Estudio de los anillos de crecimiento de Vachellia caven (Molina) Seigler & Ebinger como indicadores del cambio climático en la cuenca de Petorca, región de Valparaíso.
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Date
2024
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Universidad de Concepción
Abstract
En la actualidad, el análisis de la variabilidad histórica del clima en Chile involucra diversas disciplinas, y entre ellas destaca la dendrocronología, enfoque que ha centrado sus investigaciones en la reconstrucción climática y resiliencia de los bosques frente al cambio climático, centrándose principalmente en especies arbóreas del centro–sur del país. Sin embargo, la región central, dominada por formaciones xerofíticas, carece de representantes destacados para este tipo de estudios. Por este motivo, se seleccionó una población de la especie Vachellia caven para evaluar su potencial dendrocronológico como indicador indirecto (proxy) del clima en la cuenca alta del río Petorca, ubicada en la región de Valparaíso. Se seleccionó esta especie porque tiene amplia distribución en Chile central. El proceso incluyó la realización de cortes histológicos para comprender la disposición de los anillos en la madera. Además, se desarrollaron dos cronologías con diferentes metodologías, la primera utiliza una Tabla Unislide Velmex y la segunda utiliza el software CooRecorder. Esta última metodología mostró mayor correlación entre individuos para ser relacionada con variables climáticas locales (precipitación, temperatura máxima y mínima), regionales (déficit hídrico climático y déficit de presión de vapor), y globales (Modo Anular del Sur y el Índice Multivariado del Niño Oscilación del Sur). Los principales resultados muestran que el crecimiento radial de la población es sensible a la reducción de la precipitación de invierno (r=0.51, p< 0.05), demostrando que V. caven es una especie proxy de la variabilidad climática en las formaciones xerofíticas, y que si continua la persistencia de las condiciones de cambio climático, aumentaría la vulnerabilidad de sus poblaciones en esa región, poniendo en riesgo el almacenamiento de biomasa aérea de los ecosistemas xerofíticos de la cuenca alta del Río Petorca.
Currently, the analysis of historical climate variability in Chile involves various disciplines, among which dendrochronology stands out. This approach has focused its research on climate reconstruction and forest resilience to climate change, primarily focusing on tree species in the central-southern region of the country. However, the central region, dominated by xerophytic formations, lacks prominent representatives for this type of study. For this reason, a population of the Vachellia caven species was selected to evaluate its dendrochronological potential as an indirect indicator (proxy) of climate in the upper Petorca River basin, located in the Valparaíso region. The rationale behind this selection stems from the species' widespread distribution across central Chilean ecosystems. The process included the preparation of histological cuts to understand the arrangement of rings in the wood. Additionally, two chronologies were developed using different methodologies, the first utilizing a Velmex Unislide Table and the second using CooRecorder software. This latter methodology showed higher correlation among individuals to be related to local climatic variables (precipitation, maximum and minimum temperature), regional variables (climatic water deficit and vapor pressure deficit), and global variables (Southern Annular Mode and Multivariate El Niño Southern Oscillation Index). The main results show that the radial growth of the population is sensitive to winter precipitation reduction (r=0.51, p< 0.05), demonstrating that V. caven is a proxy species for climatic variability in xerophytic formations. If the persistence of climate change conditions continues, it would increase the vulnerability of its populations in that region, endangering the storage of aboveground biomass in xerophytic ecosystems of the upper Petorca river basin.
Currently, the analysis of historical climate variability in Chile involves various disciplines, among which dendrochronology stands out. This approach has focused its research on climate reconstruction and forest resilience to climate change, primarily focusing on tree species in the central-southern region of the country. However, the central region, dominated by xerophytic formations, lacks prominent representatives for this type of study. For this reason, a population of the Vachellia caven species was selected to evaluate its dendrochronological potential as an indirect indicator (proxy) of climate in the upper Petorca River basin, located in the Valparaíso region. The rationale behind this selection stems from the species' widespread distribution across central Chilean ecosystems. The process included the preparation of histological cuts to understand the arrangement of rings in the wood. Additionally, two chronologies were developed using different methodologies, the first utilizing a Velmex Unislide Table and the second using CooRecorder software. This latter methodology showed higher correlation among individuals to be related to local climatic variables (precipitation, maximum and minimum temperature), regional variables (climatic water deficit and vapor pressure deficit), and global variables (Southern Annular Mode and Multivariate El Niño Southern Oscillation Index). The main results show that the radial growth of the population is sensitive to winter precipitation reduction (r=0.51, p< 0.05), demonstrating that V. caven is a proxy species for climatic variability in xerophytic formations. If the persistence of climate change conditions continues, it would increase the vulnerability of its populations in that region, endangering the storage of aboveground biomass in xerophytic ecosystems of the upper Petorca river basin.
Description
Tesis presentada para optar al título de Ingeniero/a en Conservación de Recursos Naturales.
Keywords
Dendrocronología, Indicadores ambientales, Monitoreo ambiental, Cambios climáticos