IMPACTS AND MANAGEMENT OF NON-NATIVE VERTEBRATES ON PUERTO RICAN RAINFORESTS

In July 2002, we tested several indexing techniques for determining presence and activity of non-native vertebrates in 5 rainforest sites of El Yunque, Puerto Rico.  Feral cats, mongooses and roof rats were active at all sites, 3 of which were near nesting areas of the endangered Puerto Rican parrot.  Rats were especially abundant.  Using Sherman live traps, we recorded 47% trap success over a 4-night period (25 traps per night).  Trailmaster active sensors and cameras were used to photograph the visitors to track plates, scent stations and paraffin monitoring blocks.

Mongoose (Herpestes nyula)
The mongoose is a small, weasel-like carnivore that is native to Africa, southern Europe and Asia.  Mongooses were introduced to Puerto Rico for biological control of rats (Rattus rattus) in sugarcane plantations.  Because mongooses are mostly active during the day and rats active at night, they did little to control rats and soon became pests themselves.  They are now widespread throughout Puerto Rico.  They are a major reservoir for rabies and likely cause significant impacts on wildlife.

 

El Yunque rainforest. Carribean National Forest, Puerto Rico

 

Feral cat tracks were frequently recorded on track plates
 

Roof rat (Rattus rattus)
Rats are common predators of bird nests so potentially threaten the recovery of the endangered Puerto Rican parrot.

Felipe Cano, Forest Service Biologist shows off the day's catch!