Abstract:

Background & Aim: Enchytraeidae is the second most species abundant family in the Annelida Clitellata. Recognized as “micro-ecosystem engineers”, soil enchytraeids play crucial regulatory roles in improving soil structure and aggregate stability, enhancing soil porosity, air permeability and water infiltration through burrowing, ingesting and mixing mineral soil particles. In addition, as key decomposers of soil organic matter, soft-bodied enchytraeids are vital drivers of nutrient cycling and forming intimate interactions with soil microorganisms, plant roots, and other soil fauna, making them inevitably involved in the complex soil food webs. This review summarizes the research progress on soil enchytraeids regarding their trophic ecology and ecological functions, and provides future research perspectives to advance the field.
Review Results: In the field of trophic ecology, the most important advances including: (1) clearly clarifying the diverse food sources of the soil enchytraeids; (2) unveiling the biological mechanisms underlying the absorption and transformation of nutritional materials in their guts; and (3) preliminarily figuring out their trophic niches. Regarding the ecological functions of soil enchytraeids, the key findings involving: (1) clearly demonstrating the engineering roles of enchytraeids in improving the soil structures; (2) preliminaryly recognizing their important dual roles in soil carbon (i.e. enhancing organic carbon mineralization, controlling labile carbon releasing and sequestration by their effects on soil microbes) and nitrogen dynamics (i.e. increasing soil organic nitrogen mineralization, controlling inorganic nitrogen releasing and transporting); and (3) basically understanding the multiple interactions of enchytraeids with soil microorganisms, other soil fauna, and plant roots.
Prospects: Although having the abovementioned key progresses in recent years, the ecological studies of the soil enchytraeids are largely overlooked in the fundamental and applied fields. To further understand the ecological functions and potential ecosystem services of the soil enchytraeids, and to apply the soil enchytraeids to practical applications and sustainable development, the interdisciplinary perspectives are needed in the future studies of enchytraeids regarding their trophic ecology and multifunctionality.

Key words: enchytraeids, trophic ecology, ecological function, ecosystem engineers