Foraging in the Anthropocene: Feeding plasticity of an opportunistic predator revealed by long term monitoring

For centuries, human activities have altered the population dynamics of wildlife. New anthropogenic food sources provide a predictable and abundant food supply that often induces very significant changes in the size, distribution, and behaviour of many populations, with ultimate consequences on the structure and functioning of natural ecosystems. Here, we combine historical and contemporary feather samples of a population of a su-perabundant, opportunistic predator, the yellow-legged gull Larus michahellis, to assess its trophic ecology and relate it to human activities in the long term. Dietary assessments were based on stable isotope analysis of carbon, nitrogen, and sulphur (δ13C, δ15N and δ34S), and were conducted through three end-point (marine prey, waste from landfills-slaughterhouses, and terrestrial invertebrates) Bayesian mixing models. Our results suggest that gulls’ diet showed a progressive decrease in the consumption of marine prey throughout the most recent period (late 20th century onwards), linked to an increase in the consumption of meat waste and small terrestrial invertebrates. Reported dietary changes over the sampling period correlated positively with the availability of marine resources around the breeding area. We provide evidence suggesting that the ability of gulls to exploit efficiently diverse anthropogenic food subsidies likely resulted in the exponential demographic increase of this population throughout the 20th century. In addition, current regulations affecting the availability of these food resources (e.g., fishing discards and landfill waste) likely reversed this trend over the last decade. Long-term evidence of population trophic plasticity, like the one we present here, is essential to implement and support management and conservation actions that limit the availability of anthropogenic resources, especially when it comes to superabundant, problematic species.info:eu-repo/semantics/publishedVersio

El valor económico no consumitivo de la vida salvaje: el caso de tres especies de cetáceos

The conservation of wildlife is one of the most pressing issues in the current times, but wildlife conservation economic values have often been largely ignored due to an absence of market prices, as setting an economic value on biodiversity or whole ecosystems can be challenging. Nevertheless, valuing wildlife can be of great significance to improve decision-making in the conservation field, as it can provide a complementary perspective based on economic principles. Whale-watching provides an opportunity for the economic valuation of wildlife. Specifically, it offers a framework in which the economic revenue allows the economic valuation of the targeted cetaceans to be estimated through the direct and indirect expenditure of the tourists who purchase whale-watching tours. Here, we performed an economic analysis based on population abundances of the three main species targeted by the whale-watching companies in the Strait of Gibraltar (Spain): long-finned pilot whales (Globicephala melas), common dolphins (Delphinus delphis) and killer whales (Orcinus orca). These species generated a total annual income of €4,089,056, €1,876,833, and €505,389, respectively, and each individual would generate an average of €14,048, €951, and €36,099 each year, respectively. Incorporating life expectancy, this corresponded to a total population value of €112,426,185, €16,685,147, and €19,171,107, respectively, over their lifetime. These values provide an idea of the potential contribution of cetaceans to the local economy but only represent their non-consumptive value based on tourism. Our results reinforce the idea that a sustainable, high-quality whale-watching culture, under ACCOBAMS High-Quality Whale-Watching requirements, should be promoted to ensure a sustainable industry, stable economic income and the viability of cetacean populations in the Strait of Gibraltar.La conservación de la vida salvaje es uno de los retos clave del mundo actual. Sin embargo, los valores económicos derivados de la conservación de la vida salvaje a menudo han sido pasados por alto debido a la ausencia de precios de mercado, ya que asignar un valor económico a la biodiversidad o a ecosistemas enteros puede ser complejo. No obstante, valorar la vida salvaje puede ser de gran importancia para mejorar la toma de decisiones en el campo de la conservación, ya que puede proporcionar una perspectiva complementaria basada en principios económicos. El avistamiento de cetáceos brinda una oportunidad para realizar este tipo de valoración económica. Específicamente, ofrece un marco en el cual los ingresos económicos generados permiten la evaluación y estimación del valor económico de los cetáceos objetivo basado en el gasto directo e indirecto de los turistas que realizan tours de avistamiento de cetáceos. En este estudio, realizamos un análisis económico basado en las abundancias poblacionales de las tres principales especies objetivo de las compañías de avistamiento de cetáceos en el Estrecho de Gibraltar (España): calderones comunes (Globicephala melas), delfines comunes (Delphinus delphis) y orcas (Orcinus orca). Estas especies generaron respectivamente un ingreso total anual de 4.089.056 €, 1.876.833 € y 505.389 €, donde cada individuo generaría un promedio de 14.048 €, 951 € y 36.099€ cada año. Al incorporar la esperanza de vida, esto se correspondió con un valor total de la población de 112.426.185 €, 16.685.147 € y 19.171.107 € a lo largo de su vida. Estos valores brindan una idea de la contribución potencial de los cetáceos a la economía local, pero solo representan su valor no consumitivo basado en el turismo. Nuestros resultados refuerzan la idea de que se debe promover una cultura de avistamiento de cetáceos sostenible y de alta calidad, bajo los requisitos de observación de cetáceos de alta calidad de ACCOBAMS, para garantizar una industria sostenible, ingresos económicos estables y la viabilidad de las poblaciones de cetáceos en el Estrecho de Gibraltar

