Regeneration dynamics of three Nothofagus species under different climatic scenarios in the Southern Andes

CAGNACCI, J; LIA, V; MARTINEZ MEIER, A; GONZALEZ-POLO, M; PASTORINO, MJ; ESTRAVIS-BARCALÁ, M; MARCHELLI, P; ARANA, MV

Conferencia; Adapting Forest ecosystems and wood products to biotic and abiotic stress; 2019

The southern region of the Andes hosts sub-Antarctic Nothofagus forest across a narrow landmass of ca. 17° of latitude. This large range embraces an extraordinary environmental diversity that will be affected according to predictions of global climate change (GCC). Due to its strong vulnerability, tree regeneration can be severely altered in these future climate scenarios. We investigate the regeneration behaviour (seedling emergence and survival) of Nothofagus obliqua, N. nervosa and N. pumilio in different climatic scenarios. We simulated germination pulses inside and outside their altitudinal niches at different moments in the seasons (late winter, early, mid and late spring) during two consecutive years and scored seedling emergence and survival every 30 days. N. obliqua is predominant at 650-850 m asl, N. nervosa at 900-1000 m and N. pumilio above 1000 m. We show that the temporal window favorable for seedling emergence is wider in the lowest (warmest) region of the altitudinal gradient (680 m) compared to the higher (colder) elevations (930-1100 m). Both air temperature and humidity separately explained a high proportion of the variability in the percentage of emergence (63 and 64% respectively). Seedlings showed inter-specific differences in the response to both factors (p