Mākaha Transpiration Study

Background

In Hawai'i, invasive species are the greatest threat to healthy and functioning native ecosystems, and climate change is expected to further constrain these ecosystems. More information is needed to understand how different species and ecosystems will respond to projected changes in temperature and rainfall. We seek to compare ecohydrological processes in paired stands: a diverse, mesic Hawaiian forest and a nearby stand dominated by strawberry guava. Working in collaboration with local resource managers, results will provide information on connections between watershed management activities and water resources.

People

Ecohydrology Lab Members

Thomas Giambelluca (PI)

Michael Nullet (Technician, data manager)

Yoshiyuki Miyazawa (Researcher)

Aurora Kagawa-Viviani (PhD student)

Honolulu Board of Water Supply

Amy Tsuneyoshi

Kaimana Wong

Observations (2017-2019)

We conducted measurements in the field for local microclimate, soil moisture, tree sapflow, and leaf-level physiology and leaf water potential. HBWS monitored canopy rainfall partitioning into stemflow and throughfall. Additional measurements included rainfall, stemflow, throughfall and streamflow water isotopes (δ¹⁸O and δ²H ) for tracing flows from canopy to root zone. The two field sites are located in native forest and a forest dominated by invader Psidium cattleyanum, but unlike our flux tower sites at HAVO, these are below the cloud zone.

Resources

Kagawa-Viviani AK and TW Giambelluca. B122-04: Ecohydrologic engineering contributes to the success of a pantropical woody invader. eLightning poster presented at the American Geophysical Union Fall Meeting, San Francisco, CA. (12/16/2020)

Funding

This work was supported by funding from the Honolulu Board of Water Supply and summarized in a final technical report submitted in April 2020.