Per pusantrų metų 26 km ilgio kelyje Vilnius–Dūkštos užregistruota 378 žuvę gyvūnai, iš jų 44 žinduoliai (6 laukinių ir 3 naminių gyvūnų rūšys), 1 paukštis ir 333 varliagyviai (rudosios Rana genties varlės). Rastas 21 suvažinėtas baltakrūtis ežys, 8 katės, 4 šunys, 4 akmeninės kiaunės, 2 rudosios žiurkės, 2 geltonkaklės pelės, 1 lapę, 1 pilkasis kiškis ir 1 karvė. Varliagyviai masiškai žūva migruodami iš žiemojimo vietų į nerštavietes. Tiek 2005, tiek 2006 metais masinis rudųjų varlių žuvimas kelyje Vilnius–Dūkštos užregistruotas balandžio pirmąjį dešimtadienį. Daugiausia žinduolių ant kelio buvo suvažinėta šiltuoju metų laiku – rugpjūčio, gegužės ir rugsėjo mėnesiais. Kadangi gyvūnai ant kelių registruojami rytą, dauguma jų suvažinėjami tamsiu paros metu. Daugiausia žinduolių (27%) suvažinėta tose vietose, kur kelią supa krūmynai, 23% - gyvenvietėse ir miesteliuose, 20% – keliui einant pievomis ir 18% – pamiškėse. Kitų biotopų reikšmė gyvūnų žuvimui kelyje Vilnius–Dūkštos buvo nedidelė – miške užregistruota tik 9% žuvusių žinduolių. Ežiai ir varliagyviai suvažinėjami visame Vilnius–Dūkštos kelio ruože: varliagyviai – ties grioviais, upeliais, laukų pelkutėmis ir ten, kur kelią supa šlapi krūmynai, ežiai – kai kelias eina pievomis ir krūmuotomis vietomis. Ištirtoje kelio atkarpoje trūksta apie susidūrimą su gyvūnais perspėjančių kelio ženklų, pavojingose vietose nėra ribojamas greitis. Šios priemonės leistų sumažinti gyvūnų žuvimą. / Animal roadkills on the road were partly conditioned by overspeeding and insufficient number of the road signs. Our results show, that animal roadkills are quite big compared to the short road segment. In the foreign countries problems of the animal roadkills receive more attention, as except damage done to the nature, there are problems of safety, material losses and possible charges to a road service if warning road signs were absent. Object of this investigation were animals, killed on the road Vilnius–Dūkštos (segment length – 26 km). Aim this work was to evaluate species composition of the killed animals, seasonality and influence of the surrounding habitats. Investigation was done while driving this segment twice per day and registering animals killed. Rules of the road were obeyed – no stops under sign or interrupting other vehicles, thus, not all of the killed animals were collected or pictures taken. Places of the roadkills were mapped. In the period of 2004.11.01–2006.05.01number of killed animals was 378; out of these 44 mammals, 1 bird (young Tawny Owl) and 333 amphibians (common/moor frogs). Biggest number of mammal roadkills was done in the dark period of the day and in August–September, while that of amphibians – in April. No kills were registered in January and February. Species composition of mammals: 21 hedgehogs, 4 stone martens, 2 yellow-necked mice, 2 brown rats, 1 fox, 1 brown hare, 8 cats and 4 dogs. According our results and literature analysis... [to full text]

