Assessing shifts in soil fungal community structure during the conversion of tropical semi-evergreen forest: implications for land use management

Large tracts of forest land are being replaced by rubber plantations (Hevea brasiliensis) all over South Asia and several parts of South America because of the rising demand for natural rubber, causing global concern. Our understanding of changes in soil fungal communities and diversity owing to agro-industrial monoculture plantations is meager. As fungal diversity is a major indicator of soil health, nutrient availability, and mobilization of ions, we analyzed soil samples from both tropical forest and rubber plantations with varying degrees of management within the rubber-growing belts of the ecologically fragile Western Ghats region in Kottayam, Kerala. Our aim was to investigate the spatial turnover of soil fungal communities and their functional diversity, with response to environmental changes induced by conversion to plantations, and to evaluate the impact of the varying levels of management practices followed in different land-use types by targeted sequencing of the fungal ITS-2 region. Conversion of the forest was not linked to a significant loss of biodiversity but rather to enormous changes in the makeup of the soil’s fungal community, accompanied by a substantial decline in ectomycorrhizal fungi, probably due to the lack of hosts. Our results also indicated that the soil physicochemical properties and biological profile of rubber plantations were improved by the three different approaches adopted here, namely cover crop, inter Crop, and weed Crop. These adopted systems can potentially play a crucial role in advancing sustainable agricultural development.