The Hawaiian Islands are home to enormous environmental gradients that make for one of the best outdoor scientific research laboratories on Earth. The Island of Hawaii alone, just one of eight main islands, contains much of the forest cover, carbon stocks and biological diversity of the entire Hawaiian Archipelago. Hawaii Island’s 3100 km2 of forests encompass most of the ecological conditions found worldwide. As a result, much of Hawaii Island’s ecosystems have remained a focus for conservation of its unique flora and fauna as well of long-term scientific study.
Few know, however, that the CAO was born in Hawaii. By 2005 and following nearly 15 years of trial-and-error style science, Carnegie scientist Greg Asner had developed new ways to measure the islands’ ecosystems from the air. In November 2006, with support from the W.M. Keck Foundation, Asner and his fledgling CAO team deployed a new airborne toolkit designed to study the unique array of ecosystems found on Hawaii Island’s five mountains.
This birth of the CAO in Hawaii could not have happened without a key partner — the Institute for Pacific Islands Forestry (IPIF). IPIF is an important research and outreach unit of the Pacific Southwest Research Station of the U.S. Forest Service. IPIF’s mission is to support the management, conservation, and restoration of natural forest and wetland ecosystems and landscapes throughout the Pacific. Its theatre of operation includes seven U.S.-affiliated political entities in the Pacific: the State of Hawai’i, the Territory of Guam, the Territory of American Samoa, the Commonwealth of the Northern Mariana Islands, the Republic of the Marshall Islands, the Federated States of Micronesia, and the Republic of Palau. But its core presence on Hawaii Island, and in the town of Hilo in particular, made for an ideal partner to help the CAO get off the ground.
“Flint and I agreed that we needed a place to foster not only CAO’s technical remote sensing evolution, but also a place that would offer real-world applications in science, conservation and management at large ecological scales”, noted Asner, referring to his long-term IPIF colleague Flint Hughes.
By 2005, the US Forest Service and the Carnegie Institution had entered into a Memorandum of Understanding (MOU) that placed a CAO satellite laboratory within IPIF. The timing was perfect because IPIF was just completing its new facility in Hilo.
“Having the CAO integrated in IPIF brought an entirely new capability to the scientific research effort here at the Institute and across Hawaii”, said Hughes in an interview about the program start. “And that investment in shared projects and programmatic support has paid off in huge ways for both organizations, and for the community.”
Hughes specifically points to the flush of advances made in areas of invasive species ecology, carbon cycling, biogeochemistry, fire ecology, and restoration of Hawaii’s threatened ecosystems. The joint CAO-IPIF team has published dozens of papers, and presented in conference venues worldwide. Their results have been viewed as pathfinding, as evidenced in the steady support that each institution’s scientists have obtained using CAO data during the past 10 years.
With 10 years of success on the books, what’s next? Asner and Hughes, along with IPIF scientists Christian Giardina and Susan Cordell, are eyeing another major CAO campaign in the near future. And the timing couldn’t be better. In recent years, new threats have emerged in Hawaii including drought, rapid land use change and deforestation, and waves of new forest pests and pathogens introduced to the islands. With the pending El Nino event predicted to be the largest on record, weather patterns may also shift to hotter and drier conditions. New CAO mapping missions are needed to reassess the island’s changing biodiversity, carbon stocks, and other responses to these continuing forces of change. In the meantime, ongoing studies using current CAO data continue at an amazing pace among a plethora of students, postdoctoral researchers, and collaborators working within the CAO-IPIF program.
“With the CAO as a key partner, we’re working for another decade of scientific discovery and outreach here in Hawaii and around the Pacific rim”, said Hughes.
Example publications from the joint CAO-IPIF program, all available on the CAO Publications page:
Asner, G.P., A.J. Elmore, R.F. Hughes, A.S. Warner, and P.M. Vitousek. 2005. Ecosystem structure along bioclimatic gradients in Hawaii from imaging spectroscopy. Remote Sensing of Environment 96:497-508.
Elmore, A.J., G.P. Asner, and R.F. Hughes. 2005. Satellite monitoring of vegetation phenology and fire fuel conditions in Hawaiian drylands. Earth Interactions 9:1-21.
Carlson, K.C., G.P. Asner, R.F. Hughes, R. Ostertag, and R.E. Martin. 2007. Hyperspectral remote sensing of canopy biodiversity in Hawaiian lowland rainforests. Ecosystems 10:536-549.
Asner, G.P., M.O. Jones, R.E. Martin, D.E. Knapp, and R.F. Hughes. 2008. Remote sensing of native and invasive species in Hawaiian forests. Remote Sensing of Environment 112:1912-1926.
Asner, G.P., D.E. Knapp, T. Kennedy-Bowdoin, M.O. Jones, R.E. Martin, J. Boardman, and R.F. Hughes. 2008. Invasive species detection in Hawaiian rainforests using airborne imaging spectroscopy and LiDAR. Remote Sensing of Environment 112:1942-1955.