Per pusantrų metų 26 km ilgio kelyje Vilnius–Dūkštos užregistruota 378 žuvę gyvūnai, iš jų 44 žinduoliai (6 laukinių ir 3 naminių gyvūnų rūšys), 1 paukštis ir 333 varliagyviai (rudosios Rana genties varlės). Rastas 21 suvažinėtas baltakrūtis ežys, 8 katės, 4 šunys, 4 akmeninės kiaunės, 2 rudosios žiurkės, 2 geltonkaklės pelės, 1 lapę, 1 pilkasis kiškis ir 1 karvė. Varliagyviai masiškai žūva migruodami iš žiemojimo vietų į nerštavietes. Tiek 2005, tiek 2006 metais masinis rudųjų varlių žuvimas kelyje Vilnius–Dūkštos užregistruotas balandžio pirmąjį dešimtadienį. Daugiausia žinduolių ant kelio buvo suvažinėta šiltuoju metų laiku – rugpjūčio, gegužės ir rugsėjo mėnesiais. Kadangi gyvūnai ant kelių registruojami rytą, dauguma jų suvažinėjami tamsiu paros metu. Daugiausia žinduolių (27%) suvažinėta tose vietose, kur kelią supa krūmynai, 23% - gyvenvietėse ir miesteliuose, 20% – keliui einant pievomis ir 18% – pamiškėse. Kitų biotopų reikšmė gyvūnų žuvimui kelyje Vilnius–Dūkštos buvo nedidelė – miške užregistruota tik 9% žuvusių žinduolių. Ežiai ir varliagyviai suvažinėjami visame Vilnius–Dūkštos kelio ruože: varliagyviai – ties grioviais, upeliais, laukų pelkutėmis ir ten, kur kelią supa šlapi krūmynai, ežiai – kai kelias eina pievomis ir krūmuotomis vietomis. Ištirtoje kelio atkarpoje trūksta apie susidūrimą su gyvūnais perspėjančių kelio ženklų, pavojingose vietose nėra ribojamas greitis. Šios priemonės leistų sumažinti gyvūnų žuvimą. / Animal roadkills on the road were partly conditioned by overspeeding and insufficient number of the road signs. Our results show, that animal roadkills are quite big compared to the short road segment. In the foreign countries problems of the animal roadkills receive more attention, as except damage done to the nature, there are problems of safety, material losses and possible charges to a road service if warning road signs were absent. Object of this investigation were animals, killed on the road Vilnius–Dūkštos (segment length – 26 km). Aim this work was to evaluate species composition of the killed animals, seasonality and influence of the surrounding habitats. Investigation was done while driving this segment twice per day and registering animals killed. Rules of the road were obeyed – no stops under sign or interrupting other vehicles, thus, not all of the killed animals were collected or pictures taken. Places of the roadkills were mapped. In the period of 2004.11.01–2006.05.01number of killed animals was 378; out of these 44 mammals, 1 bird (young Tawny Owl) and 333 amphibians (common/moor frogs). Biggest number of mammal roadkills was done in the dark period of the day and in August–September, while that of amphibians – in April. No kills were registered in January and February. Species composition of mammals: 21 hedgehogs, 4 stone martens, 2 yellow-necked mice, 2 brown rats, 1 fox, 1 brown hare, 8 cats and 4 dogs. According our results and literature analysis... [to full text]

The aim of this study was to determine the effect of density and kinship on the rate of metamorphosis of the selected species of frogs. The work was made in Rana temporaria, common frog. Tadpoles of this species have been bred at different densities kindred subjects. The regular weekly intervals were timed tadpoles until metamorphosis. It has been shown that tadpoles reared individually developed much faster and metamorphosed at larger sizes. Contrast, tadpoles raised in unrelated groups developed much more slowly than in the group composed of related individuals.

Pharmaceuticals polluting natural environments pose a greater and greater threat in today’s society. Benzodiazepines, the most common form of anxiolytic drug, can commonly be found in nature as a result of the release of human wastewater containing the drug, and have been shown to affect both fish and frog species in several different ways related to predator evasion. This study aims to determine whether a common benzodiazepine, oxazepam, has any inhibitory effect on induced behavioral defenses in the boreal frog species Rana temporaria. Larvae of R. temporaria were exposed to an oxazepam gradient, paired with three different predator regimes consisting of a control, an ambush-predator setting, and a pursuing-predator setting. The larvae were then filmed at three different Gosner stages during simulated predator encounters, while measuring maximum velocity and acceleration, as well as activity- and exploration level, and the duration of avoidance following each encounter. Tail related morphological traits were also measured in order to correlate velocity and acceleration with trait properties. Avoidance duration was found to decrease when exposed to ambush predators, regardless of oxazepam concentration. No other effect of predators could be found during this study, and no significant correlations between tail properties and velocity or acceleration were seen. Oxazepam was not found to inhibit any induced behavioral defenses, nor did it alter any of the examined behavioral traits.

