What factors affect the density of cane toads (Rhinella marina) in the Solomon Islands?

Cane toads (Rhinella marina) were introduced to the Solomon Islands in the 1940s, and quickly spread across the archipelago. Between May 2009 and August 2012, cane toads were recorded on 11 of 13 islands surveyed, and the densities of toads were estimated by distance sampling on seven of these islands. Modified Akaike's Information Criterion (AICc) tests were used to find the most parsimonious model for cane toad density in the Solomon Islands. The results showed that mean toad density was higher on Gatokae and Guadalcanal than on Bougainville, Choiseul, Kolombangara and Rendova. A plausible explanation for this is that Guadalcanal had an abundance of breeding sites, and that Gatokae may have been recently colonised with a typical sharp rise in toad densities. The model also showed that mean toad density was higher in coastal forests than in other forest types (e.g lowland, hill and montane forests). Coastal forests have higher disturbance levels as a result of villages and towns. Disturbance was associated with increased toad densities in the model. These findings suggest that cane toad management efforts should target coastal forests and disturbed areas along roads and tracks leading to important biodiversity reserves.