Soil fungal communities under plantations of different Eucalyptus species in Ethiopia: Insights for evidence-based management

Abstract

The rapid expansion of Eucalyptus plantations in Ethiopia is driven by the increasing demand for woody products, raising concerns about their ecological impact. While conserving native forests remains a priority, Eucalyptus plantations provide alternative sources of forest products and income, helping to reduce pressure on native ecosystems. However, the ecological implications of these plantations, particularly their impact on soil fungal communities, key players in nutrient cycling and ecosystem functioning, remain poorly understood. This study investigates soil fungal community dynamics in Eucalyptus globulus and Eucalyptus camaldulensis plantations across diverse environmental gradients in Ethiopia. Soil samples were collected from 24 plots, and fungal DNA was extracted and sequenced using Illumina MiSeq technology, targeting the ITS2 region. Taxonomic classification and functional guild assignment were performed. Although both plantation types supported a high level of fungal richness and diversity, fungal community composition significantly varied by the Eucalyptus species. Environmental factors, including elevation, precipitation, and temperature, were linked to variations in fungal community composition, creating distinct ecological niches. The main indicator taxa under E. camaldulensis were the species Yurkovia mendeliana, Fusarium oxysporum, Talaromyces solicola, and Westerdykella reniformis, as well as an unidentified member of the class Chytridiomycetes. Under E. globulus, the main indicator taxa were the species Saitozyma podzolica, Brachiosphaera tropicalis, Pseudoacremonium sacchari, and Preussia flanaganii, along with an unidentified member of the order Hypocreales. Although the species Archaeorhizomyces finlayi and members of the families Hydnangiaceae and Chaetomiaceae and the order Sordariales were present in both plantation types, their relative abundances differed significantly between the two species. Our findings highlight that expanding Eucalyptus plantations support soil fungal diversity. A mosaic landscape combining the two species at the landscape level could enhance fungal biodiversity and ecosystem functionality. Understanding these fungal associations provides valuable insights for evidence-based plantation management and sustainable forestry practices in Ethiopia.