Nothofagus antarctica seedling performance under the influence of Berberis microphylla shrubs with different grazing intensities in burned forests of Tierra del Fuego

Abstract

Fire and grazing in forest ecosystems modify the characteristics of plant communities, favoring colonization by sprouting shrub species. These shrubs may offer protection and facilitate greater survival in slow-growing species, which are less tolerant of biotic and abiotic stressors. The objective of this study was to evaluate Nothofagus antarctica seedling performance (survival, morphology, water potential, and biomass) under the influence of Berberis microphylla shrubs in sites with different grazing use intensities in burned forests in Tierra del Fuego, Argentina. For that, four treatment were established: N. antarctica seedlings planted a) with fence-under shrub b) with fence-outside shrub c) without fence-under shrub d) without fence-outside shrub. Edaphoclimatic conditions were measured inside and outside the shrub at the beginning of the experiment and seedling's performance was measured each summer from 2018 to 2020. Results showed that B. microphylla created favorable edaphoclimatic condition under its canopy. There was lower soil bulk density, cover of bare soil, PAR, soil and air temperatures, but also higher relative humidity, pH, and vegetation cover. N. antarctica seedlings growing under B. microphylla shrubs had less leaf number, but the survival and the other morphological variables were similar to those growing with fenced outside the shrub. Therefore, B. microphylla shrubs provide physical protection against livestock and generate a favorable microenvironment for N. antarctica seedlings in sites with a high grazing use intensity that negatively affect N. antarctica seedlings. To restore burned or degraded landscapes, our study results suggest that fencing N. antarctica seedlings or planting them under the cover of shrubs to protect N. antarctica seedlings from biotic (herbivore) and abiotic (edaphoclimatic) stress.