TY - JOUR AU - Francisco, AU - Francisco A., AU - López, David AU - Grego, Ramiro D. AU - Buma, Brian AU - Carvajal, Danny AU - Jaña, Ricardo AU - Casassa, Gino AU - Rozzi, Ricardo PY - 2021/12/31 Y2 - 2024/03/29 TI - Climatic gradients and their high influences on terrestrial ecosystems of the Cape Horn Biosphere Reserve, Chile JF - Anales del Instituto de la Patagonia JA - AIP VL - 49 IS - SE - DO - 10.22352/AIP202149012 UR - https://analesdelinstitutodelapatagonia.cl/article/view/997 SP - AB - <p>The Cape Horn Biosphere Reserve (Reserva de Biosfera Cabo de Hornos; RBCH) contain a unique type of biodiversity and ecosystems throughout the world. This environment had been less studied that their counterparts, the subpolar ecosystems of the Northern Hemisphere. The objective of this work is to present, for the first time, a detailed description of the marked climatic gradients of the RBCH and to examine how these are interrelated with the distribution of ecosystems and its vegetation formations. First, a characterization of the spatial distribution of terrestrial ecosystems defined by their dominant plant species or very marked physical characteristics was generated. Second, a spatial characterization of the main climatic-physical variables (tempera- ture, precipitation, snow cover and wind speed) was created for the RBCH using both remote sensing product (MOD10CM) and gridded climate products (CR2MET and ERA5), these data were then contrasted with empirical records of the meteorological stations that are administered by the Chilean Navy and/or the General Water Directorate (DGA). Third, the climatic gradients were characterized based on a Principal Component Analysis (PCA) with the most characteristic climatic variables here analysed: wind speed, summer temperature, elevation, snow cover and annual precipitation. We found two very marked behaviours (gradients): (i) a concentric shape mainly associated with snow cover, summer temperatures and the elevation; and (ii) a patron characterized by precipitation (&gt;50%) with a inclined orientation from north-west (greater precipitation) to south-east (less precipitation), with a decreasing rate of precipitation over 100 kilometres of 30 mm/km (~54ºS). Fourth, the interrelation between these climatic gradients and the distribution of ecosystems was analysed for the definition of environmental gradients using Canonical Components (CCA) with a constrained Inertia of 0.74. Both climatic gradients had a marked influence on the distribution of the main types of described terrestrial ecosystems. These are segregated mainly by the gradients of elevation and rainfall: glacial ecosystems, high-Andean vegetation, evergreen and deciduous forest. Precipitation is the main factor that segregates the distribution of evergreen forests and mixed forests (evergreen-deciduous) and/or deciduous. On the other hand, the distribution of peatland and grassland ecosystems is mainly associated with the intensity of winds in more exposed areas. Recent studies indicate that changes in the precipitation and temperature regime, mainly forced by the Southern Annular Mode (SAM) and the Pacific Decadal Oscillation (PDO), have favoured the advance towards higher altitudes of the Lenga (Nothofagus pumilio) forests. This rise in the altitudinal gradient of forest ecosystems generates a constriction in the area of high-Andean ecosystems located above the treeline. Therefore, in the global warming scenario, the high-Andean subantarctic flora is one of the most threatened floras in the RBCH.</p> ER -