Boomkikker en kamsalamander in Vlaanderen - Eindelijk van de ondergang gered?

Common Tree Frog and Great Crested Newt in Flanders, saved at last? Populations of Common Tree Frog (Hyla arborea) and Great Crested Newt (Triturus cristatus) in Flanders (Belgium) have experienced declines for several decades. Even now, both species are critically endangered and vulnerable, respectively. But trends have reversed. For instance, today the overall Tree Frog population amounts to several thousand individuals, while up until 2002 there only remained 200 calling males. All because professional and voluntary conservationists transformed former fishing ponds by means of temporal pond drawdown and fish removal, hence creating ephemeral ponds. This type of biomanipulation resulted in the removal of undesired (exotic) fish, that otherwise predate on the eggs and larvae of several endangered amphibian species. In addition, pond drawdown partially decreased nutrient concentrations. Furthermore, voluntary nature management focused on the terrestrial habitat by re-establishing periodic coppicing of the surrounding woody vegetation and alternately mowing the pond edges. Notwithstanding these endangered amphibians responded positively to aimed conservation measures, functional dispersal corridors and stepping stones are still lacking. Yet, the often hostile surrounding landscape is intensively used for agricultural purposes. Therefore, sustainably connected populations are almost absent. The main concern about the still fairly small local populations, is related to inbreeding depression. Currently, conservation programs for Common Tree Frog and Great Crested Newt are prepared by the Flemish government.