IMPACT OF LAND USE CHANGE AND HABITAT DEGRADATION ON BIOGEOGRAPHICAL AND FUNCTIONAL DIVERSITY OF EARTHWORMS IN RAEBARELI, UTTAR PRADESH INDIA

Abstract: In the semi-arid region of central Uttar Pradesh, anthropogenic activities have caused forests converted to agricultural land for crop production and then left as fallow for soil fertility regeneration. Overgrazing, loss of vegetation cover, surface soil layer, cause depletion of soil fertility and soil faunal diversity. The reclamation of degraded agroecosystems using biological means has caused it to change from externally regulated to an internally regulated sustainable ecosystem. Earthworms are a good indicator of change occurring in soil health due to anthropogenic modification in land management. Earthworm species richness was similar along a fertility gradient linked to the litter, organic matter, and better soil moisture and temperature condition. The ecological distribution of earthworm species was impacted, due to land management changes, with exotic species M.formosae dominating when the forest transmuted to agroecosystem. Compared to exotics, endemic species are more sensitive to changes in land management practices. But exotic Metaphire formosae could not invade into fallows subsequent to conversion of an agroecosystem. Colonization of endemic species in fallows and reclaimed agroecosystem had better adaptation to the native vegetation. Thus endemic species offered biotic resistance and preventing the invasion by exotic species there. A marked change in community shift from anecic dominated to endogeic dominated occurred when the agroecosystem was converted to fallows and then reclaimed sites. Perturbation pressure under all the sites prevented an invasion by epigeic species. Under all the sites, seasonal variation and oscillation in earthworm populations occurred, with variation in soil temperature, moisture, and rainfall. The crop cycle in the agroecosystem also affects the earthworm species abundance and distribution. Reserved forest and reclaimed agroecosystem with a higher Simpson diversity index have heterogeneous biodiversity and are a stable ecosystem, fallow, has a lower diversity index, and represents an ecosystem that is vulnerable to environmental stress.