Malformation of eye pupil in nose-horned viper (Vipera ammodytes) from a wild population

Herpetology Notes (2017), 10: 229-23

Variation of clutch characteristics in population of Eastern Hermann's tortoises (Testudo hermanni boettgeri Gmelin 1789)

We present here information on some fecundity parameters in local population of Eastern Hermann’s tortoise situated in the area of Kunovica, at the outskirts of the city of Niš. The data were collected in the field and in 97% were based on reconstruction of number and dimensions of eggs in destroyed nests what influenced on quality of information. Only two of 78 nests recorded from 2010 to 2014 were found intact. Other 76 clutches were found destroyed and therefore only some fecundity parameters were measurable, while the others were reconstructed by using formulas proposed in the relevant literature. On the basis of collected data we estimated average clutch size of Hermann’s tortoises in Kunovica as four eggs what was lower than in populations from Greece. However, the most of calculated egg dimensions (e.g. maximal width, volume and mass) were higher than in populations from Greece and France

Fluctuations in population abundance in two anurans from Central Serbia

We monitored the population size of the agile frog (Rana dalmatina) and the common toad (Bufo bufo) from 2011 or 2012, respectively, to the year 2017 at a syntopic breeding site in the vicinity of Belgrade. Adult R. dalmatina population size had minor fluctuations during the years of study (from 351 to 108 frogs). On the contrary, the adult B. bufo population was widely fluctuating towards decline (from 1158 to 141 toads). In both species, population fluctuations were not significantly related to variation of meteorological parameters (air temperature, humidity, precipitation). Density dependence effects on population size were not detected in either species. Apart from possible effects of climate change, the indicated trend towards decline of the monitored B. bufo population could also be the outcome of common population fluctuations or of increasing anthropogenic impact (vicinity of settlement and agricultural land). More years of monitoring more than one population are required to obtain precise information. Nevertheless, our results seem to be coherent with other studies that recommend conservation action for this species

Malformation of eye pupil in nose-horned viper (Vipera ammodytes) from a wild population

Herpetology Notes (2017), 10: 229-23

Amphibians in transition: a case study from Southeastern Europe

In most of Palearctic countries ranked as rich in amphibian diversity the global threats to amphibian populations are prominent. The foremost factors are loss, degradation and fragmentation of habitat, followed by pollution, competition from invasive non-native species (Sommerwerk et al. 2009), increased predatory pressure from domestic animals, and emerging infectious diseases. In combination with economic and political transition, these effects could lead to local extirpation of important fragments of European amphibian diversity. Regarding amphibian species richness, Republic of Serbia is one of top 20 countries in Palearctic region. However, with t he country moving toward market economy, a new problem arose – responsibility for environment protection within the context of a process of privatization. Lack of wastewater management plan, uncontrolled long-term population of watercourses with allochtonous invasive fish species, roadkill and illegal collection for commercial purposes influenced negatively on local amphibian populations. Additional and perhaps specific threat for local amphibian assemblages is disappearance of small and moderate water bodies, primarily in the highlands, either through backfilling or turning into fish ponds. Most of efforts concerning aquatic habitat conservation in the country are focused on bird and fish species (ICPDR National Report 2005) and the protection of specific habitats important for the conservation of amphibians are not adequately addressed. Although the general protection of inland water habitats and wetlands contributes to the conservation of amphibians, the specific small-sized habitats of particular importance for amphibians should be identified and protected. Analysis of surveys related to identification, mapping and classification of amphibian important habitats showed apparent degree of their fragility and thus further work in this matter should be carried out in order to propose and implement adequate conservation measures. The monitoring of amphibians is not widespread in the area and must be intensified, together with proper and frequent education about the importance of amphibian conservation, not just through ordinary educational programmes but among citizens in general. Recent history and current problems with political transitions make biodiversity conservation even more difficult than before, and present economic pressures mean that, without direct economic incentive, the people of the area will not be motivated to preserve amphibians‘ breeding sites

Phenotypic selection in common toad (Bufo bufo)

