Ecological restoration methods influence the structure of arbuscular mycorrhizal fungal communities in degraded drylands

摘要

Dry forest restoration success could be strongly dependent on the re-establishment of Arbuscular Mycorrhizal (AM) fungal communities. AM fungi directly influence growth of a great variety of plant species by increasing nutrient uptake and providing a network of nutrient distribution for the whole plant community. Our study focuses on how different ecological restoration techniques could influence AM fungal communities in restored dry forests in the Brazilian Caatinga. The study was conducted at the National Forest of Agit, northeastern Brazil. AM fungal communities were studied in a restoration experiment studying the effects of litter transposition, irrigation and agroforestry treatments in comparison with a control (no manipulation) and samples collected from a conserved area (Caatinga pristine woodland) and in a regeneration area (herbaceous vegetation). Total abundance of glomerospores, number of viable glomerospores, species richness and species composition of glomerospore communities were compared among all conditions. We also investigated how soil nutrients could relate to the number of viable glomerospores in the restoration treatments. Litter treatment was the most effective in improving the AM fungal communities, showing a higher number of glomerospores than the control treatment. Litter treatment also had a greater species similarity to the conserved area among all treatments. Irrigation lead to an increase in soil salinization, which was related to a decrease in glomerospore abundance. However, in the highly irrigated agroforestry treatment there was an increase in the abundance of viable glomerospores in relation to the control treatment. Organic matter and calcium were positively correlated with the number of viable glomerospores while sodium was negatively related, showing that soil salinity could affect AM fungal community structure. Our study shows that litter transposition and agroforestry treatments are promising techniques to re-establish mycorrh