Bioclimatic changes in ecoregions of southern South America: Trends and projections based on Holdridge life zones

Abstract

Modelling the potential impacts of future climate on ecosystems provides important information for environmental planning and management. The Holdridge life zones system is a land classification based on simple bioclimatic variables that can be used for evaluating the potential effect of future climates on ecosystems. However, information on future bioclimatic changes in ecoregions of southern South America is too coarse, or unavailable. Our main goals were to evaluate the usefulness of a simple bioclimatic classification system to assess the potential effects of climate change on ecological systems, and to what extent such changes would affect the ecoregions of Argentina. We analysed the multivariate distance between ecoregions of Argentina based on the area occupied by each life zone in each ecoregion and conducted an ordination of ecoregions under current and future climate scenarios. We also evaluated the correspondence between the boundaries of ecoregions and life zones. Overall, the ecoregions of Argentina are expected to face substantial change in bioclimatic conditions. In particular, ecoregions at high latitudes (e.g. Bosques Patagonicos) or altitudes (e.g. Altos Andes) are projected to exhibit similar bioclimatic conditions to ecoregions at lower latitudes or altitudes under current climate (e.g. Estepa Patagonica, Puna). The boundaries of ecoregions tended to coincide with those of life zones only in two cases and partial coincidence was the most frequent result. Further, the analysis of uncertainties of local climate data allowed to identify ecoregions where the results might be less reliable. Our study provides insights to improve conservation planning and management in Argentina. Integrating ecoregions and Holdridge life zones proved to be a useful approach for understanding the potential effects of future climate changes on ecological systems.