Introduced animals in Hawaii's natural areas

The Hawaiian islands provide superlative examples of biological evolution and are perhaps the best sites in the world for biological invasions. Introduced invertebrates such as the Argentine ant (lridomyrmex humilis) and the western yellow jacket wasp (Paravespula pensylvanica) reduce native insects and plant pollinators and may have been a factor in native bird declines. Management of invertebrates in localized areas through use of chemicals such as Tahara and diazinon is being attempted. Research on the long term effects of alien birds on native ecosystems is under way, but management currently is restricted to preservation of intact and large areas of native ecosystems. Black rats (Rattus rattus), small Indian mongooses (Herpestes auropunctatus), and feral cats (Felis catus) are thought to be especially important invaders of natural areas in Hawai'i. Research on ecology and control methods for all 3 species is under way, with registration of diphacinone for mongooses by the Animal and Plant Health Inspection Service nearly complete. Ungulates have been the most prominent alien animals in Hawai'i's ecosystems since shortly after continental man introduced them in the 18th century. Successful control and even eradication of feral cattle (Bos taurus), feral sheep (Ovis aries), mouflon (Ovis musimon), feral goats (Capra hircus), and feral pigs (Sus scrofa) has been accomplished in many areas to date through systematic, long-term programs with salaried personnel. Methods and costs of some of these programs are presented