Restoration of southern hemisphere beech (Nothofagaceae) forests: a meta‐analysis

Trophic facilitation in forest restoration: Can Nothofagus trees use ectomycorrhizal fungi of the pioneer shrub Leptospermum?

The benefits of plant-to-plant facilitation in ecological restoration are well recognized, yet the potential for indirect trophic facilitation remains understudied. Nothofagus (southern beech; Nothofagaceae) is an iconic southern hemisphere tree genus that is frequently the focus of ecological restoration efforts. One aspect of Nothofagus ecology that may limit restoration success is the availability of appropriate ectomycorrhizal fungi. It has been suggested that pioneer dual-mycorrhizal hosts such as Leptospermum species (Myrtaceae) could facilitate Nothofagus establishment by providing fungal inoculum, but the capacity for Nothofagus to use Leptospermum ectomycorrhizal fungi is unknown. To investigate potential indirect facilitation, we conducted a common garden pot trial to determine if Nothofagus cliffortioides (mountain beech) can use symbionts from Leptospermum scoparium (mānuka) ectomycorrhizal communities. Nothofagus and Leptospermum seedlings were grown in monoculture and mixed pairs with reciprocal "home" and "away" soil fungal inoculum. ITS2 metabarcoding of eDNA from hyphal ingrowth bags revealed that Nothofagus and Leptospermum inoculum contained different ectomycorrhizal fungal communities, but that half of the common ectomycorrhizal taxa identified were found in both soil types, suggesting generalist fungi exist. Nothofagus was able to form associations with some fungal species originating from Leptospermum inoculum, however, probable spore contamination meant that the proportion of root colonization associated with those species was ambiguous. Root ectomycorrhizal colonization rates were positively associated with seedling biomass, and there was some evidence of a home soil inoculum advantage in Nothofagus, but these effects were minor. Additionally, we found evidence that home inoculum provides a protective advantage against drought stress for Leptospermum seedlings. Our results indicate the potential for using Leptospermum to promote Nothofagus establishment in restoration plantings and highlight the possible benefits of considering fungal mutualists in ecological restoration projects.

Early Effects of Mycorrhizal Fungal Inoculum and Fertilizer on Morphological and Physiological Variables of Nursery-Grown Nothofagus alessandrii Plants

Nothofagus alessandrii (ruil) is an endangered relict species, endemic to the Mediterranean area of Chile, and one of the most threatened trees in the country. Its natural distribution area has been greatly reduced by the effect of human activities; the remaining fragments are mostly intervened and highly deteriorated as a habitat and refuge for the associated biodiversity. In order to produce healthy and resistant nursery plants for recovery and restoration of N. alessandrii forests, this study evaluates the early effects of mycorrhizal fungal inoculum (MFI) combined with fertilization on the cultivation of seedlings. The experiment was established under a completely randomized design with a factorial arrangement of the mycorrhizal factors (M0 = without mycorrhizal, M1 = Thelephora sp. and M2 = Hebeloma sp.) and fertilization (F1 = standard fertilization and F2 = intensive fertilization), with three replicates of each combination, for each type of plant (P1 = plants from one season and P2 = plants from two seasons). Each experimental unit corresponded to a group of 20 plants, with 720 plants in the test. The results indicate that application of fertilizer and MFI significantly affects some growth and photosynthesis parameters of ruil plants in one and two seasons. The morphological parameters obtained in the study show shoot height values ranging between 67 and 91 cm for P1 and between 96 and 111 cm for P2; while, for shoot diameter, values ranged between 7.91 and 8.24 mm for P1 and between 10.91 and 11.49 mm for P2. Although formation of fully developed mycorrhizal roots was not observed during the assay period, we conclude that inoculation of mycorrhizal fungi combined with fertilization could be an efficient strategy to produce a quality plant, in addition to maintaining a high photosynthetic capacity and, therefore, a higher percentage of survival in the field.