Breeding site selection according to suitability for amphibian larval growth under various ecological conditions in the semi-arid zone of northern Israel

Abstract

A series of field monitoring was conducted over four years on aquatic habitats to test the hypothesis that breeding habitat selection by six different amphibian species, belonging to the Anuran and Urodela orders, was according to the ecological parameters of the water body, and not necessarily according to the type of breeding site. Ecological and biological conditions of 14 different breeding sites inhabited by amphibian larvae in northern Israel, including winter ponds, pits, springs and streams, were investigated in a region where all six species exist. The larval growth period was discovered to vary in different habitats. Most breeding sites studied had Salamandra infraimmaculata larvae, although at different periods of the year. The larvae of Hyla savignyi, Bufo viridis, Rana bedriagae, Pelobates syriacus and Triturus vittatus inhabited mostly the winter ponds and pits. In most cases, the S. infraimmaculata and T. vittatus larvae were not observed during the same time period at the same breeding sites. In other winter ponds, H. savignyi, P. syriacus and T. vittatus were seen at the same time during the spring, and along with R. bedriagae in the summer. Among the various water quality parameters evaluated at the breeding site, namely, temperature, pH, soluble oxygen, electrical conductivity, ammonium (NH 4 ) and invertebrate biomass, the most influential one was the temperature. S. infraimmaculata and B. viridis were detected in ponds with temperatures ranging about 1.5-24 °C, whereas all other larvae were observed at temperatures above this range, up to 34 °C. Based on the results of the investigation, the major factors affecting the habitat selected for breeding are the ecological conditions that allow for survival, growth and metamorphosis completion of the amphibian larvae.