Effect of anthropogenic noise on call parameters of Hyla arborea (Anura: Hylidae)

Increasing urbanisation in recent decades has subjected many species and their populations to the influence of anthropogenic noise generated by human technologies. Noise pollution can negatively affect acoustic communication in representatives of different taxa and frogs, as the most vocally active amphibians, are especially vulnerable to such adverse effects. In the present study, we tested the hypothesis that anthropogenic noise could alter the mating call parameters in the European treefrog. The two chosen study sites were in the same geographic area and had similar characteristics except for the presence of anthropogenic noise source. Recordings were made in a WAV-PCM format and both spectral and temporal call parameters were analysed using specialised software. Results demonstrated significant differences in most of the studied parameters, suggesting that treefrogs are able to alter their calls and communicate successfully in moderate levels of anthropogenic noise

Winter activity of the snake-eyed lizard Ophisops elegans (Reptilia: Lacertidae) in the northwesternmost part of its range

There is a lack of information for potential winter activity of the snake-eyed lizard Ophisops elegans in Europe, where it has a limited distribution. To test the hypothesis that this species can be active during the winter months, two locations in Bulgaria were chosen. The visits were conducted in January, February and December 2022 near the village of Meden Buk and in December 2022 above the village of Mezek. A total of 19 individuals of O. elegans were recorded. In addition, we confirmed foraging behaviour based on faecal sample collection. To our knowledge, this is the northernmost record of winter activity in the snake-eyed lizard and the first consecutive observation of year-round activity for this species in Europe

New data on the distribution of Eryx jaculus (Linnaeus, 1758) (Reptilia: Serpentes) in Bulgaria

We report three newly registered localities of the javelin sand boa - Eryx jaculus along the Black Sea Coast. The nearest known localities (outside of the study area) of the species are situated at a considerable distance (100-230 km) from the recently discovered ones. The data presented here confirm the presence of E. jaculus along the Bulgarian Black Sea Coast and expand the knowledge on its distribution both in the country and in the Balkans

First survey on the invasive Pond slider (Trachemys scripta) in Bulgaria: historic development and current situation

Crvenouha kornjača (Trachemys scripta) postala je popularni ljubimac u Bugarskoj od 1990. Kroz godine sve veći broj jedinki zabilježen je i u divljini. Iako su negativni učinci na izvornim kornjače su opsežno studirao negdje drugdje, nema posebne studije (osim kratkih izvješća) obratili invaziju T. scripta u Bugarskoj. Ova studija se temelji na više od 25 godina praćenja na terenu i predstavlja prvi izvor detaljne informacije o raspodjeli Pond klizača u Bugarskoj. Ukupno 293 UTM (10 × 10 km) kvadrata sa staništa pogodna za slatkovodne kornjače ispitano. Prikupili smo 64 zapisa za 173 osoba, od 19 UTM kvadrata. Od svih promatranih osoba, samo dvije su od nominirati podvrste - ostatak pripada T. Š. elegans. U našem istraživanju je uočeno samo jednoga djeteta. Do danas nije uspješno leženja zabilježena, iako su registrirani uspješni overwinterings. Mi smo razgovarali o raznim mjere ublažavanja koje se moraju brzo pokrenut ograničiti buduće izdanje Ribnjak klizača i za uklanjanje ne-izvornih uzoraka s bugarskim ekosustava. Akcije su zahtijevali posebno da se izbjegne potencijalne epidemiološko događaja uzrokovanih parazitima s vrlo smrtonosnim učinkom na autohtonim vrstama. Takve pojave potencijalno mogu imati veći utjecaj na autohtone vrste kornjača jezerce od raznih oblika natjecanja s T. scripta.Pond sliders (Trachemys scripta) have become a popular pet in Bulgaria since 1990. Through the years a number of released specimens were observed in the wild. Although the negative effects on native turtles have been studied extensively elsewhere, no specific studies (besides brief reports) have addressed the invasion of T. scripta in Bulgaria. The present study is based on over 25 years of field monitoring and represents the first source of detailed information on the distribution of the Pond slider in Bulgaria. A total of 293 UTM (10×10 km) squares with habitats suitable for freshwater turtles were surveyed. We collected 64 records for 173 individuals, from 19 UTM squares. From all observed individuals, only two were from the nominate subspecies – the rest belong to T. s. elegans. In our study only one subadult was observed. To date no successful hatching has been recorded, although successful overwinterings have been registered. We discuss various mitigation measures that must be rapidly initiated to limit future release of Pond sliders and to remove the non-native specimens from the Bulgarian ecosystems. Actions are demanded especially to avoid the potential epizootic events caused by parasites with highly lethal effect on native species. Such outbreaks might potentially have greater impact on the native pond turtle species than various forms of competition with T. scripta

An extended mtDNA phylogeography for the alpine newt illuminates the provenance of introduced populations

