Comparative study of nature and activities of soil fungi along with soil characteristics inKanneliya natural forest reserve and adjacent disturbed forest patch

Abstract

Soil fungi in forests are crucial for ecosystem functioning by nutrient cycling through organic matterdecomposition. The Kanneliya forest reserve in Sri Lanka faces an ecological threat due to the invasionof the fern Dicranopteris Linearis, affecting the soil fungal community and challenging the restorationefforts. This study investigates the soil physicochemical properties along with substrate utilisationability of the dominantly isolated fungi in two ecosystems: the native forest patch and in adjacentdisturbed forest patch in the Kanneliya Forest Reserve. Soil pH, electrical conductivity, moisturecontent, and temperature were measured using standard methods. The Warcup soil plate method wascarried out using PDA medium to isolate soil fungi, and pure cultures of fungi were identified at thegenus level using morphological and microscopic observations. The percentage frequency ofoccurrence of each fungus was calculated separately for the two study sites. Aspergillus sp.1,Trichoderma sp.4, Rhizomucor sp.1, White sterile sp.1, and Trichoderma sp.5, the dominantly isolatedfungal species were tested for their substrate utilisation abilities (starch, cellulose and lignin) usingstandard methods. The soil temperature was significantly different within the adjacent disturbed land,but not within the native forest patch. The soil moisture content within the two study sites was notsignificantly different. The soil pH varied significantly within the undisturbed forest patch, but notwithin the disturbed land. The soil electrical conductivity within the two study sites was significantlydifferent. There were significant differences in soil electrical conductivity, moisture content, and pHbetween the two study sites, while soil temperature did not differ significantly. Among the isolatedeighteen (18) fungal species, 14 and 11 species were isolated from undisturbed and disturbed sites,respectively. Aspergillus sp.1, Aspergillus sp.2, Aspergillus sp.4, Trichoderma sp.3, Trichoderma sp.4,Trichoderma sp.5 and white sterile sp.1 were commonly isolated from both sites. Aspergillus sp.1,Rhizomucor sp.1 and White sterile sp.1 were able to utilise starch, and all fungi tested were able toutilise cellulose. Aspergillus sp.1, Trichoderma sp.4, White sterile sp.1, and Trichoderma sp.5 exhibitedthe ability to produce lignin-degrading enzyme(laccase), while none of the other fungal species testedwere able to produce peroxidase and tyrosinase, other lignin-degrading enzymes. The presentinvestigation provides insights into fungal composition and some physicochemical parameters inundisturbed and adjacent disturbed land in the Kanneliya forest reserve. Common fungal species to bothsites were isolated in a higher frequency of occurrence from the undisturbed forest patch compared tothe adjacent disturbed forest patch; this may be due to the presence of anti-fungal allelopathic chemicalsin the fern land. Further investigations on the allelopathic effect of Dicranopteris linearis on fungalgrowth are crucial to ensure the sustainability of the Kanneliya forest ecosystem.