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

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

Contributions to the functional morphology of caudate skulls: kinetic and akinetic forms

A strongly ossified and rigid skull roof, which prevents parietal kinesis, has been reported for the adults of all amphibian clades. Our μ-CT investigations revealed that the Buresch’s newt (Triturus ivanbureschi) possess a peculiar cranial construction. In addition to the typical amphibian pleurokinetic articulation between skull roof and palatoquadrate associated structures, we found flexible connections between nasals and frontals (prokinesis), vomer and parasphenoid (palatokinesis), and between frontals and parietals (mesokinesis). This is the first description of mesokinesis in urodelans. The construction of the skull in the Buresch’s newts also indicates the presence of an articulation between parietals and the exocipitals, discussed as a possible kind of metakinesis. The specific combination of pleuro-, pro-, meso-, palato-, and metakinetic skull articulations indicate to a new kind of kinetic systems unknown for urodelans to this date. We discuss the possible neotenic origin of the skull kinesis and pose the hypothesis that the kinesis in T. ivanbureschi increases the efficiency of fast jaw closure. For that, we compared the construction of the skull in T. ivanbureschi to the akinetic skull of the Common fire salamander Salamandra salamandra. We hypothesize that the design of the skull in the purely terrestrial living salamander shows a similar degree of intracranial mobility. However, this mobility is permitted by elasticity of some bones and not by true articulation between them. We comment on the possible relation between the skull construction and the form of prey shaking mechanism that the species apply to immobilize their victims

Updated distribution and species composition of the amphibians and reptiles along the Lower Danube, Bulgaria

In a recently published paper (Popgeorgiev et al. 2019), we compiled for the first time published and unpublished data on localities of the herpetofaunal species observed up to ca. 10 km south of the Bulgarian Danube River. Overall, we identified 687 published records belonging to 62 cells of the 10×10 km MGRS grid. Another 1918 records with real coordinates of our unpublished data from the past ca. 13 years belong to 1269 cells of the 1×1 MGRS grid. As a result, 34 native species – 15 amphibians (4 salamanders and 11 frogs) and 19 reptiles (1 turtle, 2 tortoises, 8 lizards and 8 snakes), and one invasive turtle, have been recorded; further species findings are unlikely. This study further identifies areas that are under-sampled and species such as Pelophylax lessonae that are cryptic. Our data are especially relevant concerning the high economic incentives to change the hydrology of the Danube, which will likely negatively impact the biodiversity along the river and its surrounding

Comparison of methodologies for the extraction of snakes’ (Reptilia: Serpentes) skin secretions and preliminary results on the presence of pheromones

During this preliminary study, 26 specimens from 8 different snake species were examined. Three methodologies for extraction of skin secretions by immersion of skin in n-hexane were used: immersing the whole body of live individuals for approximately 1 min in the field (n = 13), immersing the whole body of dead specimens (found freshly killed on road) for 24 h (n = 4), and soaking a shed skin for 24 h (n = 9). We did not immerse the head and tail to avoid contamination of the samples. All samples were collected during snakes’ active period (February – first half of June) and were analyzed by gas chromatography-mass spectrometry (GC/qMS). Based on the prevalence in the fraction of long-chained hydrocarbons, lipids or lipids with ketones we can separate the samples in three categories. The lipid fractions were present mainly in the shed skin samples, while the long-chained hydrocarbons dominated in the live specimens. According to the literature, ketones are the main component of the snakes’ pheromone communication. We found ketones in five samples, three live and two dead specimens, from five different species (Vipera ammodytes (Linnaeus, 1758), V. berus (Linnaeus, 1758), Dolichophis caspius (Gmelin, 1789), Natrix natrix (Linnaeus, 1758), and Platyceps najadum (Eichwald, 1831)). No ketones were found in the shed skin extracts. Ketones were found only in adults, both males and females. Presence of ketones was observed only for the period from the end of May to the beginning of June. Based on the preliminary results, we can suggest that secretion extraction from live specimens in the field could prove a valuable method in studies on snake pheromones in addition to the already developed methodologies. We speculate that the pheromones are present only in the reproductive and probably post-reproductive period. However, further research with larger sample size is required

Analyses of Skin Secretions of Vipera ammodytes (Linnaeus, 1758) (Reptilia: Serpentes), with Focus on the Complex Compounds and Their Possible Role in the Chemical Communication

Snakes rely heavily on chemical cues when foraging, searching for mates, etc. Snakes’ sex attractiveness pheromones comprise mainly heavy, semi-volatile compounds such as ketones. Here we investigated the composition of skin secretions of adult Vipera ammodytes (Linnaeus, 1758) individuals. The samples were analyzed by gas chromatography/mass spectrometry and the identification of the compounds was performed using commercial mass spectral libraries and retention times. The relative concentrations of all detected compounds were tested for significant differences between (1) male vs. female live individuals, (2) shed skin vs. live individuals, and (3) pre-reproductive vs. reproductive live individuals. We detected fifty-nine compounds of which six were ketones. Two ketones (2-pentacosanone and 2-heptacosanone) were present in many of the samples and thus may have an important role in the V. ammodytes chemical communication. We did not find significant differences between the relative concentrations of the compounds between male and female individuals (only three compounds are exceptions). Significant differences were found between extracts from shed skins and live individuals and between live pre-reproductive individuals and live reproductive individuals. The results of the study suggest that chemical communication in V. ammodytes involves less compounds in comparison to the known literature data for other species

Optimizing biodiversity gain of European agriculture through regional targeting and adaptive management of conservation tools

Agricultural intensification continues being a major threat for biodiversity worldwide. Despite the incorporation of diverse conservation tools in the Common Agricultural Policy (CAP) since the 1990s, European agriculture continues intensifying. The last CAP reform introduced compulsory greening, including measures to support semi-natural habitats across the wider countryside (referred to in this paper as Green and Blue Infrastructure, GBI), and by these means biodiversity. However, the actual benefits of greening implementation have not been evaluated formally through field studies, and its effectiveness is questioned. We assess the capacity of a variety of GBI features that can be supported by CAP greening to promote biodiversity across a variety of agricultural systems. We analyze the relationships between diversity (birds and plants) and a set of habitat indicators linked to distinct greening options in 115 plots from six case study areas, including arable land, pastures and mixed farming systems in Spain, Germany and Bulgaria. Relationships between biodiversity and the different GBI elements varied considerably between regions, systems and organisms' groups. Some of these relationships were non-linear. Although most GBI elements showed potential for promoting biodiversity, they should be adapted to specific conservation targets and landscape constraints regionally. The next CAP reform could include compulsory measures that support connectivity, heterogeneity and small-landscape elements characteristic in each region (e.g. field margins and trees or preventing field size enlargement), combined with more regionally-orientated voluntary measures (e.g., promoting grassland and fallow). Performance evaluation and adaptation ought to accompany the implementation of these measures to ensure their ecological success.This work is a contribution to the projects BIOGEA ‘Testing BIOdiversity Gain of European Agriculture with CAP greening’ (BiodivERsA3-2015-180), funded by the Spanish State Research Agency, the Bulgarian Science Fund, the German Federal Ministry of Education and Research, and the European Commission within the ERA-Net BiodivERsA Co-Fund scheme, and REMEDINAL TE-CM (S2018/EMT-4338). E.D.C. and V.R. are each recipient of a Juan de la Cierva - Incorporación postdoctoral fellowship (IJCI-2016-30964 and IJCI-2015-24733, respectively) from the Spanish Ministry of Science, Innovation and Universities