August 4, 2014
2,483 land iguanas were recorded in a population census conducted on North Seymour Island
A recent census of land iguanas on North Seymour Island in Galapagos reported a population of 2,483 individuals, which indicates significant stability of iguanas on this small island of 1.83 square kilometers (1.14 square miles).
The Ministry of Environment, through the Galapagos National Park (GNP), deployed a team of 26 rangers to North Seymour Island who covered 13 quadrants in which the island was divided. Prior to the census, the rangers were trained in using GPS equipment and methodology. Once they had reached their assigned quadrants, they simultaneously began recording each each land iguana they saw with its exact geographic location, gender, and age.
The census recorded 1,117 females, 873, males and 493 juveniles for a total of 2,483 land iguanas on North Seymour Island.
“In 2008, a plan for the eradication of rodents in North Seymour was successfully implemented in order to protect the ecosystem for land iguanas and other species endemic to the island, such as boobies and frigatebireds” said Victor Carrion, Galapagos National Park Ecosystem Director.
Galapagos land iguanas (Conolophus subcristatus) historically settled on Baltra; however, in 1932 and 1933 Captain Alan Hancock moved 73 iguanas to North Seymour in order to provide better conditions for survival given that goats were present on Baltra at the time. The following year, it was confirmed that this group of iguanas had adapted smoothly to their new habitat.
During World War II, Baltra Island was occupied by a U.S. military base, which contributed to the decline of land iguana populations due to habitat loss from the construction of buildings, roads, airports and docks, and introduced goats made vegetation scarce on the island.
The relocation of land iguanas to North Seymour has facilitated the survival of this species. The GNP began a captive breeding program of land iguanas with individuals from North Seymour Island in 1980. In 28 years of the program, 420 individuals have been repatriated to Baltra Island.
Translated with permission from the Galapagos National Park Directorate. Please contact Galapagos Conservancy with inquiries.