Changes in Microfungal Community in Cherrapunji—The Wettest Patch on Earth as Influenced by Heavy Rain and Soil Degradation

摘要

As part of a long time analysis to examine the ecological impacts of heavy rain coupled to soil degradation, soil fungal communities from two closely spaced sites bearing distinct ecology—one receiving heaviest rainfall but degraded patch on earth and the other pristine sacred grove forest were investigated over a period of three years. Cherrapunji besides being highest rainfall receiving area, is characterized by complete deforestation and soil erosion with sparse grasses forming the surface growth, whereas the sacred forests are conserved in their pristine nature due to religious beliefs of the indigenous tribes. The effect of deforestation and land degradation on soil microbes, soil organic carbon, soil nitrate nitrogen, soil pH, soil temperature, and fungal CFU/g were investigated from the two contrasting sites. The sites showed great variability in physical and chemical parameters including soil composition, temperature, pH, soil carbon, nitrogen content, water availability and enzyme activities. The population count of fungi was higher in sacred forest soil than degraded land of Cherrapunji. In both soil types, Penicillium perpurogenum markedly dominated and the co-dominant species (Aspergillus sp., Fusarium sp. and Trichoderma sp.) were common in both virgin and degraded soils. A total of 63 species were identified during the study period. The species composition between the two sites showed some variation as Syncephalastrum sp., S. chartarum, Gliocladium sp., Eupenicillium osmophilum and Eurotium sp. were not present in Cherrapunji. The undisturbed sacred forest fungal communities had significantly higher Simpson, Shannon and evenness indices than that of degraded soil of Cherrapunji. The prolonged anthropogenic activity in the area leading to degradation coupled with heavy rainfall has decreased the diversity level of fungal communities and masked the pristine differentiating effect of soil on the fungal community.