July 2016 marks the 10th anniversary of a scientific idea hatched in a distant valley along Kauai Island’s northern coast in the central Pacific. The 2006 conception was preceded by ten other years of research on the chemical properties of plant canopies in far flung environments ranging from desert shrublands to tropical rainforests. That preceding decade had cumulatively yielded just a hint that a tree-of-life approach to studying forests might be possible at the mother of all scales – Earth’s biosphere.
Kauai’s Limahuli Valley was the birthplace of Spectranomics — to map the linkages between plant species, canopy traits and their spectral properties. When we say canopy traits, we’re talking about the constellation of growth and defense chemicals that have evolved in plant leaves. Canopy traits are fundamental to whole plant function, and are one of three components comprising Spectranomics. When we talk about the spectral properties of plants, the second component of Spectranomics, we mean the mostly invisible way that plants interact with the Sun’s radiation. From the ultraviolet to the shortwave-infrared regions of the electromagnetic spectrum (wavelengths from 350-2500 nanometers), plants have many common and yet unique patterns of interaction with solar energy. In plant leaves, this interaction is determined by a suite of chemicals – at least 23 of them by our count, that are part and parcel to plant evolution, and which power the biosphere. Spectral properties also provide a pathway to scale from leaves to landscapes, and to the planetary level, but only if we can measure and interpret the spectra of plants over larger and larger portions of Earth.
Limahuli Valley was a fitting birth place for Spectranomics. The valley is managed by the National Tropical Botanical Garden, and the steeply sloping watershed offered a shopping spree of different tree species congregated from source forests around the tropical world. Distant plant origins among Valley trees meant more distant genetic relationships in Earth’s grand tree-of-life or phylogeny (the third arm of Spectranomics), and we used this unique setting to see if the canopy traits and spectral properties of distantly-related immigrant species are uniquely expressed in a common living environment. And they were.
Today and more than 13,000 canopy specimens later, each meticulously collected and transported from sites arrayed around the world, then analyzed in our laboratory, and archived in a Frozen Forest of more than 3,000,000 tissue samples, representing about 10,000 species, and more than a third of forest canopy species thought to occur on Earth, the resulting Spectranomics database continues to yield new discoveries about plant canopy traits, spectral properties, and their relatedness.
The advance behind Spectranomics rests not just in the massive database of the individual parts – canopy traits, spectral properties, and phylogeny, but rather in the way we measure and integrate them. From the fundamental patterns and relationships, to the applications in biodiversity mapping using aircraft such as the CAO, Spectranomics is a unique pathway to discovery as well as to conservation mapping, particularly in high-diversity tropical forests.
More broadly, Spectranomics has enabled a new and exciting interaction between field and laboratory studies of plants and ecosystems, and remote sensing at regional and national scales. This interaction has allowed us to simultaneously explore plant canopy traits and phylogeny, while learning how to measure them using advanced spectral imaging. The analytic-based forecasting capability made possible by Spectranomics has been key to planning how we should undertake spectral remote sensing, and under what ecological conditions remote sensing technology will yield new insight. This has transformed the interaction between field work and remote sensing from the traditional approach of “mapping and ground truthing” to one based on a more fundamental biological-biophysical scaling strategy in the interpretation of remotely sensed spectral data.
Spectranomics has also provided scientific guidance, and core funding support, for a new class of mapping instruments, starting with our next-generation, high-fidelity Visible-to-Shortwave Infrared (VSWIR) imaging spectrometer, built by the California Institute of Technology’s Jet Propulsion Laboratory (JPL) for the Carnegie Airborne Observatory. JPL designed and built the same instrument for its AVIRIS program, and made similar copies for the National Ecological Observatory Network.
Advancing Conservation through Spectranomics
An important, and once only dreamed of, outgrowth of Spectranomics is the emerging opportunity to partner discovery-based science with applied environmental conservation at large geographic scales. Conservation and management actions are always limited in scope by numerous interacting financial, logistical, cultural and political factors. An ability to map forest canopy diversity provides a geographically-explicit avenue for identifying high-value forest conservation targets. As land-use pressures expand, intensify and change over time, a mapping capability seated in the details of forest canopy function and composition, rather than just forest cover, will rapidly grow in importance for conservation planning. This approach is needed to identify threats, as well as current protections and opportunities for new protections. Stepping up to this challenge, the new biodiversity mapping capabilities made possible through Spectranomics are providing a toolset to support the current portfolio of Carnegie Airborne Observatory activities (for example, http://www.theborneopost.com).
In recognition of our evolving capability, we are marking the 10th anniversary of Spectranomics by integrating it into the CAO program, which will further improve the interaction between the two programs, and seed the next phase of the tree-of-life mapping from the air. For you, it means a one-stop shop for both CAO and Spectranomics publications, and its supporting technical information. We are also planning to launch Version 2.0 of the Spectranomics Data Explorer via this integrated CAO-Spectranomics website.
Meanwhile, we continue to push the Spectranomics project forward — climbing, collecting, measuring, and archiving canopy plants from around the world. Our latest field work puts us in the California Sierra Nevada mountains, the Heart of Borneo, and the Ecuadorian Amazon. There is still much to learn from careful database building across the tree-of-life, now with an established pathway for using it to map the functioning and biodiversity of Earth’s ecosystems, today from the air, perhaps tomorrow from space.
— Greg Asner & Robin Martin, Danum Valley, Heart of Borneo Rainforest
We dedicate the 10-year anniversary of our program to the scientists, engineers, technicians, students, and supporters of the Carnegie Spectranomics Project, made possible through the futuristic vision of the John D. and Catherine T. MacArthur Foundation. The Carnegie Airborne Observatory has been supported by the innovative thinkers of the Andrew Mellon Foundation, Avatar Alliance Foundation, David and Lucile Packard Foundation, Gordon and Betty Moore Foundation, Grantham Foundation for the Protection of the Environment, John D. and Catherine T. MacArthur Foundation, Mary Anne Nyburg Baker and G. Leonard Baker Jr, W.M. Keck Foundation, and William R. Hearst III.
Further Reading on Spectranomics available on Publications page – Click Techniques, then Spectranomics filter
Further Reading on Biodiversity Mapping available on Publications page – Click Projects, then Biodiversity filter