Gregarious bamboo flowering opens a window of opportunity for regeneration in a temperate forest of Patagonia

GIORDANO, CARLA V.; SÁNCHEZ, RODOLFO A.; AUSTIN, AMY T

NEW PHYTOLOGIST

Blackwell Publishing

Año: 2009 vol. 181 p. 880 - 889

0028-646X

• Rare gregarious flowering of understorey bamboo species occurs in temperateand subtropical forests around the world, but the ecological consequences ofthis phenomenon for forest regeneration are not well understood.• Field experiments were conducted in an old-growth temperate forest in Patagonia,Argentina after a massive bamboo flowering event, to examine whether light qualityand other changes in microhabitats could affect seed germination and growth ofoverstorey species.• Germination of southern beech (Nothofagus obliqua) was positively correlatedwith red:far red (R:FR) ratios in a range of microhabitats generated by the deathof the understorey bamboo (Chusquea culeou). Experimental modification ofunderstorey R:FR ratios to mimic alternative light environments reversed thisgermination response in plots with senescent understorey, but not in plots with livebamboo. Laboratory incubations demonstrated a significant interaction betweenR:FR ratios and thermal amplitude in promoting seed germination. Microhabitatsalso significantly affected the growth of emerged seedlings.• Microenvironmental changes generated by this flowering event appear to haveopened a window of opportunity for germination and growth of overstorey species.We demonstrate that natural gradients in light quality associated with this ecologicalphenomenon are a major component affecting forest regeneration in this ecosystem.