Installation of strategically placed fences is needed to protect a Kauai natural area reserve that is home to rare and endangered species, state officials say in an updated management plan.

The Department of Land and Natural Resources Division of Forestry and Wildlife updated a plan for the Hono O Na Pali Natural Area Reserve, which spans 3,580 acres in Hanalei and Waimea.

It is the first update of the management plan since it was written in 1989. It contains proposed actions for the next 10 years. Michael Wysong, natural area reserve manager for the Division of Forestry and Wildlife on Kauai, said the update was needed because surveys indicated ongoing destruction of habitats by feral pigs and predation on native seabirds by cats and farm owls.

"Those natural resources continue to decline," Wysong said.

Hono O Na Pali is home to 56 species of endangered plants and six species of endangered birds. Rare plants include the alula, which is endemic to Kauai.

Endangered birds such as the small Kauai thrush or puaiohi, Newell’s shearwaters, Hawaiian petrels and band-rumped storm-petrels nest at the reserve, which is also home to the endangered Hawaiian bat, Wysong said.

The cost of protection and preservation measures proposed in the 10-year draft management plan is estimated at $1.9 million. Of that figure, approximately $864,000 will be used to build and install 4.8 miles of fencing to keep feral animals out of sensitive areas of the reserve.

Proposed actions focus on the reserve’s upper elevation wet forest, which spans 2,290 acres. Conservationists say feral pigs and goats degrade the habitat and spread invasive weeds.

Seven-foot fences to be made of hog wire or panels and plastic deer mesh will contain gates or step-overs to allow pedestrian access for recreational and cultural use of the reserve, according to the management plan. So the fences will not impede access to the Alakai and Pihea Trails.

Wysong said the strategically placed fencing will be placed mostly in upper areas of the reserve, which is at least 3,200 feet above elevation.

In addition to the fences, staff will take advantage of the reserve’s steep cliffs to serve as natural barriers to prevent feral pigs from access to the reserve. One-way animal gates will be installed where fences cross game trails to allow animals to exit but not enter the upper plateau.

"Using strategic fencing in conjuction with natural barriers to prohibit the ingress of ungulates into the area will make ungulate control efforts more effective," the plan states. Ungulates are hoofed animals, including pigs, goats and deer.

Once the fences are installed, staff will initiate public hunts and set traps to remove the animals.

The plan also calls for the installation of helicopter landing zones to help staff better manage the site. Staff members use helicopters to reach many steep, remote areas.

The Nature Conservancy and other organizations support the plan. Trae Menard, director of forest conservation for the group, said the reserve has a high diversity of native plants.

Fencing is the best tool to prevent feral pigs from damaging the grounds, causing erosion, accelerating the invasion of weeds and degrading the watershed quality, said Menard, who also is a member of the Natural Area Reserves Commission.

The Division of Forestry and Wildlife has prepared a draft environmental assessment for the management plan. The document is available for review and comment until Nov. 23. To see it, go to hawaii.gov/dlnr/dofaw.