Effects of Environmentally Relevant Ammonium Nitrate Levels Caused by Agricultural Activities on Four Amphibian Species in The Eastern Black Sea Region

Within the scope of this research, the chronic effects of ammonium nitrate, which is the most widely used fertilizer worldwide, on the tadpoles of Marsh Frog (Pelophylax ridibundus), the Iranian Long-Legged Frog (Rana macrocnemis), the Caucasian Parsley Frog (Pelodytes caucasicus) and the Variable Green Toad (Bufotes variabilis) were examined. To assess the chronic effects of the fertilizer, the tadpoles of all the species were exposed to 0, 5, 10, 15, 20, 25 mg/L concentrations in same conditions. The chronic concentrations were applied from the 25th developmental stage to the 42nd developmental stage. It was defined at the end of the experiments that although there were some variability between different populations of the same species or between different species in the observed effects, chronic levels of ammonium nitrate caused decreased growth rate, prolonging in time to complete metamorphosis, increased abnormalities, and mortality in general. Among the 4 amphibian species, the Variable Green Toad was the most damaged one in terms of growth reduction (on average 31-41 %), abnormality rates (on average 50-75 %), prolonged time to complete metamorphose (14-21 days on average) and mortality rates (%54-100). The most adaptive species and the least damaged one was an Iranian long-legged frog for growth reduction (on average 0-15 %), prolonged time to complete metamorphose (7-9 days on average), and mortality rates (%9-15). All the harmful effects of chronic fertilizer levels caused by agricultural activities in the region had very important for examined species in our researches and it can be said that important environmental and biodiversity problems may occur if certain precautions are not taken regarding the use of the fertilizers and if the attitudes of the farmers on this issue cannot be changed.

Effects of Acute Ammonium Nitrate Levels Caused by Agricultural Activities on Four Amphibian Species in The Eastern Black Sea Region

The tadpoles of four amphibian species, namely the Marsh Frog (Pelophylax ridibundus), the Iranian Long-Legged Frog (Rana macrocnemis), the Caucasian Parsley Frog (Pelodytes caucasicus) and the Variable Green Toad (Bufotes variabilis), were exposed to acute concentrations (0 to 500 mg/L) of ammonium nitrate to assess the lethal effects (larval growth, abnormalities, mortality, and LC50 values). Eggs of each species were obtained from clean and polluted habitats in the same region and the tadpoles for experiments were provided from those eggs in the laboratory conditions. Although there was some variability between different populations of the same species or between different species in the observed effects, acute levels of ammonium nitrate caused decreased growth rate and increased abnormalities and mortality in general. Among the 4 amphibian species, the Variable Green Toad was the most damaged one in terms of growth reduction (on average 77-83%), and abnormality rates, and the most damaged one in terms of mortality rates was the Marsh Frog (on average 61-72%). Additionally, the species with the lowest concentration of ammonium nitrate, which killed half of its population, was the Marsh Frog. LC50 values for two populations of Marsh Frog were 37 and 59 mg/L. As a result of our research, it was determined that the acute fertilizer levels caused by agricultural activities in the region had very important harmful effects for all the species we examined. In this context, it can be said that very important environmental and biodiversity problems may occur if certain precautions are not taken regarding the use of the fertilizers and if the awareness of the farmers using these fertilizers cannot be raised.

The European green toad, Bufotes viridis, in Donaufeld (Vienna, Austria): status and size of the population

The European green toad, Bufotes viridis (Laurenti, 1768), is a rare and protected species in Vienna. In spring and summer 2020, we conducted a survey to assess size and status of its population in Donaufeld, an agricultural area designated for real estate development. Recaptures of photographically registered toads allowed to estimate the population size with 137 individuals (confidence interval: 104–181). Comparatively large body size indicates the presence of a well-established population. Reproductive success was high in the study year. A mismatch mating of a male B. viridis with a female Bufo bufo was observed. Mitigation measures are needed to support this population facing imminent habitat deterioration.

INSERT HOST IN THE LIFE CYCLE OF ALARIA ALATA (TREMATODA, STRIGEIDIDA) IN THE NATURAL ENVIRONMENT OF THE CENTRAL BLACK-EARTH ZONE

Currently, an increase in cases of infection of wild and domestic carnivores with the trematode Alaria alata (Trematoda, Strigeidida) is currently recorded in the Central Black-Earth Zone. The trematode A. alata has a complex life cycle involving intermediate, insert and reservoir hosts. We obtained new data on the realization of the life cycle of A. alata in the natural environment of the Central Black-Earth Zone. The moor frog (Rana arvalis), green toad (Bufotes viridis) and spade-footed toad (Pelobates fuscus) are recorded as insert hosts. Infection with mesocercarias A. alata of the moor frog is 20% (the prevalence) and 23 specimens (infection intensity). The moor frog is the most numerous species among amphibians and is characterized by high in-touch capabilities with carnivorous mammals. The moor frog is the main insert host in the circulation of A. alata in natural biocenoses. We have identified the localization of the Alaria mesocercarias in the moor frog, namely, the pericardium and subcutaneous tissue of the intermaxillary space. We determined the distribution of mesocercarias in moor frogs of this year's brood: 71% in the head; 25.8% in the hind legs; 22.6% in the trunk; and 3.2% in the front legs. The green toad and spade-footed toad were also classified as insert hosts of A. alata (prevalence of infection was less than 10%; and infection intensity was 4.0 specimens). Mesocercarias were found in frog larvae (24.6%; 2.6 sp.).

