ORCID Profile
0000-0002-2434-7207
Current Organisation
The University of Texas at Austin
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Publisher: Springer Science and Business Media LLC
Date: 26-10-2019
Publisher: American Association for the Advancement of Science (AAAS)
Date: 21-06-2019
Abstract: Coral reefs represent one of the most bio erse and rich ecosystems. Such richness conjures up images of coral heads and large colorful reef fishes. Brandl et al. show, however, that one of the most striking and important parts of the reef ecosystem is almost never seen (see the Perspective by Riginos and Leis). Small cryptobenthic fish, like blennies, make up nearly 40% of reef fish bio ersity. Furthermore, the majority of cryptobenthic fish larvae settle locally, rather than being widely dispersed, and have rapid turnover rates. Such high ersity and densities could thus provide the biomass base for larger, better-known reef fish. Science , this issue p. 1189 see also p. 1128
Publisher: Wiley
Date: 10-08-2021
DOI: 10.1002/EDN3.245
Abstract: DNA metabarcoding is an increasingly popular technique to investigate bio ersity however, many methodological unknowns remain, especially concerning the biases resulting from marker choice. Regions of the cytochrome c oxidase subunit I (COI) and 18S rDNA (18S) genes are commonly employed “universal” markers for eukaryotes, but the extent of taxonomic biases introduced by these markers and how such biases may impact metabarcoding performance is not well quantified. Here, focusing on macroeukaryotes, we use standardized s ling from autonomous reef monitoring structures (ARMS) deployed in the world's most bio erse marine ecosystem, the Coral Triangle, to compare the performance of COI and 18S markers. We then compared metabarcoding data to image‐based annotations of ARMS plates. Although both markers provided similar estimates of taxonomic richness and total sequence reads, marker choice skewed estimates of eukaryotic ersity. The COI marker recovered relative abundances of the dominant sessile phyla consistent with image annotations. Both COI and the image annotations provided higher relative abundance estimates of Bryozoa and Porifera and lower estimates of Chordata as compared to 18S, but 18S recovered 25% more phyla than COI. Thus, while COI more reliably reflects the occurrence of dominant sessile phyla, 18S provides a more holistic representation of overall taxonomic ersity. Ideal marker choice is, therefore, contingent on study system and research question, especially in relation to desired taxonomic resolution, and a multimarker approach provides the greatest application across a broad range of research objectives. As metabarcoding becomes an essential tool to monitor bio ersity in our changing world, it is critical to evaluate biases associated with marker choice.
Publisher: Wiley
Date: 22-07-2020
Publisher: Wiley
Date: 09-06-2023
DOI: 10.1111/OIK.09914
Abstract: Consumers play an important role in biogeochemical cycles through the consumption and release of essential elements such as carbon (C), nitrogen (N), and phosphorus (P). Indeed, a large proportion of consumed elements are released into the environment in inorganic (i.e. excretion) or organic form (i.e. egestion). On coral reefs, fishes represent the bulk of consumer biomass and thus play a key role in the recycling of nutrients. In recent years, excretion rates have been studied intensively, but less is known about the rate and quality of coral reef fish egestion. In this study, we quantify the elemental contents of fish feces, estimate absorption efficiencies and compare egestion and excretion rates for 51 coral reef fish species. We show that elemental concentrations decrease remarkably little from food to feces. This is due to extremely low absorption efficiencies, resulting in the egestion of large amounts of energy and nutrients. Moreover, we show that while the quality of fish feces varies across trophic guilds, it remains highly variable within trophic guilds. Finally, we demonstrate that the release of N and P through egestion outweighs the amount of nutrients recycled through excretion. Our study highlights the need to incorporate animal egestion into assessments of ecosystem functioning and food web structure.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 20-12-2019
Abstract: Allgeier and Cline suggest that our model overestimates the contributions of cryptobenthic fishes to coral reef functioning. However, their 20-year model ignores the basic biological limits of population growth. If incorporated, cryptobenthic contributions to consumed fish biomass remain high (20 to 70%). Disturbance cycles and uncertainties surrounding the fate of large fishes on decadal scales further demonstrate the important role of cryptobenthic fishes.
