The Sardinian Brook Salamander (Euproctus platycephalus) is a European endemic species that is restricted to Sardinia (Italy). It is assessed as Endangered (B2ab(iii,iv)) as it has an area of occupancy (AOO) of 408 km², and taking a precautionary approach, the species is estimated to occur in five or fewer threat-defined locations (based on invasive species and future disease threats), and there is continuing decline in the extent and quality of its habitat, and in the number of subpopulations. In addition, the species is considered to be severely fragmented.

Programmes to monitor novel diseases and remove alien invasive species from the species' habitat would assist in the recovery of subpopulations, and there is an urgent need for the EU-wide coordinated implementation of the Bsal Action Plan (Gilbert et al. 2020).

This species is endemic to Sardinia, Italy (Gasc et al. 1997, Arnold 2003), where it is mostly found in the eastern part of the island between the Limbara Mountains in the north and the Sette Fratelli Mountains in the south. There are some historical records from western Sardinia (Lecis and Norris 2003a,b; Lecis and Norris 2014; Vignoli et al. 2016), however, there are no recent records from this part of southwestern Sardinia (Corti et al. submitted 2022; G. Sotgiu pers. comm. November 2022), and it is considered possibly extinct here. Further information is needed on the range of the species in the southwest of the island; there are anecdotal records from Iglesiente (Vignoli et al. 2016), but they have not been included in this assessment until further work has been carried out to verify that they belong to this species. It is not thought to occur much more widely. It has been recorded between 50–1,800 m asl, although it is most often found between 400–800 m asl. It occurs in five or fewer threat-defined locations, its extent of occurrence (EOO) is 10,609 km², and its confirmed area of occupancy (AOO) (Vignoli et al. 2016) is less than 500 km² (408 km²).

This is generally a rare species that can be locally common in suitable habitat (e.g. over 400 specimens may be found in a single pool). The largest subpopulation is in the Gola di Gorropu (eastern-central Sardinia). In one well-studied population, the sex ratio is largely male.

The number of subpopulations is in decline (Rondinini et al. 2013, 2022; NGO Zirichiltaggi Sardinia Wildlife Conservation 2022), and the recent increase of threats (from diseases and alien species) is causing a reduction in newt abundance, especially in small and suboptimal subpopulations (G. Tessa pers. comm. September 2019). The number of subpopulations was reported to be declining in 2008. Between 1999 and 2001 it was found in 14 sites, whereas previously around 1991 it was present in 30 sites (and even in 1991 it was absent from nine other sites where it had been previously observed). Sotgiu et al. (2010) and Vignoli et al. (2016) reported a number of subpopulations comparable with the subpopulations found by Alcher in the 1970s (Alcher 1975). Declines are thought to have occurred in the last 10 years due to the introduction of fish to streams and rivers, where this species occurs (Vignoli et al. 2016). A study on a recently detected new invasive crayfish species (Procambarus virginalis Lyko, 2017) in the freshwaters of Sardinia (Sanna et al. 2021) strongly supports the statement of conservationists that the rate of decline of the population of Sardinian Brook Salamander is increasing. However, it is not clear that there is a continuing decline in the number of mature individuals (Tessa et al. 2003; V. Ferri pers. comm. 2024).

In most of the territory it is fragmented, in some places more severely (V. Ferri pers. comm. 2024), and the species is considered here to be severely fragmented.

The Sardinian Brook Salamander is a montane species of permanent and temporary stagnant and running waters, that prefers calm areas of small or large rivers. Its terrestrial habitats are generally restricted to riverine scrub or woodland, and the species may also be found in cave systems. Its breeding sites are permanent pools, water holes, small lakes and streams. The eggs are deposited between stones or are buried in sand; the larvae develop in the streams (Griffiths 1996, Rimpp 1998). The species is quite adaptable and can be found in artificial pools.

The major threats to the species are pollution of waterbodies, habitat fragmentation, predation by introduced trout, and prolonged drought (often caused by excessive water abstraction). During the 1950s, many subpopulations were lost through the application of DDT to waterbodies. The Gola di Gorroppu subpopulation and other streams in north and central Sardinia have become threatened through damage to its habitat caused by tourist activities, particularly hiking within the streams (C. Corti pers. comm. October 2022). Additional threats include Batrachochytrium dendrobatidis (Bd) with outbreaks detected from the north to the south of the island (Bovero et al. 2008, Bielby et al. 2013, Tessa et al. 2023), and the presence of the alien species of Green Frogs and the Red Swamp Crayfish Procambarus clarkii (Souty-Grosset et al. 2016, Oficialdegui et al. 2019; G. Tessa pers. comm. September 2019) and, the most recently, P. virginalis (Sanna et al. 2021). An increase in the number of alien species which have detrimental effects on local amphibian fauna (NGO Zirichiltaggi Sardinia Wildlife Conservation 2022) questions statements on the stability of subpopulations of E. platicephalus. Although already in a new dynamic balance for many decades, Natrix maura is also an important non-native predator for E. platycephalus (J. Speybroeck pers. comm. October 2022). The species is collected for the pet trade, which is thought to be slightly affecting the population.

