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Jones NP, Gilliam DS. Temperature and local anthropogenic pressures limit stony coral assemblage viability in southeast Florida. MARINE POLLUTION BULLETIN 2024; 200:116098. [PMID: 38310721 DOI: 10.1016/j.marpolbul.2024.116098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 01/07/2024] [Accepted: 01/28/2024] [Indexed: 02/06/2024]
Abstract
Climate change is viewed as the primary threat to coral reefs, with local pressures exacerbating coral cover decline. The consensus is that improving water quality may increase resilience, but disentangling water quality and temperature impacts is difficult. We used distance-based linear models and random forests to analyze spatiotemporal variation in benthic community structure and interannual changes in the coral assemblage, in relation to specific environmental metrics in Southeast Florida. Temperature accounted for most of the variation, recruitment doubled and interannual increases in coral abundance tripled when mean annual temperature reached 27 °C, until maximum temperatures exceeded 31 °C. Benefits associated with warmer temperatures were negated by poor water quality, as nutrient enrichment was related to increased macroalgal cover, reduced coral recruitment and higher coral partial mortality. We suggest reducing local pressures will contribute to reduced macroalgae and enhance coral recovery, but that temperature is the predominant influence on coral assemblages.
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Affiliation(s)
- Nicholas P Jones
- National Coral Reef Institute, Halmos College of Arts and Sciences, Nova Southeastern University, 8000 N Ocean Drive, Dania Beach, FL 33004, USA.
| | - David S Gilliam
- National Coral Reef Institute, Halmos College of Arts and Sciences, Nova Southeastern University, 8000 N Ocean Drive, Dania Beach, FL 33004, USA
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2
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Steibl S, Kench PS, Young HS, Wegmann AS, Holmes ND, Bunbury N, Teavai-Murphy TH, Davies N, Murphy F, Russell JC. Rethinking atoll futures: local resilience to global challenges. Trends Ecol Evol 2024; 39:258-266. [PMID: 38114338 DOI: 10.1016/j.tree.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/08/2023] [Accepted: 11/10/2023] [Indexed: 12/21/2023]
Abstract
Atoll islands are often perceived as inevitably lost due to rising sea levels. However, unlike other islands, atoll islands are dynamic landforms that have evolved, at least historically, to vertically accrete at a pace commensurate with changing sea levels. Rather than atoll islands' low elevation per se, the impairment of natural accretion processes is jeopardising their persistence. While global marine impacts are deteriorating coral reefs, local impacts also significantly affect accretion, together potentially tipping the scales toward atoll island erosion. Maintaining atoll island accretion requires intact sediment generation on coral reefs, unobstructed sediment transport from reef to island, and available vegetated deposition sites on the island. Ensuring the persistence of atoll islands must include global greenhouse gas emission reduction and local restoration of accretion processes.
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Affiliation(s)
- Sebastian Steibl
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.
| | - Paul S Kench
- Department of Geography, National University of Singapore, Singapore
| | - Hillary S Young
- Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, USA
| | | | | | - Nancy Bunbury
- Seychelles Islands Foundation, Victoria, Mahé, Seychelles; Centre for Ecology and Conservation, University of Exeter, Exeter, UK
| | | | - Neil Davies
- Tetiaroa Society, Tetiaroa, French Polynesia; Gump South Pacific Research Station, University of California, Berkeley, CA, USA
| | | | - James C Russell
- School of Biological Sciences, University of Auckland, Auckland, New Zealand; School of Biological Sciences, University of Aberdeen, Aberdeen, UK.
