A North American Strategic Plan to Control Invasions of the Lethal Salamander Pathogen Batrachochytrium salamandrivorans
North American Bsal Task Force
Summary
Introduction
Chytridiomycosis is a fungal disease of amphibians that has led to widespread mortality and extinctions. It is considered the greatest disease threat to biodiversity (Wake and Vredenburg 2008). In 1999, one pathogen species causing these population declines and extinctions was described: Batrachochytrium dendrobatidis, or Bd (Longcore et al. 1999). A second species that causes chytridiomycosis has been discovered more recently: B. salamandrivorans, or Bsal (Martel et al. 2013). Bsal has caused population extinctions of the fire salamander Salamandra salamandra in Europe, where it appears to have been recently introduced and its distribution is broadening (Spitzen-van der Sluijs et al. 2016; Stegen et al. 2017). Several lines of evidence support an Asian origin of Bsal (Martel et al. 2013; Laking et al. 2017; Nguyen et al. 2017; Yuan et al. 2018). Susceptibility trials of salamander species native to North America have revealed that some species are lethally affected including all tested species in the Salamandridae or newt family (Martel et al. 2014). Introduction of Bsal to North America, a hotspot of salamander diversity, could drastically reduce amphibian biodiversity and result in ecosystem effects (Gray et al. 2015; Yap et al. 2015; Richgels et al. 2016). To date, Bsal has not been detected in North America. Since effective mitigation strategies have not been developed to combat Bsal in the field, the best threat-abatement strategy currently available is to attempt to keep the pathogen from establishing in North America (Grant et al. 2017; Stegen et al. 2017). If detected, a rapid response plan is essential (Bsal Task Force 2018; Appendix 4 below).
In addition to these two core needs of preventing invasion and being able to respond quickly if Bsal were to be detected in North America, it is vital to develop a more comprehensive network of strategic actions. A multi-pronged Bsal strategic plan developed by the North American Bsal Task Force includes the following components: improved diagnostic tools to identify the pathogen with accuracy and efficiency, including a network of diagnostic laboratories able to analyze for Bsal; research advances to better understand Bsal effects on North American species and how to potentially safeguard susceptible species; a decision support framework to aid science-policy prioritizations; a data management group that tracks Bsal inventory and monitoring activities, including records of no-detections from field and captive situations; a response & management group that facilitates development of mitigation actions; critical surveillance strategies to maximize the potential for early detection of the fungus; and improved communication and outreach pathways for rapid dissemination of new developments.