Why are amphibians good indicators of a health of an ecosystem?
http://pubs.usgs.gov/fs/2004/3106/
Amphibians are good indicators of the health of an ecosystem for several reasons. One key reason is that they have a permeable skin, which allows them to absorb substances from the environment, including pollutants and chemicals. This makes them highly sensitive to changes in their habitat.
Here's how to understand why amphibians are good ecosystem health indicators:
1. Sensitivity to changes: Because amphibians breathe through their skin, they are highly susceptible to changes in the quality of their habitat, such as water and air pollution. They are often the first group of animals to show signs of environmental stress or decline.
2. Habitat requirements: Amphibians have specific habitat requirements. They need clean water bodies, suitable temperature and humidity levels, and a variety of food sources. Changes or degradation in these factors can negatively impact their population.
3. Biodiversity: As amphibians occupy the lower trophic levels in food chains, their presence or absence can indicate the availability of primary producers (such as plants) and other prey species. Their declines can also have cascading effects on the ecosystem's overall biodiversity.
4. Sensitivity to climate change: Because amphibians are ectothermic, meaning they rely on external sources for body heat, they are highly vulnerable to changes in temperature and precipitation patterns caused by climate change. Their declining populations can serve as an early warning sign of ecosystem disruption.
To assess the health of an ecosystem using amphibians as indicators, researchers conduct surveys and monitor their population trends. They assess factors like species richness, abundance, and breeding success. Any observed negative changes to amphibian populations could indicate ecosystem degradation, habitat loss, or pollution problems that may require attention to prevent further damage.