1
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Lange ID, Benkwitt CE. Seabird nutrients increase coral calcification rates and boost reef carbonate production. Sci Rep 2024; 14:24937. [PMID: 39438679 PMCID: PMC11496823 DOI: 10.1038/s41598-024-76759-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2024] [Accepted: 10/16/2024] [Indexed: 10/25/2024] Open
Abstract
While excessive anthropogenic nutrient loads are harmful to coral reefs, natural nutrient flows can boost coral growth and reef functions. Here we investigate if seabird-derived nutrient subsidies benefit the growth of two dominant corals on lagoonal reefs, submassive Isopora palifera and corymbose Acropora vermiculata, and if enhanced colony-level calcification rates can increase reef-scale carbonate production. I. palifera and A. vermiculata colonies close to an island with high seabird densities displayed 1.4 and 3.2-times higher linear extension rates, 1.8 and 3.9-times faster planar area increase, and 1.6 and 2.7-times higher calcification rates compared to colonies close to a nearby island with low seabird densities, respectively. While benthic ReefBudget surveys in combination with average coral growth rates did not indicate differences in reef-scale carbonate production across sites, coral carbonate production was 2.2-times higher at the seabird-rich island when using site-specific linear growth rates and skeletal densities. This study shows that seabird-derived nutrients benefit fast-growing branching as well as previously unstudied submassive coral taxa. It also demonstrates that nutrient subsidies benefit colony-scale and reef-scale calcification rates, which underpin important geo-ecological reef functions. Restoring natural nutrient pathways should thus be a priority for island and reef management.
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2
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Dunn RE, Benkwitt CE, Maury O, Barrier N, Carr P, Graham NAJ. Island restoration to rebuild seabird populations and amplify coral reef functioning. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2024:e14313. [PMID: 38887868 DOI: 10.1111/cobi.14313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 03/19/2024] [Accepted: 04/15/2024] [Indexed: 06/20/2024]
Abstract
Mobile organisms like seabirds can provide important nutrient flows between ecosystems, but this connectivity has been interrupted by the degradation of island ecosystems. Island restoration (via invasive species eradications and the restoration of native vegetation) can reestablish seabird populations and their nutrient transfers between their foraging areas, breeding colonies, and adjacent nearshore habitats. Its diverse benefits are making island restoration increasingly common and scalable to larger islands and whole archipelagos. We identified the factors that influence breeding seabird abundances throughout the Chagos Archipelago in the Indian Ocean and conducted predictive modeling to estimate the abundances of seabirds that the archipelago could support under invasive predator eradication and native vegetation restoration scenarios. We explored whether the prey base exists to support restored seabird populations across the archipelago, calculated the nitrogen that restored populations of seabirds might produce via their guano, and modeled the cascading conservation gains that island restoration could provide. Restoration was predicted to increase breeding pairs of seabirds to over 280,000, and prey was predicted to be ample to support the revived seabird populations. Restored nutrient fluxes were predicted to result in increases in coral growth rates, reef fish biomasses, and parrotfish grazing and bioerosion rates. Given these potential cross-ecosystem benefits, our results support island restoration as a conservation priority that could enhance resilience to climatic change effects, such as sea-level rise and coral bleaching. We encourage the incorporation of our estimates of cross-ecosystem benefits in prioritization exercises for island restoration.
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Affiliation(s)
- Ruth E Dunn
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
- The Lyell Centre, Heriot-Watt University, Edinburgh, UK
| | | | - Olivier Maury
- Institut de Recherche pour le Développement, Université de Montpellier, Sète, France
| | - Nicolas Barrier
- Institut de Recherche pour le Développement, Université de Montpellier, Sète, France
| | - Peter Carr
- Institute of Zoology, Zoological Society of London, London, UK
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3
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Peller T, Altermatt F. Invasive species drive cross-ecosystem effects worldwide. Nat Ecol Evol 2024; 8:1087-1097. [PMID: 38503866 DOI: 10.1038/s41559-024-02380-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 02/13/2024] [Indexed: 03/21/2024]
Abstract
Invasive species are pervasive around the world and have profound impacts on the ecosystem they invade. Invasive species, however, can also have impacts beyond the ecosystem they invade by altering the flow of non-living materials (for example, nutrients or chemicals) or movement of organisms across the boundaries of the invaded ecosystem. Cross-ecosystem interactions via spatial flows are ubiquitous in nature, for example, connecting forests and lakes, grasslands and rivers, and coral reefs and the deep ocean. Yet, we have a limited understanding of the cross-ecosystem impacts invasive species have relative to their local effects. By synthesizing emerging evidence, here we demonstrate the cross-ecosystem impacts of invasive species as a ubiquitous phenomenon that influences biodiversity and ecosystem functioning around the world. We identify three primary ways by which invasive species have cross-ecosystem effects: first, by altering the magnitude of spatial flows across ecosystem boundaries; second, by altering the quality of spatial flows; and third, by introducing novel spatial flows. Ultimately, the strong impacts invasive species can drive across ecosystem boundaries suggests the need for a paradigm shift in how we study and manage invasive species around the world, expanding from a local to a cross-ecosystem perspective.
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Affiliation(s)
- Tianna Peller
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland.
- Department of Aquatic Ecology, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.
| | - Florian Altermatt
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland.
- Department of Aquatic Ecology, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.
