NEWS

A paper co-authored by the Pacific Islands Climate Adaptation Science Center (PI-CASC) Manager Climate Corps (MCC) graduate Joanna Norton was recently published in Pacific Science, a journal focusing on invasive species of the Pacific Islands. The paper, “Biology and Impacts of Pacific Islands Invasive Species: Falcataria falcata (Miquel) Barneby and Grimes (Fabaceae),” was a review of Falcataria falcata, or albizia, and included the research she conducted while in the MCC program, as well as additional research for the section on beneficial uses of albizia.

For her MCC project, farmers, invasive species experts, and researchers worked together to develop and test an agricultural method of using albizia compost to determine whether it could replace chemical fertilizer and store carbon in agricultural lands on the windward side of Hawai‘i Island. This alternative application is considered climate-smart agriculture, which encompasses practices that maintain productivity and yield while enhancing resilience to climate change. 

“I was motivated to research this topic because every day, I would drive past green, lush, invaded forests and then depleted or fallow agricultural lands not producing food,” said Norton. “I thought, ‘All the nutrients for growth are here, just in the wrong resource pools.’”

Albizia is a large, fast-growing tree that was first introduced to the Pacific Islands to prevent erosion after overgrazing by introduced cattle. The trees have rapidly spread and overtaken other trees’ habitats, displacing native forests and depositing large amounts of carbon and nitrogen into soils, driving further invasion. In 2014, albizia’s massive canopies and treefall during Tropical Storm Iselle generated over $10 million in damage and left many households in Puna without utility services for weeks. 

The technique in Norton’s research is simple and was already being used to some extent by the farming community in Hawaiʻi Island, which benefited her research. Moving resource pools around could stimulate more management efforts of albizia trees in invaded areas, and testing albizia’s utility as a mulch would build on a relatively slim body of research exploring locally-sourced alternatives to chemical fertilizer. 

“My experience in the agricultural sector showed that many promising climate-smart techniques are not used widely or optimized due to a lack of peer-reviewed research, so I wanted to test some of the methods I saw individual farmers experimenting with,” said Norton. “I think that my work is adding to a body of knowledge testing farmer-approved, low-tech methods, and as we refine the techniques, the benefits to farmers will grow.”

The results of her research suggested that albizia compost is a viable alternative to chemical fertilizer in some situations, especially when the farmland is more degraded, and the crop has a longer growing season.

“We were thrilled that Joanna’s research could be integrated into this larger review paper on the ecology of albizia,” said Dr. Rebecca Ostertag, co-author and University of Hawaiʻi at Hilo biology faculty. Ostertag was also Norton’s advisor in the Tropical Conservation Biology and Environmental Science (TCBES) program. “Writing the manuscript was a collaborative project with Dr. Flint Hughes, USDA Forest Service, Institute of Pacific Islands Forestry, who was a member of Joanna’s [master’s] committee, and Dr. David Clements and undergraduate student Aidan Anderson. Clements had led a summer field course on Hawaiʻi Island, taken by Anderson, and the connections were built from there. Adding the experimental and agricultural perspectives was an essential part of the story, and the collaboration among the five of us was seamless and fun.”

While in the MCC program, Norton met many other researchers working with communities in Hawaiʻi and the Pacific, which expanded her network. “MCC’s focus on knowledge co-production, working with stakeholders to formulate questions and get answers that matter to the community, was a welcome focus in my graduate years, and I continue to use that approach whenever I can. MCC showed me that this framework is now a leading edge of climate science thinking,” she said.

Norton now works as a cassava breeder at the University of Hawaiʻi at Mānoa College of Tropical Agriculture and Human Resilience, a job she was introduced to while in graduate school.