Thomas C Adam

Thomas C Adam
University of California, Santa Barbara | UCSB · Marine Science Institute

PhD

About

61
Publications
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1,918
Citations

Publications

Publications (61)
Article
Full-text available
Understanding how foundation species recover from disturbances is key for predicting the future of ecosystems in the Anthropocene. Coral reefs are dynamic ecosystems that can undergo rapid declines in coral abundance following disturbances. Understanding why some reefs recover quickly from these disturbances whereas others recover slowly (or not at...
Article
Full-text available
Parrotfishes (Labridae: Scarini) are widely recognized for their important functional role in reducing coral-algae competition by grazing algae, yet some species are also coral predators (corallivores) and thereby have direct negative impacts on corals they prey upon. To better understand the ecological drivers of parrotfish corallivory intensity,...
Article
Full-text available
Coral reefs in the Florida Reef Tract have seen protracted loss of coral over the past several decades due to a variety of disturbances from marine heat waves, cold snaps, and disease events. Corals have not recovered despite abundant herbivorous fishes and relatively low macroalgal cover, two factors thought to facilitate resilience of corals. Thu...
Article
Full-text available
Marine heatwaves are increasing in frequency and duration, threatening tropical reef ecosystems through intensified coral bleaching events. We examined a strikingly variable spatial pattern of bleaching in Moorea, French Polynesia following a heatwave that lasted from November 2018 to July 2019. In July 2019, four months after the onset of bleachin...
Article
Microbiomes are essential features of holobionts, providing their hosts with key metabolic and functional traits like resistance to environmental disturbances and diseases. In scleractinian corals, questions remain about the microbiome's role in resistance and resilience to factors contributing to the ongoing global coral decline and whether microb...
Article
Surveying coastal systems to estimate distribution and abundance of fish and benthic organisms is labor‐intensive, often resulting in spatially limited data that are difficult to scale up to an entire reef or island. We developed a method that leverages the automation of a machine learning platform, CoralNet, to efficiently and cost‐effectively all...
Article
Understanding how functional traits drive plant-herbivore interactions often illuminates the mechanisms driving niche partitioning and functional diversity in this important guild of consumers. On coral reefs, a diverse suite of herbivorous fishes is key for controlling algal abundance and impacting benthic community dynamics. Here, we focus on how...
Article
Full-text available
The outcomes of species interactions can vary greatly in time and space with the outcomes of some interactions determined by priority effects. On coral reefs, benthic algae rapidly colonize disturbed substrate. In the absence of top‐down control from herbivorous fishes, these algae can inhibit the recruitment of reef‐building corals, leading to a p...
Article
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Both natural and anthropogenic stressors are increasing on coral reefs, resulting in large‐scale loss of coral and potential shifts from coral‐ to macroalgae‐dominated community states. Two factors implicated in shifts to macroalgae are nutrient enrichment and fishing of reef herbivores. Although either of these factors alone could facilitate estab...
Article
For many long-lived taxa, such as trees and corals, older, and larger individuals often have the lowest mortality and highest fecundity. However, climate change-driven disturbances such as droughts and heatwaves may fundamentally alter typical size-dependent patterns of mortality and reproduction in these important foundation taxa. Working in Moore...
Article
Full-text available
Global- and local-scale anthropogenic stressors have been the main drivers of coral reef decline, causing shifts in coral reef community composition and ecosystem functioning. Excess nutrient enrichment can make corals more vulnerable to ocean warming by suppressing calcification and reducing photosynthetic performance. However, in some environment...
Article
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When coral and macroalgae are alternative attractors, the trajectory of the benthic community following a major disturbance is shaped in part by whether herbivores keep macroalgae suppressed, leaving reef surfaces in a state suitable for coral colonization. Because macroalgae tend to colonize much faster than coral, an important issue is how close...
Article
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Many coral reefs have shifted from coral‐ to macroalgae‐dominated community states, heightening the need to understand resilience of coral communities. Fishing on herbivores often reduces resilience of the coral state, as lower herbivory fosters macroalgal establishment. Despite the acknowledged importance of fishing, relatively little attention ha...
Article
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Nutrient pollution is altering coastal ecosystems worldwide. On coral reefs, excess nutrients can favor the production of algae at the expense of reef‐building corals, yet the role of nutrients in driving community changes such as shifts from coral to macroalgae is not well understood. Here we investigate the potential role of anthropogenic nutrien...
Article
Full-text available
Thermal stress increases community diversity, community variability, and the abundance of potentially pathogenic microbial taxa in the coral microbiome. Nutrient pollution, such as excess nitrogen can also interact with thermal stress to exacerbate host fitness degradation. However, it is unclear how different forms of nitrogen (nitrate vs. ammoniu...
