Psathyrella atlantica V. Coimbra & Wartchow, Acta Botanica Brasilica 34 (2): 395 (2020). Psathyrella atlantica was described by Coimbra et al. (2020), based on both morphological and molecular evidence. Currently, there are no synonyms to this species, and based on morphological and phylogenetic analysis, the authors assume that this species is a genuine member of Psathyrella stricto sensu.
This is a rare species, known only from one collection found in Pernambuco State, Brazil in 2020. It is likely to become even rarer with the continued loss and degradation of the habitat in the Atlantic Forest due to human activity and climate change. Due to an estimated population size of up to 4,000 mature individuals, and decreasing, Psathyrella atlantica is assessed as Vulnerable (VU), under criteria C1;C2a(ii).
This species is found in the Atlantic Forest, and it was described as occurring at the lowland ombrophilous dense forest with a regeneration process (Coimbra et al. 2020). The species is currently known from one site, in the municipality of Tamandaré, found growing on litter deposited on the soil at ‘Reserva Biológica de Saltinho’, a biological reserve with Atlantic Forest remnants located in the municipalities of Tamandaré and Rio Formoso, Pernambuco State, Northeast Brazil. Nonetheless, the species is expected to be distributed along the Atlantic Forest in the dense ombrophilous forest areas/remnants. Considering the vegetation structure of the ombrophilous dense forest found in the ‘Reserva Biológica de Saltinho’ in Pernambuco with those ombrophilous forests that occur in the Amazon region (Condé et al. 2013), it is important to consider that P. atlantica can reach these areas, where vegetational cover is more conserved than that found in Atlantic Forest biome.
Psathyrella atlantica is a recently described species, currently known from one site, with one collection, composed by caespitose basidiomata with 11 mushrooms clustered (Coimbra et al. 2020). This site is located at ‘Reserva Biológica de Saltinho’ in the municipality of Tamandaré, Pernambuco State, Northeast Brazil. Since is expected that this species can reaches other regions where there is the presence of remnants of lowland ombrophilous dense forest, up to 100-500 additional potential sites is also expected each of them supporting around six mature caespitose individuals per site (1 collection / 1 site × 3 multiplied factor × 2 ramets). Northeastern Brazil has most of the mycology studies in Brazil (see Maia et al. 2015 and their cited references), and even with intense efforts to sample Funga in the region, the species has not been observed before or even after its description and formal publication. Thus, it is estimated that the population of Psathyrella atlantica is around 800 to 4,000 mature individuals, restricted to one subpopulation.
In the last decades, deforestation has increased in the Atlantic Forest, characterized as a hotspot for biodiversity protection, highly fragmented (Myers et al. 2000, Rezende et al. 2018). Data on deforestation rates from Atlantic Forest indicate that the original vegetation cover was reduced to less than 28%, including both forest (26%) and non-forest native formations (2%) in Brazil. The population decline of Psathyrella atlantica was estimated in light of extension loss of suitable habitat (Joly et al. 2014, Rezende et al. 2018) and the putative influence that habitat degradation has on species occupation in a given environment (Berglund & Jonsson 2005, Haddad et al. 2015), with at least 30% of the species’ population decreasing in the last three generations (20 years), due to the habitat loss. Thus, the species has a suspected population decline of at least 30% within this same timeframe.
Population Trend: Decreasing
Psathyrella atlantica is a saprophytic species, growing in the litter deposited on the soil. This species forms caespitose basidiomata composed by some slender, whitish, and with a small orange floccose-squamulose veil remnants pileus clustered mushrooms (Coimbra et al. 2020).
The Atlantic Forest is considered a hotspot for biodiversity conservation due to various anthropogenic pressures, vegetation cover conversion, and the high rate of endemism observed in the biome (Myers et al. 2000). Because the remnant of the biome is highly fragmented, the annual rate of deforestation is still high and the consequences of the effects of environmental changes due to climate change, the areas where the species can occur are highly threatened (Salazar et al. 2007, Tabarelli et al. 2010, Rezende et al. 2018). Furthermore, an emerging threat is flexibility observed in public policies for the conservation of the Atlantic Forest. Recent deregulating acts from the current Brazilian government reduced protection and provided amnesty for deforestation in the Atlantic Forest (Vale et al. 2021). Psathyrella atlantica was observed in one site that is a kind of protected area by Brazilian law (Law nº 9.995/2000), close to urban centers, sites that may be heavily threatened, even under legal protection. In addition, the areas with the occurrence of ombrophilous dense forests are located in flat coastal areas. These coastal forest formations have been fragmented, converted, and occupied since the beginning of colonization, and overall, 65% of the biome surface is covered by anthropic areas. The few remnants are under intense anthropogenic pressure due to the expansion of coastal cities, illegal hunting, and excessive exploitation of natural resources (Joly et al. 2014, Schneider et al. 2018).
Ensuring the conservation of Atlantic Forest, under the Brazilian Native Vegetation Protection Law (Law No. 12.651/2012), known the Brazilian Forest Code, and mainly under the most specific law of protection for the biome (Law No. 11.428/2006) is the most efficient short-term measure. Forest restoration actions, the creation of new preservation areas, management, maintenance, and protection of existing preservation areas are also strategies that should be adopted for the conservation of habitats where the species can potentially occur (IIS 2021).
More surveys in suitable areas for the occurrence of the species should be explored, to determine the extent of its geographic distribution along the Atlantic Forest and even in other biomes in the country, such as the ombrophilous dense forests that occur in the Amazon. Additionally, new collections may help to specify any variability of its morphological characters (Coimbra et al. 2020).
No use/trade known.
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