The population dynamics of the Common Tree Frog (Hyla arborea) during conversion to organic farming was surveyed on an arable farm in northern Germany. The conver-sion had no notable effects on the number of calling males and on the number of breeding sites of this species. We concluded that further management measures (e. g. restauration of existing ponds, digging of suitable new breeding waters) are necessary to improve the situation of H. arborea on the farm
