Authors: Moor, Helen; Bergamini, Ariel;Vorburger, Christoph;Holderegger, Rolf;Bühler, Christoph;Egger, Simon;Schmidt, Benedikt R.;

Conservation science should provide the tools to halt and reverse population declines. While it is known that habitat creation can benefit declining populations, reports of positive conservation outcomes are few. We showcase a conservation success story from the canton of Aargau in Switzerland, where hundreds of new ponds have been built over the last decades, mainly for the benefit of amphibians. Amphibians are the most threatened vertebrate group worldwide, and habitat loss is a major driver of population declines. Fitting dynamic occupancy models for 12 amphibian species to 20 years of monitoring data, we show that persistent conservation action reverses negative population trends and leads to landscape-scale stabilization or increases in metapopulation sizes of amphibian species. While there were regional and species-specific differences in the use of constructed ponds, all species colonized new ponds, which compensated or even overcompensated for declines in old ponds. Testing for effects of local and landscape-scale variables on colonization probability enabled us to make species-specific recommendations to improve pond creation, regarding pond (surface area, water table fluctuations) and landscape characteristics. Simple, but massive conservation action lead to population recovery of threatened amphibian species, and easily implementable rules of thumb can help maximise conservation efficacy.