Roberta E Martin

Roberta E Martin
Arizona State University | ASU · School of Geographical Sciences and Urban Planning

PhD

About

168
Publications
72,762
Reads
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11,455
Citations
Additional affiliations
September 2003 - present
Carnegie Institution for Science
Position
  • Scientist, Project Coordinator

Publications

Publications (168)
Article
Full-text available
Tropical forests are some of the most biodiverse ecosystems in the world, yet their functioning is threatened by anthropogenic disturbances and climate change. Global actions to conserve tropical forests could be enhanced by having local knowledge on the forestsʼ functional diversity and functional redundancy as proxies for their capacity to respon...
Article
Significance Corals exhibit highly variable responses to marine heat waves as well as to local biological and ecological circumstances that moderate them across reef seascapes. This variability makes identifying refugia—reefs possessing conditions that increase coral resilience—nearly impossible with traditional surveys. We developed and applied an...
Article
Full-text available
Assessing the impacts of anthropogenic degradation and climate change on global carbon cycling is hindered by a lack of clear, flexible and easy‐to‐use productivity models along with scarce trait and productivity data for parameterizing and testing those models. We provide a simple solution: a mechanistic framework (RS‐CFM) that combines remotely‐s...
Article
Full-text available
The global decline of coral reefs urgently requires scalable colony‐level data about phenotypic variation to improve coral conservation and management. To address this, we leveraged historical bleaching phenotypes, airborne imaging spectroscopy, and recurrent temperature stress to map coral species composition and thermal tolerance across four foca...
Article
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Coral reefs are threatened by climate change, overfishing, and pollution. Artificial reefs may provide havens for corals, both to escape warming surface waters and to assist in the geographic migration of corals to more habitable natural reef conditions of the future. The largest artificial reefs have been generated by nearly 2000 shipwrecks around...
Article
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Metrosideros polymorpha Gaud. (‘ōhi‘a) is the most abundant native forest tree in Hawai‘i and a keystone species of cultural, ecological, and economic importance. ‘Ōhi‘a forests, particularly on Hawaiʻi Island, are being severely impacted by Rapid ‘Ōhi‘a Death (ROD), which is caused by the fungal pathogens Ceratocystis lukuohia and C. huliohia. ROD...
Article
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Native forests of Hawai'i Island are experiencing an ecological crisis in the form of Rapid 'Ōhi'a Death (ROD), a recently characterized disease caused by two fungal pathogens in the genus Ceratocystis. Since approximately 2010, this disease has caused extensive mortality of Hawai'i's keystone endemic tree, known as 'ōhi'a (Metrosideros polymorpha)...
Article
Severe droughts are predicted to become more frequent in the future, and the consequences of such droughts on forests can be dramatic, resulting in massive tree mortality, rapid change in forest structure and composition, and substantially increased risk of catastrophic fire. Forest managers have tools at their disposal to try to mitigate these eff...
Article
Full-text available
Coral reefs are undergoing changes caused by coastal development, resource use, and climate change. The extent and rate of reef change demand robust and spatially explicit monitoring to support management and conservation decision-making. We developed and demonstrated an airborne-assisted approach to design and upscale field surveys of reef fish ov...
Article
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Between 2012 and 2016, California suffered one of the most severe droughts on record. During this period Sequoiadendron giganteum (Giant Sequoias) in the Sequoia and Kings Canyon National Parks (SEKI), California USA experienced canopy water content (CWC) loss, unprecedented foliage senescence, and, in a few cases, death. We present an assessment o...
Article
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National Academies' Decadal Survey, Thriving on Our Changing Planet, recommended Surface Biology and Geology (SBG) as a "Designated Targeted Observable" (DO). The SBG DO is based on the need for capabilities to acquire global, high spatial resolution, visible to shortwave infrared (VSWIR; 380-2500 nm; ~30 m pixel resolution) hyperspectral (imaging...