Foraging in the Anthropocene: Feeding plasticity of an opportunistic predator revealed by long term monitoring

For centuries, human activities have altered the population dynamics of wildlife. New anthropogenic food sources provide a predictable and abundant food supply that often induces very significant changes in the size, distribution, and behaviour of many populations, with ultimate consequences on the structure and functioning of natural ecosystems. Here, we combine historical and contemporary feather samples of a population of a superabundant, opportunistic predator, the yellow-legged gull Larus michahellis, to assess its trophic ecology and relate it to human activities in the long term. Dietary assessments were based on stable isotope analysis of carbon, nitrogen, and sulphur (δ13C, δ15N and δ34S), and were conducted through three end-point (marine prey, waste from landfills-slaughterhouses, and terrestrial invertebrates) Bayesian mixing models. Our results suggest that gulls' diet showed a progressive decrease in the consumption of marine prey throughout the most recent period (late 20th century onwards), linked to an increase in the consumption of meat waste and small terrestrial invertebrates. Reported dietary changes over the sampling period correlated positively with the availability of marine resources around the breeding area. We provide evidence suggesting that the ability of gulls to exploit efficiently diverse anthropogenic food subsidies likely resulted in the exponential demographic increase of this population throughout the 20th century. In addition, current regulations affecting the availability of these food resources (e.g., fishing discards and landfill waste) likely reversed this trend over the last decade. Long-term evidence of population trophic plasticity, like the one we present here, is essential to implement and support management and conservation actions that limit the availability of anthropogenic resources, especially when it comes to superabundant, problematic species

IStronger together : fisheries enhance pressure on Mediterranean regions and pelagic species already impacted by climate change

2nd ΣPhD Ecological Symposium, 6-7 October 2022, BlanesPeer reviewe

El concepte de “l’espai operacional segur” (SOS) i aplicacions al Mediterrani

Jornada Pesca i Ciència organizada por la Càtedra d'Estudis Marítims de la Universitat de Girona (UdG)Peer reviewe

The trophic role of Mediterranean chondrichthyans: food web modelling and extinction scenarios

Sharks International, 20-22 October 2022, ValenciaPeer reviewe

Stronger Together: Fisheries Enhance Pressure on Mediterranean Regions and Pelagic Species Already Impacted by Climate Change

VIII International Symposium on Marine Sciences, 6-8 July 2022, Las Palmas de Gran Canaria, EspañaMarine species are widely threatened by anthropogenic activities, including fishing and human-induced climate change. However, geographically broad and spatiallyexplicit assessments of the simultaneous impacts of these major threats at regional scales are mostly lacking due to the practical challenges of surveying vast geographical areas and obtaining adequately resolved data. Yet, these assessments are key for identifying highly and cumulatively impacted areas and species that should be prioritized for conservation through knowledge-based management strategies. Here, we analysed a 26-year (1993-2018) time series of highly-resolved remotely sensed environmental data to evaluate changes in optimal habitat availability (i.e., extent of marine areas encompassing optimal environmental conditions) for 15 species of small, medium and large pelagic fish inhabiting the Mediterranean Sea Large Marine Ecosystem. We then combined spatial and temporal data on fishing pressure and changes in optimal habitats to identify areas of high risk of cumulative impacts. Overall, results showed how most of the Mediterranean pelagic species went through a reduction of optimal habitat availability over the past decades. The few species that showed positive trends in optimal habitat availability did not expand largely and hence were unlikely to compensate for the loss of key functional roles at the group level. Habitat loss concentrated in the western and central basins. Similarly, fishing pressure was found to be the highest in both basins, thus overlapping with the areas experiencing a higher reduction of optimal habitat. Small and large pelagic fish were the most impacted groups, having a larger proportion of their distribution in highly, cumulative impacted areas. Redistributing fishing pressure and reducing it in highly impacted areas may alleviate the overall cumulative pressure on pelagic stocks, contributing to the necessary shift to sustainable and resilient fisheries that allow ensuring food security and achieving a healthy ecosystem in this “sea under siege”JO was supported by Universitat de Barcelona through the PREDOCS-UB grant (2021). MC received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement N° 869300 (FutureMARES project). FR was supported by the Spanish government through the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000928-S)Peer reviewe

