Pacific Islands Fish and Wildlife Office
Pacific Region

Endangered Species in the Pacific Islands

Recovery Plan for the Nesogenes rotensis

Line drawing of Nesogenes rotensis

Nesogenes rotensis is a low-growing herbaceous (non-woody) plant with small, opposite, broadly lanceolate (lance-shaped), coarsely toothed leaves. Osmoxylon mariannense is a spindly, soft-wooded tree in the ginseng family (Araliaceae), which can reach 10 meters (33 feet) in height.

Line drawing of Nesogenes rotensis

Habitat & Distribution:
Nesogenes rotensis has been found in two locations, Poña Point on Rota’s southern coast and Puntan Fina Atkos on Rota’s eastern coast. At both locations a small population exists on an exposed, raised limestone flat above a 7.6- to 30.5-meter (25- to 100-foot) seaside cliff. Although these flats are up to 30.5 meters (100 feet) above the sea, they are subject to scouring winds during severe storms. When last surveyed in 2005, only 35 to 40 individuals were known from the two populations. Nesogenes rotensis grows in association with Scaevola taccada, Terminalia samoensis, Hedyotis strigulosa, Pogonatherum paniceum, and Bikkia tetrandra.

Osmoxylon mariannense is found in limestone forests that are often shrouded in clouds and mist on the Sabana and its escarpments. As of 2003, only eight individuals were known to exist. These forests occur in patches in the formerly mined Sabana and are dominated by Hernandia labyrinthica and Elaeocarpus joga (yoga) interspersed with Pandanus (kafu) thickets.

At the time the species were listed, the Service found that critical habitat for Nesogenes rotensis and Osmoxylon mariannense was prudent but not determinable due to a lack of information regarding the physical and biological features or specific areas essential to the conservation of these species. Little new information has come to light to change this status.

Threats to Nesogenes rotensis and Osmoxylon mariannense include extreme alteration due to past and present land use practices, including ranching, development, deliberate and unintentional nonnative animal and plant introductions, agriculture, and military activities during World War II. Neither species is yet protected under Commonwealth of the Northern Mariana Islands Division of Fish and Wildlife. Typhoons are also a major impact to both species. Osmoxylon mariannense is also threatened by introduced goats, pigs, cattle, and Philippine deer that severely damage forest vegetation. Deer browse on seedlings, and other unknown sources (perhaps mice, rats, or disease) have defoliated young plants.

Attempts have been made to cultivate both species, but with limited success for Nesogenes rotensis. In 1994, the
I Chenchon Park area was designated as a protected area, and includes one population of Nesogenes rotensis, and part of the Sabana region was designated as a protected
Last updated: September 20, 2012
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