  Nicholson, E., Baxter, P.W.J., Fuller, R.A. & Possingham, H. 2013. Extinction risk in cloud forest fragments under climate change and habitat loss. Diversity and Distributions 19(5-6): 518-529.
Ryvarden, L. 1987. New and noteworthy polypores from tropical America. Mycotaxon 28(2): 525-541.
Salvador-Montoya, C.A., Millán, B., Janovec, J. & Drechsler-Santos, E.R. 2012. Lamelloporus americanus (Fungi: Polyporales): a new record for Peru. Check List 8(3): 575-576.