Publisher: Research Square Platform LLC
Date: 08-07-2020
DOI: 10.21203/RS.3.RS-37102/V1
Abstract: Background: Fish harbour erse microbiomes within their gastro-intestinal system that effect the host’s digestion, nutrition and immunity. Despite the great taxonomic ersity of fish, little is understood about fish microbiome ersity and the factors that determine its structure and composition. Damselfish are important coral reef fish species that play a strong role in determining algae and coral structure of reefs. Broadly, damselfish belong to either of two trophic guilds based on whether they are planktivorous or algae-farming. In this study, we use 16s rRNA sequencing to interrogate the intestinal microbiome of 10 damselfish species (Pomacentridae) from the Great Barrier Reef to compare the composition of their intestinal bacterial assemblages across the planktivorous and algae-farming trophic guilds. Results: We identify core intestinal bacterial taxa for each host fish species. Gammaproteobacteria, belonging to the genus Actinobacillus, were detected in 80 % of s led in iduals and suggests a possible core member of pomacentrid microbiomes. Core microbiomes of algae-farming species were more erse than planktivorous species with farming species sharing 35 ± 22 ASVs and planktivorous sharing 7 ± 3 ASVs. We also provide evidence for significant shifts in bacterial community composition along the intestines. We show that Bacteroidia, Clostridia and Mollicutes bacteria are more abundant in the anterior intestinal regions while Gammaproteobacteria are generally highest in the stomach. Finally, we highlight differences in microbiomes associated with both trophic guilds. Algae-farming and planktivorous damselfish host species significantly differed in their composition of bacteria belonging to Vibrionaceae, Lachnospiraceae and Pasteurellaceae. Conclusions: Our results demonstrate that core intestinal bacterial communities of damselfish reflect host species diet and feeding behaviour, whereby algae-farming hosts have larger and more erse core microbiomes than planktivorous hosts. We suggest that the trophic guild of a host fish species is a strong determinant of microbiome structure.
Publisher: Springer Science and Business Media LLC
Date: 31-07-2020
DOI: 10.1038/S41467-020-17731-2
Abstract: Tropical ectotherms are hypothesized to be vulnerable to environmental changes, but cascading effects of organismal tolerances on the assembly and functioning of reef fish communities are largely unknown. Here, we examine differences in organismal traits, assemblage structure, and productivity of cryptobenthic reef fishes between the world’s hottest, most extreme coral reefs in the southern Arabian Gulf and the nearby, but more environmentally benign, Gulf of Oman. We show that assemblages in the Arabian Gulf are half as erse and less than 25% as abundant as in the Gulf of Oman, despite comparable benthic composition and live coral cover. This pattern appears to be driven by energetic deficiencies caused by responses to environmental extremes and distinct prey resource availability rather than absolute thermal tolerances. As a consequence, production, transfer, and replenishment of biomass through cryptobenthic fish assemblages is greatly reduced on Earth’s hottest coral reefs. Extreme environmental conditions, as predicted for the end of the 21st century, could thus disrupt the community structure and productivity of a critical functional group, independent of live coral loss.
Publisher: Wiley
Date: 29-08-2021
DOI: 10.1002/ECE3.8045
Abstract: Trait‐based approaches are increasingly used to study species assemblages and understand ecosystem functioning. The strength of these approaches lies in the appropriate choice of functional traits that relate to the functions of interest. However, trait–function relationships are often supported by weak empirical evidence. Processes related to digestion and nutrient assimilation are particularly challenging to integrate into trait‐based approaches. In fishes, intestinal length is commonly used to describe these functions. Although there is broad consensus concerning the relationship between fish intestinal length and diet, evolutionary and environmental forces have shaped a ersity of intestinal morphologies that is not captured by length alone. Focusing on coral reef fishes, we investigate how evolutionary history and ecology shape intestinal morphology. Using a large dataset encompassing 142 species across 31 families collected in French Polynesia, we test how phylogeny, body morphology, and diet relate to three intestinal morphological traits: intestinal length, diameter, and surface area. We demonstrate that phylogeny, body morphology, and trophic level explain most of the interspecific variability in fish intestinal morphology. Despite the high degree of phylogenetic conservatism, taxonomically unrelated herbivorous fishes exhibit similar intestinal morphology due to adaptive convergent evolution. Furthermore, we show that stomachless, durophagous species have the widest intestines to compensate for the lack of a stomach and allow passage of relatively large undigested food particles. Rather than traditionally applied metrics of intestinal length, intestinal surface area may be the most appropriate trait to characterize intestinal morphology in functional studies.