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4
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Appoo J, Bunbury N, Jaquemet S, Graham NA. Seabird nutrient subsidies enrich mangrove ecosystems and are exported to nearby coastal habitats. iScience 2024; 27:109404. [PMID: 38510135 PMCID: PMC10952037 DOI: 10.1016/j.isci.2024.109404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 01/19/2024] [Accepted: 02/29/2024] [Indexed: 03/22/2024] Open
Abstract
Eutrophication by human-derived nutrient enrichment is a major threat to mangroves, impacting productivity, ecological functions, resilience, and ecosystem services. Natural mangrove nutrient enrichment processes, however, remain largely uninvestigated. Mobile consumers such as seabirds are important vectors of cross-ecosystem nutrient subsidies to islands but how they influence mangrove ecosystems is poorly known. We assessed the contribution, uptake, cycling, and transfer of nutrients from seabird colonies in remote mangrove systems free of human stressors. We found that nutrients from seabird guano enrich mangrove plants, reduce nutrient limitations, enhance mangrove invertebrate food webs, and are exported to nearby coastal habitats through tidal flow. We show that seabird nutrient subsidies in mangroves can be substantial, improving the nutrient status and health of mangroves and adjacent coastal habitats. Conserving mobile consumers, such as seabirds, is therefore vital to preserve and enhance their role in mangrove productivity, resilience, and provision of diverse functions and services.
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Affiliation(s)
- Jennifer Appoo
- UMR ENTROPIE, Université de La Réunion, 97744 Saint Denis Cedex 9, La Réunion, France
- Seychelles Islands Foundation, Victoria, Mahé, Seychelles
| | - Nancy Bunbury
- Seychelles Islands Foundation, Victoria, Mahé, Seychelles
- Centre for Ecology and Conservation, University of Exeter, Cornwall TR10 9FE, UK
| | - Sébastien Jaquemet
- UMR ENTROPIE, Université de La Réunion, 97744 Saint Denis Cedex 9, La Réunion, France
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5
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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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6
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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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7
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Spatz DR, Young LC, Holmes ND, Jones HP, VanderWerf EA, Lyons DE, Kress S, Miskelly CM, Taylor GA. Tracking the global application of conservation translocation and social attraction to reverse seabird declines. Proc Natl Acad Sci U S A 2023; 120:e2214574120. [PMID: 37036988 PMCID: PMC10120044 DOI: 10.1073/pnas.2214574120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 03/06/2023] [Indexed: 04/12/2023] Open
Abstract
The global loss of biodiversity has inspired actions to restore nature across the planet. Translocation and social attraction actions deliberately move or lure a target species to a restoration site to reintroduce or augment populations and enhance biodiversity and ecosystem resilience. Given limited conservation funding and rapidly accelerating extinction trajectories, tracking progress of these interventions can inform best practices and advance management outcomes. Seabirds are globally threatened and commonly targeted for translocation and social attraction ("active seabird restoration"), yet no framework exists for tracking these efforts nor informing best practices. This study addresses this gap for conservation decision makers responsible for seabirds and coastal management. We systematically reviewed active seabird restoration projects worldwide and collated results into a publicly accessible Seabird Restoration Database. We describe global restoration trends, apply a systematic process to measure success rates and response times since implementation, and examine global factors influencing outcomes. The database contains 851 active restoration events in 551 locations targeting 138 seabird species; 16% of events targeted globally threatened taxa. Visitation occurred in 80% of events and breeding occurred in 76%, on average 2 y after implementation began (SD = 3.2 y). Outcomes varied by taxonomy, with the highest and quickest breeding response rates for Charadriiformes (terns, gulls, and auks), primarily with social attraction. Given delayed and variable response times to active restoration, 5 y is appropriate before evaluating outcomes. The database and results serve as a model for tracking and evaluating restoration outcomes, and is applicable to measuring conservation interventions for additional threatened taxa.
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Affiliation(s)
| | | | | | - Holly P. Jones
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL60115
- Institute for the Study of the Environment, Sustainability, and Energy, Northern Illinois University, DeKalb, IL60115
| | | | - Donald E. Lyons
- National Audubon Society, Seabird Institute, Bremen, ME04551
| | - Stephen Kress
- National Audubon Society, Seabird Institute, Bremen, ME04551
- Cornell Lab of Ornithology, Ithaca, NY14850
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8
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Gunn RL, Benkwitt CE, Graham NAJ, Hartley IR, Algar AC, Keith SA. Terrestrial invasive species alter marine vertebrate behaviour. Nat Ecol Evol 2023; 7:82-91. [PMID: 36604551 PMCID: PMC9834043 DOI: 10.1038/s41559-022-01931-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/12/2022] [Indexed: 01/07/2023]
Abstract
Human-induced environmental changes, such as the introduction of invasive species, are driving declines in the movement of nutrients across ecosystems with negative consequences for ecosystem function. Declines in nutrient inputs could thus have knock-on effects at higher trophic levels and broader ecological scales, yet these interconnections remain relatively unknown. Here we show that a terrestrial invasive species (black rats, Rattus rattus) disrupts a nutrient pathway provided by seabirds, ultimately altering the territorial behaviour of coral reef fish. In a replicated ecosystem-scale natural experiment, we found that reef fish territories were larger and the time invested in aggression lower on reefs adjacent to rat-infested islands compared with rat-free islands. This response reflected changes in the economic defendability of lower-quality resources, with reef fish obtaining less nutritional gain per unit foraging effort adjacent to rat-infested islands with low seabird populations. These results provide a novel insight into how the disruption of nutrient flows by invasive species can affect variation in territorial behaviour. Rat eradication as a conservation strategy therefore has the potential to restore species interactions via territoriality, which can scale up to influence populations and communities at higher ecological levels.
