The Pacific Cooperative Studies Unit

Protecting and Preserving Hawai‘i’s Biodiversity Through Research

The famous ecologist and conservationist Aldo Leopold once wrote: “To keep every cog and wheel is the first precaution of intelligent tinkering.”

Today, Leopold’s words have become an unofficial edict of the Pacific Cooperative Studies Unit (PCSU) headquartered at the University of Hawai‘i at Mānoa (UH Mānoa) as its researchers continuously work to do both—protecting Hawaiian biodiversity, while finding ways to restore Hawai‘i through basic and applied research. Originally founded as a cooperative project between the National Park Service and UH Mānoa in 1973, PCSU has expanded over the years to include partnerships with other state and federal agencies, as well as private landowners.

The National Park Service/PCSU relationship helped to prove the feasibility and benefits of fencing large areas of forests to prevent the modification and degradation of habitat by ungulates and allow recovery of native ecosystems. A key discovery aided by PCSU science involved the ecologically disastrous relationship between the feral pig and strawberry-guava, and their role in the extermination of many native bird species from the lowlands. The seeds of the invasive plant were carried into pristine forest areas by the pigs, forming dense thickets that destroyed the native plants and habitat. At the same time, the pigs left pits from rooting and wallowing, that formed stagnant ponds to aid in the reproduction of mosquitos and the spread of avian malaria and poxvirus.

 “Many of today’s projects provide both science and logistics to island-level collaborations that address environmental problems that cannot be addressed by single land owners or jurisdictions,” said David Duffy, professor of botany and unit leader of PCSU. “Through individual watershed partnerships run by PCSU, each island manages its own native landscapes.”

Similarly, the invasive species committees (ISCs), located on each island, feature local steering committees that identify incipient invasive species of community or ecological concern. This allows local “buy in” and support as PCSU provides the science and the “boots on the ground” that undertake eradication, documenting the effectiveness of various approaches and sharing the results among the islands. The ISCs have eradicated several invasive species from each island before they could become established and have collaborated with state agencies in surveying and monitoring invasives such as Miconia, a shallow-rooted forest tree that can take over whole forests and coqui frogs that have destroyed the silence of night on the Big Island and significantly lowered property values. On the other islands, ISCs continue to work with state agencies to prevent further coqui colonizations.

The Pacific Cooperative Studies Unit has also responded to crisis situations. Originally introduced to Hawai‘i in 1868 as a gift to King Kamehameha V, the axis deer has become a major problem on Maui. In 2009, the deer was illegally introduced to the Big Island and its eradication became a priority.  Using methodology developed by PCSU using FLIR (Forward Looking Infrared Radar) equipment, officials were able to quickly and successfully remove the deer.

One of the biggest threats in recent years has been the Little Fire Ant that has become established on the Big Island. It threatens native invertebrates, agriculture and even the eyes of domestic pets because of its stings. The Hawai‘i Ant Lab, a collaborative project between the State of Hawai‘i Department of Agriculture and PCSU, developed control treatments that are eradicating incipient invasions of the ant on Kauaʻi, Maui and O‘ahu and are providing training and support to communities and businesses to control these ants on the Big Island.

The Pacific Cooperative Studies Unit also provides the staff for The Coordinating Group on Alien Pest Species (CGAPS), a partnership of agencies and non-governmental organizations that focuses on policy issues that impede the unit’s ability to prevent or control invasive species. Many of their projects also have active outreach programs that participate in community events such as county fairs, parades, flower shows and children’s workshops, as well as working with teachers and students in schools

In another collaborative effort with the National Park Service, PCSU is involved in monitoring and managing the critically endangered hawksbill turtle on the Big Island. Along with state and federal agencies, PCSU scientists have been satellite-tracking mountain-nesting seabirds on Maui, Kaua‘i and Lana‘i to study their movements at sea and assessing and managing threats on their nesting grounds. Other projects on Kaua‘i and Maui have been studying the ecology of Hawai‘i’s critically endangered endemic forest birds, determining their ecological requirements, assessing the threats to them, and measuring the effectiveness of different approaches to their management. Through the Plant Extinction Prevention Program, PCSU works to identify and protect species that have fewer than 50 individuals still remaining in their natural habitats—over one-tenth of the native flora. Leaving no stone unturned, PCSU scientists, in partnership with the O‘ahu Army Environmental program, have led the development of protective enclosures for endangered tree snails on the island.

With a staff of 400 and total awards in 2016 of almost $22 million, PCSU is a proven model for protecting the archipelago’s unique biodiversity through science, hands-on efforts and collaboration. Amazingly, PCSU receives no general fund support from the University of Hawai‘i and depends entirely on soft money for its operations. 

“Many efforts in the state are top down, run from O‘ahu,” said Duffy. “However, PCSU projects have roots on each island, responding to local needs, with local staff, and generating local support and funding from the counties.”

Hawai‘i Association of
Watershed Partnerships


Kaua‘i Watershed Alliance

Ko‘olau Mountains Watershed

Wai‘anae Mountains Watershed Partnership

East Moloka‘i Watershed Partnership

West Maui Mountains Watershed Partnership

East Maui Watershed Partnership

Leeward Haleakala¯ Watershed
Restoration Partnership

Kohala Watershed Partnership

Three Mountain Alliance

Mauna Kea Watershed Alliance

Invasive Species Committees


Coordinating Group on Alien
Pest Species

Hawai‘i Invasive Species Council

Big Island Invasive Species

Maui Invasive Species Committee

Moloka‘i/Maui Invasive Species

O‘ahu Invasive Species Committee

Kaua‘i Invasive Species Committee