Climate change in Southern Patagonia influencing over forest ecosystem processes and natural regeneration dynamics

MARTÍNEZ PASTUR, G; LENCINAS, MV; ROSAS, YM; DÍAZ DELGADO, R; PERI, PL

Leipziger

Encuentro; International Long Term Ecological Research Network (ILTER); 2019

ILTER

Climate change greatly influenced in extreme ecosystems (e.g. Southern Patagonia) where the season was shortly due to their environmental limitatons. Slightly variaton mainly influence over season length, affectng the tree and plant growth including reproducton, food availability for mammals, birds and insects, and in consequence over the primary and secondary productvity. The closeness to Antarctca and the influence of both oceans (Pacifc and Atlantc) also conditoned the regional climate of the archipelago, where temperature and rainfall paterns were highly correlated different climate phenomena (e.g. ENSO). The objectve of this work was to relate changes in climate variables and indexes with forest ecosystem processes and natural regeneraton dynamics (primary and secondary productvity, tree mortality, seed producton, understory, browsing) in SouthernPatagonia, Argentna. We employed long-term data in managed and unmanaged Nothofagus pumilio forests, where year-to-year surveys were conducted in three ranches of Tierra del Fuego and Santa Cruz provinces. We also employed long-term satellite data from MODIS mission (land and sea surface temperature, rainfall, primary productvity net) and climate indexes (ENSO, SAM). Primary productvity net of natural ecosystems are closely related to temperature and rainfall gradients, and extreme events (e.g. ENSO, SAM) influencing over the startng of the growing season, and consequently over the forest and understory growth. Tree mortality in natural stands can be related with climate too, where yearly rainfall (drought during summer) and primary productvity net (stand growth) explain most of the tree losses. Seed producton, recruitment and seedling mortality are related to land and sea surface temperature and rainfall gradients, both, during the previous winter and middle summer. Also, understory development were related to the summer length, where food availability decrease in late spring for herbivorous. In consequence, browsing over seedlings due to natural populatons of Lama guanicoe increased during these years. Finally, we also related secondary productvity (e.g. forest bird biomass) with primary productvity of forests, and it changed according this variable along the years. Long-term research allowed to understand the observed changes in the forest ecosystem processes and natural regeneraton dynamics, in the framework ofmanagement proposals and climate change. This monitoring is essental to develop new management and conservaton strategies to increase the resilience of the natural forests.