All life, including humans, rely on ecosystems that integrate physical and biological components into a complex web. Each landform, bacterium, plant and animal interacts with others, forming relationships that affect many other components. Some relationships are stronger than others, and some are only indirect. The web of relationships forms a strong, resilient ecosystem that can adapt to changes in the physical environment and continue to provide life support.
When we lose species from an ecosystem the web of relationships becomes weaker, less resilient, and less able to resist change. Like a trampoline or bungee cord with split elastics, continued slow degradation or a sudden change to the environment breaks the resiliency threshold and can result in a dramatic shift in ecosystem function, reducing its ability to support diverse life.
Amphibians are particularly sensitive to changes in the environment, particularly those that affect water and temperature conditions. They rely on environmental conditions to regulate their body temperature, and physical changes in habitat, like draining wetlands or removing vegetative cover, can dramatically alter thermal conditions. Climate disruption is a serious threat to amphibians, and most are not equipped to move ahead of climactic changes.
They are exposed to a wide range of aquatic pollutants during their sensitive egg and tadpole development phases. This can result in slow or abnormal development that affects their survival and their own ability to reproduce. Tadpoles eat algae and keep waterways clean, and grown frogs eat large quantities of insects that can impact humans and livestock. Their disappearance results in big changes in the delicate web of relationships.
For these reasons, amphibians are important sentinels of the ecosystems.