La dispersion des animaux est un processus clé pour le maintien des populations et métapopulations. En particulier, les amphibiens se déplacent beaucoup durant leur cycle de vie fait de migrations saisonnières. Ceci les rend sensibles à la structure du paysage. En effet, les modifications anthropiques comme l’aménagement d’infrastructures linéaires peuvent constituer des barrières écologiques pour les animaux et limiter le flux de gènes dans le paysage. Si les effets des routes et des lignes chemins de fer sur les déplacements des animaux ont été largement étudiés, les effets des infrastructures liées aux activités de sport d’hiver comme les pistes de ski et les remontées mécaniques sont moins bien connus. Ainsi, la perméabilité des milieux de montagne anthropisés est peu connue. Cette thèse vise à quantifier la perméabilité écologique (ou connectivité fonctionnelle), des domaines skiables pour un amphibien de montagne largement répandu : la Grenouille rousse (Rana temporaria Linnaeus 1758). Pour ce faire, nous combinons un suivi individuel de déplacements et une étude de génétique du paysage pour mieux comprendre les facteurs influençant les déplacements de grenouilles et les flux de gènes dans le paysage. Le suivi individuel est réalisé au moyen de balises GPS et d’analyses de sélection de pas (step selection analysis). L’étude de génétique du paysage est réalisée en prélevant des échantillons d’ADN dans trois domaines skiables de Savoie ainsi que dans une zone témoin située dans le Parc national de la Vanoise. Nous avons testé l’influence de plusieurs variables paysagères liées à la topographie (pente, altitude…), les habitats (réseau de zones humides, couverture du sol…) ou les activités humaines (présence de routes, de pistes de ski) sur le flux de gènes. En utilisant une nouvelle méthode d’optimisation de surface de résistance, nous montrons l’importance du réseau de zones humides pour les amphibiens de montagne. D’une part, elles servent d’habitat préférentiel et d’autre part, un réseau dense de zones humides permet d’assurer une bonne connectivité des paysages pour la Grenouille rousse. Nous mettons également en évidence que l’hétérogénéité des tailles efficaces de populations dans un paysage peut fausser les distances génétiques mesurées entre populations et nous recommandons l’utilisation de techniques pour s’affranchir de tels problèmes. Nos travaux sont importants dans une perspective de gestion durable des domaines skiables, l’aménagement de pistes de ski ou autres infrastructures de loisir pouvant être accompagnée de destructions de zones humides. / Animal disperal is a key process for maintaining populations and metapopulations. In particular, amphibians move a lot during their life cycle made of seasonal migrations. This makes them sensitive to the structure of the landscape. Indeed, anthropogenic changes such as linear infrastructure can act as ecological barriers for animals and limit gene flow within the landscape. While the effects of roads and railways on animal movements have been widely studied, the effects of infrastructure related to winter sports activities such as ski slopes and lifts are less well known. Thus, the permeability of anthropized mountain environments is little known. This thesis aims to quantify the ecological permeability (or functional connectivity) of ski areas for a widely distributed mountain amphibian: the European common frog (Rana temporaria Linnaeus 1758). To do this, we combine individual movement tracking and landscape genetics studies to better understand the factors influencing frog movements and gene flow within the landscape. Individual tracking is carried out by means of GPS tags and step selection analysis. The landscape genetics study is carried out by gathering DNA samples from three ski areas in Savoie and a control area located in the Vanoise National Park. We tested the influence of several landscape variables related to topography (slope, altitude...), habitats (wetland network, land cover...) or human activities (presence of roads, ski slopes) on gene flow. By using a new method of resistance surface optimization, we show the importance of the wetland network for mountain amphibians. On the one hand, they serve as preferential habitat and, on the other hand, a dense network of wetlands ensures good landscape connectivity for the Common frog. We also highlight that the heterogeneity in effective population sizes in a landscape can distort the genetic distances measured between populations and we recommend the use of techniques to overcome such problems. Our work is important for the sustainable management of ski areas, the development of ski slopes or other recreational infrastructure that can be accompanied by the destruction of wetlands.

