Forest active restoration for silvopastoral use in Northwestern Patagonia: relative importance of the nurse effect

CHILLO, VERONICA; AMOROSO, MARIANO; ARPIGIANI, DANIELA; REZZANO, CARLOS

NEW FORESTS

SPRINGER

Año: 2022

0169-4286

Ecological interactions, such as facilitation among plant species, has been identifed as keyfor restoration actions. The stress-gradient hypothesis predicts that facilitation increasesunder harsh environments, but disturbance type and nurse shrub characteristics may modifythis prediction. We aim at assessing the efect of two interacting factors (herbivory pressureand light availability) and palatability of the nurse shrub on the importance of nurse efectfor active restoration of mixed evergreen forests of northern Patagonia (Argentina) for silvopastoral use. We planted Austrocedrus chilensis seedlings under two silvopastoral useintensities (higher and lower according to livestock seasonal movements) and under threemicro-site treatments (palatable shrub, non-palatable shrub, inter-canopy), and evaluatedsurvival and growth during three consecutive years. Under higher use intensity (increasingstress of light availability as desiccation risk and herbivory) we found contrasting efects ofthe nurse efect on seedling survival and growth, but the palatability of nurse shrub had noefect. Under higher use intensity, seedling survival was lower, while growth was higher.Higher values of seedling survival were found under low use intensity inter-canopy microsite. Under high use, the presence of a nurse shrub is important for summer seedling survival, indicating its role in avoiding desiccation. The same occurred for winter seedlingsurvival, where a nurse shrub may decrease mainly trampling risk. We highlight the importance of considering the interaction between disturbance factors for the net outcome of thenurse efect in active restoration actions, as it may allow for diverse actions to restoration