Sebastiano Salvidio

Recent introduction of a chytrid fungus endangers Western Palearctic salamanders

A new, yet old, threat to amphibians Globally, populations of amphibians have been severely affected by a disease caused by the fungus Batrachochytrium dendrobatidis. Recently, some European salamander populations were decimated by the emergence of a new, related chytrid fungus, B. salamandrivorans. Martel et al. screened amphibians across continents. This newly emerging threat seems to have originated in Asia and traveled to Europe with salamanders transported as part of the pet trade. Asian salamanders have evolved resistance to the pathogen, but salamanders from other parts of the world are highly susceptible. Science, this issue p. 630 A new fungal disease from Asia threatens salamanders in Europe, the Middle East, and North Africa. Emerging infectious diseases are reducing biodiversity on a global scale. Recently, the emergence of the chytrid fungus Batrachochytrium salamandrivorans resulted in rapid declines in populations of European fire salamanders. Here, we screened more than 5000 amphibians from across four continents and combined experimental assessment of pathogenicity with phylogenetic methods to estimate the threat that this infection poses to amphibian diversity. Results show that B. salamandrivorans is restricted to, but highly pathogenic for, salamanders and newts (Urodela). The pathogen likely originated and remained in coexistence with a clade of salamander hosts for millions of years in Asia. As a result of globalization and lack of biosecurity, it has recently been introduced into naïve European amphibian populations, where it is currently causing biodiversity loss.

Resistance to Chytridiomycosis in European Plethodontid Salamanders of the Genus Speleomantes

North America and the neotropics harbor nearly all species of plethodontid salamanders. In contrast, this family of caudate amphibians is represented in Europe and Asia by two genera, Speleomantes and Karsenia, which are confined to small geographic ranges. Compared to neotropical and North American plethodontids, mortality attributed to chytridiomycosis caused by Batrachochytrium dendrobatidis (Bd) has not been reported for European plethodontids, despite the established presence of Bd in their geographic distribution. We determined the extent to which Bd is present in populations of all eight species of European Speleomantes and show that Bd was undetectable in 921 skin swabs. We then compared the susceptibility of one of these species, Speleomantes strinatii, to experimental infection with a highly virulent isolate of Bd (BdGPL), and compared this to the susceptible species Alytes muletensis. Whereas the inoculated A. muletensis developed increasing Bd-loads over a 4-week period, none of five exposed S. strinatii were colonized by Bd beyond 2 weeks post inoculation. Finally, we determined the extent to which skin secretions of Speleomantes species are capable of killing Bd. Skin secretions of seven Speleomantes species showed pronounced killing activity against Bd over 24 hours. In conclusion, the absence of Bd in Speleomantes combined with resistance to experimental chytridiomycosis and highly efficient skin defenses indicate that the genus Speleomantes is a taxon unlikely to decline due to Bd.

Ecology of a Speleomantes ambrosii population inhabiting an artificial tunnel

A Speleomantes ambrosii population living in an artificial tunnel in NW Italy was studied for two consecutive years. Activity on the walls varied cyclically in relation to seasonal temperatures and food abundance. The main food item was the trogloxenic dipteran Limonia nubeculosa, which accounted for more than 80% of the total ingested prey by volume. Juvenile cave salamanders had a broader trophic nich than adults. Oviposition and juvenile recruitment appeared to be seasonal. The spatial distribution inside the tunnel was related to microhabitat heterogeneity and particularly to the distance from the entrance. Juveniles were observed outside or close to the entrance more often than adults. Movement of adult salamanders were generally low and averaged 7 cm/day; some repeatedly recaptured individuals had a mean home range of 6 m 2 .

Five new species of Nectophrynoides Noble 1926 (Amphibia Anura Bufonidae) from the Eastern Arc Mountains, Tanzania

Five new species of Nectophrynoides Noble 1926 are described from the forests of the Eastern Arc Mountains of Tanzania. Two of the new species were already recognised as such, but not formally described. Two more were recognised as undescribed in the collection of the Natural History Museum, London. The fifth was collected during a field survey of the udzungwa Scarp Forest Reserve in early 2003. A description of the advertisement call and some ecological information are provided for the latter species. Little is known of the ecology and behaviour of any of the other new species. An updated key to the species of Nectophrynoides is given. The high species diversity and pattern of endemism of Nectophrynoides suggests the genus is closely associated with the geological and climatic history of the Eastern Arc Mountains. Given the limited distribution of the new species and continuing habitat loss in the Eastern Arc Mountains (a globally recognised biodiversity hotspot), a rapid conservation assessment of the status of these species is necessary.

Land abandonment may reduce disturbance and affect the breeding sites of an endangered amphibian in northern Italy

Although human-related disturbance is usually detrimental for biodiversity, in some instances it can simulate natural processes and benefit certain species. Changes in the disturbance regime, both natural and human-driven, can affect species that rely on it. The Apennine yellow-bellied toad Bombina variegata pachypus, an amphibian endemic to peninsular Italy, has declined throughout its range in the last 3 decades. We sought to identify the drivers of the decline in the region of Liguria, at the north-western limit of its distribution. In 2009 and 2010 we surveyed sites where the species occurred until 2005 and related the persistence of breeding activity to the characteristics of sites. Populations had disappeared from 50% of the sites between 2005 and 2009. Current breeding sites have less aquatic and bank vegetation, fewer predators and better insolation. Frequent disturbance events (desiccation and floods) were related to reduced vegetation, which in turn may decrease predator densities and increase insolation. In this region disturbance is provided by natural factors or, in the case of artificial water bodies, by regular maintenance carried out by landowners. The widespread land abandonment in Liguria can disrupt disturbance regimes, interrupting the removal of vegetation, and thus rapidly reduce the suitability of artificial sites. This was confirmed in our study, with most abandoned breeding sites occurring in formerly cultivated areas. Possible short-term conservation actions include creating new ponds, maintaining artificial water bodies and clearing vegetation. However, long-term conservation may be more problematic as the land abandonment process is unlikely to be reversed.