Article
Full-text available
Nitrogen pollution increases the susceptibility of corals to heat-induced bleaching. However, different forms of nitrogen (nitrate vs. ammonium/urea) may have different impacts on thermal tolerance of corals. We used an 18-month field experiment on the oligotrophic fore reef of Moorea, French Polynesia, to test how different forms of nitrogen (nitr...
Article
Full-text available
Microbes are ubiquitous throughout the world's oceans, yet the manner and extent of their influence on the ecology and evolution of large, mobile fauna remains poorly understood. Here, we establish the intestinal microbiome as a hidden, and potentially important, ‘functional trait’ of tropical herbivorous fishes—a group of large consumers critical...
Article
Climate change is increasing the frequency and magnitude of temperature anomalies that cause coral bleaching, leading to widespread mortality of stony corals that can fundamentally alter reef structure and function. However, bleaching often is spatially variable for a given heat stress event, and drivers of this heterogeneity are not well resolved....
Article
Feeding behavior of coral reef fishes often determines their species‐specific ecological roles. We studied the two most common Caribbean surgeonfishes (Acanthurus coeruleus and Acanthurus tractus) to examine their species‐specific grazing rates and feeding preferences and how these differed with environmental context. We quantified the feeding acti...
Article
Parrotfishes are key herbivores on Caribbean reefs but also feed on other benthic taxa such as corals and sponges. Here, we used in situ behavioral observations to show that Caribbean parrotfishes have species-specific feeding patterns of corallivory and spongivory. Overall, Scarus guacamaia, Scarus taeniopterus, and Sparisoma viride were the most...
Article
Full-text available
Overexploitation of key species can negatively impact ecosystem processes, so understanding the ecological roles of individual species is critical for improving ecosystem management. Here, we use coral reefs and the process of herbivory as a model to examine how species identity of consumers influence ecosystem processes to inform management of the...
Article
Full-text available
Ecological theory predicts that ecosystems with multiple basins of attraction can get locked in an undesired state, which has profound ecological and management implications. Despite their significance, alternative attractors have proven to be challenging to detect and characterize in natural communities. On coral reefs, it has been hypothesized th...
Article
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Coral reef systems can undergo rapid transitions from coral-dominated to macroalgae-dominated states following disturbances, and models indicate that these may sometimes represent shifts between alternative stable states. While several mechanisms may lead to alternate stable states on coral reefs, only a few have been investigated theoretically. We...
Data
Details of local sensitivity analysis. (PDF)
Data
Details of global sensitivity analysis. (PDF)
Data
Variant of model with direct negative effects by macroalgae on coral. (PDF)
Article
Full-text available
Parrotfishes are a diverse group of herbivores that can influence benthic community dynamics and ecosystem function on coral reefs. Different species and size classes of parrotfishes vary in their feeding ecology and can impact reef ecosystems in distinct ways. We documented differences in the feeding ecology of 9 species of parrotfishes in the Flo...
Article
Full-text available
Tropical reefs often undergo acute disturbances that result in landscape-scale loss of coral. Due to increasing threats to coral reefs from climate change and anthropogenic perturbations, it is critical to understand mechanisms that drive recovery of these ecosystems. We explored this issue on the fore reef of Moorea, French Polynesia, following a...
Article
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Resolving how species compete and coexist within ecological communities represents a long-standing challenge in ecology. Research efforts have focused on two predominant mechanisms of species coexistence: complementarity and redundancy. But findings also support an alternative hypothesis that within-species variation may be critical for coexistence...
Article
Full-text available
Coral reefs increasingly are undergoing transitions from coral to macroalgal dominance. Although the functional roles of reef herbivores in controlling algae are becoming better understood, identifying possible tipping points in the herbivory-macroalgae relationships has remained a challenge. Assessment of where any coral reef ecosystem lies in rel...
Article
The reefs surrounding the island of Moorea, French Polynesia, experienced two large pulse perturbations between 2008 and 2010, an outbreak of the crown-of-thorns seastar (Acanthaster planci) followed by a cyclone, that resulted in the reduction in live coral cover on the fore reef from ~40 to <5 %. Live coral cover in back reef and fringing reef ha...
Article
Full-text available
The recent loss of key consumers to exploitation and habitat degradation has significantly altered community dynamics and ecosystem function across many ecosystems worldwide. Predicting the impacts of consumer losses requires knowing the level of functional diversity that exists within a consumer assemblage. In this study, we document functional di...
Article
Full-text available
Herbivory is a key process on coral reefs that can facilitate reef-building corals by excluding algae that otherwise negatively impact coral settlement, growth, and survivorship. Over the last several decades, coral cover on Caribbean reefs has declined precipitously. On many reefs, large structurally complex corals have been replaced by algae and...
