Composition and relationship of the terrestrial faunas of Easter, Juan Fernandez, Desventuradas, and Galápagos islands

America has a great number of offshore islands, particularly in the fjord region of southern Chile, but there are also other truly oceanic islands lying far from the mainland and composed entirely of volcanic material.In this paper I shall attempt to present a general account of the composition of the terrestrial faunas of the oceanic islands, and to show their relationships with the faunas of other regions, before discussing the origin and possible antiquity of their older elements.Easter Island, Juan Fernandez, Desventuradas, and the Galapagos will be considered here, but the isolated Salay Gomez and the Cocos and Malpelo islands will not be dealt with because they are not sufficiently well known.In table 1 is shown the location of the islands to be considered, together with other basic data (see also fig. 1). Easter IslandThis remote island has a low and uniform topography relieved by a few craters which have no human record of volcanic activity.It is fairly arid, having no streams, lakes, or swampland, and showing surface water only in the depths of three of the craters.Its climate is warm-temperate, with its rainfall evenly distributed through the year (Cfa in the Koppen-Geiger classification).It is the only island of the four with a native human population.Man and his domestic animals, particularly sheep, have been largely responsible for the impoverishment of the flora and for this reason Easter Island has only 31 species of flowering plants.Skottsberg, in 1928, was therefore able to say