Asner, G.P., R.F. Hughes, P.M. Vitousek, D.E. Knapp, T. Kennedy-Bowdoin, J. Boardman, R.E. Martin, M. Eastwood, and R.O. Green. 2008. Invasive plants alter 3-D structure of rainforests. Proceedings of the National Academy of Sciences 105:4519-4523.
Asner, G.P., R.F. Hughes, T.A. Varga, D.E. Knapp, and T. Kennedy-Bowdoin. 2009. Environmental and biotic controls over aboveground biomass throughout a rainforest. Ecosystems 12:261-278.
Flaspohler, D.J., C.P. Giardina, G.P. Asner, P. Hart, J. Price, C.K. Lyons, and X. Castaneda. 2010. Long-term effects of fragmentation and fragment properties on bird species richness in Hawaiian forests. Biological Conservation 143:280-288.
Asner, G.P., R.F. Hughes, J. Mascaro, A.L. Uowolo, D.E. Knapp, J. Jacobson, T. Kennedy-Bowdoin, and J.K. Clark. 2011. High-resolution carbon mapping on the million-hectare Island of Hawaii. Frontiers in Ecology and Environment 9:434-439.
Kellner, J.R., G.P. Asner, K.M. Kinney, S.R. Loarie, D.E. Knapp, T. Kennedy-Bowdoin, E.J. Questad, S. Cordell, and J.M. Thaxton. 2011. Remote analysis of biological invasion and the impact of enemy release. Ecological Applications 21:2094-2104.
Litton, C.M., C.P. Giardina, J.K. Albano, M.S. Long, and G.P. Asner. 2011. The magnitude and variability of soil-surface CO2 efflux increase with temperature in Hawaiian tropical montane wet forest. Soil Biology and Biochemistry 43:2315-2323.
Kellner, J.R., G.P. Asner, S. Cordell, J.M. Thaxton, K.M. Kinney, T. Kennedy-Bowdoin, D.E. Knapp, E.J. Questad, and S. Ambagis. 2012. Potential and limitations of historical aerial photography to quantify vegetation dynamics in a dry tropical forest in Hawaii. Pacific Science 66(4):457-466.
Vaughn, N.R., G.P. Asner, and C.P. Giardina. 2013. Polar grid fraction as an estimator of montane tropical forest canopy structure using airborne lidar. International Journal of Remote Sensing 34(21):7464-7473.
Broadbent, E.N., A.M. Almeyda, G.P. Asner, C. B. Field, B.E. Rosenheim, T. Kennedy-Bowdoin, D.E. Knapp, D. Burke, C. Giardina, and S. Cordell. 2014. Linking rainforest ecophysiology and microclimate through fusion of airborne LiDAR and hyperspectral imagery. Ecosphere 5(5):art57.
Hughes, R.F., G.P. Asner, J. Mascaro, A. Uowolo, and J. Baldwin. 2014. Carbon storage landscapes of lowland Hawaii: the role of native and invasive species through space and time. Ecological Applications 24(4):716-731.
Giardina, C.P., C.M. Litton, S.E. Crow, and G.P. Asner. 2014. Warming-related increases in soil CO2 efflux are explained by increased below-ground carbon flux. Nature Climate Change 4:822-827.
Questad, E.J., J.R. Kellner, K. Kinney, S. Cordell, G.P. Asner, J.M. Thaxton, J. Diep, A. Uowolo, S. Brooks, N. Inman-Narahari, S.A. Evans, and B. Tucker. 2014. Mapping habitat suitability for at-risk plant species and its implications for restoration and reintroduction. Ecological Applications 24(2):385-395.
Selmants, P.C., C.M. Litton, C.P. Giardina, and G.P. Asner. 2014. Ecosystem carbon storage does not vary with mean annual temperature in Hawaiian tropical montane wet forests. Global Change Biology 20:2927-2937.
Inman-Narahari, F., R. Ostertag. G.P. Asner, S. Cordell, S.P. Hubbell, and L. Sack. 2014. Trade-offs in seedling growth and survival within and across tropical forest microhabitats. Ecology and Evolution 4(19):3755-3767.
Vaughn, N. R., G. P. Asner, and C. P. Giardina. 2014. Centennial impacts of fragmentation on the canopy structure of tropical montane forest. Ecological Applications 24:1638–1650.
Kinney, K.M., G.P. Asner, S. Cordell, O.A. Chadwick, K. Heckman, S. Hotchkiss, M. Jerai, T. Kennedy-Bowdoin, D.E. Knapp, E.J. Questad, J.M. Thaxton, F. Trusdell, and J.R. Kellner. 2015. Primary succession on a Hawaiian dryland chronosequence. PLoS ONE 10(6):e0123995.