Phenology and Potential Primary Productivity Response to Climate Change in the Andean Mediterranean Forests: A Remote Sensing Analysis

The Andean Mediterranean forests have shown an increase in their ecological vulnerability to global change due to more intense drought, heatwaves, and forest fires during the last 12 years. Andean Mediterranean forests are sclerophyll and deciduous communities dominated by a high degree of endemic species adapted to summer droughts. These species concentrate their productivity and phenological activity during spring and early summer when the balance between soil moisture and temperature allows growth. Under future climate scenarios, the Andean Mediterranean zone is expected to have an increase in frequency and intensity of drought and heatwaves, a decrease in forest productivity accompanied by alteration of phenological cycles, and changes in the vegetation structure and plant composition. Remote sensing data allows us to study vegetation productivity trends and its phenological events by means of the annual and inter-annual variation from vegetation indices. Vegetation indices represent the ratio between energy absorbed in red and infra-red wavelength, and are considered a proxy of the potential primary productivity of forests, and have been useful tools for monitoring changes at different spatial and temporal scales. This chapter presents a temporal analysis of the potential primary productivity trend and its associated phenology in the last two decades for the Mediterranean forests located in the Andean range of Chile. This region is important, since it has been subjected to a profound drought and several heatwave events in the last decades. To show our assessment, first we provide a brief characterization of Andean Mediterranean forest considering its biophysical, structural, and compositional characteristics. Second, we characterized the productivity and phenology considering seasonal parameters related to productivity. We finalized by presenting the analysis of the temporal change of the potential primary productivity, identifying the trends changes over time. Results presented in the chapter show how the monitoring of forest ecosystems in highly vulnerable areas to climate change can inform us on its resilience and shed a light on potential areas for conservation of communities within a biodiversity hotspot.