Written By: Emma Websdale
An increase in the Galapagos Islands’ water temperature, brought on by climate change, is threatening one of the world’s rarest seabirds, the flightless cormorant, reveals a new study.
Found on the coastlines of only two islands in the Galapagos archipelago, the flightless cormorant, classified as vulnerable on the IUCN Red List, could be pushed to extinction as climate change alters the nutrient-rich cold water provided by the Equatorial Undercurrent—a resource crucial for the cormorant’s feeding and breeding.
A decades-long historical study, led by the University of Queensland, monitored the breeding and feeding patterns of a colony of adult flightless cormorants across a 2-km stretch of the Galapagos coastline. It found that warmer waters are decreasing the available food supply, severely jeopardizing the bird’s breeding prospects.
The study, which consisted of annual checks from 1970 to 2012, found that numbers of adult pairs of the species dropped from 1000 to 400 after a period of increased water temperature, when food became scarce. The study also found that the number of clutches laid and juveniles fledged dropped as warmer water temperatures continued in the cormorant’s offshore foraging grounds.
Analysis of the data suggests that if surface temperatures of foraging areas continue to rise during the cormorant’s breeding season, the future of the cormorant will be threatened, as low breeding success rates will continue to deplete the population.
With the flightless bird’s habitat and foraging range restricted by oceanographic conditions, the results warn that its current numbers are inadequate for long-term survival.
The study also shows, however, that the population of the flightless cormorant recovered from a prior drop in numbers. The data suggest that if ocean warming ceases, another recovery could be possible if optimal food and breeding conditions return.
Other species that are being threatened by climate change are the native koala population of Australia and North America’s turtle species—both of whose population numbers are dropping as a result of habitat change heightened by climate change.