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3
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Sannassy Pilly S, Roche RC, Richardson LE, Turner JR. Depth variation in benthic community response to repeated marine heatwaves on remote Central Indian Ocean reefs. ROYAL SOCIETY OPEN SCIENCE 2024; 11:231246. [PMID: 38545610 PMCID: PMC10966399 DOI: 10.1098/rsos.231246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 12/01/2023] [Accepted: 02/21/2024] [Indexed: 04/26/2024]
Abstract
Coral reefs are increasingly impacted by climate-induced warming events. However, there is limited empirical evidence on the variation in the response of shallow coral reef communities to thermal stress across depths. Here, we assess depth-dependent changes in coral reef benthic communities following successive marine heatwaves from 2015 to 2017 across a 5-25 m depth gradient in the remote Chagos Archipelago, Central Indian Ocean. Our analyses show an overall decline in hard and soft coral cover and an increase in crustose coralline algae, sponge and reef pavement following successive marine heatwaves on the remote reef system. Our findings indicate that the changes in benthic communities in response to elevated seawater temperatures varied across depths. We found greater changes in benthic group cover at shallow depths (5-15 m) compared with deeper zones (15-25 m). The loss of hard coral cover was better predicted by initial thermal stress, while the loss of soft coral was associated with repeated thermal stress following successive warming events. Our study shows that benthic communities extending to 25 m depth were impacted by successive marine heatwaves, supporting concerns about the resilience of shallow coral reef communities to increasingly severe climate-driven warming events.
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Affiliation(s)
| | - Ronan C. Roche
- School of Ocean Sciences, Bangor University, BangorLL59 5AB, UK
| | | | - John R. Turner
- School of Ocean Sciences, Bangor University, BangorLL59 5AB, UK
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4
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Benkwitt CE, D'Angelo C, Dunn RE, Gunn RL, Healing S, Mardones ML, Wiedenmann J, Wilson SK, Graham NAJ. Seabirds boost coral reef resilience. SCIENCE ADVANCES 2023; 9:eadj0390. [PMID: 38055814 DOI: 10.1126/sciadv.adj0390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 11/03/2023] [Indexed: 12/08/2023]
Abstract
Global climate change threatens tropical coral reefs, yet local management can influence resilience. While increasing anthropogenic nutrients reduce coral resistance and recovery, it is unknown how the loss, or restoration, of natural nutrient flows affects reef recovery. Here, we test how natural seabird-derived nutrient subsidies, which are threatened by invasive rats, influence the mechanisms and patterns of reef recovery following an extreme marine heatwave using multiyear field experiments, repeated surveys, and Bayesian modeling. Corals transplanted from rat to seabird islands quickly assimilated seabird-derived nutrients, fully acclimating to new nutrient conditions within 3 years. Increased seabird-derived nutrients, in turn, caused a doubling of coral growth rates both within individuals and across entire reefs. Seabirds were also associated with faster recovery time of Acropora coral cover (<4 years) and more dynamic recovery trajectories of entire benthic communities. We conclude that restoring seabird populations and associated nutrient pathways may foster greater coral reef resilience through enhanced growth and recovery rates of corals.
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Affiliation(s)
| | - Cecilia D'Angelo
- Coral Reef Laboratory, School of Ocean and Earth Science, University of Southampton, Southampton SO143ZH, UK
| | - Ruth E Dunn
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
- The Lyell Centre, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Rachel L Gunn
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
- Animal Evolutionary Ecology, Institute of Evolution and Ecology, University of Tübingen, Auf Der Morgenstelle 28, 72076 Tübingen, Germany
| | - Samuel Healing
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - M Loreto Mardones
- Coral Reef Laboratory, School of Ocean and Earth Science, University of Southampton, Southampton SO143ZH, UK
| | - Joerg Wiedenmann
- Coral Reef Laboratory, School of Ocean and Earth Science, University of Southampton, Southampton SO143ZH, UK
| | - Shaun K Wilson
- Australian Institute of Marine Science, Indian Ocean Marine Research Centre, Crawley, WA 6009, Australia
- University of Western Australia, UWA Oceans Institute, Crawley, WA 6009, Australia
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5
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González-Barrios FJ, Estrada-Saldívar N, Pérez-Cervantes E, Secaira-Fajardo F, Álvarez-Filip L. Legacy effects of anthropogenic disturbances modulate dynamics in the world's coral reefs. GLOBAL CHANGE BIOLOGY 2023; 29:3285-3303. [PMID: 36932916 DOI: 10.1111/gcb.16686] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 03/03/2023] [Accepted: 03/07/2023] [Indexed: 05/16/2023]
Abstract