The effect of water extract from bentonite on embryonic and larval development of the green toad (bufoviridis) with different phenotypes

Ontogenesis is a complex process of morphophysiological transformations. Embryonic and postembryonic development is continuously affected by both endogenous and environmental factors, which lead to variability in morphometric parameters. The research was conducted in the laboratory of ecological embryology of the Federal State Budgetary Educational Institution of Higher Education of the North Osetian Federal University (Vladikavkaz). The results showed that under the influence of bentonite extract, the morphological parameters of green toad larvae with a brown phenotype are more variable than in larvae with an olive green phenotype in both the control and experimental groups. Thus, the embryos and larvae of the green toad with the olive green phenotype are more stable than the larvae that had the brown phenotype, both in natural circumstances and under the influence of bentonite clay extracts.

CHARACTERISTICS OF THE POLYMORPHISM OF THE GREEN TOAD BUFO VIRIDIS (LAURENTI, 1768) IN THE BIOCENOSES OF THE SOUTHERN URALS (REPUBLIC OF BASHKORTOSTAN)

The results of the study of the features of polymorphism of green toad populations in the conditions of the Trans-Urals of the Republic of Bashkortostan are presented. It was found that among the green toads in the urbanized territories of the Trans-Urals, individuals with the color type M3 ("light background, merged spots") and M4 ("dark background, merged spots") prevail. There was a decrease in the diversity index in the conditions of low-rise buildings (m=1.995), as well as industrial (m=2.843) and green zones (m=2.986) relative to the control areas (3.286<m<3.99).

The Green Toad Example: A Comparison of Pattern Recognition Software

Background Individual identification of animals is important for assessing the size and status of populations. Photo-based approaches, where animals are recognized by naturally occurring and visually identifiable features, such as color patterns, are cost-effective methods for this purpose. We compared five available programs for their power to semi-automatically identify dorsal patterns of the European green toad (Bufotes viridis). Method We created a data set of 200 pictures of known identity, two pictures for each individual, and analyzed the percentage of correctly identified animals for each software. Furthermore, we employed a generalized linear mixed model to identify important factors contributing to correct identifications. We used these results to estimate the population size of our hypothetical population. Conclusions The freely available HotSpotter application was the software which performed by far the best for our green toad example, identifying close to 100% of the photos correctly. The animals’ sex highly significantly influenced detection probability, presumably because of sex-specific differences in the pattern contrast. Population estimates were close to the expected 100 for HotSpotter, but for the other applications population size was highly overestimated. Given the clarity of our results we strongly recommend the HotSpotter software, which is a highly efficient tool for individual pattern recognition.

Occurrence of Batrachochytrium dendrobatidis in Sweden: higher infection prevalence in southern species

The chytrid fungus Batrachochytrium dendrobatidis (Bd) has caused worldwide declines in amphibian populations. While Bd is widespread in southern and central Europe, its occurrence and distribution in northernmost Europe is mostly unknown. We surveyed for Bd in breeding anurans in Sweden by sampling 1917 amphibians from 101 localities and 3 regions in Sweden (southern, northern and central). We found that Bd was widespread in southern and central Sweden, occurring in all 9 investigated species and in 45.5% of the 101 localities with an overall prevalence of 13.8%. No infected individuals were found in the 4 northern sites sampled. The records from central Sweden represent the northernmost records of Bd in Europe. While the proportion of sites positive for Bd was similar between the southern and central regions, prevalence was much higher in the southern region. This was because southern species with a distribution mainly restricted to southernmost Sweden had a higher prevalence than widespread generalist species. The nationally red-listed green toad Bufotes variabilis and the fire-bellied toad Bombina bombina had the highest prevalence (61.4 and 48.9%, respectively). Across species, Bd prevalence was strongly positively, correlated with water temperature at the start of egg laying. However, no individuals showing visual signs of chytridiomycosis were found in the field. These results indicate that Bd is widespread and common in southern and central Sweden with southern species, breeding in higher temperatures and with longer breeding periods, having higher prevalence. However, the impact of Bd on amphibian populations in northernmost Europe remains unknown.

Axanthism in amphibians: A review and the first record in the widespread toad of the Bufotes viridis complex (Anura: Bufonidae)

Axanthism in amphibians is a relatively rare color aberration reported less often than leucism or albinism. It is caused by lack of specific types of pigment cells in the skin, namely xanthophores, erythrophores, and iridophores. Here, we present the first case of occurrence of this aberration in a widely distributed toad of the green toad (Bufotes viridis) complex and provide an extensive review of axanthism occurrence in amphibians. So far it has been reported in more than 20 species from nine families of amphibians with the highest occurrence in the family Ranidae.