Article
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Reef rugosity, a metric of three-dimensional habitat complexity, is a central determinant of reef condition and multi-trophic occupancy including corals, fishes and invertebrates. As a result, spatially explicit information on reef rugosity is needed for conservation and management activities ranging from fisheries to coral protection and restorati...
Article
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Abstract Plant defense chemistry is often hypothesized to drive ecological and evolutionary success in diverse tropical forests, yet detailed characterizations of plant secondary metabolites in tropical plants are logistically challenging. Here, we explore a new integrative approach that combines visible‐to‐shortwave infrared (VSWIR) spectral refle...
Article
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Tropical forest ecosystems are undergoing rapid transformation as a result of changing environmental conditions and direct human impacts. However, we cannot adequately understand, monitor or simulate tropical ecosystem responses to environmental changes without capturing the high diversity of plant functional characteristics in the species-rich tro...
Article
Coral is the life-form that underpins the habitat of most tropical reef ecosystems, thereby supporting biological diversity throughout the marine realm. Coral reefs are undergoing rapid change from ocean warming and nearshore human activities, compromising a myriad of services provided to societies including coastal protection, fishing, and cultura...
Preprint
Full-text available
Forests are integral to global carbon cycling but are threatened by anthropogenic degradation and climate change. Assessing this global threat has been hindered by a lack of clear, flexible, and easy-to-use productivity models along with a lack of functional trait and productivity data for parameterizing and testing those models. Current productivi...
Article
Full-text available
Tropical forest ecosystems are undergoing rapid transformation as a result of changing environmental conditions and direct human impacts. However, we cannot adequately understand, monitor or simulate tropical ecosystem responses to environ ⁎ mental changes without capturing the high diversity of plant functional characteristics in the species-rich...
Article
Full-text available
We present a new method for the detection of coral bleaching using satellite time-series data. While the detection of coral bleaching from satellite imagery is difficult due to the low signal-to-noise ratio of benthic reflectance, we overcame this difficulty using three approaches: (1) specialized pre-processing developed for Planet Dove satellites...
Article
Tropical biomes are the most diverse plant communities on Earth, and quantifying this diversity at large spatial scales is vital for many purposes. As macroecological approaches proliferate, the taxonomic uncertainties in species occurrence data are easily neglected and can lead to spurious findings in downstream analyses. Here, we argue that techn...
Article
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More than half of all tropical forests are degraded by human impacts, leaving them threatened with conversion to agricultural plantations and risking substantial biodiversity and carbon losses. Restoration could accelerate recovery of aboveground carbon density (ACD), but adoption of restoration is constrained by cost and uncertainties over effecti...
Article
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Leaf reflectance spectra have been increasingly used to assess plant diversity. However, we do not yet understand how spectra vary across the tree of life or how the evolution of leaf traits affects the spectral differentiation among species and lineages. Here we describe a framework that integrates spectra with phylogenies and apply it to a global...
Chapter
Haffer’s (Science 165: 131–137, 1969) Pleistocene refuge theory has provided motivation for 50 years of investigation into the connections between climate, biome dynamics, and neotropical speciation, although aspects of the original theory are not supported by subsequent studies. Recent advances in paleoclimatology suggest the need for reevaluating...
Article
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Deconstructing functional trait variation and co-variation across a wide range of environmental conditions is necessary to increase the mechanistic understanding of community assembly processes and improve current parameterization of dynamic vegetation models. Here, we present a study that deconstructs leaf trait variation and co-variation into wit...
Article
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Foliar trait adaptation to sun and shade has been extensively studied in the context of photosynthetic performance of plants, focusing on nitrogen allocation, light capture and use via chlorophyll pigments and leaf morphology; however, less is known about the potential sun-shade dichotomy of other functionally important foliar traits. In this study...
Article
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Spatially continuous data on functional diversity will improve our ability to predict global change impacts on ecosystem properties. We applied methods that combine imaging spectroscopy and foliar traits to estimate remotely sensed functional diversity in tropical forests across an Amazon-to-Andes elevation gradient (215 to 3537 m). We evaluated th...
