Nursery fertilization shapes physiological drought responses but does not enhance field survival in Cryptocarya alba from Mediterranean central Chile
Javiera Vargas‐Muñoz, Carolina Hernández‐Fuentes, Carolina Szymañski, Marcela A. Bustamante‐SánchezAbstract
Introduction
High seedling mortality during the establishment phase remains a major constraint for forest restoration in Mediterranean‐type ecosystems, where increasing drought frequency and intensity limit post‐planting performance. Seedling survival under these conditions depends not only on site characteristics and species selection but also on functional traits acquired during nursery cultivation.
Objectives
We evaluated whether reducing nursery fertilization induces functional traits and physiological responses associated with drought tolerance, and whether these responses improve field survival of Cryptocarya alba , a native Mediterranean tree species widely used in restoration programs in central Chile.
Methods
Seedlings were grown under contrasting fertilization regimes, exposed to a controlled drought experiment, and subsequently outplanted across contrasting slope aspects representing different levels of water limitation. Morphological traits, physiological responses, and post‐planting survival were assessed.
Results
Reduced fertilization altered seedling morphology and biomass allocation and, particularly under low nitrogen (low N) availability, allowed seedlings to maintain photosynthetic activity under drought. However, these responses did not translate into improved field survival. Control seedlings showed higher final survival than seedlings grown under low N and low nitrogen–phosphorus fertilization, whereas the low phosphorus treatment did not differ significantly from the control. Survival also differed between slope aspects and among restoration sites, but the fertilization × slope interaction was not significant.
Conclusion
Physiological responses to drought induced during nursery cultivation were insufficient to improve field establishment when accompanied by substantial reductions in seedling growth. For C. alba , reduced nursery fertilization therefore provided no advantage for post‐planting survival under the conditions evaluated.