Rapidly changing conditions alter disturbance patterns, highlighting the need to better understand how the transition from pulse disturbances to more persistent stress will impact ecosystem dynamics. We conducted a global analysis of the impacts of 11 types of disturbances on reef integrity using the rate of change of coral cover as a measure of damage. Then, we evaluated how the magnitude of the damage due to thermal stress, cyclones, and diseases varied among tropical Atlantic and Indo-Pacific reefs and whether the cumulative impact of thermal stress and cyclones was able to modulate the responses of reefs to future events. We found that reef damage largely depends on the condition of a reef before a disturbance, disturbance intensity, and biogeographic region, regardless of the type of disturbance. Changes in coral cover after thermal stress events were largely influenced by the cumulative stress of past disturbances and did not depend on disturbance intensity or initial coral cover, which suggests that an ecological memory is present within coral communities. In contrast, the effect of cyclones (and likely other physical impacts) was primarily modulated by the initial reef condition and did not appear to be influenced by previous impacts. Our findings also underscore that coral reefs can recover if stressful conditions decrease, yet the lack of action to reduce anthropogenic impacts and greenhouse gas emissions continues to trigger reef degradation. We uphold that evidence-based strategies can guide managers to make better decisions to prepare for future disturbances.
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Affiliation(s)
- F Javier González-Barrios
- Biodiversity and Reef Conservation Laboratory, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | - Nuria Estrada-Saldívar
- Biodiversity and Reef Conservation Laboratory, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | - Esmeralda Pérez-Cervantes
- Biodiversity and Reef Conservation Laboratory, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | | | - Lorenzo Álvarez-Filip
- Biodiversity and Reef Conservation Laboratory, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
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6
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Losciale R, Day J, Heron S. Conservation status, research, and knowledge of seagrass habitats in World Heritage properties. CONSERVATION SCIENCE AND PRACTICE 2022. [DOI: 10.1111/csp2.12830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
| | - Jon Day
- James Cook University Douglas Queensland Australia
| | - Scott Heron
- James Cook University Douglas Queensland Australia
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7
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Schlaefer JA, Tebbett SB, Bowden CL, Collins WP, Duce S, Hemingson CR, Huertas V, Mihalitsis M, Morais J, Morais RA, Siqueira AC, Streit RP, Swan S, Valenzuela J, Bellwood DR. A snapshot of sediment dynamics on an inshore coral reef. MARINE ENVIRONMENTAL RESEARCH 2022; 181:105763. [PMID: 36206642 DOI: 10.1016/j.marenvres.2022.105763] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/25/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
Sediments are ubiquitous on coral reefs. However, studies of reef sediments have largely focused on isolated reservoirs, or processes, and rarely consider hydrodynamic drivers. We therefore provide a quantitative snapshot of sediment dynamics on a coral reef. Across a depth profile, we simultaneously examined: suspended sediments, sediment deposition and accumulation, and hydrodynamic and biological movement processes. We reveal the marked potential for the water column to deliver sediments. Currents carried 12.6 t of sediment over the 2,314 m2 study area in 6 days. Sediment traps suggested that a surprisingly high percentage of this sediment was potentially deposited (5.2%). Furthermore, wave-driven resuspension and reworking by parrotfishes separated a highly dynamic sediment regime on the shallow reef flat (3 m), from a more stagnant reef slope (4.5 m-12 m). This study provides a comprehensive model of how hydrodynamic forces and on-reef processes may shape sediment dynamics on a coral reef.
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Affiliation(s)
- Jodie A Schlaefer
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia; Commonwealth Scientific and Industrial Research Organisation (CSIRO), Oceans and Atmosphere, Hobart, Tasmania, 7000, Australia
| | - Sterling B Tebbett
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - Casey L Bowden
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - William P Collins
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - Stephanie Duce
- College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - Christopher R Hemingson
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - Victor Huertas
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - Michalis Mihalitsis
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - Juliano Morais
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - Renato A Morais
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - Alexandre C Siqueira
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - Robert P Streit
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - Sam Swan
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - Jessica Valenzuela
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - David R Bellwood
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia.
