Article
Environmental Sciences
Rachel R. R. Carlson, Jiwei Li, Larry B. B. Crowder, Gregory P. P. Asner
Summary: Turbidity from land-based runoff can have both negative and positive effects on coral bleaching during ocean heatwaves. This study used high-resolution satellite data to examine the relationship between turbidity and coral bleaching severity in Hawaii. The results showed that the effect of turbidity on bleaching severity weakened at higher temperatures, but still had a slightly negative impact in urban settings. Additionally, interactions between temperature and local variables like turbidity and wave energy were found to be the most significant drivers of bleaching severity.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Ecology
Jiwei Li, Rachel R. Carlson, David E. Knapp, Gregory P. Asner
Summary: Turbidity monitoring in shallow coastal waters is essential for marine ecosystem research, management, and protection. Satellite-based monitoring provides a larger spatial coverage and higher temporal frequency than field measurements. The new Planet Dove satellite constellation, with its high spatial resolution and daily revisit frequency, allows for detailed tracking of water turbidity dynamics in shallow coastal waters with appropriate atmospheric correction. A new algorithm was developed to estimate turbidity values in these waters using data from the Planet Dove satellite and similar multi-spectral satellites. The algorithm takes into account bottom reflectance to derive accurate turbidity values, which were validated against field measurements. The results demonstrate the effectiveness of the algorithm in accurately detecting turbidity in critical nearshore environments.
REMOTE SENSING IN ECOLOGY AND CONSERVATION
(2022)
Article
Multidisciplinary Sciences
Gregory P. Asner, Nicholas R. Vaughn, Roberta E. Martin, Shawna A. Foo, Joseph Heckler, Brian J. Neilson, Jamison M. Gove
Summary: Corals are important habitat-building organisms in tropical reefs, supporting a quarter of all ocean species and providing ecosystem services to millions of people. However, marine heat waves threaten coral reefs by killing individual colonies and reducing diversity. This study used aerial imaging spectroscopy to monitor coral mortality during a major heat wave in Hawaii, and found that certain reefs had lower coral loss and therefore may serve as refugia. Human and environmental factors, such as coastal development and sedimentation levels, played a role in differentiating resilient reefs from more vulnerable ones.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Environmental Sciences
Gregory P. Asner, Nicholas R. Vaughn, Shawna A. Foo, Joseph Heckler, Roberta E. Martin
Summary: Reef rugosity, a metric of three-dimensional habitat complexity, is crucial for determining reef condition and occupancy by various marine organisms. Using a new mapping technique, this study explored the variation of reef rugosity in the Main Hawaiian Islands, finding that water depth and reef slope are primary drivers of rugosity, while coastal development plays a secondary role. These results can aid in tracking geological and human impacts on reefs, designing marine managed areas, and improving reef resilience.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Marine & Freshwater Biology
Hiroya Abe, Naoki H. Kumagai, Hiroya Yamano
Summary: Coral reef ecosystems in the Amami Islands of Southern Japan are highly sensitive to climate change. This study used simulation models to identify priority conservation areas based on coral bleaching rates and larval connectivity. Conducting conservation and adaptation strategies according to the specific characteristics of each island is crucial to protecting these ecosystems.
Article
Biodiversity Conservation
Andreas Dietzel, Sean R. Connolly, Terry P. Hughes, Michael Bode
Summary: This study found that recent mass coral bleaching events on the Great Barrier Reef have larger and more continuous spatial footprints than previous bleaching events, posing an unprecedented threat to coral species resilience. In contrast to the impacts of a severe tropical cyclone, the bleaching events isolated severely affected reefs from the nearest mildly affected reefs by greater distances, highlighting the significant threat to coral species posed by the spatial footprint of these recent bleaching events.
