Tucked amidst naval facilities and urban development, the Honouliuli and Waiawa Units are managed to provide wetland habitat for four of Hawai‘i’s endangered waterbirds: ae‘o, ‘alae ke‘oke‘o, ‘alae ‘ula, and koloa maoli, as well as a variety of migratory shorebirds and waterfowl. The primary causes of the decline of Hawaiian waterbird species has been the loss and degradation of wetland habitat and introduced predators (e.g., rats, dogs, cats, mongoose). Other factors include alien plants, introduced fish, bull frogs, disease, and sometimes environmental contaminants. All Hawaiian waterbirds are federally listed as endangered.
The Kalaeloa Unit was established to protect and enhance the habitat for the endangered plants ‘Ewa hinahina and ‘akoko. The largest population of ‘akoko on O‘ahu and the second largest population of endangered ‘Ewa hinahina can be found within this unit. Also in the Kalaeloa Unit, exists a subterranean world few have ever seen. In these underground brackish and saline waters known as anchialine pools, translucent greens, yellows, and reds sparkle like precious gems in a treasure chest. These rare biological gems are known as anchialine pool shrimp (not listed).