Prior to the late 1880s, the Grenada frog was widespread throughout its native island nation of Grenada. During the late 1880s, a related frog species, the Johnstone’s frog, was introduced to the island. The Johnstone’s frog spread throughout the island, while the Grenada frog retreated to a small, seven-square-mile isolated pocket in the mountain rainforests.
In 2004, our Zoo, in collaboration with the Milwaukee Public Museum, and the Grenada Forestry and National Parks Department initiated a field-study to determine if these two species could coexist successfully. The Racine Zoo joined our collaborative efforts in 2009.
Our study revealed that the Grenada frog population continued to drop for three consecutive years. Grenada frogs were then sampled to determine if they were carrying the deadly
frog-killing fungus, chytrid. If the frogs had the deadly fungus, the virus would account for their steady decline and not the fact that another frog species had been introduced to the island. Unfortunately, chytrid fungus was found at all sampling sites.
Chytrid could lead to extinction of the Grenada frog. To prevent extinction, the Milwaukee County Zoo, along with our collaborators, developed a Conservation Action Plan to save the Grenada frog. Studies conducted in 2011 revealed the Grenada frog island populations had finally stabilized.