Publisher: Wiley
Date: 03-03-2023
Abstract: Bio ersity inventories and monitoring techniques for marine fishes often overlook small ( cm), bottom‐associated (‘cryptobenthic’) fishes, and few standardized, comparative assessments of cryptobenthic fish communities exist. We sought to develop a standardized, quantitative survey method for cryptobenthic fishes that permits their s ling across a variety of habitats and conditions. Fish‐specific autonomous reef monitoring structures (FARMS) are designed to s le cryptobenthic fishes using a suite of accessible and affordable materials. To generate a variety of microhabitats, FARMS consist of three layers of stacked PVC pipes in three different sizes, as well as a bottom and top level of loose PVC‐pipe fragments in a mesh basket. We deployed FARMS across a variety of habitats, including coral reefs, seagrass beds, oyster reefs, mangroves, and soft‐bottom habitats across six locations (Hawai'i, Texas, Panama, Saudi Arabia, Brazil, and Curaçao). From shallow estuaries to coral reefs beyond 100 m depth, FARMS attracted distinct communities of native cryptobenthic fishes with strong site or habitat specificity. Comparing the FARMS to communities s led with alternative methods (enclosed clove‐oil stations on coral reefs in Panama and oyster s ling units on oyster reefs in Texas) suggests that FARMS yield a subset of cryptobenthic fish species that are representative of those present on local coral and oyster reefs. While FARMS yield fewer in iduals per s le, they are efficient s ling devices relative to the s led area. We demonstrate that FARMS represent a useful tool for standardized collections of cryptobenthic fishes. While natural substrata are bound to yield more mature communities with a larger number of in iduals and wider range of specialist species, the potential to deploy and retrieve FARMS in turbid environments, beyond regular SCUBA depth, and where fish collections using anaesthetics or ichthyocides are forbidden suggests that they are a valuable complementary technique to survey fishes in aquatic ecosystems. Deploying FARMS in locations and habitats where cryptobenthic fish communities have not been studied in detail may yield many valuable specimens of unknown or poorly known species.
Publisher: Springer Science and Business Media LLC
Date: 07-12-2020
DOI: 10.1038/S41467-020-19958-5
Abstract: Domesticator-domesticate relationships are specialized mutualisms where one species provides multigenerational support to another in exchange for a resource or service, and through which both partners gain an advantage over in iduals outside the relationship. While this ecological innovation has profoundly reshaped the world’s landscapes and bio ersity, the ecological circumstances that facilitate domestication remain uncertain. Here, we show that longfin damselfish ( Stegastes diencaeus ) aggressively defend algae farms on which they feed, and this protective refuge selects a domesticator-domesticate relationship with planktonic mysid shrimps ( Mysidium integrum ). Mysids passively excrete nutrients onto farms, which is associated with enriched algal composition, and damselfish that host mysids exhibit better body condition compared to those without. Our results suggest that the refuge damselfish create as a byproduct of algal tending and the mutual habituation that damselfish and mysids exhibit towards one another were instrumental in subsequent mysid domestication. These results are consistent with domestication via the commensal pathway, by which many common ex les of animal domestication are hypothesized to have evolved.
Publisher: Proceedings of the National Academy of Sciences
Date: 20-09-2021
Abstract: Species loss can weaken the trophic interactions that underpin ecosystem functioning. Coral reefs are the world’s most erse marine ecosystem, harboring interaction networks of extraordinary complexity. We show that, despite this complexity, global coral reef food webs are governed by a suite of highly consistent energetic pathways, regardless of regional differences in bio ersity. All networks are characterized by species with narrow dietary preferences, arranged into distinct groups of predator–prey interactions. These characteristics suggest that coral reef food webs are robust to the loss of prey resources but vulnerable to local extinctions of consumer species.
Publisher: Public Library of Science (PLoS)
Date: 28-12-2020
DOI: 10.1371/JOURNAL.PBIO.3000702
Abstract: Understanding species’ roles in food webs requires an accurate assessment of their trophic niche. However, it is challenging to delineate potential trophic interactions across an ecosystem, and a paucity of empirical information often leads to inconsistent definitions of trophic guilds based on expert opinion, especially when applied to hyper erse ecosystems. Using coral reef fishes as a model group, we show that experts disagree on the assignment of broad trophic guilds for more than 20% of species, which h ers comparability across studies. Here, we propose a quantitative, unbiased, and reproducible approach to define trophic guilds and apply recent advances in machine learning to predict probabilities of pairwise trophic interactions with high accuracy. We synthesize data from community-wide gut content analyses of tropical coral reef fishes worldwide, resulting in diet information from 13,961 in iduals belonging to 615 reef fish. We then use network analysis to identify 8 trophic guilds and Bayesian phylogenetic modeling to show that trophic guilds can be predicted based on phylogeny and maximum body size. Finally, we use machine learning to test whether pairwise trophic interactions can be predicted with accuracy. Our models achieved a misclassification error of less than 5%, indicating that our approach results in a quantitative and reproducible trophic categorization scheme, as well as high-resolution probabilities of trophic interactions. By applying our framework to the most erse vertebrate consumer group, we show that it can be applied to other organismal groups to advance reproducibility in trait-based ecology. Our work thus provides a viable approach to account for the complexity of predator–prey interactions in highly erse ecosystems.
