Amblyrhynchus cristatus. The IUCN Red List of Threatened Species 2020

Abstract

Marine Iguanas occur on the large islands of Española, Fernandina, Floreana, Genovesa, Isabela, Marchena, Pinta, San Cristobál, Santa Cruz, Santa Fé, and Santiago, the mid-sized islands of Baltra, Bartolomé, Pinzón, Plaza Norte, Plaza Sur, Rábida, and Seymour Norte, smaller key populations on Darwin, Roca Redonda, and Wolf, as well as many satellite islets of the Galápagos Archipelago, Ecuador. The estimated extent of occurrence is 56,647 km2 by minimum convex polygon and the area of occupancy is estimated at 42,155 km2 using a 2x2 km grid overlay within a coastal buffer 2 km from the shore. The population size is poorly known and crudely estimated as low as 33,000 total iguanas after a strong El Niño famine and as many as 350,000 after several years of La Niña abundant food conditions, with fewer than 210,000 mature individuals. Current taxonomy describes eleven subspecies. Only one subspecies has a genetically resilient effective population size, and only one more is close to the threshold to be considered healthy; the remaining are critically low to moderate. Overall population trend is unknown, but is subject to extreme fluctuations and reductions during El Niño events (10–90% mortality), which are predicted to intensify in the future with ongoing climate change. Marine Iguana populations have been reduced by invasive alien predators such as feral cats, rats, and free-roaming pigs and dogs on five of the 13 main islands (ca 30% of the total population)....