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Affiliation(s)
- Rachel L Gunn
- Lancaster Environment Centre, Lancaster University, Lancaster, UK.
| | | | | | - Ian R Hartley
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Adam C Algar
- Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada
| | - Sally A Keith
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
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9
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Demystifying ecological connectivity for actionable spatial conservation planning. Trends Ecol Evol 2022; 37:1079-1091. [PMID: 36182406 DOI: 10.1016/j.tree.2022.09.002] [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: 03/10/2022] [Revised: 08/25/2022] [Accepted: 09/06/2022] [Indexed: 01/12/2023]
Abstract
Connectivity underpins the persistence of life; it needs to inform biodiversity conservation decisions. Yet, when prioritising conservation areas and developing actions, connectivity is not being operationalised in spatial planning. The challenge is the translation of flows associated with connectivity into conservation objectives that lead to actions. Connectivity is nebulous, it can be abstract and mean different things to different people, making it difficult to include in conservation problems. Here, we show how connectivity can be included in mathematically defining conservation planning objectives. We provide a path forward for linking connectivity to high-level conservation goals, such as increasing species' persistence. We propose ways to design spatial management areas that gain biodiversity benefit from connectivity.
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10
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Letessier TB, Johnston J, Delarue J, Martin B, Anderson RC. Spinner dolphin residency in tropical atoll lagoons: Diurnal presence, seasonal variability and implications for nutrient dynamics. J Zool (1987) 2022. [DOI: 10.1111/jzo.13000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- T. B. Letessier
- Institute of Zoology, Zoological Society of London Regent's Park London UK
- School of Biological Sciences University of Western Australia Perth SA Australia
| | - J. Johnston
- Institute of Zoology, Zoological Society of London Regent's Park London UK
- University College London London UK
| | - J. Delarue
- JASCO Applied Sciences The Roundel, St Clair's Farm Droxford UK
| | - B. Martin
- JASCO Applied Sciences The Roundel, St Clair's Farm Droxford UK
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11
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Gaiotto JV, Nunes GT, Bugoni L. Dissipation of seabird‐derived nutrients in a terrestrial insular trophic web. AUSTRAL ECOL 2022. [DOI: 10.1111/aec.13196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Juliana Vallim Gaiotto
- Waterbirds and Sea Turtles Laboratory Institute of Biological Sciences Universidade Federal do Rio Grande – FURG Avenida Itália, Km 8, Campus Carreiros Rio Grande RS 96203‐900 Brazil
| | - Guilherme Tavares Nunes
- Centro de Estudos Costeiros, Limnológicos e Marinhos Universidade Federal do Rio Grande do Sul – UFRGS Imbé Brazil
| | - Leandro Bugoni
- Waterbirds and Sea Turtles Laboratory Institute of Biological Sciences Universidade Federal do Rio Grande – FURG Avenida Itália, Km 8, Campus Carreiros Rio Grande RS 96203‐900 Brazil
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12
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Benkwitt CE, Carr P, Wilson SK, Graham NAJ. Seabird diversity and biomass enhance cross-ecosystem nutrient subsidies. Proc Biol Sci 2022; 289:20220195. [PMID: 35538790 PMCID: PMC9091852 DOI: 10.1098/rspb.2022.0195] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Mobile consumers are key vectors of cross-ecosystem nutrients, yet have experienced population declines which threaten their ability to fill this role. Despite their importance and vulnerability, there is little information on how consumer biodiversity, in addition to biomass, influences the magnitude of nutrient subsidies. Here, we show that both biomass and diversity of seabirds enhanced the provisioning of nutrients across tropical islands and coral reefs, but their relative influence varied across systems. Seabird biomass was particularly important for terrestrial and near-shore subsidies and enhancing fish biomass, while seabird diversity was associated with nutrient subsidies further offshore. The positive effects of diversity were likely driven by high functional complementarity among seabird species in traits related to nutrient storage and provisioning. However, introduced rats and non-native vegetation reduced seabird biomass and diversity, with rats having a stronger effect on biomass and vegetation having a stronger effect on diversity. Accordingly, the restoration of cross-ecosystem nutrient flows provided by seabirds will likely be most successful when both stressors are removed, thus protecting both high biomass and diversity. Recognizing the importance of mobile consumer diversity and biomass, and their underlying drivers, is a necessary step to conserving these species and the ecosystem functions they provide.
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Affiliation(s)
| | - Peter Carr
- Institute of Zoology, Zoological Society of London, Outer Circle, Regent's Park, London NW1 4RY, UK,Chagos Conservation Trust, 23 The Avenue, Sandy, Beds SG19 1ER, UK
| | - Shaun K. Wilson
- Marine Science Program, Department of Biodiversity Conservation and Attractions, Kensington, Western Australia, Australia,Oceans Institute, University of Western Australia, Crawly, Western Australia, Australia
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13
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Longley-Wood K, Engels M, Lafferty KD, McLaughlin JP, Wegmann A. Transforming Palmyra Atoll to native-tree dominance will increase net carbon storage and reduce dissolved organic carbon reef runoff. PLoS One 2022; 17:e0262621. [PMID: 35061815 PMCID: PMC8782295 DOI: 10.1371/journal.pone.0262621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 12/29/2021] [Indexed: 11/19/2022] Open
Abstract
Native forests on tropical islands have been displaced by non-native species, leading to calls for their transformation. Simultaneously, there is increasing recognition that tropical forests can help sequester carbon that would otherwise enter the atmosphere. However, it is unclear if native forests sequester more or less carbon than human-altered landscapes. At Palmyra Atoll, efforts are underway to transform the rainforest composition from coconut palm (Cocos nucifera) dominated to native mixed-species. To better understand how this landscape-level change will alter the atoll's carbon dynamics, we used field sampling, remote sensing, and parameter estimates from the literature to model the total carbon accumulation potential of Palmyra's forest before and after transformation. The model predicted that replacing the C. nucifera plantation with native species would reduce aboveground biomass from 692.6 to 433.3 Mg C. However, expansion of the native Pisonia grandis and Heliotropium foertherianum forest community projected an increase in soil carbon to at least 13,590.8 Mg C, thereby increasing the atoll's overall terrestrial carbon storage potential by 11.6%. Nearshore sites adjacent to C. nucifera canopy had a higher dissolved organic carbon (DOC) concentration (110.0 μMC) than sites adjacent to native forest (81.5 μMC), suggesting that, in conjunction with an increase in terrestrial carbon storage, replacing C. nucifera with native forest will reduce the DOC exported from the forest into in nearshore marine habitats. Lower DOC levels have potential benefits for corals and coral dependent communities. For tropical islands like Palmyra, reverting from C. nucifera dominance to native tree dominance could buffer projected climate change impacts by increasing carbon storage and reducing coral disease.