Publisher: Wiley
Date: 28-09-2023
DOI: 10.1002/EDN3.476
Publisher: Wiley
Date: 03-04-2021
DOI: 10.1111/GCB.15610
Abstract: Sea‐level rise is predicted to cause major damage to tropical coastlines. While coral reefs can act as natural barriers for ocean waves, their protection hinges on the ability of scleractinian corals to produce enough calcium carbonate (CaCO 3 ) to keep up with rising sea levels. As a consequence of intensifying disturbances, coral communities are changing rapidly, potentially reducing community‐level CaCO 3 production. By combining colony‐level physiology and long‐term monitoring data, we show that reefs recovering from major disturbances can produce 40% more CaCO 3 than currently estimated due to the disproportionate contribution of juvenile corals. However, the buffering effect of highly productive juvenile corals is compromised by recruitment failures, which have been more frequently observed after large‐scale, repeated bleaching events. While the size structure of corals can bolster a critical ecological function on reefs, climate change impacts on recruitment may undermine this buffering effect, thus further compromising the persistence of reefs and their provision of important ecosystem services.
Publisher: Springer Science and Business Media LLC
Date: 15-10-2017
DOI: 10.1007/S00442-016-3753-8
Abstract: Removal of predators is often hypothesized to alter community structure through trophic cascades. However, despite recent advances in our understanding of trophic cascades, evidence is often circumstantial on coral reefs because fishing pressure frequently co-varies with other anthropogenic effects, such as fishing for herbivorous fishes and changes in water quality due to pollution. Australia's outer Great Barrier Reef (GBR) has experienced fishing-induced declines of apex predators and mesopredators, but pollution and targeting of herbivorous fishes are minimal. Here, we quantify fish and benthic assemblages across a fishing-induced predator density gradient on the outer GBR, including apex predators and mesopredators to herbivores and benthic assemblages, to test for evidence of trophic cascades and alternative hypotheses to trophic cascade theory. Using structural equation models, we found no cascading effects from apex predators to lower trophic levels: a loss of apex predators did not lead to higher levels of mesopredators, and this did not suppress mobile herbivores and drive algal proliferation. Likewise, we found no effects of mesopredators on lower trophic levels: a decline of mesopredators was not associated with higher abundances of algae-farming damselfishes and algae-dominated reefs. These findings indicate that top-down forces on coral reefs are weak, at least on the outer GBR. We conclude that predator-mediated trophic cascades are probably the exception rather than the rule in complex ecosystems such as the outer GBR.
Publisher: Springer Science and Business Media LLC
Date: 04-04-2022
DOI: 10.1038/S41559-022-01710-5
Abstract: Human impact increasingly alters global ecosystems, often reducing bio ersity and disrupting the provision of essential ecosystem services to humanity. Therefore, preserving ecosystem functioning is a critical challenge of the twenty-first century. Coral reefs are declining worldwide due to the pervasive effects of climate change and intensive fishing, and although research on coral reef ecosystem functioning has gained momentum, most studies rely on simplified proxies, such as fish biomass. This lack of quantitative assessments of multiple process-based ecosystem functions hinders local and regional conservation efforts. Here we combine global coral reef fish community surveys and bioenergetic models to quantify five key ecosystem functions mediated by coral reef fishes. We show that functions exhibit critical trade-offs driven by varying community structures, such that no community can maximize all functions. Furthermore, functions are locally dominated by few species, but the identity of dominant species substantially varies at the global scale. In fact, half of the 1,110 species in our dataset are functionally dominant in at least one location. Our results reinforce the need for a nuanced, locally tailored approach to coral reef conservation that considers multiple ecological functions beyond the effect of standing stock biomass.
