Ecología y conservación de los cisnes sudamericanos.
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Date
2026
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Universidad de Concepción
Abstract
La biología de la conservación busca comprender y mitigar los efectos de las perturbaciones que afectan a las especies y ecosistemas, proporcionando bases científicas para su manejo y preservación. En este contexto, la ecología constituye una herramienta fundamental para comprender los procesos que determinan la distribución, abundancia y persistencia de las especies frente a crecientes presiones antrópicas. Sin embargo, para numerosas especies aún persisten importantes vacíos de conocimiento ecológico, limitando el desarrollo de estrategias de conservación efectivas. Esta situación resulta relevante en los cisnes sudamericanos, Coscoroba coscoroba y Cygnus melancoryphus, especies estrechamente asociadas a humedales y comparativamente poco estudiadas, pese a su sensibilidad frente a la pérdida y degradación del hábitat.
La presente tesis doctoral abordó la ecología y conservación de ambas especies mediante un enfoque integrador que combinó aproximaciones macroecológicas, análisis de paisaje y evaluación del potencial rol de estas especies en la provisión de servicios ecosistémicos regulatorios. A escala macroecológica, se analizaron sus patrones de abundancia a lo largo de su rango de distribución en Sudamérica, evaluando la capacidad explicativa de la hipótesis de centralidad del nicho ambiental en contraste con la hipótesis de centro abundante, y examinando sus implicancias para la conservación. Los resultados mostraron que la posición ambiental constituye un predictor más informativo del desempeño poblacional que la proximidad geográfica dentro de la distribución de estas especies. Asimismo, se detectó un desacople entre idoneidad ambiental y núcleos reales de abundancia, evidenciando que la presencia de hábitat adecuado no necesariamente determina altas densidades poblacionales. Complementariamente, se observó una marcada subrepresentación de áreas ambientalmente idóneas dentro del sistema de áreas protegidas.
A escala de paisaje, se analizó la influencia de la estructura del paisaje y de las perturbaciones antrópicas sobre las abundancias de ambas especies en humedales costeros mediterráneos de Chile. La disponibilidad de superficie hídrica emergió como el predictor más consistente, destacando la importancia de los ambientes acuáticos funcionales para la persistencia poblacional. Sin embargo, las respuestas ecológicas difirieron entre especies: C. coscoroba presentó asociaciones positivas con escenarios vinculados al uso ganadero, mientras que C. melancoryphus no registró asociaciones robustas con las variables de disturbio evaluadas. Evidenciando que las estrategias de conservación deben considerar diferencias interespecíficas.
Finalmente, se evaluó el potencial rol funcional de ambas especies en sistemas artesanales de extracción de sal en el estero Nilahue–laguna Cáhuil, Chile central. Las elevadas abundancias registradas y el alto tiempo destinado a la conducta alimentaria sugieren que ambas especies contribuyen a la remoción de vegetación acuática en los estanques salineros, aportando beneficios regulatorios en los sistemas productivos de extracción. Entregando evidencia novedosos que contribuye a ampliar la comprensión del vínculo entre biodiversidad y seres humanos en sistemas productivos.
En su conjunto, los resultados obtenidos en esta tesis aportan nuevos antecedentes para comprender los factores que determinan las abundancias de estas especies y entregan información relevante para orientar estrategias de conservación y manejo en humedales sometidos a crecientes presiones antrópicas.
