Endangered Species in the Pacific Islands
The
Final Recovery Plan for Four Species of Hawaiian Fern
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This
recovery plan covers four Hawaiian ferns that were added
to the Federal list of endangered and threatened species
on September 26, 1984.
The four ferns and their habitats have been variously affected
or are threatened by one or more of the following: habitat
degradation and/or predation by feral or domestic animals;
competition for space, light, water, and nutrients from
alien plants; human impacts; and fire.
In
addition, these ferns are subject to an increased likelihood
of extinction and/or reduced reproductive vigor from randomly
occurring events due to the small number of existing individuals
and their very narrow distributions. |
Asplenium
fragile var. insulare
- Photo credit
Tracey Wager/Colorado State University |
The
land that supports these four ferns is owned by the State of Hawai‘i,
the Federal government, and private entities. Federally owned
land consists of Hawai‘i
Volcanoes National Park and Pohakuloa Training Area on the island
of Hawai‘i,
and Schofield Barracks Military Reservation on O‘ahu.
The recovery plan details the life history, habitat, reasons for
decline, and conservation efforts for each plant.
Habitat
& Distribution:
Three
of the 4 endangered ferns have been reported from lowland forests.
Ctenitis squamigera is typically found in lowland
mesic forests, and Pteris lidgatei
appears
to be restricted to lowland wet forest. Diplazium molokaiensis
has
been reported from lowland to montane forests in mesic to wet
settings. Asplenium
fragile var. insulare
has
been reported from montane wet, mesic, and dry forest habitats
as well as subalpine dry forest and shrubland habitat.
Asplenium
fragile var.
insulare
is a member of the spleenwort family and is currently known from
9 to 11 populations on Hawai‘i
between 5,250 and 7,800 feet (1,600 and 2,380 meters) elevation.
An additional population has been reported from East Maui, in
Hanawi Natural Area Reserve, making a total of 10 to 12 known
populations of this fern.
Ctenitis
squamigera
is a member of the wood fern family. The 10 populations of this
fern that have been observed within the last 20 years are in the
Waianae Mountains of O‘ahu,
Lana‘‘i,
East and West Maui, and Moloka‘i.
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Diplazium
molokaiensis is
a member of the wood fern family. Historically, this fern
was found on Kaua‘i,
O‘ahu,
Moloka‘i,
Lana‘i,
and Maui. However, within the last 20 years, only 3 populations
have been recorded, all on east Maui.
Pteris
lidgatei is
a member of the maidenhair fern family and is currently
known on O‘ahu
and Maui. There are 7 known populations of this fern. |
Pteris
lidgatei - Photo credit University of Hawai‘i |
Recovery:
The
4 ferns in this recovery plan are currently found on lands owned
or managed by the Federal government, where Federal law protects
all plants from damage or removal: Hawai‘i
Volcanoes National Park and U.S. Army installations.
The Service
has a cooperative agreement with State and Federal agencies, and
private organizations such as The
Nature Conservancy, and private landowners in an effort to protect
these 4 endangered plants.
Recovery actions recommended for these four ferns include the
removal of feral animals, minimizing the impact of military training
activities, monitoring known populations, controlling fires and
alien weeds, building enclosures around some of the most intact
portions of native forest in conjunction with hunting on Lana‘i,
and the expansion of the Mount Ka‘ala
Natural Area Reserve. Surveys to locate and map additional populations
are also important to the recovery of these ferns.
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