GLOBAL CHANGE BIOLOGY
(2021)
Article
Biodiversity Conservation
Joseph W. P. Nakoa, John H. R. Burns, Kanoelani Steward, Lauren M. Kapono, Clifford A. Kapono
Summary: Coral reefs are declining due to various factors, and diseases affecting corals have increased in recent decades. However, the etiology of most diseases is still poorly understood. In this study, a 3D molecular cartographic platform was used to investigate the molecular characteristics of healthy and diseased coral tissues. The results showed differences in microbial diversity and molecular composition between healthy and diseased tissues, providing new insights into how diseases affect the molecular landscape of corals.
Article
Limnology
Nicholas Strait, Taylor M. Williams, Alison R. Sherwood, Randall K. Kosaki, Louise Giuseffi, Celia M. Smith, Heather L. Spalding
Summary: This study investigates nitrogen dynamics in the Hawaiian Archipelago using macroalgal tissue parameters. The results show that in the Main Hawaiian Islands, macroalgal tissue stable N isotope ratios are higher in mesophotic depths, while N content is higher in shallow depths. However, in the Northwestern Hawaiian Islands, no differences in stable N isotope ratios and N content were found between shallow and mesophotic depths. Regionally, stable N isotope ratios vary along a gradient of anthropogenic and oceanographic processes.
LIMNOLOGY AND OCEANOGRAPHY
(2022)
Article
Ecology
Michael J. Williamson, Emma J. Tebbs, Terence P. Dawson, Henry J. Thompson, Catherine E. Head, David M. P. Jacoby
Summary: This study utilizes satellite remote sensing to collect data on coral reefs' exposure to multiple environmental stressors and develops a toolbox for monitoring such exposure. Through an analysis of coral reefs worldwide, the study identifies factors such as depth, current, and sea surface temperature that contribute to environmental stress exposure.
REMOTE SENSING IN ECOLOGY AND CONSERVATION
(2022)
Article
Environmental Sciences
Jingping Xu, Jianhua Zhao, Fei Wang, Yanlong Chen, Zhongping Lee
Summary: The Sentinel-2 mission shows promise in coral reef remote sensing, with benefits such as a 5-day revisit time and 10 m spatial resolution. However, the detection capability of Sentinel-2 is constrained by water depth, making it recommended to limit bleaching detection to depths less than 10 m. By using change analysis and multiple image comparisons, detection accuracy of coral bleaching can be significantly improved.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Environmental Sciences
Oliver Selmoni, Gael Lecellier, Veronique Berteaux-Lecellier, Stephane Joost
Summary: Coral reefs worldwide are facing widespread decline of hard corals due to anomalous heat waves. Different coral taxa have different sensitivities to heat, and variations in susceptibility have been observed within the same species in different environments. Understanding taxa-specific variations is crucial for efficient reef conservation strategies.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Environmental Sciences
Alberto Candela, Kevin Edelson, Michelle M. Gierach, David R. Thompson, Gail Woodward, David Wettergreen
Summary: Global mapping of coral reef condition requires a combination of remote sensing and in situ data to achieve accurate coverage on a worldwide scale. Utilizing new techniques in remote sensing analysis, probabilistic modeling, and decision theory for sample selection can refine information from remote sensing and extrapolate in situ features with increasing accuracy. Results from a proof of concept using spaceborne remote sensing and high-quality airborne data confirm the efficacy of this approach and the power of decision theory for sample selection.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Environmental Sciences
Steven R. Schill, Valerie Pietsch McNulty, F. Joseph Pollock, Fritjof Luethje, Jiwei Li, David E. Knapp, Joe D. Kington, Trevor McDonald, George T. Raber, Ximena Escovar-Fadul, Gregory P. Asner
Summary: High-resolution benthic habitat data play a crucial role in marine conservation planning, but many countries lack the resources to create these products. By utilizing high-resolution satellite data, a first-of-its-kind regional thirteen-class benthic habitat map of the Caribbean was developed, providing a baseline for ecological data development and execution.
