Abstract

Earthworms are soil invertebrates whose roles are essential and indispensable to sustainable agroecosystem services. In the soil environment, earthworms have to cope with a number of natural and anthropogenic stressors, including water inundation. A good understanding of earthworms’ physical and biochemical responses to environmental stressors is therefore needed to conserve their population diversity and density. In this study, we assessed the responses of a tropical, endogeic earthworm to simulated acute water inundation. Earthworms were divided into batches, and each batch of earthworms was subjected to different levels of above-soil water inundation (0, 1.5, 5.0, 10.0, and 15.0 cm) fora period of 7 days, during which their survival and biochemical responses were observed. Results indicated that different inundation water depths produced differences in survival, dissolved oxygen, ammonia, and temperature responses. Earthworm survival decreased with rising water inundation, implying increased mortality with rising water inundation. The concentration of ammonia in soils increased with rising water inundation. Dissolved oxygen was highest in soil of no water inundation, and least in 10 and 15 cm water inundated soils. In addition, pH was highest in soil with no water inundation (6.8), and least in 10 cm water inundated soil (6.5). These results have implications for earthworm conservation and culture. Though earthworms are moisture-loving, excessive water flooding is inimical to their survival. A proper moisture balance is therefore needed to optimize the conservation and culture of earthworms.