Seed and seedling responses to inoculation with mycorrhizal fungi and root nodule bacteria: implications for restoration of degraded Mediterranean-type Tuart woodlands

Inoculation with beneficial soil microorganisms has the potential to enhance success of restoration, particularly in harsh Mediterranean-type ecosystems (MTEs). We investigated the effects of microorganisms (mycorrhizal fungi and root nodule bacteria) and planting material (seed and nursery-raised seedlings) on early establishment and growth of two key postdisturbance colonizing species with different life histories, life forms and functional types (Eucalyptus gomphocephala and Acacia saligna) under field conditions. Establishment and growth were monitored at 13months, following the first MTE drought period. For E. gomphocephala, establishment was higher for seedlings (81%) than for seeding (7.5%). Inoculation with ectomycorrhizal fungal spores was not beneficial. For A. saligna, establishment was also higher for seedlings (84%) than for seeding (42.5%). Mycorrhizal fungal inoculum had no effect on establishment or growth. This study has shown that in harsh MTE conditions, the use of seedlings is more effective than seeding in degraded woodlands even when attempting to reintroduce key colonizing species. The microorganism treatments tested did not result in significant improvement in establishment or growth.