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

Appendix F. Biological Integrity, Diversity, and Environmental Health and Resources of
Concern
Table F-1. Biological Integrity, Diversity, and Environmental Health (BIDEH).
Natural Processes
(biotic and abiotic processes
responsible for habitat conditions) Limiting Factors
Population/Habitat Attributes
(age class, structure, serial stage, species
composition)
Habitats (plant
communities that represent
existing BIDEH)
The upper canopy is composed of scattered
mature (100+ years), and medium stature
‘ōhi‘a (30 ft). The mid-canopy zone (10-
15 ft) is dominated by hāpu‘u (tree fern). The
vegetation at ground level, up to 6-10 ft, is
dominated by dense Dicranopteris sp. (matted
ferns), making access difficult. This habitat
type is found between 2,500 ft - 4,000 ft
elevation with many Carex sp. bogs found
scattered throughout the lower elevations.
Plant diversity is low and dominated by ‘ōhi‘a
and Dicranopteris sp. Although unstudied, it
is assumed that invertebrate diversity is also
low.
Hakalau Forest Unit
Montane wet
‘ōhi‘a/Dicranopteris
sp. forest
Hakalau Forest National Wildlife Refuge
Comprehensive Conservation Plan
Limiting factors
include a lack of native
pollinators and several
pest species (e.g.,
ungulates, rats, mice,
slugs, mosquitoes,
invasive plants, and
diseases).
The windward east-facing Hakalau
Forest Unit receives northeasterly
tradewind-dominated rainfall
throughout the year with up to 250
inches annually. Heavier rainfall
occurs October-March.
Mosquitoes, the vector
for avian diseases,
breed up to 4,500 feet
in elevation.
There is limited current
and historical human
disturbance. The threat
of wildfire is slight.
Mountain slopes are mild. Soils are
aged, eroded, and volcanic in origin.
Soils are typically poorly drained. The
ground surface is bisected by numerous
streams (surface flow). These streams
create and maintain stream channels
that are highly eroded and steep-sided,
providing protection to native and
endangered plants from grazing
ungulates.
Native bird densities are low due to disease
such as avian malaria. Consequently,
nonnative bird species dominate the avifauna.
Potential conservation species in this habitat
include endangered plant species, ‘ōpe‘ape‘a,
and koloa maoli. However, this habitat type
may best be described as a buffer zone for
invasive plants encroaching from lower
elevations.
Appendix F: Biological Integrity, Diversity, and Environmental Health and Resources of Concern F-1