Article
Geosciences, Multidisciplinary
Wenhui Zhao, Yi Huang, Steven Siems, Michael Manton
Summary: The study revealed a significant negative correlation between total cloud cover anomaly (TCCA) and lagged sea surface temperature anomaly (SSTA) in the Great Barrier Reef region, which is greater in magnitude and spatial extent compared to the SSTA-ENSO correlation. This suggests that local-scale reduced cloud cover plays a crucial role in the formation of warm shallow water and occurrence of thermal coral bleaching events in the region.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Biochemistry & Molecular Biology
Tracy D. Ainsworth, William Leggat, Brian R. Silliman, Coulson A. Lantz, Jessica L. Bergman, Alexander J. Fordyce, Charlotte E. Page, Juliana J. Renzi, Joseph Morton, C. Mark Eakin, Scott F. Heron
Summary: Coral bleaching has had a significant impact on reefs worldwide, with the realization of near-annual bleaching events in recent years. While technology allows for the prediction of large-scale bleaching, the ability to predict reef-scale and within-reef patterns in real-time for all reef users is limited.
Article
Forestry
Blaine C. Luiz, Christian P. Giardina, Lisa M. Keith, Douglass F. Jacobs, Richard A. Sniezko, Marc A. Hughes, James B. Friday, Philip Cannon, Robert Hauff, Kainana Francisco, Marian M. Chau, Nicklos Dudley, Aileen Yeh, Gregory Asner, Roberta E. Martin, Ryan Perroy, Brian J. Tucker, Ale'Alani Evangelista, Veronica Fernandez, Chloe Martins-Keli'iho'omalu, Kirie Santos, Rebekah Ohara
Summary: Metrosideros polymorpha is a keystone species in Hawaii's native forests and is of great cultural, ecological, and economic importance. However, these forests, especially on Hawaii Island, are being severely affected by Rapid 'Ohi'a Death (ROD), a disease caused by fungal pathogens. This article outlines the 'Ohi'a Disease Resistance Program (ODRP) which aims to identify and develop ROD resistance in Metrosideros polymorpha to mitigate the impacts of the disease and preserve the ecology, culture, and communities depending on this tree species.
Article
Environmental Sciences
Konrad Wessels, Xiaoxuan Li, Alexandre Bouvet, Renaud Mathieu, Russell Main, Laven Naidoo, Barend Erasmus, Gregory P. Asner
Summary: Global savannas, as the third largest carbon sink, are facing rapid changes. This study tested the ability of L-band SAR to track changes in savanna vegetation structure and found that it has a higher sensitivity than previous studies suggested.
REMOTE SENSING OF ENVIRONMENT
(2023)
Article
Environmental Sciences
Jiwei Li, Gregory P. Asner
Summary: Three-dimensional shallow benthic complexity provides valuable information for coral reef conservation and management, as it reflects the physical conditions and biodiversity of shallow coral reef environments. This study mapped global shallow water benthic complexity using satellite images and found that high complexity regions are mainly concentrated in areas with high benthic biodiversity. However, a significant portion of coral reef regions with high benthic complexity remains unprotected. The global coral reef benthic complexity map generated in this study can contribute to improving marine protected areas, reef conservation, and management.
ENVIRONMENTAL RESEARCH LETTERS
(2023)
Article
Forestry
Nicholas R. Vaughn, R. Flint Hughes, Gregory P. Asner
Summary: Fungal pathogens of the genus Ceratocystis have caused significant mortality of native 'O over bar hi'a trees on the island of Hawai'i. High resolution imaging spectroscopy has enabled the easy detection of the associated disease, Rapid 'O over bar hi'a Death (ROD). By analyzing wall-to-wall maps of affected 'O over bar hi'a canopy over four years, the study reveals the relationship between changes in canopy distribution and density and environmental drivers at different scales.
FOREST ECOLOGY AND MANAGEMENT
(2023)
Article
Ecology
M. M. Seeley, E. A. Stacy, R. E. Martin, G. P. Asner
Summary: Imaging spectroscopy can be used to map closely related plant species at a larger scale. This research focused on understanding the differences in spectral reflectance between genotypes of a single species, Metrosideros polymorpha, and its hybrids. The study found that leaf reflectance patterns successfully distinguished different varieties of M. polymorpha on Hawaii Island and populations of the same variety on different islands. The findings contribute to the use of imaging spectroscopy in biodiversity studies at the genetic level.