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8
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Tebbett SB, Bellwood DR, Johnson ER, Chase TJ. Occurrence and accumulation of heavy metals in algal turf particulates and sediments on coral reefs. MARINE POLLUTION BULLETIN 2022; 184:114113. [PMID: 36099683 DOI: 10.1016/j.marpolbul.2022.114113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 09/01/2022] [Accepted: 09/04/2022] [Indexed: 06/15/2023]
Abstract
Algal turfs form a critical interface on coral reefs that interacts with several key ecosystem processes. While we know these turfs have a remarkable propensity to accumulate sediments, which can have a range of ecosystem impacts, their role as sinks for heavy metals remains largely unexamined. Here we quantified the concentration of 15 metals in algal turf sediments from Lizard Island and Orpheus Island on the Great Barrier Reef, and specifically explored how the loads of arsenic, cobalt, iron and lead were related to turf length. Metal composition differed markedly between the two islands, with the composition at Orpheus Island suggesting closer links to terrestrial sediment sources. Furthermore, metal loads increased significantly with turf length, suggesting that longer turfs can accumulate these pollutants on reefs. Given that algal turfs are a crucial component of herbivorous/detritivorous trophic pathways, this could represent a key juncture at which these metals enter food chains.
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Affiliation(s)
- Sterling B Tebbett
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering, ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia.
| | - David R Bellwood
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering, ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
| | - Erin R Johnson
- Department of Geography and the Environment, Villanova University, 800 E. Lancaster Avenue, Villanova, PA 19085, United States of America
| | - Tory J Chase
- Department of Geography and the Environment, Villanova University, 800 E. Lancaster Avenue, Villanova, PA 19085, United States of America
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9
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Arjunwadkar CV, Tebbett SB, Bellwood DR, Bourne DG, Smith HA. Algal turf structure and composition vary with particulate loads on coral reefs. MARINE POLLUTION BULLETIN 2022; 181:113903. [PMID: 35843165 DOI: 10.1016/j.marpolbul.2022.113903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 05/10/2022] [Accepted: 06/26/2022] [Indexed: 06/15/2023]
Abstract
Algal turfs trap and retain particulates, however, little is known about the relationship between particulate accumulation and taxonomic composition of algal turfs. We investigated how particulate mass related to algal turf structure (length and density) and community composition (taxonomic and functional) on two disparate reefs. Particulate mass was positively related to algal turf length. By contrast, the relationship between particulate mass and turf density was more complex and followed a negative parabolic shape; density increased with particulate mass before stabilising and then declining. Community analyses showed taxonomic, but not functional group compositions differed significantly between reefs and with increasing particulate mass. Our results suggest high loads of particulates accumulated in algal turfs are related to a longer, lower density turf structure, typified by filamentous forms such as Cladophora. Changes in algal turf structure and composition could have a variety of bottom-up influences on coral reef ecosystems.
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Affiliation(s)
| | - Sterling B Tebbett
- College of Science and Engineering, James Cook University, Townsville, QLD, Australia; Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, Australia
| | - David R Bellwood
- College of Science and Engineering, James Cook University, Townsville, QLD, Australia; Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, QLD, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, Australia
| | - David G Bourne
- College of Science and Engineering, James Cook University, Townsville, QLD, Australia; Australian Institute of Marine Science, Townsville, QLD, Australia
| | - Hillary A Smith
- College of Science and Engineering, James Cook University, Townsville, QLD, Australia; Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, NSW, Australia.