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Affiliation(s)
- Kate Longley-Wood
- The Nature Conservancy, Protect Oceans Land and Water Program, Boston, Massachusetts, United States of America
| | - Mary Engels
- Department of Natural Resources and Society, University of Idaho, Moscow, Idaho, United States of America
| | - Kevin D. Lafferty
- U.S. Geological Survey, Western Ecological Research Center at Marine Science Institute, University of California, Santa Barbara, Santa Barbara, California, United States of America
| | - John P. McLaughlin
- University of California, Santa Barbara, Marine Science Institute, Santa Barbara, California, United States of America
| | - Alex Wegmann
- The Nature Conservancy, Sacramento, California, United States of America
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Hadj-Hammou J, McClanahan TR, Graham NAJ. Decadal shifts in traits of reef fish communities in marine reserves. Sci Rep 2021; 11:23470. [PMID: 34873242 PMCID: PMC8648868 DOI: 10.1038/s41598-021-03038-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 11/26/2021] [Indexed: 11/09/2022] Open
Abstract
Marine reserves are known to impact the biomass, biodiversity, and functions of coral reef fish communities, but the effect of protective management on fish traits is less explored. We used a time-series modelling approach to simultaneously evaluate the abundance, biomass, and traits of eight fish families over a chronosequence spanning 44 years of protection. We constructed a multivariate functional space based on six traits known to respond to management or disturbance and affect ecosystem processes: size, diet, position in the water column, gregariousness, reef association, and length at maturity. We show that biomass increased with a log-linear trend over the time-series, but abundance only increased after 20 years of closure, and with more variation among reserves. This difference is attributed to recovery rates being dependent on body sizes. Abundance-weighted traits and the associated multivariate space of the community change is driven by increased proportions over time of the trait categories: 7-15 cm body size; planktivorous; species low in the water column; medium-large schools; and species with high levels of reef association. These findings suggest that the trait compositions emerging after the cessation of fishing are novel and dynamic.
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Affiliation(s)
- Jeneen Hadj-Hammou
- Lancaster University Environment Centre, Lancaster University, Lancaster, UK.
| | - Tim R McClanahan
- Wildlife Conservation Society, Global Marine Programs, Bronx, NY, 10460, USA
| | - Nicholas A J Graham
- Lancaster University Environment Centre, Lancaster University, Lancaster, UK
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15
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Do Invasive Mammal Eradications from Islands Support Climate Change Adaptation and Mitigation? CLIMATE 2021. [DOI: 10.3390/cli9120172] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Climate change represents a planetary emergency that is exacerbating the loss of native biodiversity. In response, efforts promoting climate change adaptation strategies that improve ecosystem resilience and/or mitigate climate impacts are paramount. Invasive Alien Species are a key threat to islands globally, where strategies such as preventing establishment (biosecurity), and eradication, especially invasive mammals, have proven effective for reducing native biodiversity loss and can also advance ecosystem resilience and create refugia for native species at risk from climate change. Furthermore, there is growing evidence that successful eradications may also contribute to mitigating climate change. Given the cross-sector potential for eradications to reduce climate impacts alongside native biodiversity conservation, we sought to understand when conservation managers and funders explicitly sought to use or fund the eradication of invasive mammals from islands to achieve positive climate outcomes. To provide context, we first summarized available literature of the synergistic relationship between invasive species and climate change, including case studies where invasive mammal eradications served to meet climate adaptation or mitigation solutions. Second, we conducted a systematic review of the literature and eradication-related conference proceedings to identify when these synergistic effects of climate and invasive species were explicitly addressed through eradication practices. Third, we reviewed projects from four large funding entities known to support climate change solutions and/or native biodiversity conservation efforts and identified when eradications were funded in a climate change context. The combined results of our case study summary paired with systematic reviews found that, although eradicating invasive mammals from islands is an effective climate adaptation strategy, island eradications are poorly represented within the climate change adaptation and mitigation funding framework. We believe this is a lost opportunity and encourage eradication practitioners and funders of climate change adaptation to leverage this extremely effective nature-based tool into positive conservation and climate resilience solutions.
