Do Disturbances differentially affect early regeneration stages of native and non-native conifers in Northwestern Patagonia?

RELVA, M.A.; NUÑEZ, C.

Mar del Plata

Conferencia; 2nd World Conference on Biological Invasions and Ecosystem Functioning; 2011

Grupo de Investigación y Educación en Temas Ambientales

Disturbances may modify resistance mechanisms of plant communities creating conditions that favor exotic plant species colonization and expansion, being early Regeneration stages key periods in such processes. Few studies have focused on the simultaneous effects of different disturbances on plant invasion processes. We studied the synergistic effect of adult Austrocedrus chilensis tree mortality (dieback caused by a root pathogen) and exotic deer on seedling survival of this native conifer and of an introduced conifer, Pseudotsuga menziesii (used in plantations, invasive elsewhere) in temperate forest in northwestern Patagonia, Argentina. We performed a two-year experiment registering seedling survival of sowed seeds of both conifers, in a factorial design, with deer (exclosure and control) and dieback (open vs. close canopy) as disturbance agents. We also measured photosynthetic active radiation (PAR) and soil humidity for microsite characterization. We did not find a synergistic effect between the studied factors. Deer exclusion did not have a significant effect, while canopy openness had a strong negative effect on seedling survival of both species (P