Examinando por Autor "Pulgar, J."

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    Living on a trophic subsidy: Algal quality drives an upper-shore herbivore’s consumption, preference and absorption but not growth rates
    (Public Library of Science, 2018-04) Quintanilla-Ahumada, D.; Quijón, P.A.; Navarro, J.M.; Pulgar, J.; Duarte, C.
    The transfer of seaweeds from subtidal bottoms to nearby intertidal rocky shores is a common but often overlooked phenomenon. Freshly detached seaweeds often represent critical trophic subsidies for herbivores living in upper-shore rocky intertidal areas, such as the marine snail Diloma nigerrima. This species relies on three species of seaweeds for food and displays feeding strategies to deal with a resource that is scarce and at times unpredictable. This study focused on the nutritional quality of freshly detached algae (Durvillaea antarctica, Lessonia spicata and Lessonia trabeculata) and measured Diloma nigerrima’s algal consumption rates in trials with and without choice. Absorption efficiency and growth of individual snails fed on each alga were also measured. Durvillaea antarctica had the highest nutritional quality and was the most consumed algae in both single and multiple-choice trials. Absorption efficiency was also highest for D. antarctica but growth rates of snails fed with this species were similar to those fed with the other algae. Combined, these results suggest that D. nigerrima has the ability to discriminate among seaweeds based on their nutritional quality. A potential increase in oxygen uptake when D. nigerrima is consuming the preferred food item is also proposed as a plausible hypothesis to explain the mismatch between snails’ preference and growth rate. These results aim to guide further studies on trophic subsidies and their role in coastal systems. © 2018 Quintanilla-Ahumada et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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    Predation and anthropogenic impact on community structure of boulder beaches
    (INST CIENCIAS MAR BARCELONA, 2016) Aldana, M.; Maturana, D.; Pulgar, J.; Garcia-Huidobro, M.R.
    Predator impacts on intertidal community structure have been studied for rocky platforms, but intertidal boulder fields, a habitat with a greater extension and heterogeneity, have not yet been considered. Keeping in mind that disturbances are considered an important force in determining intertidal habitat diversity, the aims of this work were to describe and quantify boulder field community structure and to assess boulder field community dynamics by proposing possible food webs, taking into consideration predatory and anthropogenic impacts. These aims were achieved by installing predator-exclusion cages outfitted with rocks that were monitored monthly over one year in two study zones, a Management and Exploitation Area for Benthic Resources (MEABR, Playa Chica) and open-access area (OAA, Playa Grande). For both study zones, juveniles were the dominant observed ontogenetic state and invertebrate richness and density were higher inside exclusion cages. Furthermore, the MEABR had a differentiated impact on community structure and dynamics in comparison with the OAA. In conclusion, the roles played by boulder fields in intertidal diversity, especially in recruitment and as a nursery zone, are important to consider in management plans.
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    Upwelling promotes earlier onset & increased rate of Gonadal development of four coastal herbivores
    (Rosenstiel School of Marine and Atmospheric Science, 2017-07) Aldana, M.; García-Huidobro, M.R.; Pulgar, V.M.; Pulgar, J.
    Upwelling can lead to physiological adjustments in organisms to cope with changing physical and biological conditions. Physiological heterokairy describes changes in the physiological itinerary of an animal, typically in response to environmental variability. We determined the effects of upwelling on the onset and rate of gonadal development in the herbivore intertidal fish, Scartichthys viridis (Valenciennes, 1836), and subtidal Mollusca, Fissurella maxima G. B. Sowerby I, 1834, Fissurella cumingi Reeve, 1849, and Fissurella latimarginata G. B. Sowerby I, 1835. In animals from an area with upwelling, gonadal tissue was detected in individuals with a body size smaller than counterparts from a non-upwelling zone. Further, the rate of gonadal tissue growth was higher in animals from an upwelling zone. This heterokairy may be a consequence of constant exposure to higher energy resources in animals from upwelling areas.