No abstract

1. The disappearance and deterioration of amphibian breeding habitats is a major cause of their global extinction. In Europe, this problem affects the yellow-bellied toad Bombina variegata, which inhabits small ponds in the early stages of succession, where no predatory invertebrate species normally occur. Nonetheless, as habitats, small temporary ponds are highly endangered, a situation that is intensifying with urban spread. 2. A system of 13 pairs of artificial ponds was constructed in 2012 for the breeding of B. variegata with the aim of reconnecting disjunct populations. During the 2 years of the study, one of the twin ponds was regularly cleared of emergent vegetation and invertebrates. The survival rates of the tadpoles released in the cleared and uncleared ponds were analysed.3. The survival rate of the tadpoles released into the cleared ponds was higher than of those introduced into the uncleared ones. Tadpole survival rates were also higher in new, single ponds, constructed in 2013.4. The lower survival rates of the introduced tadpoles are best explained by the presence of predatory aquatic invertebrates, particularly the large diving beetle Dytiscus marginalis. Experimentally obtained consumption rates indicate that oneDytiscus larva is capable of destroying a typical clutch of B. variegata tadpoles within a few hours, much faster than any of the other insect predators tested.5. The impact of freshwater invertebrates on tadpoles is frequently studied but rarely quantified. For conservation measures to be effective, quantitative standards need to be applied that describe the impact of predation in a predictable manner.6. Construction of artificial small ponds is broadly accepted as an important conservation measure compensating for the disappearance of natural amphibian breeding sites. This function of artificial ponds may be substantially enhanced by the periodic removal of invertebrate predators.

The impact of the motorway on pollution was evaluated by determining chosen heavy metals and acid reaction (pH) in the pine bark, in forest and meadow topsoil. The content of these environmental contaminants was determined in the topsoil and in the bark of around 40 year-old Scots pines (Pinus sylvestris L.) growing right next to the soil analyzed. The pollutants were examined at localities situated around 5, 200, 1500 m away from the motorway. To evaluate influence of Cd, Pb, Zn, Cu and the topsoil pH on pedofauna, five meadows localities situated 1, 20, 40, 150, 1550 m away from the motorway were examined. It was detected that in the forest habitats analyzed the bark was characterized by considerably higher acidity (pH 3.14-3.88) than the topsoil of the pines analyzed (pH 5.45-7.22). Except of Cd at locality 200 m and Cu at 1500 m from motorway, the higher concentration of heavy metals was noted in topsoil. In the meadow soil of the locality 150 m from the motorway the highest concentrations of Cd and Zn were detected. The greatest diversity of the meso and macrofauna and trophic relations the most resembling natural were detected in the area furthest away from the motorway, where the content of the heavy metals was the lowest. The lowest density and diversity of meso- and macrofauna were detected in the area situated 40 m, where the concentration of heavy metals was higher than at 1, 20 and 1550 m from the motorway situated localities.

This study reports the effect of dietary nickel (Ni) and a combination of Ni and zinc (Zn) on the accumulation of lead (Pb), cadmium (Cd), Ni and Zn in muscles, liver and kidneys of rabbits. Female rabbits (Oryctolagus cuniculus) of experimental groups were fed a granular mixture with addition of various concentrations of Ni or Ni+Zn (E1 - 17.5 g NiCl(2) per 100 kg of feed mixture, group E2 - 35.0 g NiCl(2) per 100 kg of feed mixture, group E3 - 17.5 g NiCl(2) per 100 kg of feed mixture and 30 g ZnCl(2) per 100 kg of feed mixture, group E4 - 35.0 g NiCl(2) per 100 kg of feed mixture and 30 g ZnCl(2) per 100 kg of feed mixture). Group C without inclusion of Ni or Zn served as control. After the 90-day experimental period biological material (liver, kidney, musculus longissimus dorsi, musculus biceps femoris) was taken from the animals. Samples were analyzed by the AAS method. Ni added to the FM caused an increase in Cd concentration in the kidneys of the rabbits, significantly in the E3 group in comparison with the control group. In the liver an insignificant decrease of Cd concentration was found. Zn addition in the amount of 30 g to the diet caused an increase of Cd level in the kidney as well as in the liver. Ni and Zn treatment caused a significant decrease of Pb accumulation in the m. longissimus dorsi of rabbits. This study indicates that dietary inclusion of Ni and Zn caused specific interactions among the observed metals.

No abstract