Article
Full-text available
Global climate change is rapidly altering disturbance regimes in many ecosystems including coral reefs, yet the long-term impacts of these changes on ecosystem structure and function are difficult to predict. A major ecosystem service provided by coral reefs is the provisioning of physical habitat for other organisms, and consequently, many of the...
Article
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Pocillopora is one of the most abundant and widely distributed coral genera, with a geographic range spanning the entire tropical Pacific and Indian Oceans as well as the Red Sea and Arabian Gulf. Across this enormous geographic range, Pocillopora is a major reef builder (second in importance and abundance only to Acropora) that can dominate a wide...
Article
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Abstract Elucidating patterns and causes of interaction among mutualistic species is a major focus of ecology, and recent meta-analyses of terrestrial networks show that network-level reciprocal specialization tends to be higher in intimate mutualisms than in nonintimate mutualisms. It is largely unknown, however, whether this pattern holds for and...
Article
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Cleaner mutualisms on coral reefs, where specialized fish remove parasites from many species of client fishes, have greatly increased our understanding of mutualism, yet we know little about important interspecific interactions between cleaners. Here, we explore the potential for competition between the cleaners Labroides dimidiatus and Labroides b...
Article
1. Indirect interactions resulting from changes in organismal traits such as behaviour [i.e. trait-mediated indirect interactions (TMIIs)] are widespread in biological communities, yet few studies have explored the potential for mutualisms to initiate TMIIs. 2. This study used a combination of behavioural observations and manipulative field experim...
Data
Dynamics of herbivorous sea urchins. Patterns of abundance (mean±95%) of herbivorous sea urchins on the (A) forereef, (B) backreef, and (C) fringing reef. (TIF)
Data
Results of mixed-effects ANOVA on the (a) density and (b) biomass of herbivorous fish in each of the three habitat types. Results of post hoc Tukey tests for the fixed effect of year are indicated; years not sharing the same letter are significantly different at P<0.05. (DOC)
Data
Results of mixed-effects ANOVA on the density of herbivorous sea urchins in each of the three habitat types. Results of post hoc Tukey tests for the fixed effect of year are shown; years not sharing the same letter are significantly different at P<0.05. (DOC)
Data
Size frequency distributions of C. sordidus surveyed twice annually at 13 sites between 2004 and 2008. Distributions show consistent ontogenetic patterns of habitat use among seasons. (TIF)
Data
Size frequency distributions of S. psittacus surveyed twice annually at 13 sites between 2004 and 2008. Distributions show consistent ontogenetic patterns of habitat use among seasons. (TIF)
Data
Detailed methods and results. (DOC)
Data
Size frequency distributions of S. psittacus in each of the three habitat types over time. Between 2008 and 2010 S. psittacus increased in density and biomass more than 20-fold. Size distributions differed among habitats with nearshore habitats having a greater proportion of small individuals. (TIF)
Data
Size frequency distributions of C. sordidus in each of the three habitat types over time. Between 2008 and 2010 C. sordidus doubled in density on the forereef while shifting in median length from 12 to 15 cm, together resulting in a tripling in biomass. Size distributions differed among habitats with nearshore habitats having a greater proportion o...
Data
Results of mixed effects ANOVA on the cover of (a) coral, (b) macroalgae, and (c) bare space/turf/CCA in each of the three habitat types. Results of post hoc Tukey tests for the fixed effect of year are indicated; years not sharing the same letter are significantly different at P<0.05. (DOC)
Data
Results of mixed-effects ANOVA on the density of parrotfishes in each of the three habitat types. Results of post hoc Tukey tests for the fixed effect of year are shown; years not sharing the same letter are significantly different at P<0.05. (DOC)
Article
Full-text available
Coral reefs world-wide are threatened by escalating local and global impacts, and some impacted reefs have shifted from coral dominance to a state dominated by macroalgae. Therefore, there is a growing need to understand the processes that affect the capacity of these ecosystems to return to coral dominance following disturbances, including those t...
Article
Full-text available
Many species disperse during their lifetime. Two factors that can affect the performance of individuals following dispersal are the presence of conspecifics and intrinsic habitat quality at the settlement site. Detecting the influence of these factors can be difficult for at least two reasons: (1) the outcomes of interactions with conspecifics are...
Article
Partner choice is likely to be an important mechanism for the maintenance of cooperation in many mutualisms, and cleaner mutualisms among fish have been a model system for testing predictions of partner choice theories. Fish seeking to be cleaned (clients) face two potential problems: cleaners may cheat them by feeding on tissue or mucous, and they...
Article
Full-text available
Ctenogobiops is a genus of Indo-Pacific gobies that form obligate, mutualistic associations with shrimp in the genus Alpheus. This study provides a molecular phylogenetic analysis of eight Ctenogobiops species: C. aurocingulus, C. crocineus, C. feroculus, C. formosa, C. maculosus, C. mitodes, C. tangaroai, and C. tongaensis. We recover two clades w...

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