Taxonomic Notes
Recent literature has adopted the spelling Podarcis raffeonae for this species following a proposed emendation by Michaels and Bauer (2004). Arribas (2017) concluded that this emendation was unjustified and this assessment consequently retains the spelling raffonei, and this arrangement was accepted by Speybroeck et al. (2020).
Justification
The Aeolian Wall Lizard is endemic to Europe, where it is restricted to the Aeolian Archipelago (Italy). It is assessed as Endangered (EN B1ab(iii,v)+2ab(iii,v)) globally and for the EU 27 Member States on the basis that this species' extent of occurrence is little more than 1,100 km2 and its area of occupancy is possibly as low as 16 km2 (only a very small fraction of which contains suitable habitat), it is considered to occur at four locations and as a severely fragmented population, and there is a continuing decline in the number of mature individuals in at least the largest subpopulation, that of Vulcano, apparently driven primarily by competitive exclusion from - and possibly hybridisation with - the Italian Wall Lizard, Podarcis siculus, and by increases in the rat population. On Vulcano Island, there is also continuing decline in the quality of available habitat because of wildfires and habitat loss driven by overgrazing. It is considered likely to be extinct in two of the three localities on Vulcano (Vulcanello and Grand Cratere area).
Geographic Range Information
This species is endemic to Europe, where it is restricted to the Aeolian Islands (Italy). On Vulcano Island, it is confirmed to the Capo Grosso Peninsula (Lo Cascio 2010), and it is present in tiny areas on three further small rocky islets: Strombolicchio, La Canna and Scoglio Faraglione. Lo Cascio and Sciberras (2020) considered the Capo Grosso subpopulation to be extinct, however, this is erroneous, and this subpopulation is still extant and has been subject to systematic monitoring for the last decade (Ficetola et al. 2021; D. Salvi, G.F. Ficetola and L. Vignoli pers. comm. 2022). Two other subpopulations known from Vulcano, in the Vulcanello and Gran Cratere areas, are considered extinct (Capula et al. 2002, D'Amico et al. 2018).
The available area of suitable habitat is considerably lower than the island area on every island where it occurs, with the total area of habitat available being estimated at 5,525 m2, slightly more than half of this in Punta Capo Grosso on Vulcano Island (Ficetola et al. 2021). Capo Grosso reaches an estimated elevation of 30 m asl (Lo Cascio 2010).
The species is considered to occur in four locations; a single remaining subpopulation on Volcano Island is exposed to threats from the invasive lizard and an increase in rat density. The other three remaining subpopulations (Strombolicchio, La Canna and Scoglio Faraglione islets) each represents a separate location defined by a primary threat from stochastic events.
Population Information
The islet populations of the Aeolian Wall Lizard are stable while that on Vulcano is in decline. Based on a combination of modelling, removal sampling, and previous literature evidence, the global population is likely to be a few hundreds of individuals (Capula and Lo Cascio 2010). Ficetola et al. (2021) estimated around 2,000 and 2,500 individuals spread between the four extant subpopulations (Ficetola et al. 2021). Lo Cascio et al. (2014) estimated for the small La Canna Islet a subpopulation of 50-80 individuals across an area as small as 5 m2; for Scoglio Farglione about 200-400 individuals, while for Strobolicchio Islet about 500-700 individuals (Lo Cascio 2006, Capula and Lo Cascio 2010). Ficetola et al. (2021) believe that none of the other islets is believed to contain as many as 1,500 individuals and only the Vulcano subpopulation is thought to exceed 700.
On Vulcano, the only large island where it occurs, Speybroeck et al. (2016) suggested that the subpopulation appears to be "rapidly heading towards extinction", however this is considered speculative at present (D. Salvi pers. comm. 2022). Between the 1950s and the 1970s the species was described as abundant in several areas of the island (Mertens 1955); surveys of the same areas in 1989-1999, in which time the Italian Wall Lizard (Podarcis siculus) was common and widespread on the island, very few individuals were found (Capula et al. 2002). In Vulcanello and in the Valley between the Gran Cratere and Mount Saraceno the species is considered to be extinct (Capula et al. 2002), suggesting that the species survives on this island only in Capo Grosso. Although "recent" unpublished reports exist for the summit of the Gran Cratere there have otherwise been no published records from either site in more than 20 years (D'Amico et al. 2018) despite ongoing research at this site over the past decade (D. Salvi pers. comm. 2023), and the unpublished reports from Gran Cratere are considered erroneous by Lo Cascio and Sciberras (2020).
Average capture rates in 2015 and 2017 were 3.75 and 3.3 individuals/person-hour respectively (Ficetola et al. 2021). Although in 2015 only one animal with traits resembling those of the Podarcis siculus was found among 31 sampled animals (Ficetola et al. 2021), by 2017 53% of 131 sampled animals (estimated by these authors to represent at least 10% of the Vulcano subpopulation) expressed a green "siculus-like" phenotype. These authors caution that genomic evidence is necessary to demonstrate whether this represents true hybridisation or rather a seasonal colour change in true P. siculus, the latter of which has been observed in captivity. Genomic analyses on the Capo Grosso subpopulation is in progress (D. Salvi and G.F. Ficetola unpubl. data).