Fisheries-enhanced pressure on Mediterranean regions and pelagic species already impacted by climate change

18 pages, 7 figures, 2 tables, supplemental files https://doi.org/10.1525/elementa.2022.00028.-- Data accessibility statement: The source data on which we base our findings are all open access and can be found at https://www.aquamaps.org/ and https://marine.copernicus.eu/. All of the generated TIF files will be available at the public repository https://digital.csic.es/ upon publication. All the code used in our analyses is stored in a dedicated GitHub repository and will be available upon request via the authorsMarine species are widely threatened by anthropogenic activities, including fishing and human-induced climate change. However, geographically broad and spatially explicit assessments of the simultaneous impacts of these major threats at regional scales are mostly lacking due to the practical challenges of surveying vast geographical areas and obtaining adequately resolved data. Yet, these assessments are key for identifying highly and cumulatively impacted areas and species that should be prioritized for conservation through knowledge-based management strategies. Here, we analysed a 26-year (1993–2018) time series of highly resolved remotely sensed environmental data to evaluate changes in optimal habitat availability (i.e., extent of marine areas encompassing optimal environmental conditions) for 15 species representative of small, medium and large pelagic fish inhabiting the Mediterranean Sea Large Marine Ecosystem. We then combined spatial and temporal data on fishing pressure and changes in optimal habitats to identify areas of high risk of cumulative impacts. Overall, results show how most of the studied Mediterranean pelagic species experienced a reduction in optimal habitat availability over the past decades. The few species that showed positive trends in optimal habitat availability expanded only to a small degree and hence were unlikely to compensate for the loss of key functional roles at the group level. Habitat loss concentrated in the western and central regions. Similarly, fishing pressure was found to be higher in these regions, thus overlapping with the areas experiencing a higher reduction of optimal habitat. Small and large pelagic fish were the most impacted groups, having a larger proportion of their distributions in highly, cumulative impacted areas. Redistributing fishing pressure and reducing it in highly impacted areas may alleviate the overall cumulative pressure on pelagic stocks, contributing to the necessary shift to sustainable and resilient fisheries that would ensure food security and a healthy ecosystem in this highly impacted basinJO was supported by Universitat de Barcelona through the PREDOCS-UB grant (2021). MC received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 869300 (FutureMARES project) and the Spanish project ProOceans (Ministerio de Ciencia e Innovación, Proyectos de I + D + I (RETOSPID2020-118097RB-I00). FR was supported by the Spanish government through the “Severo Ochoa Centre of Excellence” accreditation (CEX2019-000928-S) and the Ramón y Cajal programme (Spanish Ministerio de Ciencia e Innovación, RYC2020-030078-I). JO, FR and MC acknowledge the institutional support of the “Severo Ochoa Centre of Excellence” accreditation (CEX2019-000928-S). FR also acknowledges support by the Spanish government through the project SOSPEN (grant agreements Nº PID2021-124831OA-I00, Spanish Ministerio de Ciencia e Innovación)Peer reviewe

Spatiotemporal analyses of tracking data reveal fine-scale, daily cycles in seabird–fisheries interactions

