Endangered Species in the Pacific Islands
Recovery Plan for Three Plant Species on Nihoa Island
This recovery plan covers 3 endangered plant taxa found only on the island of Nihoa in the Northwestern Hawaiian Islands. Amaranthus brownii, an annual herb, Pritchardia remota, a palm, and Schiedea verticillata, a perennial herb, were listed as endangered on September 20, 1996.
The 3 plant taxa covered by this plan have probably always been rare and restricted to the island, although Pritchardia remota may have once occurred on Laysan Island. Their current habitat, uninhabited by humans, is protected as a national wildlife refuge managed by the U.S. Fish and Wildlife Service and is part of the Papahānaumokuākea Marine National Monument.
Schiedea verticillata -
Photo credit Craig Rowland/USFWS
Habitat & Distribution:
Amaranthus brownii is the rarest native plant on Nihoa.It typically grows in shallow soil on rocky outcrops at elevations between 100 and 800 feet (30 and 242 meters). In 1983, two known groups of this plant species
contained a total of approximately 35 plants and were located in the east end of the island. The U.S. Fish and Wildlife Service surveys the island annually but since 1983, none of these plants have been seen, as most of the surveys occur in the summer when the island is accessible and the plant is an annual that
only grows in the winter.
Most of the populations of Pritchardia remota are located in scattered, small groves in two valleys. A few trees also grow at the bases of basaltic cliffs on the steep outer slopes of each of the two valleys. Plants grow from 50 to 500 feet (15 to 151 meters) in elevation.
Schiedea verticillata typically grows in soil pockets and cracks on coastal cliff faces at elevations between 100 and 800 feet (30 and 242 meters). The plants are primarily on the western half of the island with two subpopulations on the north cliffs of the island.
Recovery actions outlined in the plan include increased monitoring of plant populations and potential pests and weeding of alien plants. Several botanical gardens have plants or seeds of Pritchardia remota, also known as "loulu" in Hawaiian, and Schiedea verticillata in their collections, but attempts to grow Amaranthus brownii in cultivation has not been successful.
The recovery plan calls for the collection of seeds and tissues, as well as research on long-term storage of seeds, propagation and micropropagation, and outplanting techniques.