Palmyra Atoll has one of the best remaining examples of Pisonia Grandis, a tropical coastal strand forest found in the Pacific, and one of the last predator-dominated marine ecosystems in the world. Many nationally and internationally threatened, endangered, and depleted species thrive at Palmyra Atoll, including sea turtles, pearl oysters, giant clams, reef sharks, coconut crabs, a large diversity of fish (at least 418 species), and marine mammals. Palmyra supports 10 nesting seabird species, including one of the largest Red-footed Booby colonies in the world and the largest Black Noddy colony in the Central Pacific. Palmyra is the only moist tropical atoll ecosystem in the Central Pacific whose natural resources are not being impacted by growing human populations. However, non-native introduced black rats on Palmyra severely affected seabird, native crab, and plant populations. Invasive rats preyed on burrow nesting seabirds and limited the recruitment of native tree species.
In 2011, Island Conservation, The U.S. Fish and Wildlife Service (USFWS), and The Nature Conservancy removed invasive rats from the atoll to protect native species from extinction. Since the removal of invasive rats, we have recorded a 130 percent increase in native tree seedlings, including the first record of new Pisonia seedlings since the removal of rats took place, and arthropods (such as insects, spiders, and crabs) have increased by 367 percent. Prior to removal, rats significantly altered the atoll’s ecosystem by consuming seeds and native animals. The University of California, Santa Cruz Coastal Conservation Action Lab; USFWS; and the U.S. Geological Survey are monitoring the response of Palmyra’s terrestrial ecosystem by comparing measures of seabird, shorebird, plant, and invertebrate populations taken before and after rat removal.
Photos : Island Conservation and Erik Oberg