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10
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Nakamura M, Murakami T, Kohno H, Mizutani A, Shimokawa S. Rapid recovery of coral communities from a mass bleaching event in the summer of 2016, observed in Amitori Bay, Iriomote Island, Japan. MARINE BIOLOGY 2022; 169:104. [PMID: 35915766 PMCID: PMC9331011 DOI: 10.1007/s00227-022-04091-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 07/05/2022] [Indexed: 06/15/2023]
Abstract
UNLABELLED Devastating bleaching of coral communities at Amitori Bay, Iriomote Island, Japan, occurred in 2016 during the third global mass bleaching event in 2014-2017. The present study documented changes in coral communities in Amitori Bay from just before until after the 2016 bleaching event (2016-2020), by measuring coral cover and recruitment at nine sites (with two additional sites in 2018) in the bay. Spawning rates of acroporid corals were also monitored from 2017 to 2019 by visual observation and using bundle collectors to observe how long the effect of bleaching persisted. Reductions of 64.7 and 89.5% from 2016 to 2017 were observed in cover and recruitment of all coral families, respectively. Coral cover of all coral families recovered to pre-bleaching levels by 2020 and recruitment in 2020 was about two times greater than the pre-bleaching level. These results mirrored those of acroporids. Spawning rates of Acropora corals increased significantly from 40.6% in 2017 to 90.0% in 2019. Recovery of coral cover 4 years after the severe bleaching event was likely related to regrowth of remnants and of surviving juveniles of < 5 cm. The sudden increase in recruitment was likely driven by a combination of larval supply from other populations, increased numbers of reproductive adults, increases in spawning rates, and increased larval retention in the bay due to wind conditions in 2020. This study suggests that coral communities as in Amitori Bay will be critical for local-scale community persistence, serving as both source and sink populations. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s00227-022-04091-2.
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Affiliation(s)
- Masako Nakamura
- School of Marine Science and Technology, Tokai University, Shimizu, Shizuoka, 424-8610 Japan
| | - Tomokazu Murakami
- Monitoring and Forecast Research Department, National Research Institute for Earth Science and Disaster Prevention, Tsukuba Ibaraki, 305-0006 Japan
| | | | - Akira Mizutani
- Island Ecosystem Research, Taketomi, Okinawa 907-1541 Japan
| | - Shinya Shimokawa
- Monitoring and Forecast Research Department, National Research Institute for Earth Science and Disaster Prevention, Tsukuba Ibaraki, 305-0006 Japan
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11
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Tebbett SB, Morais J, Bellwood DR. Spatial patchiness in change, recruitment, and recovery on coral reefs at Lizard Island following consecutive bleaching events. MARINE ENVIRONMENTAL RESEARCH 2022; 173:105537. [PMID: 34837738 DOI: 10.1016/j.marenvres.2021.105537] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/16/2021] [Accepted: 11/21/2021] [Indexed: 06/13/2023]
Abstract
The world's coral reef ecosystems are steadily being reconfigured by climate change. Lizard Island, on Australia's Great Barrier Reef, offers an opportunity to examine coral reef reassembly following disturbance, as this location has been impacted by consecutive tropical cyclones and consecutive coral bleaching events. Based on repeatedly monitoring the same 349 photoquadrats around Lizard Island over a 5-year period (2016-2021) we revealed that bleaching in 2016 drove a ∼50% reduction in hard coral cover, and a concomitant increase in algal turf cover. From 2018 to 2021, significant increases (>600%) in coral cover were detected on two semi-exposed reefs and were associated with substantial Acropora recruitment. By contrast, fourteen lagoonal and back reefs exhibited virtually no recovery nor Acropora recruitment. Given that the timeframe between disturbances is set to decrease, our results suggest that some recovery is possible immediately after severe cumulative disturbances, although this recovery may be highly spatially heterogenous.
