Trends in US Imports of Amphibians in Light of the Potential Spread of Chytrid Fungus, Batrachochytrium dendrobatidis (Bd), and Implications for Conservation

Abstract

ABSTRACTAmphibian populations around the world are declining in part due to diseases from infection with the chytrid fungi Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bs). While declines in more charismatic megafauna are common sources of public awareness and concern, such as the loss of elephants to poaching or polar bears to climate change, amphibians have been suffering a dramatic decline due to the outbreak of deadly fungal diseases with relatively little public attention. Various amphibian advocacy groups work to raise awareness of the issue, but given the limited funding and resources allocated to this cause, there remains a general lack of momentum to tackle the growing conservation threats to this group of animals and to examine policy weaknesses that may need to be adapted to help ensure their conservation. The international trade in live amphibians certainly contributes towards the global spread of these pathogens, but the true extent of spread remains unknown. To determine the degree to which the importation of amphibians into the United States was correlated with presence of known vectors of Bd spread, we compared US Fish and Wildlife Service wildlife trade records for all commercially traded live animals imported to the US from 2006 to 2014 against known species-level infection susceptibility. Approximately 26,859,034 live amphibians were imported into the US for commercial purposes between January 2006 and December 2014., Of these, 59.8% were specimens of species known to be susceptible to Bd infection and therefore may have introduced Bd into the country. Our findings demonstrate significant declines in the annual import quantities of 14 Bd-susceptible species between 2006 and 2014. These reductions could be due to a variety of factors, ranging from possible increased domestic production and a reduced need for foreign-sourced animals to reduced demand from changing market behaviors to the potential disease-driven decline of wild populations and greater difficulty in supplying these specimens. Our research supports the need for continued implementation of US policy, particularly the Lacey Act, to closely regulate wildlife imports to reduce the spread of highly virulent pathogens that threaten native species. Additionally, a rapid response mechanism is needed to control the introduction and spread of wildlife disease vectors when emergencies arise. Although the impact of the wildlife trade is just one facet of the overall amphibian conservation landscape, the information we present herein provides reason to develop increasingly robust rapid-response policies to protect wild amphibian populations in the midst of an emerging global disease crisis.