Why are amphibian populations considered indicators of environmental health?

Amphibians are considered vital indicators of environmental health primarily because they are exceptionally sensitive to changes in their surroundings.1

This sensitivity is largely due to their unique physiology. Most amphibians possess moist, permeable skin that facilitates cutaneous respiration, allowing for the direct exchange of gases, water, and ions between their bodies and the environment. Because they rely on this skin for breathing and maintaining water balance, they are highly susceptible to pollutants, toxins, and shifts in water quality.231

Furthermore, many amphibians occupy both aquatic and terrestrial habitats throughout their life cycles, often requiring standing water for breeding and larval development. This "double life" exposes them to stressors in multiple ecosystems, including habitat destruction, climate change, and the spread of diseases such as amphibian chytridiomycosis. Because they are so reactive to these environmental pressures, their population trends often serve as an early warning system for the degradation of the ecosystems they inhabit.31