Monitoring and Research


The crested toads have been difficult to monitor due to their fossorial nature. They spend the majority of their lives within the crevices and caverns of their karst limestone habitat and they typically only surface during large rain events.

Karst limestone

Karst limestone habitat










Recovery Group partners are increasing monitoring efforts at all known toad locations, as well as historical sites, to learn more about the toad’s natural history, decipher population dynamics, and determine presence/absence in areas of historic or suitable habitat and evaluate reintroduction strategies.



Hydrological station at Tamarindo



The wild population at Tamarindo, Guánica has been monitored since it was discovered in 1984. The majority of data at Tamarindo has been collected by the DNER through systematic visual counts during breeding events. However, monitoring efforts in Tamarindo have also included the collection of precipitation data, tracking adult toads via radio telemetry, monitoring the ponds hydrological systems and chemistry parameters, evaluating tadpole diets and foraging behaviors, monitoring toadlet dispersal and microhabitat usage, habitat characterizations, documenting predation events, controlling predators, health and disease surveillance etc.








Monitoring takes place at all of the reintroduction sites (Manglillo, Gabia and El Tallonal). Biologists at these sites monitor tadpole development, document predation events, remove invasive species, conduct health and disease surveillance, mark individual toads using PIT tags, monitor toadlet dispersal and habitat utilization, use automated recording devices, and conduct systematic counts during breeding events.