<p>Worldwide amphibians and reptiles are declining with habitat fragmentation and destruction as the primary cause. Riparian areas are important for the herpetofauna, but as land is converted to agriculture or harvested for timber the areas are diminishing. The aim of this study was to examine amphibian and reptile abundance in relation to distance from water and in relation to habitat characteristics, foremost per cent deciduous trees. The survey was conducted during spring at six different locations, with continuous forest along streams or rivers, outside of Karlstad, Sweden. Animals were searched along four lines parallel to the water and each study area was visited five times. Statistical analyses were made for grass snake (<em>Natrix natrix</em>), common lizard (<em>Lacerta vivipara</em>) and frogs with joined data of common frog (<em>Rana temporaria</em>) and moor frog (<em>R. arvalis</em>). As expected both reptiles were positively correlated with per cent deciduous trees, with the strongest significance for the common lizard. For grass snake there was also a difference between survey periods, which might reflect the importance of weather. Frogs revealed no trends to trees, but there was a significant difference for habitat characteristics like amount woody debris and per cent bare ground. None of the species were correlated with distance from water which was surprising, especially for the frogs which is more dependent on water than the reptiles. Grass snakes hunt in the water, but the common lizard has no such associations to the water, yet the latter did reveal a slight trend towards being more numerous closer to the water. The causes behind lacking correlation to distance from water may be many, but water characteristics seem very important. Many amphibians prefer warm and calm ponds over running water that in general are colder and likely to inhabit more predators. It was assumed that the amphibians breed in the streams or rivers, but it is possible that other water bodies may have served as breeding sites, which mean the starting point was incorrect.</p>

<p>For ectotherms living in seasonal environments, time available for development and growth is often constrained by the length of the growth season. Declining season length towards higher latitudes often select for latitudinal clines in development and growth rates, exhibiting increasing growth and developmental rates towards the north. However, the physiological and ecological factors enabling these clines are poorly understood.</p><p>Our study system included eight populations of <i>Rana temporaria</i> along a 1500 km latitudinal gradient. We found increased growth rates in populations at higher latitudes to be the result of higher growth efficiency, partly due to increased relative gut length. Populations with higher growth rates also exhibited lower standard metabolic rates, implying that fast-growing individuals are able to achieve high growth rates by spending less energy on maintenance metabolism under low activity conditions.</p><p>Predator densities, and antipredatory defenses in prey, are assumed to decrease towards higher latitudes. While all study populations responded to predator presence by decreasing activity and foraging, high latitude populations maintained higher activity levels in the presence of the predator. In trials with a free-ranging predator, high latitude tadpoles experienced higher mortality than those from the low latitudes. The higher activity level in the northern populations increases mortality under predation risk, but is probably needed to maintain high growth and development rates.</p><p>When competing over resources, tadpoles from the low latitude population were inferior competitors, as indicated by their longer development time when raised together with high latitude tadpoles. We found no effect of latitude on size-corrected burst speed. The general effect of predator presence on burst speed depended on food availability, with well fed tadpoles being faster in the absence, and food restricted being faster in the presence of a predator.</p>

