Restoration Plantings Promote Functional Recovery of Soil Fungi

The global scale of biodiversity loss and land degradation has prompted the establishment of ambitious international restoration agreements, with the goal of returning biodiverse and functional ecosystems. Restoration interventions are often vegetation focused, and while they yield positive, measurable outcomes, they do not always lead to whole ecosystem recovery. Although soil microbiota such as fungi are integral ecosystem components (e.g., as symbionts, decomposers and drivers of nutrient cycling), they are largely absent from restoration planning and monitoring. Therefore, how fungi respond to ecosystem restoration, especially over longer time scales, is largely unknown. Here, we show trends of reduced dominance of soil fungal pathotrophs across a restoration chronosequence 6 years after initial sampling. This decline in soil fungal pathotrophs is consistent with continued functional recovery, despite little evidence of additional whole-community fungal recovery. Fungal community composition was also strongly associated with soil properties, particularly phosphorus, consistent with persistent land-use legacies constraining further recovery. The observed change in fungal functional composition is consistent with previous studies reporting higher relative abundance of pathotrophic fungi in ecologically degraded sites. Our study provides valuable insights into how soil fungal communities respond to restoration plantings and highlights the importance of repeated sampling. Our findings also demonstrate the value of considering both taxonomic and functional indicators when assessing ecosystem recovery.