Roads exert multiple effects on wildlife, from animal mortality, habitat and population fragmentation, to modification of animal reproductive behaviour. Amphibians are the most frequently road-killed ...animal group. Many studies have attempted to analyse the factors driving amphibian casualties on roads, but these factors are limited to the roads themselves (e.g., traffic, type of roads, roads crossing water bodies) or to structures along them (e.g., ditches, walls). Sometimes, roadkills are related to land use along the roads. We analysed the influence of landscape factors on roadkill hotspots at the national level (Slovenia). Specifically, we aimed at: (1) identifying hotspots of roadkills, (2) analysing whether records of amphibian presence on roads are related to the distribution of water bodies and (3) analysing which factors (proximity to water bodies or human factors) explain the distribution of hotspots. Hotspots were identified by Malo’s method. Roadkills were modelled with Maxent for the first time in Slovenia. The relationships between amphibian presence and hotspots with factors were analysed with GLM. A total of 237 road sections were identified as hotspots, corresponding to 8% of road sections and containing 90% of road-killed individuals. Proximity to forests, meadows and agricultural land were the most important variables in Maxent models. The number of roadkills depended on the proximity to agricultural land, forests, water bodies and wetland areas, while the number of hotspots additionally depended on the proximity to urban settlements.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The accelerating rates of international trade, travel, and transport in the latter half of the twentieth century have led to the progressive mixing of biota from across the world and the number of ...species introduced to new regions continues to increase. The importance of biogeographic, climatic, economic, and demographic factors as drivers of this trend is increasingly being realized but as yet there is no consensus regarding their relative importance. Whereas little may be done to mitigate the effects of geography and climate on invasions, a wider range of options may exist to moderate the impacts of economic and demographic drivers. Here we use the most recent data available from Europe to partition between macroecological, economic, and demographic variables the variation in alien species richness of bryophytes, fungi, vascular plants, terrestrial insects, aquatic invertebrates, fish, amphibians, reptiles, birds, and mammals. Only national wealth and human population density were statistically significant predictors in the majority of models when analyzed jointly with climate, geography, and land cover. The economic and demographic variables reflect the intensity of human activities and integrate the effect of factors that directly determine the outcome of invasion such as propagule pressure, pathways of introduction, eutrophication, and the intensity of anthropogenic disturbance. The strong influence of economic and demographic variables on the levels of invasion by alien species demonstrates that future solutions to the problem of biological invasions at a national scale lie in mitigating the negative environmental consequences of human activities that generate wealth and by promoting more sustainable population growth.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
After the first confirmed record of the Italian agile frog in the Dragonja River Valley, a herpetological field survey was organized in 2012 to estimate the species range in this area. We confirmed ...its reproduction in the Slovenian part of the watersheds of the rivers Dragonja, Mirna and upper part of Rižana. Here we present a preliminary report on the presence of this amphibian in the Slovenian part of Istra.
The American bullfrog Lithobates catesbeianus is one of the 100 worst alien species in the world. It has been introduced to several European countries. During our field search activities in May 2014 ...and June 2015, a male bullfrog advertisement call was heard at Fiesa Lakes in Slovenia. On September 2015, a male specimen of the American bullfrog was caught in a funnel trap at the same location. These are the first records of the occurrence of this invasive species in Slovenia. Further studies should be conducted to evaluate if an actual population is present in the area. Eradication measures should commence immediately as chances for the establishment of naturalized bullfrog populations here are high.
Quantifying rarity at the intraspecific level is an important task for conservation biologists because rare phenotypes have a higher extinction risk than common ones. However, quantitative ...assessments of rarity are lacking at this level, preventing to adequately protect rare and endangered variants that are part of the pool of common species. Our aim was to take benefit of high-resolution volunteer-based occurrence data to assess quantitatively rarity patterns of facultative paedomorphosis, in the Alpine newt (Ichthyosaura alpestris). This polyphenism is composed of two morphs, a rare adult phenotype retaining gills and a common phenotype metamorphosing. We included multiple spatial scales (i.e., resolution) and combined 15,613 occurrence records from the atlas databases of the seven countries in the European Alps to understand how spatial scale may affect rarity metrics. Our analyses revealed that the rarer phenotype was 292 times rarer than the common phenotype, occupying a very small and fragmented area of occupancy. Yet, rarity depended on the spatial resolution of the data. Rarity estimates were up to 1300 times lower at the coarser than at the finer spatial scale. Both the rarity of the rare phenotype and the presence of threats (i.e., fish introductions) make paedomorphs critically endangered whereas the common phenotype was widespread at all spatial scales. Altogether, these results show how rarity metrics can differ between spatial scales for rare and common organisms, suggesting that fine-grain data should be used to assess intraspecific rarity. They also show that combining datasets from distribution atlases is efficient to estimate rarity.
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•Using citizen-based data helps to quantify rarity patterns at the intraspecific level•Combining distribution atlases gives broad assessment of intraspecific diversity•Alternative morphs show very different commonness and rarity patterns•Spatial scale affects our ability to assess the rarity of rare phenotypes•Intraspecific diversity is threatened by anthropogenic environmental change
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
V okviru skupine za dvoživke je bilo med 23. julijem in 2. augustom 1997 na Raziskovalnem taboru študentov biologije Središče ob Dravi ’97 na skupno 68 najdiščih najdenih 12 vrst dvoživk.
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