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

Montane wet koa/ ‘ōhi‘a forest
Hakalau Forest National Wildlife Refuge
Comprehensive Conservation Plan
Located between 5,000-6,000 ft, the montane wet koa/„ōhi„a forest habitat type is comprised of
mixed age class koa and „ōhi„a. Various flowering and fruiting trees can be found at the midcanopy
level including: „ākala, „ōlapa, pilo, pūkiawe, „ōhelo, kōlea, kāwa„u. Mixed ferns and epiphytes can
also occur in the midcanopy. The ground cover in the montane wet koa/„ōhi„a forest is dominated by
fern species such as Dryopterus sp. (Tomonari-Tuggle 1996). Slopes in this habitat are moderate.
A diverse assemblage of native and endangered plants and animals occurs in this habitat type. This
includes the koloa maoli and the „ōpe„ape„a (USFWS, unpubl.).
In addition to habitat threats present in other areas of the HFU, the montane wet koa/„ōhi„a forest has
been exposed to greater human disturbance, especially cattle grazing. Areas previously forested in
koa and „ōhi„a that have been exposed to browsing have largely been converted to grasslands,
suggesting that the habitat type cannot tolerate this land use (Stine 1985, Tomonari-Tuggle 1996).
Montane mesic koa forest
The montane mesic koa forest habitat type can be found at the highest elevation of the unit between
6,000 - 6,600 ft. Koa is the dominant vegetation cover in this area and the trees are mixed ages.
Characteristic midcanopy species within this forest include „ōlapa, „ākala, pilo, pūkiawe, „ōhelo,
kōlea, kāwa„u, ferns, and epiphytes.
A low concentration of native forest birds currently occurs in this habitat. Nēnē are found throughout
the habitat. This habitat preference is likely biased since captive-bred birds are released in this area.
„Ōpe„ape„a and the „io have been recorded in the montane mesic koa forest. Various native and
endangered plants and a single native grass, Deschampsia nubigena, are also present here.
This forest shares similar threats as other habitats within the HFU. The historical area of mesic koa
forest was reduced to nonnative grassland by grazing, timber harvest, and fires; however, the Refuge
is working to restore this habitat by outplanting native species. Nonnative grasses include various
species of Anthoxanthum, Holcus, Pennisetum, and Ehrharta.
Aquatic habitats (streams, ponds, Carex bogs)
Several streams are located within the HFU. Streams start as intermittent in higher elevations and for
some become perennial at lower elevations of the Refuge (Figure 4-2). Some streams are found in
gulches or with steep walls, thereby providing better protection for endangered and native plants
from grazing by ungulates. Fauna within the streams are unknown and unstudied, but invertebrates
are believed to be the main users of this habitat. Threats to these habitats include gorse, which can
displace native riparian vegetation, and ungulates and rats, which can affect water quality through
soil disturbance and feces deposition.
The Refuge also has manmade and semipermanent natural ponds. These habitats are seasonal and the
manmade ponds will not be maintained by Refuge staff as they have transitioned to Carex and
Juncus vegetation, which can be used by koloa maoli.
Carex bog habitat is discussed previously under montane wet „ōhi„a/uluhe forest.
Chapter 4. Refuge Biology and Habitats 4-9