Manipulating water for amphibian conservation

Amphibian populations globally are in decline. One important threat is the abstraction of water resources that alter surface-water hydrology. Conservation actions aimed at restoring or manipulating surface-water is frequently employed as a management tool, but empirical evidence on the effectiveness of these approaches is scarce. In this systematic review we summarise the global experience of manipulating water for amphibian conservation. We explore examples of manipulating water to conserve amphibian species and communities. Approaches vary in their frequency of implementation and in their success. Extending hydroperiod to match larval requirements shows encouraging results, as does off-season drying to control predators. Spraying water into the environment has several potential applications, but successes are limited. Despite some promising interventions, we identified few (n = 17) empirically supported examples of successful water manipulation to benefit amphibians. It is unclear if this stems from publication bias or if it is an artefact of language selection. Manipulating water shows great potential in amphibian conservation, particularly at sites with a proximal water source and regions where aridity is increasing due to climate change. Regardless of the scale of the intervention or its perceived probability of success, high-quality reporting of empirical results will progress our understanding of how water manipulations can benefit threatened amphibian populations.