Apparent absence of the amphibian chytrid fungus (Batrachochytrium dendrobatidis) in frogs in Malaita Province, Solomon Islands

Abstract

A major driver of global biodiversity loss is disease. One of the most devastating wildlife diseases known is chytridiomycosis, which is caused by the amphibian chytrid fungus Batrachochytrium dendrobatidis, and is implicated in population declines in over 500 frog species. Thought to originate in Asia, B. dendrobatidis now has a global distribution, likely due to human movement and trade. The pathogen has yet to be detected in Melanesia, but there have been few surveys for B. dendrobatidis in the region, and none in the Solomon Islands archipelago, a biogeographic region with a unique and culturally important frog fauna. We swabbed 200 frogs of eight species in three genera in lowland and highland sites in East Kwaio on the island of Malaita in the Solomon Islands. All frogs tested negative for the pathogen but it is possible that the pathogen is present despite non-detection, so further surveys for the pathogen are needed throughout the country. Despite this, it is safest to take a precautionary approach and assume that B. dendrobatidis has not yet been introduced to the Solomon Islands, and that naïve native amphibian populations may be at risk of decline if the pathogen is introduced. Protocols are needed to prevent the accidental import of infected frogs via tourism or in logging or mining equipment. Monitoring of frog populations near areas of high risk such as ports is also recommended. The frogs of the Solomon Islands archipelago are biologically unique and culturally significant, and protecting them from the potentially devastating impacts of B. dendrobatidis is vital.

Infectious disease as a driver of declines and extinctions

“…As described earlier, the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) has caused waves of extinction of frogs globally. Melanesia has an intact frog fauna with high levels of species richness and endemicity and, as yet, no evidence of Bd infection (Dahl et al, 2012;Bower et al, 2019;Alabai et al, 2020;Oliver et al, 2022). Specific protocols at points of entry and monitoring for Bd are therefore justified.…”