Holdridge Life Zone Map: Republic of Argentina

Ecological zonation is a fundamental tool for territorial and ecosystem management. The Holdridge model is a system of ecological zoning based on the identification of bioclimatic units (life zones) that employs the variables of biotemperature, precipitation, potential evapotranspiration (EVP), EVP/P ratio, latitude, and altitude. Argentina displays high environmental variability. However, despite the completion of several comprehensive zonations of intrinsic scientific value, the country lacks an ecological zonation with objectively and precisely delimited units that may be repeated through time. The objective of this study was to identify and map the Holdridge life zones present in Argentina. Available climatic data were integrated at 1 km spatial resolution. The applied model revealed high environmental heterogeneity, with a total of 83 life zones. Of this total, 72 corresponded to life zones in the original triangular model of 120 life zones described by Holdridge, and 11 were new life zones, extending the original model to a total of 131. The model recognized five latitudinal regions, from boreal to tropical, and seven altitudinal belts, from basal to nival. Northwest Argentina contained the highest concentration of life zones. The life zones with the most geographic extent are Warm Temperate Dry Forest (15 percent of the nation) and Subtropical Dry Forest (9 percent), while Warm Temperate Alpine Wet Tundra and Subtropical Alpine Wet Tundra covered less than 0.1 percent. A wide range of biotemperatures, precipitation levels, and elevations, and their diverse combinations, explains why so many life zones are present. Several factors influence climatic systems operating in Argentina, including its geographic location and north-south latitudinal extension (from about 21° to 55° S); the presence and characteristics of different portions of the Cordillera de los Andes (which reach elevations of up to 7000 m above sea level) in the west; the eastern lowlands; and the circumpolar oceanic current and related currents in the southern Pacific and southern Atlantic Oceans. Application of the Holdridge system to Argentina resulted in an objective, detailed, and precise country bioclimatic zonation that highlights its environmental heterogeneity, which supports natural ecosystems, cultivated species, agriculture, forestry, and livestock production. This assessment can serve as a useful tool for evaluating the spatial evolution of climate change, land management and other sociocultural aspects, biodiversity conservation, and other objectives.