Final Comprehensive Conservation Plan - U.S. Fish and Wildlife ...

Hakalau Forest National Wildlife Refuge
Comprehensive Conservation Plan
In 2003, 6,823 ac of critical habitat were designated for C. pyrularia. Critical habitat has been
designated at the HFU. The critical habitat unit located completely within the HFU provides habitat
for three populations of 300 individuals; however, no individuals occurred on the unit at the time of
designation. The south and north-central portion of the second critical habitat unit is also located
within the Refuge unit (Federal Register 2003b). Ex situ, or offsite, planting is needed to increase
population numbers at these areas (USFWS, publ.).
4.9.5 Hāhā (Cyanea hamatiflora)
Several species within the Cyanea genus are referred to by the Hawaiian name hāhā. The genus is
endemic to the Hawaiian Islands, with 11 species and 5 subspecies on Hawai„i Island. Cyanea
hamatiflora subsp. carlsonii is an endangered species typically found in montane wet „ōhi„a and
mesic koa/„ōhi„a forests of the west side of the island. This palm-like tree can grow between 9.8-26 ft
in height. The sessile leaves average between 20-31 in long and the flowers cluster in groups of 5-10
(USFWS 1996a). The sepals and magenta petals of C. hamatiflora subsp. carlsonii are fused into an
oval tube. The berries are oval and purplish red in color. The other subspecies – hamatiflora – is
common throughout East Maui. The Hawai„i Island subspecies can be distinguished by its stalkless
leaves, larger flower stalks, and longer calyx lobes (USFWS 1996a, Mitchell et al. 2005).
The current distribution of the species ranges from 5,220-5,700 ft on the western slopes of Hualālai
(Mitchell et al. 2005). In 2003, 14 individuals existed in the Honua„ula Forest Reserve within the
Wai„aha watershed and a single individual was known from the Kīpāhoehoe NAR within the Ki„ilae
watershed (Federal Register 2003b). Currently, populations occur at the Honua„ula Forest Reserve
and at privately owned land at Kēōkea in South Kona. In 2005, about 16 plants were recorded at
„Ōlelomoana. Fifty-one individuals were outplanted within the native range at the Honua„ula Forest
Reserve and Pu„u Wa„awa„a. These outplantings have not been successful and the population has
declined to roughly 3-4 individuals (Mitchell et al. 2005).
Although no C. hamatiflora carlsonii are currently known from the KFU, the area is considered a
key potential habitat for the species (Federal Register 2003b). No individuals have been found in the
areas since the 1960s (USFWS, unpubl.). Approximately 2,583 ac of land in South Kona were
designated as critical habitat for this species in 2003. Of this total, approximately 1,475 ac lie within
KFU (USFWS 2008). Three additional critical habitat units were designated in the Honua„ula Forest
Reserve, South Kona Forest Reserve, and Kīpāhoehoe NAR (Federal Register 2003b).
Potential risks to C. hamatiflora include cattle, rats, nonnative plants, and small, disjunct populations
(USFWS 1996a). Ungulate disturbance provides an opportunity for invasive plants, such as banana
poka, to take over an area and directly compete with C. hamatiflora carlsonii. In addition,
reproductive success is reduced by a limited gene pool and further depleted by birds and rats that eat
the seeds. Caterpillar seed damage has also been observed on this species (USFWS 1996a).
4.9.6 ‘Aku‘aku (Cyanea platyphylla)
Cyanea platyphylla, or „aku„aku, is a small unbranched shrub endemic to the island of Hawai„i. The
palm-like shrub reaches between 3-10 ft tall and is covered by short spines on the upper portion of
the stems. The leaves of juvenile plants have prickles on the leaves and stalks and measure between
4.1-10 in long and 1.6 -3 in wide. Adult plants have only sparsely prickled leaves. Adult leaves are
4-62 Chapter 4. Refuge Biology and Habitats