Deciphering tree responses to a changing climate: A case study in Southern beeches of Patagonia

CAVIA, R; GONZALEZ POLO, M; GAISCHUK, S; LIA, M.V.; ESTRAVIS-BARCALA, M; WANG, H; WEIGEL, D; ARANA, M.V; CAGNACCI, J; MARTÍNEZ-MEIER, A.; MATTERA, MG; BELLORA N

Santa Fe

Congreso; XXXIII Argentinian meeting of Plant Physiology; 2021

As a result of climate change, several forest biomes are facing increasing temperatures, extreme cold waves and/or severe droughts. Thus, it becomes essential to understand the way in which trees respond to changes in the environment. This work takes place in the Patagonian forests, the southernmost woody ecosystems of the world, where two Nothofagus species co-exist in non-overlapping thermal niches. While N. obliqua is predominant at lower and warmer environments around 650-850 meters above sea level (m), N. pumilio inhabits higher and colder montane environments, above 1000m. In this work, species? behavior was analyzed in three common gardens at 680, 930 and 1340m. Results showed that phenology of germination, which is environmentally regulated across altitude, contributes to the ability of survival of young N. obliqua and N. pumilio seedlings. Out of the species? natural range, phenology of germination was uncoupled from the favorable climatic window for seedling survival of N. obliqua. This behaviour was not observed in N. pumilio, for which survival was successful in all altitudes. Contrary, at later developmental stages, plants of N. pumilio presented signs of physiological stress in the lowest and warmest environments of the gradient, whereas N. obliqua showed equal performance along all altitudes tested. This suggests that, in N. obliqua and N. pumilio, small environmental changes such as those occurring along altitude constrain growth and/or survival, affecting different developmental stages. Overall, the results indicate different responses of these species to changes in climate and strategies aimed to explore its underlying genetic determinants will be presented.