Soil Fungal Communities under Pinus patula Schiede ex Schltdl. & Cham. Plantation Forests of Different Ages in Ethiopia

Untangling the effect that replacing Ethiopia's natural forests with exotic tree plantations has on arbuscular mycorrhizal fungi

Arbuscular mycorrhizal fungi (AMF) have a broad distribution and establish symbiotic relationships with vascular plants in tropical regions. They play a crucial role in enhancing plant nutrient absorption, mitigating pathogenic infections, and boosting the resilience of host plants to abiotic stresses, including drought under specific conditions. Many natural forests in Ethiopia are being replaced by monospecific plantations. However, the impact of these actions on AMF is unknown and, despite their ecological functions, AMF communities in various forest systems have not been thoroughly investigated. In this study, we assessed soil AMF communities in natural and plantation forests by DNA metabarcoding of the ITS2 rDNA region and assessed the influence of climate and environmental variables on the AMF community. In total, 193 AMF operational taxonomic units (OTUs), comprising nine families and 15 genera, were recorded. Glomerales was the dominant order (67.9 % of AMF OTUs) and Septoglomus fuscum, Diversispora insculpta, and Funneliformis mosseae were the dominant species. AMF were more abundant in natural forests than in plantation forests and the composition of AMF communities differed significantly from those of plantation forest. In plantation forests, soil pH, organic carbon, total nitrogen, and available phosphorus significantly influenced the composition of AMF communities, whereas in natural forest, electrical conductivity, annual rainfall, and cumulative rainfall before sample collection were significantly correlated with AMF. SIMPER analysis identified the AMF responsible for composition variances among different forest types, with the Glomeraceae family being the most significant contributor, accounting for nearly 60 % of the dissimilarity. Our findings further our understanding of the ecological niche function and the role of AMF in Ethiopia's natural forest systems and highlight the importance of prioritizing the sustainable development of degraded natural forests rather than plantations to ensure the preservation of habitats conducive to maintaining various AMF communities when devising conservation and management strategies.

Long-term effects of forest fires on fungal community and soil properties along a hemiboreal Scots pine forest fire chronosequence

We studied long-term effects of forest fires on the dynamics of soil fungal community along a post-fire chronosequence in hemiboreal Scots pine stands in north-western Estonia. Effects of fire on soil and fungi were studied on six sites that differed in time since fire (10, 21, 36, 67, 78 and 181 years ago), without further management interventions. Soil fungal communities along the chronosequence were dominated by soil saprotrophs and ectomycorrhizal (EcM) fungi. Across the chronosequence, the most dominant phylum was Ascomycota. The most abundant OTUs were identified as Umbelopsis sp., Hyaloscyphaceae sp. and Pezoloma ericae with relative abundances of 9.5, 8.9 and 6.8 %, respectively. Fungal species richness was similar among sample areas except in the area where fire occurred 36 years ago, where it was significantly lower. There were considerable differences in EcM fungal species composition along the chronosequence. The most recently burned site had Piloderma sphaerosporum, Pseudotomentella sp. and Clavulinaceae sp. as most abundant EcM OTUs while in three oldest burned areas Clavulinaceae sp. and Cortinarius sp. were abundant. Soil C and N stocks were lower in the most recently burned area but differences with other areas were not statistically significant. Soil pH had a significant effect on fungal species composition. Older areas had substantially lower pH compared to more recently burned areas.

Changes in Rhizosphere Soil Fungal Communities of Pinus tabuliformis Plantations at Different Development Stages on the Loess Plateau

