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Espíndola WD, Carlo TA. Seabird guano inputs increase impacts from introduced mammals on the native plants and animals of an oceanic island. Oecologia 2024; 204:975-984. [PMID: 38597960 DOI: 10.1007/s00442-024-05546-7] [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: 01/23/2024] [Accepted: 02/20/2024] [Indexed: 04/11/2024]
Abstract
Seabirds create fluxes of nutrients from marine to terrestrial ecosystems that influence the food webs of small islands. We investigated how guano inputs shape terrestrial food webs by comparing species of selected plant and animal species in a red-footed booby colony in Mona Island (Puerto Rico, Caribbean Sea), to sites of the island lacking guano inputs. We quantified guano deposition and its relationship to plant biomass production, fecundity and density, as well as the activity of native and introduced animal species. In general, guano inputs increased the gross primary plant productivity, size, and fecundity by twofold. Guano inputs were also associated with twofold increases in density of Anole lizards, but also to increases in the activity of introduced pigs (> 500%), goats (> 30%), and cats (> 500%), which negatively impact native species. In particular, elevated pig and cat activity within the booby colony was correlated with lower activity of endemic ground lizards and of introduced rats. Our results also suggest that severe droughts associated with climate change exacerbate the negative effects that introduced species have on vegetation and reduce the positive effects of seabird guano inputs. Our findings underscore the importance of allochthonous guano inputs in subsidizing plant productivity and native and endemic species in small oceanic islands, but also in increasing the negative impacts of introduced mammals. Management and conservation efforts should focus on the exclusion (or eradication) of introduced mammals, particularly pigs and goats, from remnant seabird colonies in Mona Island.
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Affiliation(s)
- Walter D Espíndola
- Biology Department and Ecology Program, The Pennsylvania State University, University Park, PA, USA
| | - Tomás A Carlo
- Biology Department and Ecology Program, The Pennsylvania State University, University Park, PA, USA.
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Assis CL, Novaes CM, Dias MAPC, Guedes JJM, Feio RN, Garbino GST. Predation of vertebrates by domestic cats in two Brazilian hotspots: incidental records and literature review. NEOTROPICAL BIODIVERSITY 2023. [DOI: 10.1080/23766808.2022.2161735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Clodoaldo Lopes Assis
- Programa de Pós-Graduação em Biologia Animal, Departamento de Biologia Animal, Universidade Federal de Viçosa, Viçosa, Brasil
| | - Camila Moura Novaes
- Laboratório de Manejo e Conservação de Fauna, Departamento de Engenharia Florestal, Universidade Federal de Viçosa, Viçosa, Brasil
| | | | - Jhonny José Magalhães Guedes
- Programa de Pós-Graduação em Ecologia e Evolução, Departamento de Ecologia, Universidade Federal de Goiás – Campus Samambaia, Goiânia, Brasil
| | - Renato Neves Feio
- Programa de Pós-Graduação em Biologia Animal, Departamento de Biologia Animal, Universidade Federal de Viçosa, Viçosa, Brasil
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Caseiro-Silva F, Faria FA, Barreto CT, Fernandez CN, Bugoni L. Colonial waterbirds provide persistent subsidies to swamp forests along an estuarine island food chain. Oecologia 2023; 202:113-127. [PMID: 37148379 DOI: 10.1007/s00442-023-05377-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 04/23/2023] [Indexed: 05/08/2023]
Abstract
Birds are excellent vectors of allochthonous matter and energy due to their high mobility, with more intense flow when waterbirds congregate in breeding colonies, feeding in surrounding aquatic and terrestrial areas, and promoting nutritional pulses to nutrient-poor environments. In southern Brazil, a swamp forest on an estuarine island is used by waterbirds for breeding, providing an opportunity to investigate the potential effects of transport of matter between nutrient-rich environments. Soil, plants, invertebrates, and blood from terrestrial birds were collected and stable isotopes compared to similar organisms in a control site without heronries. Values of δ15N and δ13C from waterbirds were higher in the colony in comparison to the control site (spatial effect). The enrichment of 15N and 13C provided during the active colony period persisted after the breeding period, especially for δ15N, which was higher in all compartments (temporal effect). Moreover, the enrichment of 15N occurred along the entire trophic chain (vertical effect) in the colony environment, including different guilds of invertebrates and land birds. The enrichment in 13C seems to lose strength and was mostly explained by factors such as trophic guild rather than site, especially in birds. Bayesian mixture models with terrestrial vs. estuarine endpoints demonstrated that all organisms from both colony and control environments had assimilated estuarine matter. Finally, detritivorous invertebrates showed greater assimilation when compared to other guilds. This study demonstrates that adjacent nutrient-rich environments, such as palustrine forests and estuaries, are nutritionally enriched in several dimensions from nearby autochthonous subsidies that are maintained throughout the year.
