Local and global climate signals from tree rings of Parkinsonia praecox in La Guajira, Colombia

摘要

Land use change and climate change have been increasingly contributing to loss or reduction of biological and economic productivity of arid lands. The dry climate and physiographic characteristics of the Peninsula of La Guajira on the Colombian Caribbean coast are considered to be crucial drivers of the loss of vegetative cover and soil erosion; however, little knowledge exists on long-term changes in climate in the area. This study presents a tree-ring chronology from Parkinsonia praecox (18 trees, 45 radii) that allows the reconstruction of local and global climate drivers spanning the last 63 years. Tree-ring width was strongly correlated with rainfall and wind data, indicating that annual tree growth was closely related to local climatic variability. The chronology also strongly correlated with an index of ENSO severity (El Ni?o Southern Oscillation), suggesting that large-scale climatic phenomenon also have important influence on Parkinsonia growth. To further investigate rainfall-growth relationships, climate data series of annual rainfall and rainfall from September to November (SON), the rainiest months, were reconstructed using transfer functions. These data series did not exhibit a clear trend of change in rainfall over the last 63 years. The transfer functions reconstructed the total annual rainfall (R ~2 = 0.8), and SON (R ~2 = 0.7). This study constitutes the first attempt to reconstruct climatic patterns in Colombia with techniques of dendrochronology, and demonstrates the potential of Parkinsonia praecox for studying climatic patterns along the American subtropics, ranging from Mexico to Argentina.