Hellbenders are giant aquatic salamanders — North Americas largest — that depend on pristine, cold, well-oxygenated streams with large flat rocks for nesting. Population declines of 75-90% have been documented across their range.
Hellbenders in sedimented streams cannot find suitable flat rocks for nesting, causing reproductive failure. Reduced dissolved oxygen from warming and sedimentation causes chronic hypoxic stress in animals that depend on cutaneous respiration. Disease from the chytrid fungus Batrachochytrium salamandrivorans causes mortality in some populations. The combination of habitat degradation and disease creates compound welfare pressure on one of the most charismatic and ancient amphibians in North America.