Abrachium floriforme was initially described as Aseroë floriformis by Baseia & Calonge (2005) in Restinga areas in the Atlantic Forest of Rio Grande do Norte, Brazil. Based on morphological and molecular data, the species was inserted in a genus named after its main characteristic, which is the absence of arms in the receptacle, receiving the name Abrachium floriforme (Baseia & Calonge) Baseia & T.S. Cabral, published by Cabral et al. (2012).
Abrachium floriforme is an endemic Brazilian species of gasteroid fungi found in coastal and forestal areas of Atlantic Forest, and reaching forestal areas inside the Caatinga domain. The areas where the species is found are threatened by strong and recurrent anthropic actions without control of the existing environmental laws of Brazil. These actions are reducing the species habitat, resulting in a predicted 44,3% population decline in the next 30 years (3 generations), making this species Vulnerable (VU A3c; C1+2a(ii)).
Abrachium floriforme has its distribution mainly known for coastal forest areas and Restingas of the Atlantic Forest, from the Rio Grande do Norte to the Santa Catarina States in Brazil, as well as some additional areas located in the Caatinga (Ceará, Bahia and Piauí States), and in the transition between Atlantic Forest and Cerrado (São Paulo State) (Baseia & Calonge, 2005; Trierveiler-Pereira & Baseia, 2009; 2011; Trierveiler-Pereira et al., 2019; Fernandes et al., 2021). In the coastal areas of the Atlantic Forest, the known sites are about 50 km apart, however, this distance increases to 300 to 400 km between sites located in the Caatinga. This species is expected to occur in a single population from coastal areas of the Brazilian Atlantic Forest, to wetter forests inserted in the Caatinga (eg. “brejos de altitude”), and in some transitional areas of the Atlantic Forest with the Cerrado in the Brazilian southeast region.
Based on the GBIF database, there are a total of 105 occurrence records, all in Brazil, and mostly in coastal areas in Atlantic Forest (the first record in 2004 at Dunas do Natal State Park, in Natal, Rio Grande do Norte State, growing on soil (Baseia & Calonge, 2005). Additional data were published for Bahia, Rio Grande do Norte, Ceará (Trierveiler-Pereira & Baseia, 2009) and Paraíba (Trierveiler-Pereira & Baseia, 2011) before the proposition of the genus Abrachium by Cabral et al. (2012). After that, records were made for the Caatinga domain in northeastern Brazil (Baseia et al., 2014), Atlantic Forest in Southeast and South Brazil (Trierveiler-Pereira et al., 2019), and the transitional area between Atlantic Forest and Cerrado in the State of São Paulo (Fernandes et al., 2021).
Is possible to assume 800 sites of a potential area of occurrence, with 6 mature individuals per site, and predicted population size of 4.800, or at least the double of this (9,600) for total mature individuals in a single population that extends from the coastal portions of the Atlantic Forest to the forest areas inserted in the Caatinga and the ecotone Atlantic Forest/Cerrado in São Paulo State. As the species grows in soil and has an ephemeral sporome, it can be considered a generation length of 10 years.
The population decline was estimated in light of extension loss of suitable habitat for the Atlantic rainforest (and “Restinga”) and Caatinga (Joly et al., 2014; Beuchle et al., 2015; Câmara et al., 2015; Rezende et al., 2018; Antongiovanni et al., 2020; Silva et al., 2020; Fundação SOS Mata Atlântica & INPE, 2021) and the putative influence that habitat degradation has on species occupation in a given environment (Berglund & Jonsson, 2003; Haddad et al., 2015). Based on this information, we can assume a mean of global habitat loss of 22,15%, and precautionarily assume the double of this value as a population decline of the fungus, reaching 44,3% within three generations (30 years). For these reasons this species can be considered as Vulnerable (VU) under criteria A3c; C1+2a(ii)).
Population Trend: Decreasing
Abrachium floriforme was only found growing on soil with litter cover, in shaded forest environments. Species from the northeast was found in the initial months of the year (January to June, with sporadic records in August and September in Rio Grande do Norte and Bahia State), while samples from the Southeast and South occur in August to January (with sporadic records between March to May in Rio de Janeiro State). Abrachium is currently a monospecific genus exclusive to Brazil, which uses insects as the main dispersal strategy for its spores. The spores are arranged in a disc-shaped mucilage in the upper portion of the flower-shaped sporome receptacle. Due to the strong odor, insects are attracted to the mucilage with spores, and this sticks to the animal’s body, allowing dispersions over relatively long distances, according to the flight area reached by the insect (usually from the Order Diptera).
Abrachium floriforme is threatened by anthropic processes that influence the vegetation reduction of Atlantic Forest and Caatinga biomes. In the Atlantic Forest, threats are based on agricultural activities, monoculture plantations, and growing urbanization (Rezende et al. 2018). Regarding the Caatinga, the exaggerated fragmentation due to anthropic actions has already reduced the biome to half of its total extension, and the remaining fragments are influenced by fire, deforestation for the formation of pastures, and biological invasion, mainly in the northern and northeastern portion of the biome (Câmara et al. 2015; Beuchle et al., 2015; Antongiovanni et al., 2020). Threats to insects, the main spore dispersers of the species, are also a threat since without a disperser this species has no other technique to expand its area, except using asexual mycelial growth.
Maintenance of conservation areas, as well as the creation of new areas in potential locations that have not yet been registered for the fungus. Effective control of human activities, especially illegal deforestation, clandestine fires and agricultural activities, and monoculture plantations should also be better controlled by competent authorities.
It is necessary to expand the phylogenetic analysis of some of the materials from the south and southeast of Brazil. Samples from these areas have more orange and yellowish colors, while species from the northeast, both from the Atlantic Forest and the Caatinga, show colors in shades of pink. This unique variation in color needs to be further studied, considering that the species from the Northeast is the correct species of Abrachium floriforme, once it was the first described, and the others may or may not indicate new taxa or just geographic varieties of this taxa.
No commercial or traditional use was known for the species.