The Loss of Salamanders in the U.S.

Biological and cultural diversity are closely linked. Biodiversity has influenced human evolution, artistic expression, and belief systems, and human cultures protect biodiversity through science, art, ethics, and values. International collaborations have enriched scientific research on disease ecology and contributed to conservation of global amphibian biodiversity. The problem of amphibian population declines was “discovered” during the First World Congress of Herpetology when many examples of missing species came to light. Those anecdotes stimulated two decades of global research on host-pathogen ecology. The discovery of Batrachochytrium dendrobatidis (Bd), the pathogenic fungus responsible for many population declines, resulted from scientific exchange among researchers on three continents. The extent of the problem wasn’t known until the 2004 Global Amphibian Assessment which quantified the status of all amphibians. The GAA found that ~43% of species were in decline, habitat loss was driving declines in the temperate zone, but many recent, enigmatic declines were widespread in tropical amphibians, with dozens of species listed as presumably extinct in the past 20 years.  Scientists expected more epidemics to follow as Bd spread around the globe, but monitoring showed Bd was already present on all continents, and that enzootic disease was the norm.  Researchers found susceptibility to disease varied among species, climates, exposure history, and fungal lineage. Genetic studies have found that Bd varies geographically, with endemic lineages on four continents, many genetic variants, and even a new species, B. salamandrivorans.  Bsal is a pathogenic fungus of salamanders spread through international trade from Asia into Europe. Bsal has not been detected in the US, and multidisciplinary collaborations developed to find solutions to slow the spread of Bsal. On 12 January 2016 the USFWS issued a rule restricting imports of salamanders into the US to prevent the introduction of Bsal.  Preventing the loss of amphibian biodiversity matters both ethically and practically. Amphibians are important members of many ecosystems, they provide food to birds, fish, and mammals; they regulate algal and aquatic insect populations; and they move energy and nutrients between terrestrial and aquatic ecosystems. Amphibian skin chemistry may provide humans with new drugs useful in battling diseases, and their ability to regenerate limbs and organs may contribute to new biomedical developments. Stewardship of biodiversity is not only ethical, but also has practical benefits.