INVESTIGADORES
MARTINEZ PASTUR Guillermo Jose
congresos y reuniones científicas
Título:
Climate change in Southern Patagonia influencing over forest ecosystem processes and natural regeneration dynamics
Autor/es:
G MARTÍNEZ PASTUR; R DIAZ DELGADO; YM ROSAS; MV LENCINAS; PL PERI
Lugar:
Leipzig
Reunión:
Congreso; ILTER Open Science Meeting; 2019
Resumen:
Climate change greatly influenced in extreme ecosystems (e.g. Southern Patagonia) where the season was shortly due to their environmental limitations. Slightly variation mainly influence over season length, affecting the tree and plant growth including reproduction, food availability for mammals, birds and insects, and in consequence over the primary and secondary productivity. The closeness to Antarctica and the influence of both oceans (Pacific and Atlantic) also conditioned the regional climate of the archipelago, where temperature and rainfall patterns were highly correlated different climate phenomena (e.g. ENSO). The objective of this work was to relate changes in climate variables and indexes with forest ecosystem processes and natural regeneration dynamics (primary and secondary productivity, tree mortality, seed production, understory, browsing) in Southern Patagonia, Argentina. 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 productivity net) and climate indexes (ENSO, SAM). Primary productivity net of natural ecosystems are closely related to temperature and rainfall gradients, and extreme events (e.g. ENSO, SAM) influencing over the starting 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 productivity net (stand growth) explain most of the tree losses. Seed production, 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 populations of Lama guanicoe increased during these years. Finally, we also related secondary productivity (e.g. forest bird biomass) with primary productivity 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 regeneration dynamics, in the framework of management proposals and climate change. This monitoring is essential to develop new management and conservation strategies to increase the resilience of the natural forests.