The Sovi Basin is a site within the Pacific-Asia Biodiversity Transect (PABITRA) network. It is located in Naitasiri Province, Viti Levu, and represents the largest area of undisturbed lowland forest within the Fiji Islands. It is considered to be one of the most biologically diverse areas within the Polynesia-Micronesia biodiversity hot spot. Four intensive surveys conducted between 2003 and 2015 assessed vertebrate fauna within the Sovi Basin. The study confirmed the biological importance of the site when compared with other locations within Fiji: 85%, 50%, 39%, and 38% of the Viti Levu fauna of birds, mammals, herpetofauna, and ichthyofauna were recorded during the surveys, respectively. In addition to the rich native and endemic fauna, invasive species were recorded (mongoose, feral pigs, black rats, red-vented bulbuls, tilapia, and cane toads), the impact of which is completely unknown. Further monitoring and possible management of these invasive species is needed to ensure that the Sovi Basin is appropriately managed for nature conservation. In addition, emerging threats such as a proposed mining scheme and agricultural activities are discussed in relation to the ecological integrity of the site for conservation purposes.