Residential Prairie Gardens and Turfgrass Lawns Support a Similar Earthworm Population.

Little is known of the effects of incorporating native vegetation into residential landscapes on soil macro fauna. We will present a study in which we investigated whether prairie gardens planted within residential lawns would affect earthworm abundance. Earthworms were sampled from prairie gardens and adjacent lawns in five residential properties within the greater metropolitan area of Madison, Wisconsin, USA, in the autumn of 2007 and 2008. On both sampling dates, soil temperature and soil moisture were similar between vegetation types. Although standing plant biomass was significantly greater within prairie gardens (0.820 kg m^-2) than in lawns (0.238 kg m^-2; p < 0.001), earthworm abundance was not significantly affected by vegetation type (p = 0.618). In 2007, earthworm abundance was greater in prairie gardens (191 ind. m^-2) than in lawns (142 ind. m^-2), however in 2008 an opposite trend was observed (149 and 175 ind. m^-2, respectively). Additionally, earthworm maturity and pigmentation measurements indicated a similar population composition between vegetation types. Despite the limitations of non-destructive sampling within private residential properties, these findings suggest that prairie gardens do not provide a vegetative landscape practice that either promotes or discourages earthworm abundance relative to adjacent turfgrass. Direction and implication for future research will be offered as a result of our work with urban earthworms.