Wpływ hydrobiologicznych właściwości zbiorników wodnych na rozwój kijanek żaby trawnej (Rana temporaria L.)

Abstract

Research on the influence of hydro-biological properties of reservoirs on the development of tadpoles of Rana temporaria L. was carried out in five natural, low-lying reservoirs in a small area near Kraków. Each reservoir represented different hydro-biological properties. The following physico-chemical properties of the water in each reservoir were during the development of tadpoles: temperature, pH value, alkalinity, the amount of oxygen dissolved O[2] mg/l, the percentage of saturation with oxygen. During the period of development of larvae in April, May, June, July, 1967 altogether 1587 tadpoles of Rana temporaria L. were caught in the reservoirs. Their stage of development was defined and the complete body length measured. The average length of the tadpoles at the stage of maximum development ranged from 29-41 mm, the maximum length being 32-44 mm. The average length of newly transformed specimens was within 10-13 mm. In each of the reservoirs the course of the development of tadpoles including the time of metamorphosis and the average size of tadpoles at the stage of maximum development and the newly transformed ones were different. Factors such as the ranging and level of the water temperature during the life of the tadpoles as well as the oxygen conditions in a given reservoir remain essentially connected with the length of the development and the size of the tadpoles. pH value of the water within pH 6,1-6,4 has no adverse effect on the course of the development end the size of the tadpoles. The occurrence of tadpoles of Rana temporaria L. in all of the reservoirs, including those with extremely unfavourable hydro-biological conditions and in which exclusively the tadpoles of this frog were present, shows them to be eurytopic organisms.