Ecology and Distribution of Earthworms in India: A Systematic Review

One of the most significant biotic fauna, an ecological engineer, and a biological indicator of the soil are earthworms, also known as farmer's friends. They play an important role in the mineralization and decomposition of organic matter, and recycling of organic wastes, leading to improvement in soil structure and fertility. They facilitate the increase of microbial biomass and activity, as well as the mobilization of nutrients, by broadening the surface area of organic compounds. The diversity, population size, and spatial arrangement of earthworm species may be used as indicators of the soil and weather conditions within a given geographical region. They function as bioindicators, aiding in the comprehension of the physico-chemical characteristics of their environment. The density and stratification in both horizontal and vertical directions contribute to the process of pedogenesis and formation of soil profiles. These organisms exhibit lower occurrence rates in soils that have undergone disturbance and tend to manifest activity solely under conditions of adequate moisture. The present article provides a comprehensive overview of the ecological characteristics and geographical distribution of earthworms across various habitats in diverse regions of India.