Studies on earthworm diversity with respect to soil properties in different land use systems in Koraput region of the Eastern Ghats, India

To understand the impact of soil properties and land use systems on earthworm diversity in the biodiversity-rich Eastern Ghats Highlands of India, the present study was carried out in six land use systems i.e., moist deciduous forest, dry deciduous forest, fallow land, cropland, compost pit, and, sewage soil. The study area has been divided into 10 x 10 km(2) grids and 25% grids were randomly selected for sampling from April to December 2022. A total of 16 species of earthworms under 14 genera and 8 families were recorded, out of which 15 species are new records for the region. The most taxonomically rich family was the Megascolecidae. The most abundant species are endogeic followed by epigeic and anecic. Based on Hill numbers, the highest values of Shannon index (D-1 = 9.89) and Simpson diversity (D-2 = 9.14) were found for the fallow land. Earthworm abundance showed a significant difference among six land use systems [F (5,84) = 3.256, p < 0.05] and seasons [F (2,87) = 46.463, p < 0.01]. Furthermore, earthworms showed a significant positive relationship with moisture (r = 0.538, p < 0.01), organic carbon (r = 0.560, p < 0.01), available Nitrogen (r = 0.525, p < 0.01), and clay content (r = 0.535, p < 0.01), whereas negatively correlated with sand content (r = - 0.513, p < 0.01) of soil. Cropland showed high species richness, and fallow land exhibited increased diversity due to elevated moisture, moderate edaphic factors, and proximity to pristine forests. The presence of a high number of native species urges their conservation in this region through land management.