To find out environmental impacts on the biodiversity after the large-scale landfill executed from 2007, the annual succession of the benthic macrofauna was monitored in the lower Tamagawa River, adjacent to the Haneda International Airport at the innermost of Tokyo Bay.

During this study conducted from 2007 to 2010, a total of 267 samples were taken. In each sample, 0.1m² and 10 cm (in subtidal) or 30 cm (in tidal flat) deep sediment was collected, then, sieved with a 1 mm mesh. All animals remained on the sieve were collected. After identified, number of individuals and wet weight of each species were estimated.

Since 2007, as a consequence from nMDS analyses with Bray-Curtis similarity indices, the overall structure of the macrofauna has showed no remarkable change, while some dominant species seemed to alter their spatial patterns annually.