Amphibian and Reptile Diversity in the Southern Udzungwa Scarp Forest Reserve, South-Eastern Tanzania

The Udzungwa Scarp Forest Reserve is one of the largest forest patches within the Udzungwa Mountains of South-central Tanzania. It covers an area of about 200 km2 on the south eastern slopes of Udzungwa range. Since 1998 five sites in the southern part of the Udzungwa Scarp Forest Reserve, ranging from 400 to 1900 m a.s.l., have been surveyed and a list of Reptiles (33 species) and Amphibians (36 species) is given. Among them 21.7% and 53.6% of the species are endemic or near endemic to the Udzungwa Mountains and to the Eastern Arc Mountains respectively. Concern is raised for the preservation of this unique highland forest-dependent fauna in the light of continuing habitat alteration.

Comparison of two non-lethal methods for dietary studies in terrestrial salamanders

Abstract Context. Concerns about conservation and ethics in amphibian research have been raised recently; therefore, non-lethal methods should always be preferred to investigate food habits in wild populations. However, there are no studies that compared the data obtained by different non-lethal dietary methods in amphibians. Aims. We compared the dietary habits obtained from stomach flushing, a method validated against stomach dissection, and faecal analysis on the same 31 individuals of the European plethodontid Speleomantes strinatii, a completely terrestrial salamander. Methods. After being stomach-flushed in the field, salamanders were kept in the laboratory at constant humidity and temperature to obtain faecal samples. Analyses comprised diversity and niche overlap indexes, as well as permutation, repeated-measures tests and graphical methods. Key results. Niche overlap between the two samples was low (Ojk = 0.58) and prey diversity was significantly (P = 0.001) higher in stomach contents. There were also differences in the abundance of fly larvae, springtails and ants and the interpretation of the population trophic strategy varied according to the sampling method used. Key conclusions. Stomach flushing and faecal analysis gave different information, because, apparently, a differential prey degradation occurred. During the digestive process, ants became dominant, whereas springtails and fly larvae became under-represented in faecal samples. Therefore, on the basis of faecal analysis, diet diversity was underestimated and many individuals improperly appeared as ant-specialist feeders. Implications. In terrestrial salamanders, results from stomach flushing and faecal analysis should not be compared among studies, populations or species. Moreover, stomach flushing should always be preferred when assessing the trophic strategy and the role in food webs of salamanders.

A New Dwarf Forest Chameleon from the Udzungwa Mountains of Tanzania, East Africa, (Squamata: Rhampholeon Günther, 1874)

Abstract A new species of Rhampholeon from the montane and submontane escarpment forests of the Udzungwa Mountains is described. This pigmy chameleon has a maximum total length of 64 mm and bears a close morphological resemblance to Rhampholeon uluguruensis, differing mainly by possessing finer cranial scalation and more thornlike hemipenal papillae arranged in two proximal rows of four (occasionally five) and two followed by a single terminal row of four (occasionally five) papillae. The only known populations of this species are found in Udzungwa escarpement forests between 1200 and 2000 m a.s.l. The zoogeography and systematics of related species of the genus Rhampholeon in the Eastern Arc Mountains of Tanzania and Malawi are reviewed and an updated key to the Genus Rhampholeon is presented.

Population dynamics and regulation in the cave salamander Speleomantes strinatii

Time series analysis has been used to evaluate the mechanisms regulating population dynamics of mammals and insects, but has been rarely applied to amphibian populations. In this study, the influence of endogenous (density-dependent) and exogenous (density-independent) factors regulating population dynamics of the terrestrial plethodontid salamander Speleomantes strinatii was analysed by means of time series and multiple regression analyses. During the period 1993–2005, S. strinatii population abundance, estimated by a standardised temporary removal method, displayed relatively low fluctuations, and the autocorrelation function (ACF) analysis showed that the time series had a noncyclic structure. The partial rate correlation function (PRCF) indicated that a strong first-order negative feedback dominated the endogenous dynamics. Stepwise multiple regression analysis showed that the only climatic factor influencing population growth rate was the minimum winter temperature. Thus, at least during the study period, endogenous, density-dependent negative feedback was the main factor affecting the growth rate of the salamander population, whereas stochastic environmental variables, such as temperature and rainfall, seemed to play a minor role in regulation. These results stress the importance of considering both exogenous and endogenous factors when analysing amphibian long-term population dynamics.

Generalisation within specialization: inter-individual diet variation in the only specialized salamander in the world

Specialization is typically inferred at population and species level but in the last decade many authors highlighted this trait at the individual level, finding that generalist populations can be composed by both generalist and specialist individual. Despite hundreds of reported cases of individual specialization there is a complete lack of information on inter-individual diet variation in specialist species. We studied the diet of the Italian endemic Spectacled Salamander (Salamandrina perspicillata), in a temperate forest ecosystem, to disclose the realised trophic niche, prey selection strategy in function of phenotypic variation and inter-individual diet variation. Our results showed that Salamandrina is highly specialized on Collembola and the more specialized individuals are the better performing ones. Analyses of inter-individual diet variation showed that a subset of animals exhibited a broader trophic niche, adopting different foraging strategies. Our findings reflects the optimal foraging theory both at population and individual level, since animals in better physiological conditions are able to exploit the most profitable prey, suggesting that the two coexisting strategies are not equivalent. At last this species, feeding on decomposers of litter detritus, could play a key role determining litter retention rate, nutrient cycle and carbon sequestration.