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Affiliation(s)
- Sterling B Tebbett
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, 4811, Australia.
| | - Juliano Morais
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, 4811, Australia
| | - David R Bellwood
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, 4811, Australia
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12
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Regime shifts on tropical coral reef ecosystems: future trajectories to animal-dominated states in response to anthropogenic stressors. Emerg Top Life Sci 2021; 6:95-106. [PMID: 34927689 DOI: 10.1042/etls20210231] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/22/2021] [Accepted: 11/25/2021] [Indexed: 02/01/2023]
Abstract
Despite the global focus on the occurrence of regime shifts on shallow-water tropical coral reefs over the last two decades, most of this research continues to focus on changes to algal-dominated states. Here, we review recent reports (in approximately the last decade) of regime shifts to states dominated by animal groups other than zooxanthellate Scleractinian corals. We found that while there have been new reports of regime shifts to reefs dominated by Ascidacea, Porifera, Octocorallia, Zoantharia, Actiniaria and azooxanthellate Scleractinian corals, some of these changes occurred many decades ago, but have only just been reported in the literature. In most cases, these reports are over small to medium spatial scales (<4 × 104 m2 and 4 × 104 to 2 × 106 m2, respectively). Importantly, from the few studies where we were able to collect information on the persistence of the regime shifts, we determined that these non-scleractinian states are generally unstable, with further changes since the original regime shift. However, these changes were not generally back to coral dominance. While there has been some research to understand how sponge- and octocoral-dominated systems may function, there is still limited information on what ecosystem services have been disrupted or lost as a result of these shifts. Given that many coral reefs across the world are on the edge of tipping points due to increasing anthropogenic stress, we urgently need to understand the consequences of non-algal coral reef regime shifts.
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Koester A, Ford AK, Ferse SCA, Migani V, Bunbury N, Sanchez C, Wild C. First insights into coral recruit and juvenile abundances at remote Aldabra Atoll, Seychelles. PLoS One 2021; 16:e0260516. [PMID: 34874982 PMCID: PMC8651144 DOI: 10.1371/journal.pone.0260516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 11/12/2021] [Indexed: 11/19/2022] Open
Abstract
Coral recruitment and successive growth are essential for post-disturbance reef recovery. As coral recruit and juvenile abundances vary across locations and under different environmental regimes, their assessment at remote, undisturbed reefs improves our understanding of early life stage dynamics of corals. Here, we first explored changes in coral juvenile abundance across three locations (lagoon, seaward west and east) at remote Aldabra Atoll (Seychelles) between 2015 and 2019, which spanned the 2015/16 global coral bleaching event. Secondly, we measured variation in coral recruit abundance on settlement tiles from two sites (lagoon, seaward reef) during August 2018-August 2019. Juvenile abundance decreased from 14.1 ± 1.2 to 7.4 ± 0.5 colonies m-2 (mean ± SE) during 2015-2016 and increased to 22.4 ± 1.2 colonies m-2 during 2016-2019. Whilst juvenile abundance increased two- to three-fold at the lagoonal and seaward western sites during 2016-2018 (from 7.7-8.3 to 17.3-24.7 colonies m-2), increases at the seaward eastern sites occurred later (2018-2019; from 5.8-6.9 to 16.6-24.1 colonies m-2). The composition of coral recruits on settlement tiles was dominated by Pocilloporidae (64-92% of all recruits), and recruit abundance was 7- to 47-fold higher inside than outside the lagoon. Recruit abundance was highest in October-December 2018 (2164 ± 453 recruits m-2) and lowest in June-August 2019 (240 ± 98 recruits m-2). As Acroporid recruit abundance corresponded to this trend, the results suggest that broadcast spawning occurred during October-December, when water temperature increased from 26 to 29°C. This study provides the first published record on coral recruit abundance in the Seychelles Outer Islands, indicates a rapid (2-3 years) increase of juvenile corals following a bleaching event, and provides crucial baseline data for future research on reef resilience and connectivity within the region.