Publisher: Springer Science and Business Media LLC
Date: 27-01-2020
Publisher: Elsevier BV
Date: 08-2021
Publisher: Wiley
Date: 30-07-2019
DOI: 10.1002/FEE.2088
Publisher: Springer Science and Business Media LLC
Date: 27-10-2020
DOI: 10.1038/S41597-020-00711-Y
Abstract: Somatic growth is a critical biological trait for organismal, population, and ecosystem-level processes. Due to its direct link with energetic demands, growth also represents an important parameter to estimate energy and nutrient fluxes. For marine fishes, growth rate information is most frequently derived from sagittal otoliths, and most of the available data stems from studies on temperate species that are targeted by commercial fisheries. Although the analysis of otoliths is a powerful tool to estimate in idual growth, the time-consuming nature of otolith processing is one barrier for collection of comprehensive datasets across multiple species. This is especially true for coral reef fishes, which are extremely erse. Here, we provide back-calculated size-at-age estimates (including measures of uncertainty) based on sagittal otoliths from 710 in iduals belonging to 45 coral reef fish species from French Polynesia. In addition, we provide Von Bertalanffy growth parameters which are useful to predict community level biomass production.
Publisher: Wiley
Date: 03-06-2019
Publisher: Cold Spring Harbor Laboratory
Date: 04-03-2020
DOI: 10.1101/2020.03.04.977116
Abstract: The ersity of life on our planet has produced a remarkable variety of biological traits that characterize different species. Such traits are widely employed instead of taxonomy to increase our understanding of bio ersity and ecosystem functioning. However, for species’ trophic niches, one of the most critical aspects of organismal ecology, a paucity of empirical information has led to inconsistent definitions of trophic guilds based on expert opinion. Using coral reef fishes as a model, we show that experts often disagree on the assignment of trophic guilds for the same species. Even when broad categories are assigned, 60% of the evaluated trait schemes disagree on the attribution of trophic categories for at least 20% of the species. This disagreement greatly h ers comparability across studies. Here, we introduce a quantitative, unbiased, and fully reproducible framework to define species’ trophic guilds based on empirical data. First, we synthesize data from community-wide visual gut content analysis of tropical coral reef fishes, resulting in trophic information from 13,961 in iduals belonging to 615 reef fish species across all ocean basins. We then use network analysis to cluster the resulting global bipartite food web into distinct trophic guilds, resulting in eight trophic guilds, and employ a Bayesian phylogenetic model to predict trophic guilds based on phylogeny and maximum body size. Our model achieved a misclassification error of 5%, indicating that our approach results in a quantitative and reproducible trophic categorization scheme, which can be updated as new information becomes available. Although our case study is for reef fishes, the most erse vertebrate consumer group, our approach can be applied to other organismal groups to advance reproducibility in trait-based ecology. As such, our work provides an empirical and conceptual advancement for trait-based ecology and a viable approach to monitor ecosystem functioning in our changing world.
Publisher: Wiley
Date: 31-07-2017
DOI: 10.1002/ECE3.3288
Publisher: Wiley
Date: 03-2022
DOI: 10.1002/ECE3.8613
Abstract: Coral reefs provide a range of important services to humanity, which are underpinned by community‐level ecological processes such as coral calcification. Estimating these processes relies on our knowledge of in idual physiological rates and species‐specific abundances in the field. For colonial animals such as reef‐building corals, abundance is frequently expressed as the relative surface cover of coral colonies, a metric that does not account for demographic parameters such as coral size. This may be problematic because many physiological rates are directly related to organism size, and failure to account for linear scaling patterns may skew estimates of ecosystem functioning. In the present study, we characterize the scaling of three physiological rates — calcification, respiration, and photosynthesis — considering the colony size for six prominent, reef‐building coral taxa in Mo'orea, French Polynesia. After a seven‐day acclimation period in the laboratory, we quantified coral physiological rates for three hours during daylight (i.e., calcification and gross photosynthesis) and one hour during night light conditions (i.e., dark respiration). Our results indicate that area‐specific calcification rates are higher for smaller colonies across all taxa. However, photosynthesis and respiration rates remain constant over the colony‐size gradient. Furthermore, we revealed a correlation between the demographic dynamics of coral genera and the ratio between net primary production and calcification rates. Therefore, intraspecific scaling of reef‐building coral physiology not only improves our understanding of community‐level coral reef functioning but it may also explain species‐specific responses to disturbances.
Location: United States of America
No related grants have been discovered for Jordan Casey.