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16
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Estimating Pelagic Fish Biomass in a Tropical Seascape Using Echosounding and Baited Stereo-Videography. Ecosystems 2021. [DOI: 10.1007/s10021-021-00723-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Carr P, Trevail A, Bárrios S, Clubbe C, Freeman R, Koldewey HJ, Votier SC, Wilkinson T, Nicoll MAC. Potential benefits to breeding seabirds of converting abandoned coconut plantations to native habitats after invasive predator eradication. Restor Ecol 2021. [DOI: 10.1111/rec.13386] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Peter Carr
- Institute of Zoology Zoological Society of London, Regent's Park London NW1 4RY U.K
- Environment and Sustainability Institute, Centre for Ecology and Conservation University of Exeter, Penryn Campus Cornwall TR10 9EZ U.K
| | - Alice Trevail
- Environment and Sustainability Institute, Centre for Ecology and Conservation University of Exeter, Penryn Campus Cornwall TR10 9EZ U.K
| | - Sara Bárrios
- Conservation Science Royal Botanic Gardens, Kew London TW9 3AE U.K
| | - Colin Clubbe
- Conservation Science Royal Botanic Gardens, Kew London TW9 3AE U.K
| | - Robin Freeman
- Institute of Zoology Zoological Society of London, Regent's Park London NW1 4RY U.K
| | - Heather J. Koldewey
- Institute of Zoology Zoological Society of London, Regent's Park London NW1 4RY U.K
- Environment and Sustainability Institute, Centre for Ecology and Conservation University of Exeter, Penryn Campus Cornwall TR10 9EZ U.K
| | - Stephen C. Votier
- Environment and Sustainability Institute, Centre for Ecology and Conservation University of Exeter, Penryn Campus Cornwall TR10 9EZ U.K
- School of Energy, Geoscience, Infrastructure and Society Heriot‐Watt University Edinburgh EH14 4AS U.K
| | - Tim Wilkinson
- Conservation Science Royal Botanic Gardens, Kew London TW9 3AE U.K
| | - Malcolm A. C. Nicoll
- Institute of Zoology Zoological Society of London, Regent's Park London NW1 4RY U.K
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Benkwitt CE, Gunn RL, Le Corre M, Carr P, Graham NAJ. Rat eradication restores nutrient subsidies from seabirds across terrestrial and marine ecosystems. Curr Biol 2021; 31:2704-2711.e4. [PMID: 33887185 DOI: 10.1016/j.cub.2021.03.104] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 02/04/2021] [Accepted: 03/31/2021] [Indexed: 12/21/2022]
Abstract
Biological invasions pose a threat to nearly every ecosystem worldwide.1,2 Although eradication programs can successfully eliminate invasive species and enhance native biodiversity, especially on islands,3 the effects of eradication on cross-ecosystem processes are unknown. On islands where rats were never introduced, seabirds transfer nutrients from pelagic to terrestrial and nearshore marine habitats, which in turn enhance the productivity, biomass, and functioning of recipient ecosystems.4-6 Here, we test whether rat eradication restores seabird populations, their nutrient subsidies, and some of their associated benefits for ecosystem function to tropical islands and adjacent coral reefs. By comparing islands with different rat invasion histories, we found a clear hierarchy whereby seabird biomass, seabird-driven nitrogen inputs, and the incorporation of seabird-derived nutrients into terrestrial and marine food chains were highest on islands where rats were never introduced, intermediate on islands where rats were eradicated 4-16 years earlier, and lowest on islands with invasive rats still present. Seabird-derived nutrients diminished from land to sea and with increasing distance to rat-eradicated islands, but extended at least 300 m from shore. Although rat eradication enhanced seabird-derived nutrients in soil, leaves, marine algae, and herbivorous reef fish, reef fish growth was similar around rat-eradicated and rat-infested islands. Given that the loss of nutrient subsidies is of global concern,7 that removal of invasive species restores previously lost nutrient pathways over relatively short timescales is promising. However, the full return of cross-ecosystem nutrient subsidies and all of their associated demographic benefits may take multiple decades.
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Affiliation(s)
| | - Rachel L Gunn
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - Matthieu Le Corre
- UMR ENTROPIE, Université de La Réunion, IRD, CNRS, IFREMER, Université de Nouvelle-Calédonie, Avenue René Cassin, 97490 Sainte Clotilde, La Réunion
| | - Peter Carr
- Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK; Environment and Sustainability Institute, University of Exeter, Penryn Campus, Cornwall TR10 9EZ, UK
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Natural nutrient subsidies alter demographic rates in a functionally important coral-reef fish. Sci Rep 2021; 11:12575. [PMID: 34131172 PMCID: PMC8206227 DOI: 10.1038/s41598-021-91884-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 05/31/2021] [Indexed: 11/25/2022] Open
Abstract
By improving resource quality, cross-ecosystem nutrient subsidies may boost demographic rates of consumers in recipient ecosystems, which in turn can affect population and community dynamics. However, empirical studies on how nutrient subsidies simultaneously affect multiple demographic rates are lacking, in part because humans have disrupted the majority of these natural flows. Here, we compare the demographics of a sex-changing parrotfish (Chlorurus sordidus) between reefs where cross-ecosystem nutrients provided by seabirds are available versus nearby reefs where invasive, predatory rats have removed seabird populations. For this functionally important species, we found evidence for a trade-off between investing in growth and fecundity, with parrotfish around rat-free islands with many seabirds exhibiting 35% faster growth, but 21% lower size-based fecundity, than those around rat-infested islands with few seabirds. Although there were no concurrent differences in population-level density or biomass, overall mean body size was 16% larger around rat-free islands. Because the functional significance of parrotfish as grazers and bioeroders increases non-linearly with size, the increased growth rates and body sizes around rat-free islands likely contributes to higher ecosystem function on coral reefs that receive natural nutrient subsidies. More broadly, these results demonstrate additional benefits, and potential trade-offs, of restoring natural nutrient pathways for recipient ecosystems.
