Pathogens on the move
Fungi spread around the world by plane, ship and land vehicles. This leads to devastating ecological damage.
For the Kihansi Broom Toad, the end came very suddenly. The range of these small, yellow-brown amphibians, called Nectophrynoides asperginis, was limited to the four-kilometer-long Kihansi Gorge in Tanzania. In June 2003, biologists counted around 18,000 specimens there; the following winter it was just five. Since 2009, the species has been listed as "extinct in the wild" on the International Union for Conservation of Nature's IUCN Red List.
Professionals are now caring for the last surviving Kihansi toads as part of a Tanzanian-American breeding program. One day the two to three centimeter large animals should return to their old home. But that could be difficult. Because they were wiped out by severe interventions in their habitat, but also by the fungus Batrachochytrium dendrobatidis - a treacherous enemy that may still be lurking there.
B. dendrobatidis has been known since 1998 and is considered one of the most dangerous pathogens of amphibian diseases. The fungus lodges in the skin of its victims, disrupting their breathing and metabolism, wiping out entire populations in a very short time. He is putting further pressure on many amphibian species that were already threatened by pollution, habitat loss and other problems. Even in intact ecosystems, it triggered mass extinctions. It decimated amphibians particularly badly in the tropical regions of Australia and Central and South America …
