Bartalinia mellea is a pathogenic species found only once, in the north slope of Cerro Tres Picos (south of Buenos Aires province) in 1988. This site is characterized by fragmented patches of natural grassland. The fungus was found on a shrubby plant, Mimosa rocae, which grows in grassland ecosystems over rocky outcrops. Besides the host plant being mostly distributed in Uruguay, and it can also occurs in one state of Brazil, the fungus is believed to be potentially restricted to a dry climate with long periods of insolation and very low temperatures in winter. So, it is suspected that the distribution of the fungus is restrict to southern mountains of Buenos Aires province of Argentina. These mountains are of low height (up to 1250 m asl) so the grassland ecosystems are mainly threatened by human activities such as tourist hiking, plants extraction, anthropogenic fire, introduction of invasive species and land use changes, resulting in its decline. There are no many sites in the mountains ranges of Buenos Aires province (Argentina). Also considering its host risk of extinction (VU in a national red list) it is parsimonious to assess the species as in decreasing. On the other hand, without clear information on its percentual of decreasing and impossibility to understand its population size the species is assessed as DD.

Bartalinia mellea F. Anderson & Bianchin. Mycotaxon 60: 193 (1996)

Bartalinia mellea is a pathogenic species found only once, in the north slope of Cerro Tres Picos (south of Buenos Aires province) in 1988. This site is characterized by fragmented patches of natural grassland. The fungus was found on a shrubby plant, Mimosa rocae, which grows in grassland ecosystems over rocky outcrops. Besides the host plant being mostly distributed in Uruguay, and it can also occurs in one state of Brazil, the fungus is believed to be potentially restricted to a dry climate with long periods of insolation and very low temperatures in winter. So, it is suspected that the distribution of the fungus is restrict to southern mountains of Buenos Aires province of Argentina. These mountains are of low height (up to 1250 m asl) so the grassland ecosystems are mainly threatened by human activities such as tourist hiking, plants extraction, anthropogenic fire, introduction of invasive species and land use changes, resulting in its decline. There are no many sites in the mountains ranges of Buenos Aires province (Argentina). Also considering its host risk of extinction (VU in a national red list) it is parsimonious to assess the species as in decreasing. On the other hand, without clear information on its percentual of decreasing it is able to understand its population size.

Bartalinia mellea is a pathogenic species found exclusively associated with Mimosa rocae, a plant occurring in the southern mountains of Buenos Aires province (Argentina), Bom Jesus city in (Rio Grande do Sul state) southern Brazil and Uruguay. This plant is found growing between 200 and 700 m asl. Bartalinia mellea has a very restricted distribution, it was found only once in the north slope of Cerro Tres Picos (south of Buenos Aires province) in 1988. That is the southern limit of the host plant where it is probably affected by the dry climate in general, long periods of insolation and very low temperatures in winter and the fungus species would be restrict to this condition in Buenos Aires province.

The species is currently known from one site with only one collection from the southern limit of the host plant. It is a very specific pathogenic species only found associated with Mimosa rocae (Fabaceae). In these mountains the plant occurs in small patches of 100-200m2 and although it usually responds positively to livestock grazing, its reproductive strategies make it a plant that cannot expand its distribution area (Long, 2018). On the other hand, M. rocae is considered vulnerable (VU) among the threat categories in Buenos Aires province (Alonso et al., 2009; Delucchi, 2006; Delucchi & Hernández, 2015) and in priority conservation status for the National System of Protected Areas (SNAP) of Uruguay. Although Bartalinia mellea is known from only one site (one of the mountains ranges from the south of Buenos Aires province) it is suspected that its potential distribution is restricted to the mountain ranges, considering the weather conditions of annual rains and temperatures. These mountains are of low height (up to 1250 m asl) so the grassland ecosystems are mainly threatened by human activities such as tourist hiking, plants extraction, anthropogenic fire, introduction of invasive species and land use changes, resulting in its decline. Also, considering its host risk of extinction (VU in a national red list) it is parsimonious to assess the species as in decreasing. On the other hand, there is no clear information on its percentual of decreasing and up to now it not able to understand the fungal species population size.

B. mellea was isolated from Mimosa rocae chlorotic leaves, and further artificial inoculation on healthy leaves has proven that the species can infect and reproduce under these conditions. Thus, the species is considered as a M. rocae pathogen, a shrub species that grows in grassland ecosystems over rocky outcrops. B. mellea is also considered pathogenic by Anderson & Bianchinotti (1996). Additionally, the species is considered specific to M. rocae as different plant taxa were screened for fungal pathogens in the region, and B. mellea was only isolated from M. rocae, found causing a clear symptom. The host plant also occurs in Uruguay and one state of Brazil, but it is expected that the potential area of occurrence of the fungus is restricted to the southern mountains of Buenos Aires province in Argentina. The fungus is expected to occur along its host’s distribution only in the two mountain ranges of Buenos Aires due to similar conditions of temperatures and annual rainfall.

Bertalinia mellea is an endemic species restricted to grassland ecosystems over rocky outcrops in the southern mountains of Buenos Aires province. These mountains are of low height (up to 1250 m asl) so the grassland ecosystems are fragmented patches mainly in high areas and in the base
are surrounded by urban settlements. The habitat is threatened by human activities such, tourist hiking, anthropogenic fire, introduction of invasive species and land use changes and climate change, resulting in its decline (Long & Grassini, 1997; Zalba & Villamil, 2002).

The main action to prevent the decline of the species is the protection of its habitat (including the host) by the establishment of public policies of conservation of the natural grassland ecosystems in the southern Buenos Aires province.

It is needed to expand knowledge about the distribution of the species, more accurately if it is present in the mountain system of Tandilia in Buenos Aires and to confirm that it is not present in Uruguay and Brazil. Also, it is important to understand better the threats and if in fact how it is affecting the size population.

No use/trade is known.