One of the most important problems for evolutionary biologists is to investigate the patterns and strength of phenotypic selection acting on quantitative traits in natural populations. Measurement of selection is complicated by the presence of correlations between characters; selection on a particular trait produces not only a direct effect, but indirect effects as well. Despite the growing body of phenotypic selection studies in a variety of taxa, studies on amphibians are still sparse. The aim of this study was to estimate patterns and strength of selection acting on a set of correlated characters in a natural population of Bufo bufo from the vicinity of Belgrade, Serbia. Morphological traits (body length, fore- and hind leg length) were measured, while fitness was assayed as fecundity and gonad weight for females and males, respec­tively. The regression approach was used to estimate selection differentials and gradients. Selection patterns differed between the sexes - linear selection differentials showed significant total directional selection for body size in females, but not in males. In males, differentials were significant for both fore- and hind leg lengths. Sample size did not permit identification of significant nonlinear (quadratic) selection.Jedan od najvažnijih problema za evolucione biologe je procena obrazaca i intenziteta fenotipske selekcije koja deluje na kvantitativne osobine u prirodnim populacijama. Procenu selekcije komplikuje i prisustvo korelacije između osobina; selekcija koja deluje na datu osobinu ima ne samo direktan efekat na tu osobinu, već i indirektan na raspodelu korelisanih osobina. Uprkos rastućoj količini informacija o fenotipskoj selekciji kod različitih taksona, studije na vodozemcima su još uvek vrlo retke. Cilj ovog rada bio je da se procene obrasci i intenzitet selekcije koja je delovala na skup korelisanih osobina u prirodnoj populaciji Bufo bufo iz okoline Beograda. Merene su morfološke osobine(dužina tela, dužina prednjih i zadnjih ekstremiteta); fitnes je procenjen preko fekunditeta kod ženki, odnosno težine gonada kod mužjaka. Regresioni metod je primenjen za procenu selekcionih diferencijala i gradijenata. Obrasci selekcije su se razlikovali među polovima - linearni selekcionih Diferencijali ukazuju na značajnu ukupnu direkcionu selekciju za veličinu tela kod ženki, ali ne i kod mužjaka. Kod mužjaka, diferencijali su bili značajni i za prednje i za zadnje ekstremitete. Zbog veličine uzorka nije bilo moguće naći značajnu nelinearnu(kvadratnu) selekciju.nul

Deliberate tail loss in Dolichophis caspius and Natrix tessellata (Serpentes: Colubridae) with a brief review of pseudoautotomy in contemporary snake families

Deliberate tail loss was recorded for the first time in three large whip snakes (Dolichophis caspius) and one dice snake (Natrix tessellata). Observations were made in different years and in different locations. In all cases the tail breakage happened while snakes were being handled by researchers. Pseudoautotomy was confirmed in one large whip snake by an X-Ray photo of a broken piece of the tail, where intervertebral breakage was observed. This evidence and literature data suggest that many colubrid species share the ability for deliberate tail loss. However, without direct observation or experiment it is not possible to prove a species' ability for pseudoautotomy, as a broken tail could also be evidence of an unsuccessful predator attack, resulting in a forcefully broken distal part of the tail.North-Western Journal of Zoology (2016), 12(2): 367-37

First record of the four-lined snake Elaphe quatuorlineata (Lacépède, 1789) in Serbia

This paper presents the first record of four-lined snake Elaphe quatuorlineata in Serbia. In Serbia and Montenegro, according to the literature data, this species was found only in Mediterranean and submediterranean Montenegro. We present here data about founding site and suggest conservation measures for this species in Serbia

Effect of climatic conditions on post-hibernation body condition and reproductive traits of Bufo bufo females

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Assessment of age and intersexual size differences in Bufo bufo

Numerous studies have underlined the complex nature of relationship between age, size, and reproductive traits in anurans. One of the most intriguing problems for evolutionary biologists is intersexual difference in body size (SSD). For testing various hypotheses about SSD, we need reliable estimates of its extent (the important issue being the choice of trait for analysis) as well as the accurate determination of individual age. The measures of SSD may be subject to error if estimated from populations with unknown age distribution; amphibians continue to grow throughout their life and SSD is linked to sex differences in traits such as age at maturity and lifespan. In the present paper, we analyze problems involved in accurate determination of age structure and factors that may lead to under- or overestimation of individual age, as well as the problem of appropriate choice of traits, in the light of our experience and results of investigating populations of common toad (Bufo bufo) in the vicinity of Belgrade.Brojne studije istakle su složenu prirodu odnosa između starosti, veličine tela i reproduktivnih osobina kod bezrepih vodozemaca. Za evolucione biologe jedan od najintrigantnijih problema je interseksualna razlika u veličini tela (SSD). Za testiranje hipoteza koje se tiču SSD, neophodne su tačne procene njene veličine (izuzetno je važno pitanje izbora osobina koje se koriste u toj analizi), kao i precizno određivanje starosti. Procena SSD može biti pogrešna ako nije poznata uzrasna struktura date populacije; vodozemci nastavljaju da rastu tokom života, a SSD je povezana sa interseksualnim razlikama u osobinama kao što su vreme polnog sazrevanja i dužina života. U ovom radu analiziramo probleme vezane za tačnu procenu uzrasne strukture i činioce koji mogu da dovedu do precenjenih ili potcenjenih vrednosti, kao i probleme adekvatnog izbora osobina za analizu, s obzirom na naša iskustva i rezultate proučavanja populacija Bufo bufo iz okoline Beograda.Projekat ministarstva br. 172