Assessing bioindication with earthworms in an intensively farmed rural landscape (Yuanqiao and Daqiao villages in Qianjiang Municipality, located in Hubei Province, subtropical China)

Earthworm species diversity, population density, biomass, age-structure, av erage individual weight, and pattern of distribution were studied in the ag ricultural landscape of two adjacent villages in Qianjiang Municipality loc ated on the Jiang-Han plain, Hubei Province, China. We identified 16 earthw orm species belonging to three families (Moniligastridae, Megascolecidae, a nd Lumbricidae). Among these, Amynthas hupeiensis and Metaphire guillelmi w ere the dominant species, and were recorded in significant numbers in diffe rent seasons and in the various land-use systems studied. The highest earthworm population density was found in June, before the hot summer, and averaged 23 ind. m(-2), with a maximum of 239 ind. m(-2). Among the nine land-use systems distributed in the landscape, home gardens, inte nsively cropped commercial vegetable fields and their margins with weeds an d bushes generally showed a higher earthworm population density, species di versity, and biomass compared with the other systems. These observations co nfirm the importance of an heterogeneous agricultural landscape in preservi ng earthworm abundance and diversity and the possibility to use this group as a possible tool for monitoring landscape changes and sustainability of a gricultural practices.