Johngarthia planata
Johngarthia planata, sometimes known as the Clipperton crab, is a bright orange species of land crab that lives on Clipperton Island in the eastern Pacific; on Malpelo Island, west of Colombia; and on Socorro Island in the Revillagigedo Islands off Mexico, 900 km north of Clipperton. It is omnivorous and feeds on seaweed, vegetation and sometimes carrion.
, Paris, France
The introduction of pigs on Clipperton Island by guano miners in the 1890s reduced the crab population: this in turn allowed grassland to gradually cover about 80 percent of the land surface. The elimination of these pigs in 1958 — as the result of a personal project by Kenneth E. Stager — has caused most of this vegetation to disappear, resulting in the return of millions of J. planata. A 2005 report by the NOAA's Southwest Fisheries Science Center in La Jolla, California, USA indicates that the increased rat presence has led to a decline in the crab population, causing a corresponding increase in both vegetation and coconut palms. This report urgently recommended eradication of rats so that vegetation might be reduced and the island might return to its "pre-human" state.
