Pu’u wa’awa’a  (Bonamia menziesii)

Classified as Critically Endangered (CR) on the IUCN Red List (1).

The pu’u wa’awa’a is a highly threatened (1), woody vine that is found only in the Hawaiian Islands (3). The branches, which grow up to ten metres long (2), twist and wind around themselves and other vegetation as it sprawls across the ground or creeps upwards (3). The vine, which has a fuzzy texture when young, bears leathery leaves, oblong or oval in shape, that measure up to three to nine centimetres long and one to four centimetres wide (2). The upper surface of the leaf may be covered with sparse hairs, but is typically hairless (2), while the underside of the leaf is covered with dense, fuzzy, brown hairs (2) (3). The pu’u wa’awa’a produces white to greenish, funnel-shaped flowers (2), measuring about 2.5 centimetres long (3). The flowers are borne singly or in clusters of three on short stalks which have tiny, modified leaves (known as bracts) at their base (2). The fruits of the pu’u wa’awa’a are brown, papery capsules and contain one or two oval seeds embedded in black pulp (2) (3).

The pu’u wa’awa’a is a member of the ‘morning glory’ family (the Convolvulaceae), of which there are almost 2,000 species worldwide (2) (4). The pu’u wa’awa’a is the only morning glory species, and indeed the only species of the Bonamia genus, endemic to the Hawaiian Islands (2).

The pu’u wa’awa’a is found only in the Hawaiian Islands, where it occurs on five of the largest islands: Hawaii, Maui, Lana'i, Oahu and Kaua'i. In the past it could also be found on the island of Molokai (1). The total number of plants remaining in the wild is thought to not exceed several hundred (1).

This plant inhabits dry to mesic forest, where it may grow on steep slopes as well as on level ground (2), at elevations between 30 and 800 metres (5). It is also occasionally found in wet forests (2).

There is currently no information available on the life-history of this rare plant (2).

The habitat favoured by this Critically Endangered species is being destroyed or altered by agriculture, the grazing and trampling of pigs, goats, deer and cattle, and fire (1) (2). Competition with a number of alien plant species, such as fountain grass (Pennisetum setaceum) on Hawaii Island, is also impacting the pu’u wa’awa’a, while the beetle (Physomerus grossipes) poses a significant future threat on Oahu, where it has recently been introduced (2).

The pu’u wa’awa’a is listed as Endangered in the United States (6), which means that it is forbidden to remove the species from the wild and that care must be taken not to disturb its fragile habitat. A number of conservation strategies have since been put in place, which should hopefully help protect this species from the threats it faces. This includes fencing plants to protect them from cattle, such as on the Navy’s Lualualei Naval Reservation where a program of alien plant removal is also ongoing (2), and the development of fire protection plans, such as in Kanepuu Preserve on Lanai Island (2), which should reduce the threat pu’u wa’awa’a faces from fire.

This plant has been successfully propagated at a number of arboretums, although reintroduction of cultivated individuals to the wild has not yet been attempted (2). While it is important that cultivation of this plant continues, which acts as an insurance against this species’ extinction, it is even more vital to continue conservation efforts in the wild. Most important is the construction of further enclosures, to protect the plant against pigs, goats, deer and cattle, and the development of plans to help control alien plant species (2). Further research on this species’ life-history would also be of enormous benefit, and enable conservationists to fully understand the management needed to protect this species.

To learn about efforts to conserve Hawaiian plants, see:

• Rare Plant Conservation in Hawai’i:
  http://www.state.hi.us/dofaw/Plants/Hawaii/Hawaii.htm
• Hawaii Plant Extinction Prevention Program:
  http://hawaiipepp.blogspot.com

For more information on the pu’u wa’awa’a, see:

• Center for Plant Conservation:
  http://www.centerforplantconservation.org/Collection/CPC_ViewProfile.asp?CPCNum=606