Batrachochytrium salamandrivorans (Bsal) is an emerging fungal pathogen affecting amphibians and is closely related to B. dendrobatidis (Bd), which has had a devastating impact on amphibian populations around the world. Both pathogens cause the infectious disease chytridiomycosis, and both are believed to have originated in Asia (for Bsal: Martel et al. 2014, for Bd: O'Hanlon et al. 2018). While Bd can cause disease in frogs, salamanders and caecilians, Bsal has only been reported to cause disease in salamanders and newts, although the pathogen has been detected in some frog species (Martel et al. 2013). Bd has spread globally, but at present, Bsal is only known in Asia and has been introduced to Europe, most likely through the pet trade in salamanders (Martel et al. 2014, Nguyen et al. 2017). Currently in Europe, Bsal has been detected in the wild in the Netherlands, Belgium, Germany (e.g. Thein et al. 2020) and Spain (Martel et al. 2020), and has been shown to be highly pathogenic to most urodelan taxa in Europe (Martel et al. 2014). Laboratory trials for susceptibility to Bsal found this species to be highly susceptible to the disease (Gilbert et al. 2020, A. Martels and F. Pasmans pers. comm. September 2021). Based on current distribution data for Bsal, it is expected that the natural advancement of the infection could be up to 10 km per year which would result in a conservative advancement of 400–500 km per 50 years. Extinction risk modelling demonstrates that this species would be at significant risk from the natural spread of the fungus in the next 50 years, and could be categorised under Endangered or Vulnerable under criterion E if it was found in mainland Europe. However, this is an island species and Sardinia currently has no records of Bsal. This does not take into consideration the human-induced introduction of the disease, and should a new outbreak occur on Sardinia then it will need to be reassessed as soon as possible as this is a very plausible future threat.

This species is found in the pet trade; collection from the wild for trade is thought to be slightly affecting the population (G. Tessa pers. comm. September 2019).

Conservation Actions In-Place
This species is listed on Appendix II of the Bern Convention and on Annex IV of the EU Natural Habitats Directive. The species is protected by regional legislation (Regional Law n. 23/1998 (art. 5, c. 3)). The Gola di Gorroppu has been designated as a Site of Community Importance under the Habitats Directive. In addition, a number of subpopulations live in established and planned protected areas, including Parco Regionale Sette Fratelli, Parco Nazionale Gennargentu-Golfo di Orosei, and Parco Regionale Monte Limbara.

The development of a citizen science project is also underway to help with the monitoring of amphibian species in Italy (F. Ficetola and R. Manenti pers. comm. September 2019). Furthermore, monitoring of all Natura 2000 sites and species is ongoing in Italy, including this species (F. Ficetola and R. Manenti pers. comm. September 2019). A reintroduction project is in place, where 30 individuals born in captivity at the Fondazione Bioparco di Roma as part of a project funded and sponsored by EAZA and Amphibian ARK (Tapley et al. 2015) were reintroduced in 2019 at a location in the Sette Fratelli (CA) area where the species was known until the late 1990s (L. Vignoli pers. comm. October 2022). The reintroduced individuals reproduced in 2020. All animals were screened for known diseases (F. Ficetola pers. comm. October 2022).

Conservation Needed
Programmes to monitor diseases, and remove trout and other alien species from the species' habitat would assist in the recovery of subpopulations (G. Tessa pers. comm. September 2019). There is also an urgent need for an EU (European Union) wide coordinated approach and implementation of the Bsal Action Plan by Gilbert et al. (2020), which was commissioned by the European Commission.

Research Needed
If an outbreak of Bsal was to occur within this species' range, population monitoring would need to be carried out immediately and this species would need to be reassessed. Long-term monitoring of subpopulations is necessary to avoid future population decline, particularly to set a baseline against potential disease introduction (F. Ficetola pers. comm. October 2022).