Conservation biology seeks to understand and mitigate the effects of disturbances affecting species and ecosystems, providing scientific foundations for their management and preservation. In this context, ecology constitutes a fundamental tool for understanding the processes that determine the distribution, abundance, and persistence of species under increasing anthropogenic pressures. However, significant gaps in ecological knowledge still persist for numerous species, limiting the development of effective conservation strategies. This situation is particularly relevant for the South American swans, Coscoroba coscoroba and Cygnus melancoryphus, species closely associated with wetlands and comparatively understudied despite their sensitivity to habitat loss and degradation. This PhD thesis addressed the ecology and conservation of both species through an integrative approach combining macroecological approaches, landscape analyses, and assessment of the potential role of these species in the provision of regulating ecosystem services. At the macroecological scale, abundance patterns were analysed throughout their distributional range in South America, evaluating the explanatory capacity of the environmental niche centrality hypothesis in contrast to the abundant-centre hypothesis, and examining its implications for conservation. The results showed that environmental position constitutes a more informative predictor of population performance than geographic proximity within the distribution of these species. Likewise, a mismatch between environmental suitability and actual abundance nuclei was detected, demonstrating that the presence of suitable habitat does not necessarily determine high population densities. Additionally, a marked underrepresentation of environmentally suitable areas within the protected areas system was observed. At the local scale, the influence of landscape structure and anthropogenic disturbances on the abundances of both species in Mediterranean coastal wetlands of Chile was analysed. Water surface availability emerged as the most consistent predictor, highlighting the importance of functional aquatic environments for population persistence. However, ecological responses differed between species: C. coscoroba showed positive associations with scenarios linked to livestock use, whereas C. melancoryphus exhibited a stronger dependence on water availability and a weaker relationship with disturbance variables. This demonstrates that conservation strategies must consider interspecific differences in landscape use and tolerance to disturbances. Finally, the potential functional role of both species was evaluated in artisanal salt extraction systems in the Nilahue estuary–Cáhuil lagoon, central Chile. The high abundances recorded and the considerable amount of time devoted to feeding behaviour suggest that both species contribute to the removal of aquatic vegetation in salt ponds, providing regulating benefits within extraction production systems. Delivering novel evidence that contributes to expanding the understanding of the relationship between biodiversity and humans in productive systems. Overall, the results obtained in this thesis provide new insights into the factors determining the abundances of these species and deliver relevant information to guide conservation and management strategies in wetlands subjected to increasing anthropogenic pressures.
Conservation biology seeks to understand and mitigate the effects of disturbances affecting species and ecosystems, providing scientific foundations for their management and preservation. In this context, ecology constitutes a fundamental tool for understanding the processes that determine the distribution, abundance, and persistence of species under increasing anthropogenic pressures. However, significant gaps in ecological knowledge still persist for numerous species, limiting the development of effective conservation strategies. This situation is particularly relevant for the South American swans, Coscoroba coscoroba and Cygnus melancoryphus, species closely associated with wetlands and comparatively understudied despite their sensitivity to habitat loss and degradation. This PhD thesis addressed the ecology and conservation of both species through an integrative approach combining macroecological approaches, landscape analyses, and assessment of the potential role of these species in the provision of regulating ecosystem services. At the macroecological scale, abundance patterns were analysed throughout their distributional range in South America, evaluating the explanatory capacity of the environmental niche centrality hypothesis in contrast to the abundant-centre hypothesis, and examining its implications for conservation. The results showed that environmental position constitutes a more informative predictor of population performance than geographic proximity within the distribution of these species. Likewise, a mismatch between environmental suitability and actual abundance nuclei was detected, demonstrating that the presence of suitable habitat does not necessarily determine high population densities. Additionally, a marked underrepresentation of environmentally suitable areas within the protected areas system was observed. At the local scale, the influence of landscape structure and anthropogenic disturbances on the abundances of both species in Mediterranean coastal wetlands of Chile was analysed. Water surface availability emerged as the most consistent predictor, highlighting the importance of functional aquatic environments for population persistence. However, ecological responses differed between species: C. coscoroba showed positive associations with scenarios linked to livestock use, whereas C. melancoryphus exhibited a stronger dependence on water availability and a weaker relationship with disturbance variables. This demonstrates that conservation strategies must consider interspecific differences in landscape use and tolerance to disturbances. Finally, the potential functional role of both species was evaluated in artisanal salt extraction systems in the Nilahue estuary–Cáhuil lagoon, central Chile. The high abundances recorded and the considerable amount of time devoted to feeding behaviour suggest that both species contribute to the removal of aquatic vegetation in salt ponds, providing regulating benefits within extraction production systems. Delivering novel evidence that contributes to expanding the understanding of the relationship between biodiversity and humans in productive systems. Overall, the results obtained in this thesis provide new insights into the factors determining the abundances of these species and deliver relevant information to guide conservation and management strategies in wetlands subjected to increasing anthropogenic pressures.
Description
Tesis presentada para optar al grado de Doctor/a en Sistemática y Biodiversidad.
Keywords
Cisnes, Humedales Chile, Conservación de la biodiversidad