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Affiliation(s)
- Anna Koester
- Marine Ecology Department, Faculty of Biology & Chemistry, University of Bremen, Bremen, Germany
- Seychelles Islands Foundation, Victoria, Mahé, Seychelles
| | - Amanda K. Ford
- School of Agriculture, Geography, Environment, Ocean and Natural Sciences, University of the South Pacific, Suva, Fiji
| | - Sebastian C. A. Ferse
- Marine Ecology Department, Faculty of Biology & Chemistry, University of Bremen, Bremen, Germany
- Leibniz Centre for Tropical Marine Research, Bremen, Germany
| | - Valentina Migani
- Institute for Ecology, Faculty of Biology & Chemistry, University of Bremen, Bremen, Germany
| | - Nancy Bunbury
- Seychelles Islands Foundation, Victoria, Mahé, Seychelles
- Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn, United Kingdom
| | - Cheryl Sanchez
- Seychelles Islands Foundation, Victoria, Mahé, Seychelles
- Department of Biology, University of Pisa, Pisa, Italy
| | - Christian Wild
- Marine Ecology Department, Faculty of Biology & Chemistry, University of Bremen, Bremen, Germany
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Etongo D, Arrisol L. Vulnerability of fishery-based livelihoods to climate variability and change in a tropical island: insights from small-scale fishers in Seychelles. DISCOVER SUSTAINABILITY 2021; 2:48. [PMID: 35425911 PMCID: PMC8573566 DOI: 10.1007/s43621-021-00057-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 10/29/2021] [Indexed: 06/14/2023]
Abstract
While climate shocks and stressors are not unique to developing countries, their impacts are expected to be most acute here due to limitations in the assets and infrastructure required for adaptation. This study assesses the vulnerability of fishery-based livelihoods to the impacts of climate variability and change across two major islands in Seychelles based on 80 household surveys and three shared dialogue workshops (SDWs) with small-scale fishers. Results showed that the percentage of fishers' households that depend mainly on fisheries as a source of income was 95% and 97% for Mahe and Praslin respectively with alternative income streams along the fishing value chain such as transportation, fish mongers and processor. Fishers on Mahe Island had a dependency ratio index that was slightly higher than those on Praslin. Overall, fishing households on Mahe showed greater vulnerability on socio-demographic profile index compared to their counterparts on Praslin. However, greater livelihood diversification was recorded for householders on Mahe than Praslin as fishers earned income from tourism-related activities such as guest house, car rental, boat ride, and sales of coconuts as mentioned during the SDWs. Fishers on Mahe struggled to find fish for 3 months during the southeast monsoon season compared to 2 months for those on Praslin given that access is granted to fish in the lagoon during this season. More importantly, the voluntary closure of some fishing zones between the months of November to April on Praslin is a sustainability strategy that witnessed an increase in size and number for both rabbit and parrotfish. Further studies are needed in two key areas as follows: the role of subsidies and sustainable fisheries management, and a value-chain approach to vulnerability of small-scale fishers within the fishery sector in Seychelles.
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Affiliation(s)
- Daniel Etongo
- James Michel Blue Economy Research Institute, University of Seychelles, Anse Royale, Seychelles
- Department of Environmental Sciences, University of Seychelles, Anse Royale, Seychelles
| | - Lyn Arrisol
- James Michel Blue Economy Research Institute, University of Seychelles, Anse Royale, Seychelles
- Department of Environmental Sciences, University of Seychelles, Anse Royale, Seychelles
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Tebbett SB, Bellwood DR. Algal turf productivity on coral reefs: A meta-analysis. MARINE ENVIRONMENTAL RESEARCH 2021; 168:105311. [PMID: 33798994 DOI: 10.1016/j.marenvres.2021.105311] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/14/2021] [Accepted: 03/19/2021] [Indexed: 05/26/2023]
Abstract
Algal turfs are an abundant and highly productive component of coral reef ecosystems. However, our understanding of the drivers that shape algal turf productivity across studies and among reefs is limited. Based on published studies we considered how different factors may shape turf productivity and turnover rates. Of the factors considered, depth was the primary driver of turf productivity rates, while turnover was predominantly related to turf biomass. We also highlight shortcomings in the available data collected on turf productivity to-date; most data were collected prior to global coral bleaching events, within a limited geographic range, and were largely from experimental substrata. Despite the fact turfs are a widespread benthic covering on most coral reefs, and one of the major sources of benthic productivity, our understanding of their productivity is constrained by both a paucity of data and methodological limitations. We offer a potential way forward to address these challenges.
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Affiliation(s)
- Sterling B Tebbett
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, 4811, Australia.
| | - David R Bellwood
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, 4811, Australia
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