Lactifluus caatingae Sá & Wartchow, New Zealand Journal of Botany 57(3): 172 (2019).
Lactifluus caatingae was described based on both morphological and molecular evidence (Sá et al. 2019). The specific epithet caatingae refers to the Caatinga biome.
This is a rare species, known only from three collections found in Piauí State, Brazil in 2019. 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, thus Lactifluus caatingae is assessed as Endangered (EN), under criterion A3c.
The species is currently known from the exclusive Brazilian biome Caatinga, a mosaic of spinose shrubs mixed with seasonally dry forests. Lactifluus caatingae was found growing scattered on sandy soil in a seasonally deciduous broadleaved forest, in the municipality of Caracol, at ‘Parque Nacional da Serra das Confusões’, a national reserve located in the State of Piauí, Northeastern Brazil, which covers the municipalities of Alvorada do Gurguéia, Canto do Buriti, Caracol, Cristino Castro, Guaribas, Jurema and Tamboril do Piauí. It is expected that this species can reach other parts of Caatinga and the ecotones bordering the Cerrado and Atlantic Forest biomes. Especially in the Cerrado, some sandy areas near Caatinga, with savanna vegetation, partially sandy or sandy-quartzenic soils, that occur in many parts of Cerrado (Spera et al. 1999) can favor the species occurrence.
The species is currently known from one site, with three collections (Sá et al. 2019). This is a species with medium to high detectability, with rusty-brown to brownish orange scattered basidiomes that in sandy soil and dry forest can be easily observed. Although studies on Russulaceae in Brazil began in the mid-19th century and continuous efforts to survey the species of this taxon have taken place in recent years until 2013 there were only 41 species in the family (Sá et al. 2013). In the Caatinga biome, there are only two described milkcap species so far: Lactarius rupestris Wartchow and the species assessed herein, Lactifluus caatingae.
It is estimated that between 24% to 51% of the dry forest that makes up the Caatinga could be deforested by 2050 (the next 30 years). Since no other collection was found so far or before, even with extensive surveys to Funga in the Northeast Region of Brazil being carried, it is supposed that at some moment in the past, this species was much more abundant. Based on the existing collections and assuming that between 100 to 200 potential sites may favor the occurrence of the species, each of them supporting around 30 mature individuals per site, is estimated that the current population of Lactifluus caatingae is around 1,200 and no more than 2,500 mature individuals, restricted to one subpopulation.
The population decline of Lactifluus caatingae was estimated in light of extension loss of suitable habitat (Beuchle et al. 2015, Câmara et al. 2015) and the putative influence that habitat degradation has on species occupation in a given environment (Berglund & Jonsson 2005, Haddad et al. 2015). There has been a habitat loss of about 37% to Caatinga within the past three generations (20 years) and is estimated a loss of environmental quality of about 51% until 2050 (next 30 years), thus, it is assumed an estimative to this species population decline of at least 30% (three generations) within this same timeframe.
Population Trend: Decreasing
Lactifluus caatingae was described as occurring scattered in the sandy soil in a seasonally deciduous broadleaved forest, at the Brazilian Caatinga biome.
It is estimated that between 24% to 51% of the dry forest that makes up the Caatinga could be deforested by 2050 (the next 30 years). Considered a biologically “poor” ecosystem in the past, the Caatinga has been neglected for a long time, without effective conservation measures. Until 2010, about 63% of the natural vegetation cover remained in the biome (Beuchle et al. 2015). In 2018, grassland vegetation predominated in the biome (46.8%), with only 5.6% of its territory under anthropic uses in the form of managed pasture, due to the limitation of economic activities due to the semi-arid climate. Although about half of the biome’s vegetation cover remains, the remnants are fragmented by the presence of rural establishments, subsistence crops, pastures, or agroforestry systems (Antongiovanni et al. 2020, IBGE 2020). The main threats to the species are the degradation and loss of habitat quality, including desertification, the alteration of biogeochemical cycles caused by changes in land use and cover in the Caatinga, anthropogenic actions such as the opening of roads, which can cause impacting edge effects in up to 15 km into the vegetation, as well as other anthropogenic uses of the ecosystem (Santos and Tabarelli 2002, Ribeiro et al. 2016, Antongiovanni et al. 2020).
