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Climate Change and Endangered Species Conservation in the Wai‘anae Mountains

The Pacific RISA Team recently took a field day to volunteer with the Army Natural Resources Program on Oʻahu (ANRPO) in the Wai‘anae Mountains, where we got to see firsthand what it takes to manage and restore some of Hawai‘i’s most remote and precarious native ecosystems.

View of the North Shore of Oʻahu from the ridgeline. Credit: Krista Jaspers

Through a cooperative agreement with the University of Hawai’i Office of the Vice President for Research and Innovation (OVPRI), the U.S. Army Garrison is responsible for ensuring compliance with the Federal Endangered Species Act on more than 50,000 acres of U.S. Army training ground on the island of Oʻahu. The ANPRO manages 90 of the 474 federally listed endangered species in Hawaiʻi, including plants, birds, land snails, and insects. These ecologically and culturally valuable species are often located in remote, mountainous terrain that can only be accessed by highly trained biologists and technicians using 4WD vehicles and helicopters. To attain the program’s goal of balancing the requirements of the Army’s training mission with its natural resource responsibilities, the ANRPO maintains nurseries and a seed bank for rare endemic species, and engages in monitoring and surveying activities, biocontrol research and deployment, eradication of invasive plant and animal species, building fencing to keep out feral pigs and goats, and hosts public volunteer workdays to foster community engagement in conservation.

The Pacific RISA team was most excited to see the highly endangered Hawaiian land snails, known as kāhuli, which through habitat loss, climate change, predator introduction, and over-collection have been disappearing at an alarming rate. There are estimated to have once been up to 750 species across the Hawaiian Islands, but 90% of them are now thought to be extinct. Our hike would take us through forests of native species (many of which are being managed by ANRPO), up to two protected snail enclosures, one managed by the Army, and the other by the State’s Division of Forestry and Wildlife (DOFAW) and Snail Extinction Prevention Program (SEPP).

Empty shells of Achatinella mustelina, and the shell of the Rosy wolf snail (Euglandina rosea), a threat to native species. Credit: Krista Jaspers.

We met ANRPO Conservation Manager Jane Beachy and Rare Plant Program Coordinator Tim Chambers at the ANRPO baseyard where we were briefed, equipped with weeding tools, and fitted with spiked shoes for the steep and often muddy trail. After a 45 minute drive to the trailhead in the Wai‘anae Mountains, we hiked to Kahanahāiki, where we immediately noticed biocontrol on the very pervasive and invasive strawberry guava (Psidium cattleianum), and passed a number of rodent traps and fencing designed to keep out feral goats and pigs. Tim stopped along the way to point out the extensive work ANRPO has done to reintroduce native species, including grasses, ferns, and more well-known species like koa and ʻōhiʻa. ANRPO must not only contend with extreme conditions, predators. and invasives, but also the effects of climate change, which climate models predict will result in higher temperatures and drier conditions in the Wai‘anae Mountains.

From L to R: Beautiful ʻōhiʻa (Metrosideros polymorpha) in bloom; Chelsey Bryson with native fern kupukupu (Nephrolepis exaltata subsp. hawaiiensis); Endemic koʻokoʻolau (Bidens torta) in bloom. Credit: Krista Jaspers.

We reached the Army snail enclosure, designed to keep out a multitude of predators, and got to work weeding out invasive species throughout the enclosure. The Army snail enclosure was recently invaded by yellow crazy ants (Anoplolepis gracilipes), so the remaining snails have been removed to SEPP’s captive rearing facility.

From L to R: Rare Plant Program Coordinator Tim Chambers explains how the snail enclosure’s barrier keeps predators out; Conservation Manager Jane Beachy applies herbicide to a stubborn weed; the team celebrates weeding the entire Army snail enclosure. Credit: Krista Jaspers.

Our next stop was the State snail enclosure, where we immediately spotted the native tree snail Achatinella mustelina, endemic to the Wai‘anae Mountains and listed as critically endangered by the IUCN Red List Ranking. The snails seem to be thriving there – we found many of them living on the underside of the leaves of the pāpala kēpau (Rockia sandwicensis) and olopua (Notolaea sandwicensis) trees.

Achatinella mustelina on the underside of the leaves of the Olopua tree (Notolaea sandwicensis). Credit: Krista Jaspers.

The hike back took us along a ridgeline where we had sweeping views of the North and West shores of O‘ahu. It also took us past a very successful plot of reintroduced hāhā (Cyanea grimesiana subsp. obatae), federally listed as endangered and found only in the Wai‘anaes. The hāhā was in bloom and its floral display seemed to surprise even our guides – their enthusiasm was contagious, and we all clambered down a steep hillside to get a closer look. ANRPO collaborates with DOFAW’s Native Ecosystem Protection and Management (NEPM) program to manage this unusual lobelia.

From L to R: Conservation Manager Jane Beachy in a grove of outplanted rare endemic hāhā (Cyanea grimesiana subsp obatae) ; Hāhā in bloom. Credit: Krista Jaspers.

We would like to thank Jane and Tim for sharing their time and mo‘olelo (stories) about the good, the bad, and the ugly of what it takes to restore an ecosystem, and for the incredible job they are doing of managing natural resources in the Wai‘anaes under so much uncertainty.

Team members Mari Ching, Laura Brewington, Krista Jaspers, and Chelsey Bryson. Credit: Krista Jaspers.

Army Natural Resources Program Oʻahu
https://oanrp.com/about/

Hawaii Snail Extinction Prevention Program
https://dlnr.hawaii.gov/ecosystems/sepp/

How to Help Native Snails
https://dlnr.hawaii.gov/ecosystems/sepp/howtohelp/

ANRPO and UH
https://research.hawaii.edu/noelo/anpro-and-uh/

Oʻahu Invasive Species Committee (OISC)
https://www.oahuisc.org/

Division of Forestry and Wildlife: Native Ecosystems Protection and Management, Rare Plant Program
https://dlnr.hawaii.gov/ecosystems/rare-plants/