Article
1.The network of minor veins of angiosperm leaves may include loops (reticulation). Variation in network architecture has been hypothesized to have hydraulic and also structural and defensive functions. 2.We measured venation network trait space in eight dimensions for 136 biomass-dominant angiosperm tree species along a 3,300 m elevation gradient...
Article
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Tropical forest leaf albedo (reflectance) greatly impacts how much energy the planet absorbs; however; little is known about how it might be impacted by climate change. Here, we measure leaf traits and leaf albedo at ten 1-ha plots along a 3,200-m elevation gradient in Peru. Leaf mass per area (LMA) decreased with warmer temperatures along the elev...
Article
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Rapid ‘Ōhi‘a Death (ROD) is a disease aggressively killing large numbers of Metrosideros polymorpha (‘ōhi‘a), a native keystone tree species on Hawaii Island. This loss threatens to deeply alter the biological make-up of this unique island ecosystem. Spatially explicit information about the present and past advancement of the disease is essential f...
Article
Full-text available
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 ra...
Article
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Trade-offs among plant functional traits indicate diversity in plant strategies of growth and survival. The leaf economics spectrum (LES) reflects a trade-off between short-term carbon gain and long-term leaf persistence. A related trade-off, between foliar growth and anti-herbivore defense, occurs among plants growing in contrasting resource regim...
Article
Hotter droughts are becoming more common as climate change progresses, and they may already have caused instances of forest dieback on all forested continents. Learning from hotter droughts, including where on the landscape forests are more or less vulnerable to these events, is critical to help resource managers proactively prepare for the future....
Article
Drought is expected to become an increasingly important stressor on forests globally, and understanding the physiological mechanisms driving tree drought response is essential for developing effective mitigation and conservation measures for these ecosystems. In 2014, during California's 2012-2016 "hotter" drought in which higher temperatures exace...
Article
Full-text available
The network of minor veins of angiosperm leaves may include loops (reticulation). Variation in network architecture has been hypothesized to have hydraulic and also structural and defensive functions. 2.We measured venation network trait space in eight dimensions for 136 biomass-dominant angiosperm tree species along a 3,300 m elevation gradient in...
Article
Full-text available
Spatial information on forest functional composition is needed to inform management and conservation efforts, yet this information is lacking, particularly in tropical regions. Canopy foliar traits underpin the functional biodiversity of forests, and have been shown to be remotely measurable using airborne 350–2510 nm imaging spectrometers. We used...
Article
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Forest carbon stocks in rapidly developing tropical regions are highly heterogeneous, which challenges efforts to develop spatially-explicit conservation actions. In addition to field-based biodiversity information, mapping of carbon stocks can greatly accelerate the identification, protection and recovery of forests deemed to be of high conservati...
Article
California experienced severe drought from 2012 to 2016, and there were visible changes in the forest canopy throughout the State. In 2014, unprecedented foliage dieback was recorded in giant sequoia (Sequoiadendron giganteum) trees in Sequoia National Park, in the southern California Sierra Nevada mountains. Although visible changes in sequoia can...
Article
Recent drought (2012-2016) caused unprecedented foliage dieback in giant sequoias (Sequoiadendron giganteum), a species endemic to the western slope of the southern Sierra Nevada in central California. As part of an effort to understand and map sequoia response to droughts, we studied the patterns of remotely sensed canopy water content (CWC), both...
Article
Full-text available
High resolution spectroscopy can be used to measure leaf chemical and structural traits. Such leaf traits are often highly correlated to other traits, such as photosynthesis through the, leaf economics spectrum. We measured VNIR (visible – near infrared) leaf reflectance (400-1075nm) of sunlit and shaded leaves in ~150 dominant species across ten 1...
