Relación entre la disponibilidad de alimento y la abundancia de gaviotas (charadriiformes: laridae) en la Bahía de Valparaíso, Chile Central
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Date
2023
Authors
Barattini Varas, Nicolás
Profesor/a Guía
Facultad/escuela
Idioma
es
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Publisher
Universidad Andrés Bello
Nombre de Curso
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Abstract
Las aves marinas presentan adaptaciones fisiológicas y morfológicas que les
permiten utilizar el ambiente marino y terrestre, éstas se encuentran en los
niveles superiores de la trama trófica, presentando altas tasas de alimentación y
requerimientos energéticos. Un factor que se relaciona con la abundancia de
aves marinas es la disponibilidad de alimento, la cual está determinada por la
productividad de los océanos, donde los sistemas de surgencia, como el sistema
de corriente de Humboldt, adquieren gran relevancia. Se estudió si la influencia
de la disponibilidad de alimento sobre la abundancia de aves pertenecientes al
Orden Charadriiformes registrada en estudios anteriores, también es posible
observarla para especies de gaviota en la bahía de Valparaíso, región donde se
concentra la mayor riqueza de aves marinas en Chile. Con este propósito, se
utilizó una base de datos de abundancia de cuatro especies de gaviota obtenidos
entre los años 2007 y 2017 en la zona, y otra base de datos de la concentración
de clorofila-a. se utilizaron modelos lineales generalizados, análisis de varianza
(ANOVA) y análisis de comparaciones múltiples sobre ambas variables para
determinar entre qué estaciones existieron diferencias significativas, y se
estimaron los promedios estacionales. Para relacionar ambas variables se
realizaron correlaciones cruzadas, lo que permitió establecer el desfase temporal
de cada ave. Tanto la abundancia mensual de cada gaviota como la
concentración mensual de clorofila-a presentaron diferencias significativas entre
estaciones. Se estimó que para tres de las especies la mayor abundancia se
observó en invierno, y para una en verano, mientras que las mayores
concentraciones de clorofila-a se presentaron en primavera. La abundancia de
las cuatro especies se correlación positivamente y de forma significativa con las
concentraciones de clorofila-a, cada una presentó un desfase temporal y un
coeficiente de correlación diferente, lo que estaría relacionado con la fenología
reproductiva y migratoria de cada especie.
Seabirds have physiological and morphological adaptations that allows them to use the marine and terrestrial environment; they are found in the upper levels of the trophic web, presenting high feeding rates and energy requirements. One factor that is related to seabird abundance is food availability, which is determined by the productivity of the oceans, where upwelling systems, such as the Humboldt current system, acquire great relevance. We studied whether the influence of food availability on the abundance of birds belonging to the Order Charadriiformes recorded in previous studies can also be observed for gull species in Valparaíso Bay, region that concentrates the greatest seabird richness in Chile. For this purpose, we used a database of abundance of four gull species obtained between 2007 and 2017 in the área, and another database of chlorophyll-a concentration. Generalized linear models, analysis of variance (ANOVA) and analysis of multiple comparisons on both variables were used to determine between which seasons there were significant differences, and seasonal averages were estimated. To relate both variables, croos-correlations were performed, which allowed to establish the time lag of each bird. Both monthly abundance of each gull and monthly concentration of chlorophyll-a showed significant differences between seasons. It was estimated that for three of the species the highest abundance was observed in winter, and for one in summer, while the highest chlorophyll-a concentrations occurred in spring. Abundance of the four species correlated positively and significantly with chlorophyll-a concentrations, each one presented different time lag and correlation coefficient, which would be related to reproductive and migratory phenology of each species.
Seabirds have physiological and morphological adaptations that allows them to use the marine and terrestrial environment; they are found in the upper levels of the trophic web, presenting high feeding rates and energy requirements. One factor that is related to seabird abundance is food availability, which is determined by the productivity of the oceans, where upwelling systems, such as the Humboldt current system, acquire great relevance. We studied whether the influence of food availability on the abundance of birds belonging to the Order Charadriiformes recorded in previous studies can also be observed for gull species in Valparaíso Bay, region that concentrates the greatest seabird richness in Chile. For this purpose, we used a database of abundance of four gull species obtained between 2007 and 2017 in the área, and another database of chlorophyll-a concentration. Generalized linear models, analysis of variance (ANOVA) and analysis of multiple comparisons on both variables were used to determine between which seasons there were significant differences, and seasonal averages were estimated. To relate both variables, croos-correlations were performed, which allowed to establish the time lag of each bird. Both monthly abundance of each gull and monthly concentration of chlorophyll-a showed significant differences between seasons. It was estimated that for three of the species the highest abundance was observed in winter, and for one in summer, while the highest chlorophyll-a concentrations occurred in spring. Abundance of the four species correlated positively and significantly with chlorophyll-a concentrations, each one presented different time lag and correlation coefficient, which would be related to reproductive and migratory phenology of each species.
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Tesis (Licenciado en Biología)
Keywords
Aves Marinas, Alimentación y Alimentos, Gaviotas, Investigaciones, Chile, Valparaíso