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

Grasslands
Hakalau Forest National Wildlife Refuge
Comprehensive Conservation Plan
Grasslands for nēnē foraging are created as part of the maintenance of fuel breaks (50 acres) as well
as an existing 15-acre site (for nesting) maintained near the administrative site at Hakalau cabin.
Currently these grasslands are a combination of native and nonnative grasses. Nēnē typically use
mid- to high-elevation native and nonnative shrubland and early successional grasslands, native
alpine grasslands and shrublands, and open native and nonnative alpine shrubland-woodland
community interfaces. Threats to this habitat type are wildfire.
4.3.2 Kona Forest Unit
The habitat types within the KFU are influenced by rainfall, elevation, and historical volcanism. In
addition, human activities such as logging and cattle ranching have impacted the wet, mesic, and dry
habitat types throughout the KFU (Figure 4-3). As in the HFU, former pasture land, dominated by
nonnative grasses, as well as a large section of lowland wet/mesic forest dominated by nonnative tree
and shrub species (e.g., Christmas berry and strawberry guava species) are found within the KFU.
Montane wet ‘ōhi‘a forest
The montane wet „ōhi„a forest occurs in two elevational bands: a lower gradient between 2,000-
3,000 ft and an upper gradient between 3,500-4,500 ft. Both the lower and upper gradients have an
upper tree canopy that is dominated by a closed canopy of mature „ōhi„a. The canopy is between 60-
80 ft high.
In the lower gradient, midcanopy species include a mix of introduced species such as Christmas
berry and strawberry guava, as well as the native hame, „ie„ie, kōlea, hāpu„u, „ōhi„a, and various
epiphytes. The groundcover in the lower gradient is dominated by introduced Koster‟s curse and
thimbleberry, as well as a mix of introduced and native ferns. In the upper gradient, the midcanopy
contains „ōhi„a, pilo, Clermontia sp., „ōlapa, kāwa„u, kōlea, pūkiawe, hāpu„u, „ie„ie, and epiphytes.
Ferns (both introduced and native species) and introduced grasses are the primary groundcover.
There are three primary differences between the upper and lower elevation gradients in montane wet
„ōhi„a forest habitat type at the KFU. Compared to the lower gradient, the upper gradient has higher
plant diversity in the midcanopy. The ground cover in the upper canopy is dominated by grasses,
while the ground cover in the lower gradient is mostly herbaceous. In addition, the lower elevation
gradient of this habitat type receives more rainfall annually than the upper gradient.
As a result of the lack of mosquitoes and increased plant diversity, the upper gradient of this habitat
type supports a diverse native bird community. The „ōpe„ape„a and various endangered plants also
occur in these areas.
Invasive species, such as ungulates, rats, mice, slugs, mosquitoes, and plants, threaten the montane
wet „ōhi„a forest at the KFU. In addition, plants are limited due to a lack of native pollinators.
Farming, ranching, and fires have also affected the native landscape, transforming native forests into
grasslands.
4-10 Chapter 4. Refuge Biology and Habitats