Article
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Tropical elevation gradients are natural laboratories to assess how changing climate can influence tropical forests. However, there is a need for theory and integrated data collection to scale from traits to ecosystems. We assess predictions of a novel trait-based scaling theory, including whether observed shifts in forest traits across a broad tro...
Article
Ongoing tropical deforestation and forest degradation, combined with climate change, call for improved forest functional and biological diversity mapping to support increasingly tactical decision-making for conservation action. We combine a new map of forest canopy functional and biological composition with extensive protected area and indigenous l...
Article
Full-text available
One of the major challenges in ecology is to understand how ecosystems respond to changes in environmental conditions, and how taxonomic and functional diversity mediate these changes. In this study, we use a trait-spectra and individual-based model, to analyse variation in forest primary productivity along a 3.3 km elevation gradient in the Amazon...
Data
Fig. S1 Correlation among climate variables for the study sites in Peru. Fig. S2 Correlation among climate variables among study sites used in the global analysis. Fig. S3 Differences in leaf water repellency for species occurring at two neighboring sites. Fig. S4 Partitioning of sources of variance for leaf water repellency. Fig. S5 Relationsh...
Article
Full-text available
Coral reefs of the Spratly archipelago in the South China Sea are undergoing rapid transformation through military base and outpost development, destructive fishing practices and other factors. Despite increasing pressure on the ecologically unique reefs throughout this region, limited direct access to them has made it difficult to monitor reef cov...
Article
The carbon isotopic composition of plant leaf wax biomarkers is commonly used to reconstruct paleoenvironmental conditions. Adding to the limited calibration information available for modern tropical forests, we analyzed plant leaf and leaf wax carbon isotopic compositions in forest canopy trees across a highly biodiverse, 3.3 km elevation gradient...
Article
Functional biogeography may bridge a gap between field-based biodiversity information and satellite-based Earth system studies, thereby supporting conservation plans to protect more species and their contributions to ecosystem functioning. We used airborne laser-guided imaging spectroscopy with environmental modeling to derive large-scale, multivar...
Article
Understanding functional trait-environment relationships (TERs) may improve predictions of community assembly. However, many empirical TERs have been weak or lacking conceptual foundation. TERs based on leaf venation networks may better link individuals and communities via hydraulic constraints. We report measurements of vein density, vein radius,...
Article
Full-text available
Context Many arboreal mammals in Neotropical forests are important seed dispersers that influence the spatial patterns of tree regeneration via their movement patterns, which in turn are determined by the canopy structure of the forest itself. However, the relationship between arboreal mammal movement and canopy structure is poorly understood, due...
Article
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With the goal of advancing remote sensing in biodiversity science, Spectranomics represents an emerging approach, and a suite of quantitative methods, intended to link plant canopy phylogeny and functional traits to their spectral-optical properties. The current Spectranomics database contains about one half of known tropical forest canopy tree spe...
Article
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Remote sensing is increasingly needed to meet the critical demand for estimates of forest structure and composition at landscape to continental scales. Hyperspectral images can detect tree canopy properties, including species identity, leaf chemistry and disease. Tree growth rates are related to these measurable canopy properties but whether growth...
Article
Distributions of foliar nutrients across forest canopies can give insight into their plant functional diversity and improve our understanding of biogeochemical cycling. We used airborne remote sensing and Partial Least Squares Regression (PLSR) to quantify canopy foliar nitrogen (N) across ~164 km2 of wet lowland tropical forest in the Osa Peninsul...
Article
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Leaf wetting is often considered to have negative effects on plant function, such that wet environments may select for leaves with certain leaf surface, morphological, and architectural traits that reduce leaf wettability. However, there is growing recognition that leaf wetting can have positive effects. We measured variation in two traits, leaf dr...
Article
Waxy compounds form the boundary layer of the living leaf and contribute biomarkers to soils, and lake and marine sediments. Cataloguing the variation in leaf wax traits between species and across environmental gradients may contribute to the understanding of plant functional processes in modern ecosystems, as well as to calibration efforts support...