Nematodes as sensitive indicators of change at dredged material disposal sites

Demonstration of the recovery of marine habitats from perturbation, or of the effectiveness of protective measures, is dependent on the sensitivity of the target group in responding to change. This paper highlights the utility of the nematode component of the meiofauna as a tool for assessing disturbance from dredgings disposal. Transect surveys were conducted at three major dredged material disposal sites around the U.K. coast. Both gross effects due to the direct impact of dredgings within the disposal sites and lesser consequences arising from the transport of material away from the sires were evident with nematode community analyses. The same nematode species, Sabatieria pulchra group (both breviseta and punctata) and Daptonema tenuispiculum were found to dominate at all disposal sites, despite appreciable environmental differences between locations and variability in the nature of the deposited dredged material. These studies have established that nematode communities can provide a sensitive indicator of change in response to dredged material disposal at a variety of locations and have introduced a new monitoring tool for a practice that has a wide significance around the U.K. coast. The implications of the findings for the future monitoring of dredged material disposal and other waste inputs are discussed.