`Ala`alahua (Alectryon macrococcus var. auwahiensis)

Global Rank: T1 - Critically Imperiled
Legal Status: N/A
Family: Sapindaceae
State: HI
Nature Serve ID: 158032
Lifeform: Tree
Date Inducted in National Collection: 02/10/1987

Description:

Alectryon macrococcus is a tree that can grow to 11 meters tall. It has reddish-brown branches and glossy leaves with a netted pattern of veins. Leaves are composed of two to five pairs of egg-shaped leaflets that are slightly asymmetrical. The fruit of this tree provided food for the early Hawaiians, as both the seed and the scarlet-colored, fleshy aril around it have mild but slightly sweet flavors. Unfortunately, what made this fruit appealing to Hawaiians also makes it appealing to the introduced black twig borer and imported rats. This is currently a major threat to the continued survival of the species, as fruit and seeds are eaten before they have a chance to germinate. (Wagner et al. 1999 and USFWS 1992) There are currently two varieties recognized for this species, and both are listed as federally endangered. The first, variety macrococcus, is found on four Hawaiian islands. The second, discussed here, is variety auwahiensis and found only on the island of Maui. It differs from the other variety of Alectryon macrococcus in that its lower leaflet surface has a dense covering of rust-colored. (Wagner et al. 1999 and USFWS 1992)

Where is `Ala`alahua (Alectryon macrococcus var. auwahiensis) located in the wild?

Habitat:

This species is found in diverse mesic to wet-mesic and upper dryland forest that occurs on a well-weathered substrate at elevations between 333 and 1,210 m (1,092 and 3,969 ft). (Wagner et al 1999 & USFWS 2002b) Associates include the following native plant species: Diospyros sandwicensis, Dodonaea viscosa, Osteomeles anthyllidifolia, Alphitonia ponderosa, Santalum ellipticum, Xylosma hawaiiensis, Streblus pendulinus (aiai), Pouteria sandwicensis, or Pleomele auwahiensis. (USFWS 2002b)

Distribution:

This particular variety is found only on the island of Maui, on the south slope of the volcano Haleakala, at elevations of 1,017 and 3,562 m (1,168 and 3,337 ft). (Wagner et al. 1999 and USFWS 2002b)

States & Provinces:

`Ala`alahua can be found in Hawaii

Conservation Actions

Nature Serve Biotics

05/02/2017

Endemic to the south slope of Haleakala on Maui, with a total of 9 trees remaining. The black twig borer, habitat degradation (particularly by cattle), predation of fruits and flowers by introduced rodents, and competition with alien plants pose threats to the remaining individuals.

01/01/2010

As stated by the USFWS (2002b), threats include: Infestations by the black twig borer Seed predation by mice and rats Habitat degradation by feral pigs, deer, and escaped cattle Competition with introduced plants for resources such as light, space

01/01/2010

Currently, 22 individuals of A. macrococcus var. auwahiensis are known from two populations. Both populations occur on the leeward side of the island of Maui on private and State owned lands. (USFWS 2002b) from two populations with 22 individuals on leeward East Maui in Auwahi in the Hana District and on the ridge east of Pahihi Gulch on private and State owned (Kahikinui Forest Reserve) lands

01/01/2010

None known.

01/01/2010

In April, 2002, the U.S. Fish and Wildlife Service determined that a designation of critical habitat was prudent for both varieties of this species. (USFWS 2002)

01/01/2010

Monitoring is necessary, and actions should be taken to remove the threat of browsing animals to remaining individuals. Research and management efforts should be directed toward helping these plants successfully reproduce in the wild.

01/01/2010

Propagation and maintenance of ex situ plants is a priority. Research is needed on long term seed storage techniques.