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20
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Liao Z, Yu K, Chen B, Huang X, Qin Z, Yu X. Spatial distribution of benthic algae in the South China Sea: Responses to gradually changing environmental factors and ecological impacts on coral communities. DIVERS DISTRIB 2021. [DOI: 10.1111/ddi.13243] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Affiliation(s)
- Zhiheng Liao
- Coral Reef Research Center of China Guangxi University Nanning China
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea Guangxi University Nanning China
- School of Marine Sciences Guangxi University Nanning China
| | - Kefu Yu
- Coral Reef Research Center of China Guangxi University Nanning China
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea Guangxi University Nanning China
- School of Marine Sciences Guangxi University Nanning China
- Southern Marine Science and Engineering Guangdong Laboratory Zhuhai China
| | - Biao Chen
- Coral Reef Research Center of China Guangxi University Nanning China
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea Guangxi University Nanning China
- School of Marine Sciences Guangxi University Nanning China
| | - Xueyong Huang
- Coral Reef Research Center of China Guangxi University Nanning China
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea Guangxi University Nanning China
- School of Marine Sciences Guangxi University Nanning China
| | - Zhenjun Qin
- Coral Reef Research Center of China Guangxi University Nanning China
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea Guangxi University Nanning China
- School of Marine Sciences Guangxi University Nanning China
| | - Xiaopeng Yu
- Coral Reef Research Center of China Guangxi University Nanning China
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea Guangxi University Nanning China
- School of Marine Sciences Guangxi University Nanning China
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21
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Knowlton N. Ocean Optimism: Moving Beyond the Obituaries in Marine Conservation. ANNUAL REVIEW OF MARINE SCIENCE 2021; 13:479-499. [PMID: 32503374 DOI: 10.1146/annurev-marine-040220-101608] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
While the ocean has suffered many losses, there is increasing evidence that important progress is being made in marine conservation. Examples include striking recoveries of once-threatened species, increasing rates of protection of marine habitats, more sustainably managed fisheries and aquaculture, reductions in some forms of pollution, accelerating restoration of degraded habitats, and use of the ocean and its habitats to sequester carbon and provide clean energy. Many of these achievements have multiple benefits, including improved human well-being. Moreover, better understanding of how to implement conservation strategies effectively, new technologies and databases, increased integration of the natural and social sciences, and use of indigenous knowledge promise continued progress. Enormous challenges remain, and there is no single solution; successful efforts typically are neither quick nor cheap and require trust and collaboration. Nevertheless, a greater focus on solutions and successes will help them to become the norm rather than the exception.
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Affiliation(s)
- Nancy Knowlton
- National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA;
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Koester A, Migani V, Bunbury N, Ford A, Sanchez C, Wild C. Early trajectories of benthic coral reef communities following the 2015/16 coral bleaching event at remote Aldabra Atoll, Seychelles. Sci Rep 2020; 10:17034. [PMID: 33046828 PMCID: PMC7550576 DOI: 10.1038/s41598-020-74077-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/24/2020] [Indexed: 01/12/2023] Open
Abstract
Documenting post-bleaching trajectories of coral reef communities is crucial to understand their resilience to climate change. We investigated reef community changes following the 2015/16 bleaching event at Aldabra Atoll, where direct human impact is minimal. We combined benthic data collected pre- (2014) and post-bleaching (2016–2019) at 12 sites across three locations (lagoon, 2 m depth; seaward west and east, 5 and 15 m depth) with water temperature measurements. While seaward reefs experienced relative hard coral reductions of 51–62%, lagoonal coral loss was lower (− 34%), probably due to three-fold higher daily water temperature variability there. Between 2016 and 2019, hard coral cover did not change on deep reefs which remained dominated by turf algae and Halimeda, but absolute cover on shallow reefs increased annually by 1.3% (east), 2.3% (west) and 3.0% (lagoon), reaching, respectively, 54%, 68% and 93% of the pre-bleaching cover in 2019. Full recovery at the shallow seaward locations may take at least five more years, but remains uncertain for the deeper reefs. The expected increase in frequency and severity of coral bleaching events is likely to make even rapid recovery as observed in Aldabra’s lagoon too slow to prevent long-term reef degradation, even at remote sites.
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Affiliation(s)
- Anna Koester
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, Leobener Straße 6, 28359, Bremen, Germany.
| | - Valentina Migani
- Institute for Ecology, Faculty of Biology and Chemistry, University of Bremen, Leobener Straße 5, 28359, Bremen, Germany
| | - Nancy Bunbury
- Seychelles Islands Foundation, PO Box 853, Victoria, Mahé, Seychelles.,Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn, TR10 9FE, UK
| | - Amanda Ford
- School of Marine Studies, Faculty of Science, Technology and Environment, University of the South Pacific, Suva, Fiji
| | - Cheryl Sanchez
- Seychelles Islands Foundation, PO Box 853, Victoria, Mahé, Seychelles
| | - Christian Wild
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, Leobener Straße 6, 28359, Bremen, Germany
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23
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Global distribution and conservation status of ecologically rare mammal and bird species. Nat Commun 2020; 11:5071. [PMID: 33033235 PMCID: PMC7545165 DOI: 10.1038/s41467-020-18779-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/09/2020] [Indexed: 01/23/2023] Open
Abstract
Identifying species that are both geographically restricted and functionally distinct, i.e. supporting rare traits and functions, is of prime importance given their risk of extinction and their potential contribution to ecosystem functioning. We use global species distributions and functional traits for birds and mammals to identify the ecologically rare species, understand their characteristics, and identify hotspots. We find that ecologically rare species are disproportionately represented in IUCN threatened categories, insufficiently covered by protected areas, and for some of them sensitive to current and future threats. While they are more abundant overall in countries with a low human development index, some countries with high human development index are also hotspots of ecological rarity, suggesting transboundary responsibility for their conservation. Altogether, these results state that more conservation emphasis should be given to ecological rarity given future environmental conditions and the need to sustain multiple ecosystem processes in the long-term.