For ectotherms living in seasonal environments, time available for development and growth is often constrained by the length of the growth season. Declining season length towards higher latitudes often select for latitudinal clines in development and growth rates, exhibiting increasing growth and developmental rates towards the north. However, the physiological and ecological factors enabling these clines are poorly understood. Our study system included eight populations of Rana temporaria along a 1500 km latitudinal gradient. We found increased growth rates in populations at higher latitudes to be the result of higher growth efficiency, partly due to increased relative gut length. Populations with higher growth rates also exhibited lower standard metabolic rates, implying that fast-growing individuals are able to achieve high growth rates by spending less energy on maintenance metabolism under low activity conditions. Predator densities, and antipredatory defenses in prey, are assumed to decrease towards higher latitudes. While all study populations responded to predator presence by decreasing activity and foraging, high latitude populations maintained higher activity levels in the presence of the predator. In trials with a free-ranging predator, high latitude tadpoles experienced higher mortality than those from the low latitudes. The higher activity level in the northern populations increases mortality under predation risk, but is probably needed to maintain high growth and development rates. When competing over resources, tadpoles from the low latitude population were inferior competitors, as indicated by their longer development time when raised together with high latitude tadpoles. We found no effect of latitude on size-corrected burst speed. The general effect of predator presence on burst speed depended on food availability, with well fed tadpoles being faster in the absence, and food restricted being faster in the presence of a predator.

Worldwide amphibians and reptiles are declining with habitat fragmentation and destruction as the primary cause. Riparian areas are important for the herpetofauna, but as land is converted to agriculture or harvested for timber the areas are diminishing. The aim of this study was to examine amphibian and reptile abundance in relation to distance from water and in relation to habitat characteristics, foremost per cent deciduous trees. The survey was conducted during spring at six different locations, with continuous forest along streams or rivers, outside of Karlstad, Sweden. Animals were searched along four lines parallel to the water and each study area was visited five times. Statistical analyses were made for grass snake (Natrix natrix), common lizard (Lacerta vivipara) and frogs with joined data of common frog (Rana temporaria) and moor frog (R. arvalis). As expected both reptiles were positively correlated with per cent deciduous trees, with the strongest significance for the common lizard. For grass snake there was also a difference between survey periods, which might reflect the importance of weather. Frogs revealed no trends to trees, but there was a significant difference for habitat characteristics like amount woody debris and per cent bare ground. None of the species were correlated with distance from water which was surprising, especially for the frogs which is more dependent on water than the reptiles. Grass snakes hunt in the water, but the common lizard has no such associations to the water, yet the latter did reveal a slight trend towards being more numerous closer to the water. The causes behind lacking correlation to distance from water may be many, but water characteristics seem very important. Many amphibians prefer warm and calm ponds over running water that in general are colder and likely to inhabit more predators. It was assumed that the amphibians breed in the streams or rivers, but it is possible that other water bodies may have served as breeding sites, which mean the starting point was incorrect.

The increasing level of the UV-B irradiation due to depleting of the ozone layer is considered to be one of the causes of global amphibian declines. The UV-B radiation causes damage to the DNA in the nuclei of the skin cells and their eventual death. In many amphibian species there was found a negative influence of the UV-B radiation on the hatching success of tadpoles and their subsequent viability. It has been assumed that tadpoles are able to actively avoid places with the higher exposure of the UV-B radiation thanks to their locomotion. In this experiment tadpoles could have chosen between a zone with the UV radiation (UV-B and UV-A) and without the UV radiation. The tadpoles have not been exposed to the UV radiation before the measurement started. The location of the tadpoles during the measurement was recorded by CCD camera. A computer program EthoVision then evaluated the time that these tadpoles spent in each of the zones and the total path length these tadpoles has swum in the zones. The measurements were performed for two groups of tadpoles differing in age to determine whether the level of development may affect the tadpoles' preference to the UV radiation. The tadpoles in both groups spent more time in the zone without the UV radiation. The tadpoles in the more advanced development phase have spent 7 times more time in average in the zone without the UV radiation than in the zone with it. The tadpoles from the second group have spent in average 2.5 times more time in the zone without the UV radiation than in the zone with the UV radiation. The total swimming path length of advanced tadpoles was almost 2.5 times longer in the zone without the UV radiation than in the zone with the UV radiation. Conversely, the total path length of younger tadpoles did not significantly differ between the zones. The total time spent in the zones with / without the UV radiation did not differ between the groups of tadpoles. Also the total path length did not differ between the groups in the zone with the UV-B radiation. However, the total path length of tadpoles had differed between groups in the zone without the UV radiation.