Article
Multidisciplinary Sciences
Megan M. Seeley, Roberta E. Martin, Christian Giardina, Blaine Luiz, Kainana Francisco, Zachary Cook, Marc A. Hughes, Gregory P. Asner
Summary: Plant pathogens pose a growing threat to forest health, impacting the ecological, economic, and cultural goods and services provided by global forests. Remote sensing methods have been used to identify disease resistance in agricultural crops but have had limited application in forest trees. However, in the case of Metrosideros polymorpha or Modified Letter Turned CommaOhiModified Letter Turned Commaa, a native Hawaiian tree, remote sensing was able to detect resistance to Ceratocystis wilt caused by the fungal pathogen Ceratocystis lukuohia, which is significant for disease control efforts.
Article
Environmental Sciences
Megan M. Seeley, Roberta E. Martin, Nicholas R. Vaughn, David R. Thompson, Jie Dai, Gregory P. Asner
Summary: Imaging spectroscopy is a useful tool for studying ecosystem functioning, but its application in assessing intra-specific trait variation across environmental gradients needs more testing. Selection of specific genotypes and their effects on trait variation and functional diversity are unclear.
Article
Ecology
Nicoletta Stork, Amy Mainzer, Roberta Martin
Summary: Mediterranean-type ecosystems are facing ecological stress, with non-native species invasions driven by fire regimes, climate change, and human disturbances. This study assesses ecosystem health in the Santa Monica Mountains from 2014 to 2020, focusing on the effects of the 2018 Woolsey Fire. The analysis shows an increase in non-native cover and rapid regrowth of non-native species after the fire, raising concerns for the future of native vegetation and highlighting the damage caused by densely populated non-native plant communities.
Correction
Green & Sustainable Science & Technology
Bing Lin, Yiwen Zeng, Gregory P. Asner, David S. Wilcove
NATURE SUSTAINABILITY
(2023)
Article
Behavioral Sciences
Erin C. Netoskie, Kristina L. Paxton, Eben H. Paxton, Gregory P. Asner, Patrick J. Hart
Summary: The recent development of animal-borne sensors combined with location data has allowed researchers to study how animals modify their behavior in response to specific habitat features. In a study on the endemic Hawaiian thrush, researchers used a novel acoustic transmitter to investigate the vocal behaviors of the bird and how they interacted with different habitat characteristics in a fragmented forest landscape. The study revealed that the use of different vocalization types by the bird varied across the landscape and was associated with distinct habitat features. The research also showed context-specific changes in behavior, including courtship, aggression, and social interactions.
Article
Engineering, Civil
Nadine Keller, Ilja van Meerveld, Christopher David Philipson, Gregory P. Asner, Elia Godoong, Hamzah Tangki, Jaboury Ghazoul
Summary: As secondary tropical forests grow, the changes in canopy structure and density affect the interception loss. However, the effects of tropical forest regeneration on mean throughfall are poorly studied. This hampers the estimation of interception loss for regenerating forests.
JOURNAL OF HYDROLOGY
(2023)
Article
Environmental Sciences
Megan M. Seeley, Gregory P. Asner
Summary: The role of intraspecific trait variation in functional ecology has gained attention in recent years. This study used remote sensing data of the tree species Metrosideros polymorpha to quantify the environmental controls on intraspecific trait variation. The results showed that elevation was the most important predictor for all canopy traits.
Article
Environmental Sciences
Megan M. Seeley, Nicholas R. Vaughn, Brennon L. Shanks, Roberta E. Martin, Marcel Konig, Gregory P. Asner
Summary: This study provides accurate and high-resolution spatial data on the keystone species Metrosideros polymorpha in Hawai'i Island, using airborne imaging spectroscopy and LiDAR. The study compares two tree species classification techniques and finds that the support vector machine (SVM) model better reproduces the spatial distribution of M. polymorpha than spectral mixture analysis (SMA) model.