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Affiliation(s)
- Felipe Caseiro-Silva
- Laboratório de Aves Aquáticas e Tartarugas Marinhas (LAATM-FURG), Universidade Federal do Rio Grande-FURG, Rio Grande, Brazil.
| | - Fernando Azevedo Faria
- Laboratório de Aves Aquáticas e Tartarugas Marinhas (LAATM-FURG), Universidade Federal do Rio Grande-FURG, Rio Grande, Brazil
| | - Cindy Tavares Barreto
- Laboratório de Aves Aquáticas e Tartarugas Marinhas (LAATM-FURG), Universidade Federal do Rio Grande-FURG, Rio Grande, Brazil
| | - Cínthia Negrine Fernandez
- Laboratório de Aves Aquáticas e Tartarugas Marinhas (LAATM-FURG), Universidade Federal do Rio Grande-FURG, Rio Grande, Brazil
| | - Leandro Bugoni
- Laboratório de Aves Aquáticas e Tartarugas Marinhas (LAATM-FURG), Universidade Federal do Rio Grande-FURG, Rio Grande, Brazil
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Linhares BDA, Bugoni L. Seabirds subsidize terrestrial food webs and coral reefs in a tropical rat-invaded archipelago. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2023; 33:e2733. [PMID: 36057541 DOI: 10.1002/eap.2733] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 06/06/2022] [Accepted: 06/23/2022] [Indexed: 05/23/2023]
Abstract
Allochthonous resource fluxes mediated by organisms crossing ecosystem boundaries may be essential for supporting the structure and function of resource-limited environments, such as tropical islands and surrounding coral reefs. However, invasive species, such as black rats, thrive on tropical islands and disrupt the natural pathways of nutrient subsidies by reducing seabird colonies. Here, we used stable isotopes of nitrogen and carbon to examine the role of seabirds in subsidizing the terrestrial food webs and adjacent coral reefs in the Abrolhos Archipelago, Southwest Atlantic Ocean. By sampling invasive rats and multiple ecosystem compartments (soil, plants, grasshoppers, tarantulas, and lizards) within and outside seabird colonies, we showed that seabird subsidies led to an overall enrichment in 15 N across the food web on islands. However, contrary to other studies, δ15 N values were consistently lower within the seabird colonies, suggesting that a higher seabird presence might produce a localized depletion in 15 N in small islands influenced by seabirds. In contrast, the nitrogen content (%N) in plants and soils was higher inside the colonies, corresponding to a higher effect of seabirds at the base of the trophic web. Among consumers, lizards and invasive rats seemed to obtain allochthonous resources from subsidized terrestrial organisms outside the colony. Inside the colony, however, they showed a more direct consumption of marine matter, suggesting that subsidies benefit these native and invasive animals both directly and indirectly. Nonetheless, in coral reefs, scleractinian corals assimilated seabird-derived nitrogen only around the two smaller and lower-elevation islands, as demonstrated by the substantially higher δ15 N values in relation to the reference areas. This provides evidence that island morphology may influence the incorporation of seabird nutrients in coral reefs around rat-invaded islands, likely because guano lixiviation toward seawater is facilitated in small and low-elevation terrains. Overall, these results showed that seabirds affected small islands across all trophic levels within and outside colonies and that these effects spread outward to coral reefs, evidencing resiliency of seabird subsidies even within a rat-invaded archipelago. Because rats are consumers of seabird chicks and eggs, however, rat eradication could potentially benefit the terrestrial and nearshore ecosystems through increased subsides carried by seabirds.
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Affiliation(s)
- Bruno de Andrade Linhares
- Universidade Federal do Rio Grande (FURG), Programa de Pós-Graduação em Oceanografia Biológica, Rio Grande, Brazil
- Universidade Federal do Rio Grande (FURG), Laboratório de Aves Aquáticas e Tartarugas Marinhas (LAATM), Instituto de Ciências Biológicas, Rio Grande, Brazil
| | - Leandro Bugoni
- Universidade Federal do Rio Grande (FURG), Laboratório de Aves Aquáticas e Tartarugas Marinhas (LAATM), Instituto de Ciências Biológicas, Rio Grande, Brazil
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The foraging ecology of invasive black rats (Rattus rattus) differs in two nearby islands in a dry tropical archipelago in Brazil. Biol Invasions 2022. [DOI: 10.1007/s10530-022-02975-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Balzani P, Haubrock PJ. Expanding the invasion toolbox: including stable isotope analysis in risk assessment. NEOBIOTA 2022. [DOI: 10.3897/neobiota.76.77944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Species introductions are a major concern for ecosystem functioning, socio-economic wealth, and human well-being. Preventing introductions proved to be the most effective management strategy, and various tools such as species distribution models and risk assessment protocols have been developed or applied to this purpose. These approaches use information on a species to predict its potential invasiveness and impact in the case of its introduction into a new area. At the same time, much biodiversity has been lost due to multiple drivers. Ways to determine the potential for successful reintroductions of once native but now extinct species as well as assisted migrations are yet missing. Stable isotope analyses are commonly used to reconstruct a species’ feeding ecology and trophic interactions within communities. Recently, this method has been used to predict potentially arising trophic interactions in the absence of the target species. Here we propose the implementation of stable isotope analysis as an approach for assessment schemes to increase the accuracy in predicting invader impacts as well as the success of reintroductions and assisted migrations. We review and discuss possibilities and limitations of this methods usage, suggesting promising and useful applications for scientists and managers.