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Seraphim MJ, Sloman KA, Alexander ME, Janetski N, Jompa J, Ambo-Rappe R, Snellgrove D, Mars F, Harborne AR. Interactions between coral restoration and fish assemblages: implications for reef management. JOURNAL OF FISH BIOLOGY 2020; 97:633-655. [PMID: 32564370 DOI: 10.1111/jfb.14440] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 06/01/2020] [Accepted: 06/18/2020] [Indexed: 06/11/2023]
Abstract
Corals create complex reef structures that provide both habitat and food for many fish species. Because of numerous natural and anthropogenic threats, many coral reefs are currently being degraded, endangering the fish assemblages they support. Coral reef restoration, an active ecological management tool, may help reverse some of the current trends in reef degradation through the transplantation of stony corals. Although restoration techniques have been extensively reviewed in relation to coral survival, our understanding of the effects of adding live coral cover and complexity on fishes is in its infancy with a lack of scientifically validated research. This study reviews the limited data on reef restoration and fish assemblages, and complements this with the more extensive understanding of complex interactions between natural reefs and fishes and how this might inform restoration efforts. It also discusses which key fish species or functional groups may promote, facilitate or inhibit restoration efforts and, in turn, how restoration efforts can be optimised to enhance coral fish assemblages. By highlighting critical knowledge gaps in relation to fishes and restoration interactions, the study aims to stimulate research into the role of reef fishes in restoration projects. A greater understanding of the functional roles of reef fishes would also help inform whether restoration projects can return fish assemblages to their natural compositions or whether alternative species compositions develop, and over what timeframe. Although alleviation of local and global reef stressors remains a priority, reef restoration is an important tool; an increased understanding of the interactions between replanted corals and the fishes they support is critical for ensuring its success for people and nature.
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Affiliation(s)
- Marie J Seraphim
- School of Health and Life Sciences, University of the West of Scotland, Paisley, UK
| | - Katherine A Sloman
- School of Health and Life Sciences, University of the West of Scotland, Paisley, UK
| | - Mhairi E Alexander
- School of Health and Life Sciences, University of the West of Scotland, Paisley, UK
| | | | - Jamaluddin Jompa
- Faculty of Marine Science and Fisheries, Hasanuddin University, Makassar, Indonesia
| | - Rohani Ambo-Rappe
- Faculty of Marine Science and Fisheries, Hasanuddin University, Makassar, Indonesia
| | - Donna Snellgrove
- Waltham Petcare Science Institute, Melton Mowbray, Leicestershire, UK
| | | | - Alastair R Harborne
- Institute of Environment and Department of Biological Sciences, Florida International University, North Miami, Florida, USA
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26
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Perez‐Correa J, Carr P, Meeuwig JJ, Koldewey HJ, Letessier TB. Climate oscillation and the invasion of alien species influence the oceanic distribution of seabirds. Ecol Evol 2020; 10:9339-9357. [PMID: 32953065 PMCID: PMC7487247 DOI: 10.1002/ece3.6621] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 06/30/2020] [Accepted: 07/09/2020] [Indexed: 12/29/2022] Open
Abstract
Spatial and temporal distribution of seabird transiting and foraging at sea is an important consideration for marine conservation planning. Using at-sea observations of seabirds (n = 317), collected during the breeding season from 2012 to 2016, we built boosted regression tree (BRT) models to identify relationships between numerically dominant seabird species (red-footed booby, brown noddy, white tern, and wedge-tailed shearwater), geomorphology, oceanographic variability, and climate oscillation in the Chagos Archipelago. We documented positive relationships between red-footed booby and wedge-tailed shearwater abundance with the strength in the Indian Ocean Dipole, as represented by the Dipole Mode Index (6.7% and 23.7% contribution, respectively). The abundance of red-footed boobies, brown noddies, and white terns declined abruptly with greater distance to island (17.6%, 34.1%, and 41.1% contribution, respectively). We further quantified the effects of proximity to rat-free and rat-invaded islands on seabird distribution at sea and identified breaking point distribution thresholds. We detected areas of increased abundance at sea and habitat use-age under a scenario where rats are eradicated from invaded nearby islands and recolonized by seabirds. Following rat eradication, abundance at sea of red-footed booby, brown noddy, and white terns increased by 14%, 17%, and 3%, respectively, with no important increase detected for shearwaters. Our results have implication for seabird conservation and island restoration. Climate oscillations may cause shifts in seabird distribution, possibly through changes in regional productivity and prey distribution. Invasive species eradications and subsequent island recolonization can lead to greater access for seabirds to areas at sea, due to increased foraging or transiting through, potentially leading to distribution gains and increased competition. Our approach predicting distribution after successful eradications enables anticipatory threat mitigation in these areas, minimizing competition between colonies and thereby maximizing the risk of success and the conservation impact of eradication programs.
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Affiliation(s)
- Julian Perez‐Correa
- Zoological Society of LondonInstitute of ZoologyLondonUK
- Escuela de Ciencias AmbientalesFacultad de IngenieríaUniversidad Espíritu SantoSamborondónEcuador
- Imperial College LondonLondonUK
| | - Peter Carr
- Zoological Society of LondonInstitute of ZoologyLondonUK
- Centre for Ecology and ConservationUniversity of ExeterCornwallUK
| | - Jessica J. Meeuwig
- Centre for Marine Futures, Oceans Institute and School of Animal BiologyThe University of Western AustraliaCrawleyWAAustralia
| | - Heather J. Koldewey
- Centre for Ecology and ConservationUniversity of ExeterCornwallUK
- Conservation and PolicyZoological Society of LondonLondonUK
| | - Tom B. Letessier
- Zoological Society of LondonInstitute of ZoologyLondonUK
- Centre for Marine Futures, Oceans Institute and School of Animal BiologyThe University of Western AustraliaCrawleyWAAustralia
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27
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Biodiversity increases ecosystem functions despite multiple stressors on coral reefs. Nat Ecol Evol 2020; 4:919-926. [PMID: 32424279 DOI: 10.1038/s41559-020-1203-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 04/08/2020] [Indexed: 11/08/2022]
Abstract
Positive relationships between biodiversity and ecosystem functioning (BEF) highlight the importance of conserving biodiversity to maintain key ecosystem functions and associated services. Although natural systems are rapidly losing biodiversity due to numerous human-caused stressors, our understanding of how multiple stressors influence BEF relationships comes largely from small, experimental studies. Here, using remote assemblages of coral reef fishes, we demonstrate strong, non-saturating relationships of biodiversity with two ecosystem functions: biomass and productivity. These positive relationships were robust both to an extreme heatwave that triggered coral bleaching and to invasive rats which disrupt nutrient subsidies from native seabirds. Despite having only minor effects on BEF relationships, both stressors still decreased ecosystem functioning via other pathways. The extreme heatwave reduced biodiversity, which, due to the strong BEF relationships, ultimately diminished both ecosystem functions. Conversely, the loss of cross-system nutrient subsidies directly decreased biomass. These results demonstrate multiple ways by which human-caused stressors can reduce ecosystem functioning, despite robust BEF relationships, in natural high-diversity assemblages.
