@article{75286857dc8e413ebcfcccb84527703b,
title = "A spectral mapping signature for the Rapid Ohia Death (ROD) pathogen in Hawaiian forests",
abstract = "Pathogenic invasions are a major source of change in both agricultural and natural ecosystems. In forests, fungal pathogens can kill habitat-generating plant species such as canopy trees, but methods for remote detection, mapping and monitoring of such outbreaks are poorly developed. Two novel species of the fungal genus Ceratocystis have spread rapidly across humid and mesic forests of Hawai'i Island, causing widespread mortality of the keystone endemic canopy tree species, Metrosideros polymorpha (common name: ōhi'a). The process, known as Rapid Ohia Death (ROD), causes browning of canopy leaves in weeks to months following infection by the pathogen. An operational mapping approach is needed to track the spread of the disease. We combined field studies of leaf spectroscopy with laboratory chemical studies and airborne remote sensing to develop a spectral signature for ROD. We found that close to 80% of ROD-infected plants undergo marked decreases in foliar concentrations of chlorophyll, water and non-structural carbohydrates, which collectively result in strong consistent changes in leaf spectral reflectance in the visible (400-700 nm) and shortwave-infrared (1300-2500 nm) wavelength regions. Leaf-level results were replicated at the canopy level using airborne laser-guided imaging spectroscopy, with quantitative spectral separability of normal green-leaf canopies from suspected ROD-infected brown-leaf canopies in the visible and shortwave-infrared spectrum. Our results provide the spectral-chemical basis for detection, mapping and monitoring of the spread of ROD in native Hawaiian forests.",
keywords = "Ceratocystis, Hawai'i, Hyperspectral remote sensing, Imaging spectroscopy, Invasive species, Leaf spectroscopy, Metrosideros polymorpha, Pathogen, Ōhi'a",
author = "Asner, {Gregory P.} and Martin, {Roberta E.} and Keith, {Lisa M.} and Heller, {Wade P.} and Hughes, {Marc A.} and Vaughn, {Nicholas R.} and Hughes, {R. Flint} and Christopher Balzotti",
note = "Funding Information: measurements to establish quantitative chemical and spectral differences between foliage from Keywords: Ceratocystis; Hawaiʻi; hyperspectral remote sensing; imaging spectroscopy; invasive brown canopies suspected of Rapid Ohia Death in Hawaiian forests. We found that ROD-infected species; leaf spectroscopy; Metrosideros polymorpha; ʻōhiʻa; pathogen M. polymorpha trees undergo marked decreases in foliar concentrations of chlorophyll, water and non-structural carbohydrates, and these declines generated consistent changes in leaf spectral reflectance in the visible (400–700 nm) and shortwave-infrared (1300–2500 nm) wavelength regions. Leaf-level results were replicated at the canopy level using airborne laser-guided imaging spectroscopy, Biological invasions arean imwithpoquantitativertant driver ofspectralglobal envseparabilityironmental chanof normalge capablgre ofeen-leafcausingM. polymorpha canopies from suspected enormous ecological damage ROD-infectedrequiring billionsbrofown-leafdollars in canopies.managemenOurt efindingsffort [1–3]pr. Amoovideng athfunctionally-basede measurement to detect most problematic typesof invindividualasions are thotrse eesinvolsuspectedving pestsofanRODd pathinfectionogens that ausingttack hosairbornet plants.imaging spectroscopy. Although such invasions commonly threaten agricultural crops, they can also impact natural ecosystems [4,5]. A good example is Dutch elm disease, caused by Ascomycete fungi, which devastated Acknowledgments: This study was supported by funds from the U.S. Forest Service and the Carnegie multiple elm tree species acrossInstitutionEurope anford Science.North AmericThe Carnegiea over the Airbornepast centuryObservatory[6,7]. Howevhaser, been made possible by grants and donations few pestsorpathogens have beento Gdoc.P. Asnerumented fromas thedrivers AvaoftarmaAlliancessive naturFoundation,al forest losMarsin gartropicaet A.l oCarr gill Foundation, David and Lucile Packard sub-tropical ecosystems. Foundation, Gordon and Betty Moore Foundation, Grantham Foundation for the Protection of the Environment, W. M. Keck Foundation, John D. and Catherine T. MacArthur Foundation, Andrew Mellon Foundation, Mary Anne Nyburg Baker and G. Leonard Baker Jr, and William R. Hearst III. Remote Sens.2018, 10,x; doi:FOR PEERREVIEW www.mdpi.com/journal/remotesensing Author Contributions: Gregory P. Asner conceived and designed the experiments; all co-authors performed the experiments; Gregory P. Asner, Roberta E. Martin, Wade P. Heller, Marc A. Hughes, Christopher Balzotti, and Nicholas R. Vaughn analyzed the data; Lisa M. Keith, Wade P. Heller and R. Flint Hughes contributed reagents/materials/analysis tools; Gregory P. Asner and Roberta E. Martin wrote the paper. Publisher Copyright: {\textcopyright} 2018 by the authors.",
year = "2018",
month = mar,
day = "1",
doi = "10.3390/rs10030404",
language = "English (US)",
volume = "10",
journal = "Remote Sensing",
issn = "2072-4292",
publisher = "Multidisciplinary Digital Publishing Institute (MDPI)",
number = "3",
}