Human influences challenge penguin populations

The ecology of penguins makes these iconic swimming and diving seabirds of the Southern Hemisphere unusually susceptible to environmental changes. Pronounced warming in the Antarctic, as well as commercial fishing, mining, and oil and gas development at lower latitudes, has led to declines in many species, according to P. Dee Boersma, of the University of Washington in Seattle. In the July/August 2008 issue of BioScience, Boersma provides a first-person account based on 30 years of studying the birds. Counts of the penguin populations at the 43 remaining breeding "hotspots," even once every five years, could provide valuable insights into the variability of the ocean ecosystem and the populations' viability, Boersma writes. Yet counts are carried out only rarely, if at all. The task is urgent, because many populations seem to be in rapid decline even as some temperate populations have expanded their range southward. Rapid reductions of sea ice off Antarctica in recent years threaten Adélie and emperor penguins, which need ice, but may benefit some populations of relatively ice-intolerant gentoo and chinstrap penguins. Increased snow and rain, another result of the changing climate, reduce breeding success in some gentoo and Adélie penguins.

Temperate penguins, such as Galápagos, Peruvian, and African species, are all declining. Mining of guano, egg harvesting, commercial fishing, and oil spills are the chief causes, according to Boersma, although tourism and increasingly severe El Niño events, probably resulting from climate change, are also partly responsible.

The threats to all penguin species are likely to grow in coming years. Boersma recommends the formation of a nongovernmental organization dedicated to monitoring major aggregations of penguins. Such an organization could provide advance warning of urgent threats and thus make amelioration possible.

Source: American Institute of Biological Sciences