Burrowing invertebrate communities in small and large agricultural drainage ditches

Biogeochemical processes occurring within drainage ditches are of special interest for their ability to remove pollution from water draining from agricultural fields. Bioturbation by macroinvertebrates is an important process that contributes to the regulation of biogeochemical processes occurring at the sediment-water interface of aquatic habitats. A quantitative survey of sediment-dwelling macroinvertebrates was done to determine the extent to which bioturbation is occurring in drainage ditches.  Macroinvertebrates were sampled from sediment cores taken from four pairs of small (field) and large (collection) ditches on Maryland’s Eastern Shore monthly from March 2011 to February 2012. Species were assigned to functional groups of bioturbation according to trophic position and modes of burrowing. Patterns in burrowing invertebrate density, diversity, and community composition were analyzed in relation to ditch size class and seasonal changes to water quality and quantity. Results from this study will help to determine the extent to which burrowing benthic invertebrates may be considered for management of drainage ditches to improve water quality.