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Romero J, Alonso H, Freitas L, Granadeiro JP. Food web of the oceanic region of the archipelago of Madeira: The role of marine megafauna in the subtropical northeast Atlantic ecosystem. MARINE ENVIRONMENTAL RESEARCH 2024; 195:106382. [PMID: 38309039 DOI: 10.1016/j.marenvres.2024.106382] [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: 06/09/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 02/05/2024]
Abstract
Many oceanic areas are still in need of baseline information on their structure and functioning. This is particularly important due to the ever-increasing impacts of global changes, which have led to the decline of marine life, and top predators in particular. The study of the structure and functioning of food webs can help understand the consequences of the disappearance of this group in marine ecosystems. Here, we develop a mass-balanced model for the marine Exclusive Economic Zone of the archipelago of Madeira, with emphasis on the role of marine megafauna in this ecosystem. A total of 50 functional groups were defined, representing coastal and open ocean areas, and epipelagic and deep-sea levels. The total biomass of the Madeira system was calculated at 52.68 t km-2, with lower trophic level organisms comprising 89.9 % of its biomass. Marine megafauna, namely pelagic sharks and coastal birds had the highest impacts across other trophic levels and were classified as keystone species, together with monk seals. The food web was characterized by a linear-like food chain, with a large proportion of specialized organisms, including dolphins, shearwaters, and large pelagic fish. The low mean trophic level of the system was 2.03, much lower than that of fisheries (4.3) targeting mainly tunas and Black scabbardfish. Considering the importance of marine megafauna in this food web and the threats they are facing; monitoring studies of key species in the region should be a priority. This study can now be used to build a needed ecosystem-based fisheries management and integrate conservation measures to declining species.
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Affiliation(s)
- Joana Romero
- Centre for Environmental and Marine Studies (CESAM), Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal.
| | - Hany Alonso
- Sociedade Portuguesa para o Estudo das Aves, Av. Alm. Gago Coutinho 46A, 1700-031, Lisbon, Portugal
| | - Luís Freitas
- Museu da Baleia da Madeira, Rua Garcia Moniz 1, 9200-031, Caniçal, Madeira, Portugal
| | - José Pedro Granadeiro
- Centre for Environmental and Marine Studies (CESAM), Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal
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Campioni L, Dell'Omo G, Vizzini S, De Pascalis F, Badalamenti F, Massa B, Rubolini D, Cecere JG. Year-round variation in the isotopic niche of Scopoli's shearwater (Calonectris diomedea) breeding in contrasting sea regions of the Mediterranean Sea. MARINE ENVIRONMENTAL RESEARCH 2022; 178:105650. [PMID: 35644078 DOI: 10.1016/j.marenvres.2022.105650] [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: 12/02/2021] [Revised: 05/11/2022] [Accepted: 05/14/2022] [Indexed: 06/15/2023]
Abstract
Top marine predators are key components of marine food webs. Among them, long-distance migratory seabirds, which travel across different marine ecosystems over the year, may experience important year-round changes in terms of oceanographic conditions and availability of trophic resources. We tested whether this was the case in the Scopoli's shearwater (Calonectris diomedea), a trans-equatorial migrant and top predator, by sampling birds breeding in three environmentally different regions of the Mediterranean Sea. The analysis of positional data and stable isotopes (δ1³C and δ15N) of target feathers revealed that birds from the three regions were spatially segregated during the breeding period while they shared non-breeding areas in the Atlantic Ocean. Isotopic baseline levels of N and C (meso-zooplankton) were significantly different among marine regions during breeding. Such variation was reflected at the higher trophic levels of pelagic and demersal fish muscles as well as in shearwater feathers grown in the Mediterranean. δ15N- and δ13C-adjusted values of shearwaters were significantly different among populations suggesting that birds from different breeding areas relied on prey species from different trophic levels. Conversely, the non-breeding spatial and isotopic niches overlapped greatly among the three populations. Shearwater trophic niches during breeding were narrower and segregated compared to the non-breeding period, revealing a high plasticity in trophic resource use. Overall, this study highlights seasonal and region-specific use of trophic resources by Scopoli's shearwater, suggesting a broad trophic plasticity and possibly a high adaptability to environmental changes.
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Affiliation(s)
- Letizia Campioni
- MARE - Marine and Environmental Sciences Center, Ispa - Instituto Universitário, Rua Jardim Do Tabaco 34, 1149-041, Lisbon, Portugal.
| | | | - Salvatrice Vizzini
- Dipartimento di Scienze Della Terra e Del Mare, Università Degli Studi di Palermo, Via Archirafi 18, 90123, Palermo, Italy; Consorzio Nazionale Interuniversitario per le Scienze Del Mare, CoNISMa, Piazzale Flaminio 9, 00196, Roma, Italy
| | - Federico De Pascalis
- Dipartimento di Scienze e Politiche Ambientali, Università Degli Studi di Milano, Via Celoria 26 I, 20133, Milano, Italy
| | - Fabio Badalamenti
- Institute of Anthropic Impacts and Sustainability in Marine Environment (CNR-IAS), Via Lungomare Cristoforo Colombo 4521, 90149, Palermo, Italy
| | | | - Diego Rubolini
- Dipartimento di Scienze e Politiche Ambientali, Università Degli Studi di Milano, Via Celoria 26 I, 20133, Milano, Italy; Istituto di Ricerca Sulle Acque, IRSA-CNR, Via Del Mulino 19 I, 20861, Brugherio, (MB), Italy
| | - Jacopo G Cecere
- Area Avifauna Migratrice, Istituto Superiore per La Protezione e La Ricerca Ambientale (ISPRA), Ozzano Emilia, (BO), Italy
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Cuesta-García M, Rodríguez A, Martins AM, Neves V, Magalhães M, Atchoi E, Fraga H, Medeiros V, Laranjo M, Rodríguez Y, Jones K, Bried J. Targeting efforts in rescue programmes mitigating light-induced seabird mortality: First the fat, then the skinny. J Nat Conserv 2022. [DOI: 10.1016/j.jnc.2021.126080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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