10 pages, 4 figures, 1 table.-- Data was generated within the frame of LIFE+ Project INDEMARES. Data are available at the following address: http://seabirdtracking.org/mapper/?dataset_id=874. Please contact specifically J. M. Arcos. SEO/BirdLife ([email protected])Human fisheries provide scavengers with abundant and predictable feeding opportunities that may schedule their behavioural patterns. Using miniaturized global positioning system (GPS) tracking technology, we evaluated how Audouin’s gull (Ichthyaetus audouinii), a Mediterranean endemic seabird that makes extensive use of feeding opportunities provided by fisheries, co-occurred (i.e. presumably interacted) with the most important fishing fleets operating off the NE Iberian Peninsula (i.e. diurnal trawlers and nocturnal purse seiners), both in space and time. Results showed that individuals were able to adapt their distribution and activity patterns to the scheduled routines of these fisheries. Waveform analyses based on co-occurring positions revealed that most interactions with trawlers occurred during the afternoon (16:00 h GMT + 1) when discarding occurs as vessels return to port. In contrast, gull-purse seiner interactions largely occurred at night (between 02:00 and 04:00 h) coinciding with the setting and hauling of the nets. Moreover, we found an individual component in seabird–fishery interactions, showing that there may be differential use of fisheries by individuals within the population. In addition to implications for our understanding of the behavioural ecology of this species, these results may have important management implications, particularly under the current European Union Common Fisheries Policy scenario of largely restricting discardsWith the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)This research was funded by the Spanish “Ministerio de Economía, Industria y Competitividad” (MEIyC; CGL2016-08963-R) and LIFE+ INDEMARES (LIFE 07NAT/E/00732). JO-C was supported by a Department Collaboration (18CO1/006033) from the Spanish "Miniterio de Educación y Formación Profesional". FR was funded by MEIyC “Subprograma Juan de la Cierva-Incorporación” (IJCI-2015-24531)Peer reviewe

Foraging in the Anthropocene: Feeding plasticity of an opportunistic predator revealed by long term monitoring

10 pages, 4 figures, 4 tables, supplementary data https://doi.org/10.1016/j.ecolind.2021.107943For centuries, human activities have altered the population dynamics of wildlife. New anthropogenic food sources provide a predictable and abundant food supply that often induces very significant changes in the size, distribution, and behaviour of many populations, with ultimate consequences on the structure and functioning of natural ecosystems. Here, we combine historical and contemporary feather samples of a population of a superabundant, opportunistic predator, the yellow-legged gull Larus michahellis, to assess its trophic ecology and relate it to human activities in the long term. Dietary assessments were based on stable isotope analysis of carbon, nitrogen, and sulphur (δ13C, δ15N and δ34S), and were conducted through three end-point (marine prey, waste from landfills-slaughterhouses, and terrestrial invertebrates) Bayesian mixing models. Our results suggest that gulls’ diet showed a progressive decrease in the consumption of marine prey throughout the most recent period (late 20th century onwards), linked to an increase in the consumption of meat waste and small terrestrial invertebrates. Reported dietary changes over the sampling period correlated positively with the availability of marine resources around the breeding area. We provide evidence suggesting that the ability of gulls to exploit efficiently diverse anthropogenic food subsidies likely resulted in the exponential demographic increase of this population throughout the 20th century. In addition, current regulations affecting the availability of these food resources (e.g., fishing discards and landfill waste) likely reversed this trend over the last decade. Long-term evidence of population trophic plasticity, like the one we present here, is essential to implement and support management and conservation actions that limit the availability of anthropogenic resources, especially when it comes to superabundant, problematic speciesThis work was supported by FAU2008-00012-C02-01 from INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Spain), CGL2009-11278/BOS from Ministerio de Ciencia e Innovación from the Spanish Government, Fondos FEDER, 2017/2349 of the PLEAMAR programme with the collaboration of the Fundación Biodiversidad, from the Ministerio para la Transición Ecológica (Spain), cofounded by the EMFF (European Union), and REN2003-07050 Aplicación de biomarcadores a la gestión de una especie problemática (Larus cachinnans). CERCA Programme from Generalitat de Catalunya is also acknowledged. RR was supported by a postdoctoral Ramón y Cajal contract (RYC-2017-22055) and VMP was supported by a pre-doctoral contract BES-2014-068025 both from the Spanish Ministerio de Economía, Industria y CompetitividadWith the institutional support of the ‘Severo OchoaCentre of Excellence’ accreditation (CEX2019-000928-S)Peer reviewe