Many herpetofauna species have been introduced outside of their native range. MtDNA barcoding is regularly used to determine the provenance of such populations. The alpine newt has been introduced across the Netherlands, the United Kingdom and Ireland. However, geographical mtDNA structure across the natural range of the alpine newt is still incompletely understood and certain regions are severely undersampled. We collect mtDNA sequence data of over seven hundred individuals, from both the native and the introduced range. The main new insights from our extended mtDNA phylogeography are that 1) haplotypes from Spain do not form a reciprocally monophyletic clade, but are nested inside the mtDNA clade that covers western and eastern Europe; and 2) haplotypes from the northwest Balkans form a monophyletic clade together with those from the Southern Carpathians and Apuseni Mountains. We also home in on the regions where the distinct mtDNA clades meet in nature. We show that four out of the seven distinct mtDNA clades that comprise the alpine newt are implicated in the introductions in the Netherlands, United Kingdom and Ireland. In several introduced localities, two distinct mtDNA clades co-occur. As these mtDNA clades presumably represent cryptic species, we urge that the extent of genetic admixture between them is assessed from genome-wide nuclear DNA markers. We mobilized a large number of citizen scientists in this project to support the collection of DNA samples by skin swabbing and underscore the effectiveness of this sampling technique for mtDNA barcoding

A review of distribution and conservation status of <em>Zamenis situla</em> (Linnaeus, 1758) (Reptilia: Colubridae) in Bulgaria

The leopard snake is one of the rarest snake species in Bulgaria. It is included in the Red Data Book of Bulgaria as threatened species under high anthropogenic pressure. Its distribution range in Bulgaria includes only three very distant regions in the southern part of the country. Precise literature data about the leopard snake in Bulgaria are scarce. The aim of this paper is to present distribution data as well as to review the conservation status of the leopard snake in Bulgaria

Diet of the Viviparous lizard Zootoca vivipara (Lichtenstein, 1823) (Reptilia: Lacertidae) from its southern range

The Viviparous lizard Zootoca vivipara (Lichtenstein, 1823) is widespread across Eurasia, but in Bulgaria it is considered a glacial relict, restricted to the high mountains. In spite of its wide distribution, there is still lack of knowledge on its dietary habits, especially from the southern part of the range. In order to shed light on its diet, we conducted а study in three mountain sites in Bulgaria (Vitosha, Rila and Stara Planina Mtns.). They were visited in 2016 and 2017 during the lizard's active season (May–September); 343 Viviparous lizards were captured by hand and measured and weighed. To investigate the food preferences, we adopted a non-invasive method, obtaining faecal samples, which were then analysed under a stereoscopic microscope. A total of 290 faecal samples that could be assigned to individual specimens with determined age and sex were collected. We calculated the relative abundance and occurrence of each prey category. Data were compared by sex and age classes (immatures vs. adults) as a whole and for each of the three sites. A total of 19 prey categories were detected and the number of categories per study site varied between 16 and 18. The most common invertebrates were Araneae and Auchenorrhyncha. Statistically significant differences between immatures and adults were found as adults showed more diverse diet. No such differences between sexes were detected

Emergence and dispersal of snakes after syntopic hibernation

A communal hibernaculum situated in Southwestern Bulgaria and its adjacent area (4 km in diameter) was studied. Seven snake species used this hibernating den, Malpolon insignitus, Dolichophis caspius, Platyceps najadum, Elaphe quatuorlineata, Telescopus fallax, Vipera ammodytes and Xerotyphlops vermicularis. The emergence of the snakes was related to the rise of daily temperatures. Malpolon insignitus emerged from hibernation earlier in the spring than the other species, and most individuals were the first to leave the hibernaculum. There was a temporal segregation among the basking area in early spring, between the latter species and D. caspius, which were the two most abundant species. These two species also used the same area of the hibernaculum, in contrast to P. najadum and E. quatuorlineata, which used a different area. After spring dispersal, M. insignitus and D. caspius used the same microhabitats during the rest of the active period. The earlier emergence of M. insignitus (and earlier departure from the site) probably reduces the competition for basking sites. The early departure of the species may give advantage in the competition for optimal microhabitats with D. caspius

Crepuscular and nocturnal activity of the Nose-horned viper, Vipera ammodytes (Linnaeus, 1758) is more common than previously reported

Different snake species may be active at various times of the day. In Europe, most snake species are predominantly diurnal, but about a third are partially or principally crepuscular and/or nocturnal. Here, we report the first instance of multiple in situ observations of the crepuscular and nocturnal activity of V. ammodytes in Bulgaria. Overall, usually as a result of general herpetological surveys and chance observations between 2001–2020, we recorded crepuscular/nocturnal activity of twenty-seven individuals from both sexes and all age classes (juvenile to adult), observed from April to September, following warm (maximum daily Tair = 20–28 °C) and hot (Tair > 28 °C) days. These records represent less than 1.5% of all our personal viper observations. However, given that our observations occurred throughout the country, within five different climatic zones, we hypothesise that nocturnal activity of V. ammodytes is more common than previously reported