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28
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Perry CT, Morgan KM, Lange ID, Yarlett RT. Bleaching-driven reef community shifts drive pulses of increased reef sediment generation. ROYAL SOCIETY OPEN SCIENCE 2020; 7:192153. [PMID: 32431891 PMCID: PMC7211869 DOI: 10.1098/rsos.192153] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 03/27/2020] [Indexed: 05/26/2023]
Abstract
The ecological impacts of coral bleaching on reef communities are well documented, but resultant impacts upon reef-derived sediment supply are poorly quantified. This is an important knowledge gap because these biogenic sediments underpin shoreline and reef island maintenance. Here, we explore the impacts of the 2016 bleaching event on sediment generation by two dominant sediment producers (parrotfish and Halimeda spp.) on southern Maldivian reefs. Our data identifies two pulses of increased sediment generation in the 3 years since bleaching. The first occurred within approximately six months after bleaching as parrotfish biomass and resultant erosion rates increased, probably in response to enhanced food availability. The second pulse occurred 1 to 3 years post-bleaching, after further increases in parrotfish biomass and a major (approx. fourfold) increase in Halimeda spp. abundance. Total estimated sediment generation from these two producers increased from approximately 0.5 kg CaCO3 m-2 yr-1 (pre-bleaching; 2016) to approximately 3.7 kg CaCO3 m-2 yr-1 (post-bleaching; 2019), highlighting the strong links between reef ecology and sediment generation. However, the relevance of this sediment for shoreline maintenance probably diverges with each producer group, with parrotfish-derived sediment a more appropriate size fraction to potentially contribute to local island shorelines.
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Affiliation(s)
- Chris T. Perry
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
| | - Kyle M. Morgan
- Asian School of the Environment, Nanyang Technological University, Singapore639798, Singapore
| | - Ines D. Lange
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
| | - Robert T. Yarlett
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
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29
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Suggett DJ, Smith DJ. Coral bleaching patterns are the outcome of complex biological and environmental networking. GLOBAL CHANGE BIOLOGY 2020; 26:68-79. [PMID: 31618499 DOI: 10.1111/gcb.14871] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 09/20/2019] [Indexed: 05/26/2023]
Abstract
Continued declines in coral reef health over the past three decades have been punctuated by severe mass coral bleaching-induced mortality events that have grown in intensity and frequency under climate change. Intensive global research efforts have therefore persistently focused on bleaching phenomena to understand where corals bleach, when and why-resulting in a large-yet still somewhat patchy-knowledge base. Particularly catastrophic bleaching-induced coral mortality events in the past 5 years have catalyzed calls for a more diverse set of reef management tools, extending far beyond climate mitigation and reef protection, to also include more aggressive interventions. However, the effectiveness of these various tools now rests on rapidly assimilating our knowledge base of coral bleaching into more integrated frameworks. Here, we consider how the past three decades of intensive coral bleaching research has established the basis for complex biological and environmental networks, which together regulate outcomes of bleaching severity. We discuss how we now have enough scaffold for conceptual biological and environmental frameworks underpinning bleaching susceptibility, but that new tools are urgently required to translate this to an operational system informing-and testing-bleaching outcomes. Specifically, adopting network models that can fully describe and predict metabolic functioning of coral holobionts, and how this functioning is regulated by complex doses and interactions among environmental factors. Identifying knowledge gaps limiting operation of such models is the logical step to immediately guide and prioritize future experiments and observations. We are at a time-critical point where we can implement new capacity to resolve how coral bleaching patterns emerge from complex biological-environmental networks, and so more effectively inform rapidly evolving ecological management and social adaptation frameworks aimed at securing the future of coral reefs.
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Affiliation(s)
- David J Suggett
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - David J Smith
- Coral Reef Research Unit, School of Biological Sciences, University of Essex, Colchester, UK
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30
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Affiliation(s)
- M Thibault
- Laboratoire d'Excellence Labex-CORAIL, Institut de Recherche pour le Développement (IRD), UMR ENTROPIE (IRD-Université de La Réunion-CNRS), BP A5, Nouméa Cedex 98848, New Caledonia, France.
| | - F Houlbrèque
- Laboratoire d'Excellence Labex-CORAIL, Institut de Recherche pour le Développement (IRD), UMR ENTROPIE (IRD-Université de La Réunion-CNRS), BP A5, Nouméa Cedex 98848, New Caledonia, France
| | - A Lorrain
- University of Brest, CNRS, IRD, Ifremer, LEMAR, F-29280 Plouzane, France
| | - E Vidal
- Laboratoire d'Excellence Labex-CORAIL, Institut de Recherche pour le Développement (IRD), UMR ENTROPIE (IRD-Université de La Réunion-CNRS), BP A5, Nouméa Cedex 98848, New Caledonia, France
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