Xylobolus gongylodes is a saprotrophic species found occurring on large dead hardwood stumps associated with preserved forest patches. The species has only five records from Argentina and Paraguay, occurring in the Chaco-Paranaense transition following the biographical corridor formed by the Paraguay-Paraná fluvial system, within the Atlantic Forest ecoregion. The species habitat has been suffering with several threats, such as cattle ranching, illegal logging, fire and agricultural plantations (Miño and Atienza 2017). Between 1999 and 2016, ca. 28% of the Atlantic Forest in Paraguay has been lost (De Ponte et al. 2017), and there is no evidence that the deforestation rates and loss of forest quality have recently diminished or ceased (Rodríguez Cañete 2022). Based on the species requirements, and the reduction in its habitat area and quality, coupled with no evident slowdown of these trends, it is conservatively suspected that its population size is decreasing and will reach a population loss of approximately 60 to 80% in 40 years, from 1999 to 2039. Therefore, X. gongylodes is assessed as Endangered (EN A4c).

Xylobolus gongylodes Popoff & J.E. Wright (Popoff & Wright 1994)

Xylobolus gongylodes is a saprotrophic species found occurring on large dead hardwood stumps associated with preserved forest patches. The species occurs in Argentina and Paraguay, in the Chaco-Paranaense transition following the biographical corridor formed by the Paraguay-Paraná fluvial system, within the Atlantic Forest ecoregion. Between 1999 and 2016, ca. 28% of the Atlantic Forest in Paraguay has been lost (De Ponte et al. 2017), and there is no evidence that the deforestation rates and loss of forest quality have recently diminished or ceased (Rodríguez Cañete 2022). As the species habitat is facing important threats and reductions that will not cease, the assessment of X. gongylodes is required.

The species has been found exclusively on dead snags of hardwood trees within the Atlantic forest ecoregion, with five records distributed in five sites in Argentina and Paraguay. The type specimen was collected from Cerro Muralla in Parque Nacional Cerro Cora in Paraguay. Additional specimens (four) are from Biological Reserve Yacyreta Island and Tilinski Hotel in Paraguay and Natural Reserve Apipe Grande and Puerto Yacarei in Argentina. It is expected that the species occurs in the Chaco-paranaense transition following the biographical corridor formed by the Paraguay-Paraná fluvial system, throughout the Atlantic Forest ecoregion.

The species is known from five records, two sites in Argentina and three in Paraguay. It is expected that the species could be found in no more than 50 sites throughout its potential distribution within the Chaco-paranaense transition following the biogeographical corridor formed by the Paraguay-Paraná fluvial system (Oakley et al. 2005). The total population size is estimated to be no more than 6,000 mature individuals distributed in one subpopulation. Its habitat area has diminished by around 28% from 1999 to 2016 due to forest coverage loss (De Ponte et al. 2017). The species grows mostly exclusively on large decayed hardwood stumps in mature forest patches, and the availability of this type of substrate diminishes with timber extraction, one of the main threats to the habitat of this species. Considering that the rate of deforestation and loss of forest quality remained constant until 2020 (Rodríguez Cañete 2022) and that there is no evidence that this rate will diminish in the next 15 years, it is conservatively suspected that population size is decreasing and will reach a population loss of approximately 60-80% in 40 years (1999 to 2039), equivalent to three generations of this species.

Xylobolus gongylodes is found growing mostly exclusively on large decayed hardwood stumps in mature forests patches, two essential requirements for the species development. The species is expected to occur in the Chaco-paranaense transition, following the biogeographical corridor formed by the Paraguay-Paraná fluvial system (Oakley et al. 2005).

Paraguay is among the most deforested countries in Latin America (Hansen et al. 2013). The Atlantic forest ecoregion is considered one of the most threatened tropical forests and between 1999 and 2016 around 28% of the Atlantic forest has been lost in Paraguay (De Ponte et al. 2017). Additionally to the loss of forest cover due to the expansion of the agricultural and cattle frontier, illegal logging, unplanned management of forest extraction, fires, natural phenomena (floods and droughts), and illicit crops among others are the biggest threats to the species (Miño and Atienza 2017).

There are no conservation actions implemented for this species. More protected areas with the ecological conditions (mature forests) suitable for the species are needed. Additionally, the protected areas should have better management and more protection against illegal activities such as wood extraction and crops. Ex-situ conservation is required if the species is able to be cultivated using in vitro techniques.

Monitoring the presence of the species in the original collection sites is needed, as well as surveys in other sites with potencial to have this species. Studies are also needed to determine correlations of species occurrence with phytogeographical regions, such as the Paraguay-Paraná fluvial corridor, and to determine if there is substrate specificity (host species, genus or family). The ex-situ conservation requires research in order to have the species conserved in vitro cultivation.

The species has not any known use or trade.

Da Ponte, E; Mack, B; Wohlfart, C; Rodas, O; Fleckenstein, M; Oppelt, N; Dech, S; Kuenzer, C. 2017. Assessing forest cover dynamics and forest perception in the Atlantic Forest of Paraguay, combining remote sensing and household level data. Forests 8(10):1-21.
Oakley, L. J., Prado, D. y Adámoli, J. (2005). Aspectos biogeográficos del corredor fluvial Paraguay-Paraná. Instituto Superior de Correlación Geológica,Miscelánea, 14, 245–258.
Popoff, O.F. & Wright, J.E. (1994) Two new corticioid fungi (Aphyllophorales) from NE Argentina and Paraguay. Mycotaxon 51: 317–324.
Miño, V. G., & Atienza, O. U. (2017). La Deforestación en el Bosque Atlántico del Alto Paraná y la Normativa Ambiental Aplicable. Investigaciones Jurídicas, Humanas y Sociales, 3(1).
Rodríguez Cañete, C. M. (2022). Incidencia de la deforestación en la captación de dióxido de carbono y provisión de oxígeno en Paraguay. Periodo 1990-2020. Población y Desarrollo, 28(54), 6-15.