Fungal communities from forest systems in ethiopia

Résumé

Afromontane forests originally dominated the highland parts of Ethiopia, delivering a wide range of social, economic and environmental benefits including key components of biodiversity. However, anthropogenic disturbances are causing a dramatic decline of these forests and gradually changed the scene. Among the factors, forest fires are increasingly contributing to the loss to these forests systems in the country. On the other hand, plantations of exotic trees are also another form of forests in the highland parts of Ethiopia. They are also serving as sources of industrial wood, firewood, farm implements, poles and posts. Owing to their rapid growth, plantations are subjected to traditional management systems mainly of a “plant, clear fell and replant” cycle method or "coppicing". For the last decades, researches have been conducted to assist the development, management and conservation of both forest systems in the country. However, fungal communities associated with these forests have been neglected and their knowledge is limited by lack of studies in Ethiopia. Previous studies indicated that forest fire and plantation forest management affected the macrofungal community in forest systems where the gestation period is long, although such impacts are yet understudied in Ethiopia. Furthermore, the information about ethnomycology and mushroom cultivation practices is scarce and the available works are even fragmented and limited in their scops to represent the country adequately. Thus, we aimed to compile and assess the existing literature on mushrooms in Ethiopia, and also, to conduct field systematic research to know fungal diversity and production according to stand development and fires in plantations and natural forests respectively. Both review of literature and field studies were carried out for the purpose. The review made included all information available in the country while the field study was conducted at Wondo Genet forest area. In the field we established plots taking into consideration the similarity of the areas in terms of ecological conditions such as climate, altitude, and soil. For the purpose, in the Dry Afromontane forests, two burned and one unburned forest areas were selected. A total of nine sample plots, i.e. three in each area, were established. Similarly, a total of 18 plots were also established in Pinus patula (9 plots) and Eucalyptus grandis (9 plots) stands. In all cases the plots covered an area of 100 m2, with a rectangular shape (2 m x 50 m). All sporocarps found in the plots were fully harvested weekly during the rainy season in July and August in 2015. Fresh weight measurements were carried out in situ and the data are given in kilograms per hectare per year. Also, abundance, the number of sporocarps per species, data was taken from each plot. Sample fruit bodies from each species were taken to the laboratory and dried. Some samples were preserved as herbaria specimens, and they were used for molecular and microscopic taxa identification. Composite soil samples were also collected from each plot to determine main edaphic variables that could explain the fungal communities. Richness, Shannon index, and Fresh weight (for the edible and total taxa) estimates were subjected to one-way ANOVA analysis and a post-hoc least square means difference test (LSD, P ≤ 0.05) in order to test for differences among treatments. Fungal species accumulation curves and the Rényi diversity profile were also generated to compare fungal richness and diversity among different age groups in the plantation forests. An ordination analysis based on fungal fresh weight data was also used in order to identify and correlate significant edaphic explanatory variables related to taxa composition. The review summarizes issues related to the diversity of wild mushrooms, main ecological niches and their associated fungal species, ethnomycology and mushroom cultivation practices in Ethiopia. Threats and the need for future conservation of wild mushrooms in the country are also reported. The results from field observations indicated that a total of 61 taxa were collected from the Dry Afromontane forests, of which 22 were edible, belonging to Basidiomycota division. In this study, fungal diversity and richness were affected just after fire. Fire also affected the production of edible fungal species. Fungal community composition was significantly correlated with edaphic variables such as Organic Matter, Ca and P values. Similarly, we also found a total of 53 and 29 fungal taxa belonging to Basidiomycota division, with the exception of Xylaria hypoxylon which is Ascomycota in P. patula and E. grandis plantations respectively. Majority of the collected taxa in plantations were saprophytic. However, about 6% of the taxa collected in P. patula were ectomycorrhizal fungi. Of the total taxa collected, about 36% and 31% were classified as edible in P. patula and E. grandis tree plantations respectively. Taxa richness, Shannon diversity, and sporocarp yields showed significantly increasing trends with age of both stands. The fungal community composition in P. patula stands also correlated significantly with N, K, and pH. Generally, the findings from review paper can serve as base line information and indicator for further mycological studies in Ethiopia. On the other hand, the results from preliminary field studies have important implication to describe the status of fungal biodiversity, sporocarps production and their succession in natural and the plantation forest systems in Ethiopia. The results also provide management implications to conserve Dry Afromontane forests in Ethiopia through adding economic value from mushrooms. The deliberate presence of mature trees in the plantations could lead to an increase in the production and fungal diversity, with their associated economic and ecological benefits.