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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: 0.5] [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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Pinho CJ, Lopes EP, Paupério J, Gomes I, Romeiras MM, Vasconcelos R. Trust your guts? The effect of gut section on diet composition and impact of Mus musculus on islands using metabarcoding. Ecol Evol 2022; 12:e8638. [PMID: 35309743 PMCID: PMC8901889 DOI: 10.1002/ece3.8638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 01/20/2022] [Accepted: 01/27/2022] [Indexed: 11/11/2022] Open
Abstract
DNA metabarcoding is widely used to characterize the diet of species, and it becomes very relevant for biodiversity conservation, allowing the understanding of trophic chains and the impact of invasive species. The need for cost-effective biodiversity monitoring methods fostered advances in this technique. One question that arises is which sample type provides a better diet representation.Therefore, with this study, we intended to evaluate if there were differences in diet estimates according to the section of the gastrointestinal tract analysed and which section(s) provided the best diet representation. Additionally, we intended to infer the ecological/economic impacts of an invader as a model of the potential effects in an originally mammal-free ecosystem.We examined the gut contents of the house mouse Mus musculus introduced to Cabo Verde, considering three sections: stomach, small intestine, and large intestine. We applied a DNA-metabarcoding approach using two genetic markers, one specific for plants and another for invertebrates.We showed that this invader consumed 131 taxa (73 plants and 58 invertebrates). We obtained significant differences in the composition of two of the three sections, with a higher incidence of invertebrates in the stomach and plants in the intestines. This may be due to stomach inhibitors acting on plants and/or to faster absorption of soft-body invertebrates compared to the plant fibers in the intestines. We verified that the impact of this invader in the ecosystem is predominantly negative, as at least 50% of the ingested items were native, endemic, or economically important taxa, and only 19% of the diet items were exotics.Overall, results showed the need to analyse only two gastrointestinal tract sections to obtain robust diet data, increasing the cost-effectiveness of the method. Furthermore, by uncovering the native taxa most frequently preyed on by mice, this DNA-metabarcoding approach allowed us to evaluate efficiently which are at the highest risk.
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Affiliation(s)
- Catarina J. Pinho
- CIBIOCentro de Investigação em Biodiversidade e Recursos Genéticos, InBIOLaboratório Associado, Campus de Vairão, Universidade do PortoVairãoPortugal
- Departamento de BiologiaFaculdade de Ciências da Universidade do PortoPortoPortugal
- BIOPOLISProgram in Genomics, Biodiversity and Land PlanningCIBIO, Campus de VairãoVairãoPortugal
| | - Evandro P. Lopes
- CIBIOCentro de Investigação em Biodiversidade e Recursos Genéticos, InBIOLaboratório Associado, Campus de Vairão, Universidade do PortoVairãoPortugal
- Departamento de BiologiaFaculdade de Ciências da Universidade do PortoPortoPortugal
- BIOPOLISProgram in Genomics, Biodiversity and Land PlanningCIBIO, Campus de VairãoVairãoPortugal
- ISECMAR‐UTAInstituto Engenharia e Ciências do Mar da Universidade Técnica do AtlânticoMindeloCabo Verde
| | - Joana Paupério
- CIBIOCentro de Investigação em Biodiversidade e Recursos Genéticos, InBIOLaboratório Associado, Campus de Vairão, Universidade do PortoVairãoPortugal
- BIOPOLISProgram in Genomics, Biodiversity and Land PlanningCIBIO, Campus de VairãoVairãoPortugal
| | - Isildo Gomes
- INIDAInstituto Nacional de Investigação e Desenvolvimento AgrárioSantiagoCabo Verde
| | - Maria M. Romeiras
- LEAF‐ISALinking Landscape, Environment, Agriculture and Food, Instituto Superior de AgronomiaUniversidade de LisboaLisboaPortugal
| | - Raquel Vasconcelos
- CIBIOCentro de Investigação em Biodiversidade e Recursos Genéticos, InBIOLaboratório Associado, Campus de Vairão, Universidade do PortoVairãoPortugal
- BIOPOLISProgram in Genomics, Biodiversity and Land PlanningCIBIO, Campus de VairãoVairãoPortugal
- ISECMAR‐UTAInstituto Engenharia e Ciências do Mar da Universidade Técnica do AtlânticoMindeloCabo Verde
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