Wood frogs survive complete freezing during winter by converting two-thirds of their body water to ice, a physiological feat that depends on vernal pool habitats increasingly threatened by development.
Wood frog welfare involves both the extraordinary physiological stress of freeze-thaw cycles and the habitat vulnerability that places their populations at risk. The freeze tolerance adaptation protects individuals from the welfare cost of winter starvation by essentially suspending metabolism, but requires intact vernal pool habitats for breeding recovery. Fragmented habitats that isolate populations reduce genetic diversity that enables adaptive responses to environmental change. Protection of vernal pool habitats protects not just wood frogs but the entire ecological community that depends on these temporary wetlands.