The main required conservation actions include the management and maintenance of the protected areas where the species can be found, along with developing conservation plans to ensure the protection of Caatinga.
More surveys in suitable areas for the occurrence of the species should be explored, to determine the extent of its geographic distribution along with the Caatinga biome and even in other biomes in the country, such as Cerrado. Investigation of the bromatological aspects of the species, in order to verify its eventual edibility, as observed in other species of the genus, are also necessary researches.
No use/trade known. This may be another edible species in the genus Lactifluus, however, bromatological studies are needed.
Antongiovanni, M., Venticinque, E.M., Matsumoto, M., Fonseca, C.R. 2020. Chronic anthropogenic disturbance on Caatinga dry forest fragments. Journal of Applied Ecology 57: 2064-2074. https://doi.org/10.1111/1365-2664.13686
Berglund, H., Jonsson, B.G. 2005. Verifying an extinction debt among lichens and fungi in northern Swedish boreal forests. Conservation Biology19(2): 338-348. https://doi.org/10.1111/j.1523-1739.2005.00550.x
Beuchle, R., Grecchi, R.C., Shimabukuro, Y.E., Seliger, R., Eva, H.D., Sano, E., Achard, F. 2015. Land cover changes in the Brazilian Cerrado and Caatinga biomes from 1990 to 2010 based on a systematic remote sensing sampling approach. Applied Geography 58: 116-127.
Câmara, G., Soterroni, A., Ramos, F., Carvalho, A., Andrade, P., Souza, R.C., Mosnier, A., Mant, R., Buurman, M., Pena, M., Havlik, P., Pirker, J., Kraxner, F., Obersteiner, M., Kapos, V., Affonso, A., Espíndola, G., Bocqueho, G. 2015. Modelling Land Use Change in Brazil: 2000–2050”. São José dos Campos, Brasília, Laxenburg, Cambridge. INPE, IPEA, IIASA, UNEP-WCMC, 1st edition.
Haddad, N.M., Brudvig, L.A., Clobert, J. et al. 2015. Habitat fragmentation and its lasting impact on Earth’s ecosystems. Science Advances 1: e1500052. https://doi.org/10.1126/sciadv.1500052
Instituto Brasileiro de Geografia e Estatística – IBGE. 2020. Agência de Notícias - IBGE retrata cobertura natural dos biomas do país de 2000 a 2018. https://agenciadenoticias.ibge.gov.br/agencia-sala-de-imprensa/2013-agencia-de-noticias/releases/28943-ibge-retrata-cobertura-natural-dos-biomas-do-pais-de-2000-a-2018
Ribeiro, K., Sousa-Neto, E.R.S., Carvalho, J.A., Lima, J.R.S., Menezes, R.S.C., Duarte-Neto, P.J., Guerra, G.S., Ometto, J.P.H.B. 2016. Land cover changes and greenhouse gas emissions in two different soil covers in the Brazilian Caatinga. Science of The Total Environment 571: 1048-1057. https://doi.org/10.1016/j.scitotenv.2016.07.095
Sá, M.C.A., Baseia, I.G., Wartchow F. 2013. Checklist of Russulaceae from Brasil. Mycotaxon 125: 303.
Sá, M.C.A., Delgat, L., Verbeken, A., Sulzbacher, M.A., Baseia, I.G., Wartchow F. 2019. A new species of Lactifluus (Russulales, Agaricomycetes) from the Brazilian caatinga semiarid region. New Zealand Journal of Botany 57(3): 169-178. https://doi.org/10.1080/0028825X.2019.1587474
Santos, A.M., Tabarelli, M. 2002. Distance from roads and cities as a predictor of habitat loss and fragmentation in the caatinga vegetation of Brazil. Brazilian Journal of Biology 62(4b): 897-905. https://doi.org/10.1590/S1519-69842002000500020
Spera, S.T., Reatto, A., Martins, E.S., Correia, J.R., Cunha, T.J.F. 1999. Solos Areno-Quartzosos no Cerrado: características, problemas e limitações ao uso. Embrapa Cerrados 7: 1-48.