Ecophysiological behavior of woody species in NW Patagonia: are the exotic species more able to cope with climate change than native species?

GYENGE, J.E.; FERNÁNDEZ M.E.

Seúl, Corea

Congreso; XXIII IUFRO World Congress; 2010

IUFRO (International Union of Forest Research Organizations)

In this study we analyze the ecophysiological behavior of adult plant of several woody species growing in NW Patagonia (South-America), in response to changes in environmental (soil water, vapor pressure deficit (VPD)) and management conditions (tree density), in order to estimate the potential impact of predicted conditions in the framework of regional climatic change (temperature increase with similar or lower precipitation levels). A differential behavior was observed comparing exotic (Pinus ponderosa and Pseudotsuga menziesii) versus all native studied species (Nothofagus antarctica, Austrocedrus chilensis, Lomatia hirsuta, Schinus patagonicus, Diostea juncea). The latter always presented an early stomatal conductance decrease under increasing VPD, even when soil water content was high. In contrast, both exotic species presented high canopy conductance levels until threshold VPD values higher than those of native species, maintaining high rates of gas exchange under water deficits in the atmosphere, or even in the soil (in the case of ponderosa pine). These results suggest that, contrary to what could happen with exotic species, the productivity and survival of native species would be seriously limited under air temperature raise, independently of precipitation levels, threatening the sustainability of several forest species of Patagonian forests.