Parasites and Fungi Are the Cause of Declining Frog Populations

Parasites and Fungi are the Cause of Declining Frog Populations

1. Around the world, frogs are declining at an alarming rate due to threats like pollution, disease and climate change. While some declines are clearly due to habitat destruction, others are not associated with obvious environmental factors. Causal hypotheses include the introduction of predators or competitors, increased ultraviolet (UV-B) irradiation, acid precipitation, adverse weather patterns, environmental pollution, infectious disease, or a combination of these. Frogs bridge the gap between water and land habitats, making them the first indicators of ecosystem changes. The decline in diversity could end up harming larger ecosystems since frogs are an important part of the food web -- other creatures eat them and their eggs. Amphibians’ physiology (permeable skin) and complex water-and-land life cycle expose them to more environmental changes than most animals, and though they have survived climate changes before, today's changes are accelerating too rapidly for frogs to keep pace. Though fungi and habitat destruction have been implicated in the disappearances, the frogs’ plight comes down to one problem: Amphibians are extremely sensitive to changes in their environment.

2. A fungal infection seems to be hitting those rare species of frogs harder than common ones, found a new study, leading to local extinctions and a homogenized version of nature where everything is more similar than it used to be. Threats to amphibians include the deadly chytrid fungus, which infects amphibians' skin and interferes with their ability to absorb water and oxygen. Scientists believe that this fungus came from African clawed frogs which carry the fungus on their skin but suffer no ill effects from it. African clawed frogs have spread far beyond their native habitat, carrying the fungus with them, due to global trade. Scientists around the world have used these frogs for research and people have also kept the...