At least 50% of the global population was estimated to occur in the Capo Grosso subpopulation in 2017. Subsequently, this species began a rapid decline, inferred to be the result of an increase in the rat population (L. Vignoli and B. Gambioli pers. comm. 2022). Recolonisation from elsewhere is impossible and the other subpopulations are small and fragmentary, but apparently self-sustaining. As such the species is at least close to qualifying as a severely fragmented population (Capula and Lo Cascio 2010).
Habitat and Ecology Information
The species is confined to rocky habitat with scarce vegetation (La Canna), scattered casmophilous plant communities (Strombolicchio, Scoglio Faraglione) and shrublands (Capo Grosso) (Capula and Lo Cascio 2010, Ficetola et al. 2021). On Vulcano, Capula et al. (2002) reported that it has never been observed in cultivated or degraded areas at least in the last 50 years. Its diet consists of small invertebrates, including marine crustaceans found in the intertidal belt in the La Canna subpopulation (Lo Cascio et al. 2014), but include also vegetal matter (Lo Cascio 2006). It is an egg-laying species, with one or two clutches of four to eight eggs laid between March and May (Capula and Lo Cascio 2010).
Threats Information
This species has one of the smallest ranges and is the most endangered among European vertebrates (Capula and Lo Cascio 2011), and its known subpopulations are at high risk from stochastic events as a consequence.
It is likely that the introduction of the Italian Wall Lizard (Podarcis siculus) to Vulcano Island, probably in the late 19th Century, may have contributed to the decline and current restricted range of Podarcis raffonei through a combination of competition and hybridisation (Capula et al. 2002); wildfires and habitat loss driven by overgrazing and urbanisation have also been implicated (Capula and Lo Cascio 2010, Ficetola et al. 2021). P. siculus is now widespread at low elevations, and in all habitat types on Vulcano, and D'Amico et al. (2018) suggest that the species may have excluded the native lizard from lower elevations on Gran Cratere. Areas of dense maquis vegetation have been strongly reduced on all bigger islands where the species probably occurred due to land clearance, fire, urban development, tourism, and agriculture, and this has been particularly extensive on Vulcano since the 1950s (Capula et al. 2002, Lo Cascio 2010). Information is however lacking to determine the exact causes of decline and the contributions of different factors (Ficetola et al. 2021). A very rapid increase in the incidence of green ("siculus-like") individuals in Capo Grosso is a cause for significant concern, however these authors caution that this is complicated by the plasticity of Podarcis colouration (Ficetola et al. 2021). This subpopulation also appears to be undergoing a severe decline correlated with an increase in rat density (L. Vignoli and B. Gambioli pers. comm. 2022). However, the amount of the occurrence of hybrids P. raffonei x P. siculus within this latter population is still unclear. Capula et al. (2002) suggested that overcollection may be a threat to all subpopulations, but this is not described as a potential impact by more recent work (e.g., Lo Cascio 2010, Ficetola et al. 2021).
Use and Trade Information
Capula et al. (2002) suggested that harvesting and trade may then have been underway in this species, primarily for scientific research but potentially also for commercial use, as there was no regulation on its use. Research collection is now regulated by permits and there is no evidence that this lizard is the commercial pet trade.
Conservation Actions Information
This species is listed in Annex III of the Bern Convention. There is a need to update the EU Habitats Directive to include this species, which is presently not included as it was formerly regarded as a subspecies (Gippoliti et al. 2017). All subpopulations other than that on Scoglio Faraglione are found in protected areas (Natural Reserve, SIC, ZPS). A recovery program is urgently needed, probably including captive breeding as a component. Forty adults of the typical morph collected in 2017 were taken into captivity to establish a breeding program at the Fondazione Bioparco of Rome (Ficetola et al. 2021; L. Vignoli pers. comm. 2022). D'Amico et al. (2018) propose a program to control and if possible, eradicate Italian Wall Lizards from Capo Grosso, Gran Cratere and Vulcanello on Vulcano Island, in combination with exclusion fences to prevent recolonisation and biosecurity protocols to prevent further introductions; it has however several critical aspects, both from the ethical standpoints and that of actual feasibility. A plan for regular monitoring of this species is lacking and this should be a priority for this narrowly distributed endemic lizard, especially given evidence of declines on Vulcano. Genomic research is underway to confirm the extent of hybridisation (Salvi and Ficetola, unpubl. data), and demographic research to assess the lizard's population status (L. Vignoli and B. Gambioli pers. comm. 2022). All islet populations are regularly monitored and have been since 1995 (P. Lo Cascio pers. comm.).
A three-year project (Save The Aeolian Lizard) is underway managed by the local association “Nesos" with the support of international foundations (MAVA, FPA2). The project, approved by Italian and regional government institutions, started in Lipari in 2022. A captive breeding and reproduction program carried out in the Aeolian islands aims to reintroduce the species to some islets where there will be no competition problems as P. raffonei will be the only Podarcis species present. The project started from few individuals of the populations of Strombolicchio and Scoglio Faraglione. Furthermore, in preparation for this project, these selected islets (Podarcis free) have been carefully studied from a naturalistic point of view in order to avoid any potential negative impact of the Aeolian Wall Lizard on these delicate natural ecosystems. (P. Lo Cascio and C. Corti pers. comm, 2023). The project was also presented to the scientific community in the occasion of the 8th World Congress of Herpetology held in China (Lo Cascio and Corti 2016).