Browsing by Author "Fica-Rojas, Eliseo"

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    Independent Effects of Species Removal and Asynchrony on Invariability of an Intertidal Rocky Shore Community
    (2022) Fica-Rojas, Eliseo; Catalan, Alexis M.; Broitman, Bernardo R.; Perez-Matus, Alejandro; Valdivia, Nelson
    Ecological stability depends on interactions between different levels of biological organization. The insurance effects occur when increasing species diversity leads to more temporally invariable (i.e., more stable) community-level properties, due in part to asynchronous population-level fluctuations. While the study of insurance effects has received considerable attention, the role of dominant species that contribute with particular functional traits across different level of organizations is less understood. Using a field-based manipulative experiment, we investigated how species richness and different types of parameters at the population level, such as the invariability of dominants, population invariability, and population asynchrony, influence the community invariability. The experiment involved the repetitive removal of the canopy forming alga Mazzaella laminarioides (hereafter "Mazzaella") during 32 months in two rocky intertidal sites of northern-central Chile. We predicted that the invariability of dominants enhances community invariability, that the effect of multispecies population-level parameters on community invariability are dependent on species richness, and that subdominant algae are unable to fully compensate the loss of canopies of the dominant species. Biomass of algae and mobile invertebrates was quantified over time. We observed independent effects of Mazzaella removal and community-wide asynchrony on community invariability. While canopy removal reduced community invariability, population asynchrony boosted community invariability regardless of the presence of canopies. In addition, filamentous and foliose algae were unable to compensate the loss of biomass triggered by the experimental removal of Mazzaella. Canopy removal led to a severe decrement in the biomass of macrograzers, while, at the same time, increased the biomass of mesograzers. Asynchrony stemmed from compensatory trophic responses of mesograzers to increased abundances of opportunistic algae. Thus, further work on consumer-resource interactions will improve our understanding of the links between population- and community-level aspects of stability.
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    Stability of rocky intertidal communities, in response to species removal, varies across spatial scales
    (2021) Valdivia, Nelson; Lopez, Daniela N.; Fica-Rojas, Eliseo; Catalan, Alexis M.; Aguilera, Moises A.; Araya, Marjorie; Betancourtt, Claudia; Burgos-Andrade, Katherine; Carvajal-Baldeon, Thais; Escares, Valentina; Gartenstein, Simon; Grossmann, Mariana; Gutierrez, Barbara; Kotta, Jonne; Morales-Torres, Diego F.; Riedemann-Saldivia, Barbara; Rodriguez, Sara M.; Velasco-Charpentier, Catalina; Villalobos, Vicente, I; Broitman, Bernardo R.
    Improving our understanding of stability across spatial scales is crucial in the current scenario of biodiversity loss. Still, most empirical studies of stability target small scales. We experimentally removed the local space-dominant species (macroalgae, barnacles, or mussels) at eight sites spanning more than 1000 km of coastline in north- and south-central Chile, and quantified the relationship between area (the number of aggregated sites) and stability in aggregate community variables (total cover) and taxonomic composition. Resistance, recovery, and invariability increased nonlinearly with area in both functional and compositional domains. Yet, the functioning of larger areas achieved a better, albeit still incomplete, recovery than composition. Compared with controls, smaller disturbed areas tended to overcompensate in terms of total cover. These effects were related to enhanced available space for recruitment (resulting from the removal of the dominant species), and to increasing beta diversity and decaying community-level spatial synchrony (resulting from increasing area). This study provides experimental evidence for the pivotal role of spatial scale in the ability of ecosystems to resist and recover from chronic disturbances. This knowledge can inform further ecosystem restoration and conservation policies.
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    The natural diet of Prolatilus jugularis inhabiting Lessonia trabeculata kelp forests of south-central Chile
    (2024) Gartenstein, Simon; Fica-Rojas, Eliseo; Perez-Matus, Alejandro; Godoy, Natalio; Torres-Canete, Felipe; Valdivia, Nelson
    Kelp forests support species-rich food webs that predator-prey interactions may sustain. Here, we analyze prey availability and stomach contents of the predatory fish Prolatilus jugularis in an unexplored subtidal kelp forest of Lessonia trabeculata in south-central Chile. In the kelp forest, 42 invertebrate taxa and 1016 individuals were observed. In the diet of P. jugularis, 21 taxa and 130 individuals were identified. Crustacea, particularly amphipods, were the dominant and more frequent taxa in the kelp forest and stomach contents. Annelida and Mollusca were also present in the kelp forest and diets but were less abundant. We did not find a statistically significant correlation between kelp forest and stomach-content prey abundances and frequencies. Also, dominance structure significantly differed between kelps and stomach contents. Our results indicate that P. jugularis could feed in other habitats outside the survey area. Seven predatory fish were sampled in the kelp forest. Pinguipes chilensis was the dominant fish, with 65% of the total fish biomass, followed by P. jugularis with 20%.