The soil fungal community is an important factor in the forest ecosystems, and a better understanding of its composition and dynamic changes will contribute to the maintenance, preservation, and sustainable development of the forest ecosystems. Pinus tabuliformis has been widely planted for local ecological restoration on the Loess Plateau in China in recent decades. However, these plantations have been degraded to different degrees with increasing stand age. Hence, we tried to find the possible causes for the plantation degradation by analyzing soil environmental changes and soil fungal community composition at different stand ages. We collected rhizosphere soil samples from young (10-year-old), middle-aged (20-year-old), and near-mature (30-year-old) P. tabuliformis plantations in this region and characterized their soil properties and soil fungal community diversity and composition. Our results showed that with increasing stand age, the contents of organic carbon, ammonium nitrogen (AN) and nitrate nitrogen (NN) in the soil increased significantly, while the content of available phosphorus (AP) decreased significantly. The main factors affecting the composition of the soil fungal community were the contents of AP, AN, and NN in the soil. In addition, the genus Suillus was the dominant ectomycorrhizal (ECM) fungus in all periods of P. tabuliformis plantations in this region. The results of structural equation modeling showed that the community composition of ECM fungi was significantly correlated with stand age, soil NN, and AP contents, and that of pathogenic (PAG) fungi was significantly correlated with soil AN and AP contents. The decrease in the relative abundance of ECM fungi and the increase in the relative abundance of PAG fungi would exacerbate the degradation of P. tabulaeformis plantation. Our results illustrated that the content of soil AP is not only an important factor limiting the development of plantations, but it also significantly affects the community composition of soil fungi in the rhizosphere of the P. tabuliformis plantation. This study provides a novel insight into the degradation of P. tabuliformis plantations and builds a solid foundation for their subsequent management, restoration, and sustainable development on the Loess Plateau of China.

Metabarcoding analysis of the soil fungal community to aid the conservation of underexplored church forests in Ethiopia

Most of the Dry Afromontane forests in the northern part of Ethiopia are located around church territories and, hence, are called church forests. These forests are biodiversity islands and provide key ecosystem services to local communities. A previous study of church forest fungal species was based on sporocarp collections. However, to obtain a complete picture of the fungal community, the total fungal community present in the soil needs to be analyzed. This information is important to integrate church forests into global biodiversity conservation strategies and to understand what actions are required to conserve church forests and their biological components, including fungi, which are known for their exceptionally high diversity levels. We assessed soil fungal communities in three church forests using ITS2 rDNA metabarcoding. In total, 5152 fungal operational taxonomic units representing 16 fungal phyla were identified. Saprotrophs followed by ectomycorrhizal fungi and animal pathogens dominated fungal communities. Significant differences in diversity and richness were observed between forests. Non-metric multidimensional scaling confirmed that fungal community composition differed in each forest. The composition was influenced by climatic, edaphic, vegetation, and spatial variables. Linear relationships were found between tree basal area and the abundance of total fungi and trophic groups. Forest management strategies that consider cover, tree density, enrichment plantations of indigenous host tree species, and environmental factors would offer suitable habitats for fungal diversity, production, and function in these forest systems. The application of the baseline information obtained in this study could assist other countries with similar forest conservation issues due to deforestation and forest fragmentation.

Exploring the Relationships between Macrofungi Diversity and Major Environmental Factors in Wunvfeng National Forest Park in Northeast China

In this paper, we analyze the macrofungi communities of five forest types in Wunvfeng National Forest Park (Jilin, China) by collecting fruiting bodies from 2019–2021. Each forest type had three repeats and covered the main habitats of macrofungi. In addition, we evaluate selected environmental variables and macrofungi communities to relate species composition to potential environmental factors. We collected 1235 specimens belonging to 283 species, 116 genera, and 62 families. We found that Amanitaceae, Boletaceae, Russulaceae, and Tricholomataceae were the most diverse family; further, Amanita, Cortinarius, Lactarius, Russula, and Tricholoma were the dominant genera in the area. The macrofungi diversity showed increasing trends from Pinus koraiensis Siebold et Zuccarini forests to Quercus mongolica Fischer ex Ledebour forests. The cumulative species richness was as follows: Q. mongolica forest A > broadleaf mixed forest B > Q. mongolica, P. koraiensis mix forest D (Q. mongolica was the dominant species) > Q. mongolica and P. koraiensis mix forest C (P. koraiensis was the dominant species) > P. koraiensis forest (E). Ectomycorrhizal fungi were the dominant functional group; they were mainly in forest type A and were influenced by soil moisture content and Q. mongolica content (p < 0.05). The wood-rotting fungus showed richer species diversity than other forest types in broadleaf forests A and B. Overall, we concluded that most fungal communities preferred forest types with a relatively high Q. mongolica content. Therefore, the deliberate protection of Q. mongolica forests proves to be a better strategy for maintaining fungal diversity in Wunvfeng National Forest Park.