Dredging Impacts Verified in Relation to Scientific Evidence (DIVERSE)
- Reference:
- 08/P40
- Organisation:
- Cefas (with University of St Andrews and Marine Ecological Surveys Ltd)
- Amount Funded:
- £194,118
- Status:
- Current
License conditions require aggregate dredging companies, on
cessation of activities, to leave the seabed in a similar physical
condition to that which existed prior to dredging. This
precautionary measure is designed to maximize the chances of the
return of a similar pre-dredge faunal community.
However, evidence from a small number of studies has shown that
aggregate dredging has the potential to result in persistent
changes to the particle size composition of sediments in the
vicinity of extraction sites. Such changes are most likely to
result from the practice of screening, whereby unwanted sediment
fractions are returned to the seabed.
Where these changes occur, the communities that colonise the
post-dredge sediments may be somewhat different to those of
pre-dredge or reference site sediments. Rather than assume such
changes are detrimental, our aim is to investigate the significance
of these changes in terms of ecosystem health. During this project
we will address 3 specific questions:
i. Do the modified communities present in areas of altered
sediment composition and dynamics perform some or all of the same
functions as those present before dredging?
ii. At what level of disturbance are there discernible effects on
ecosystem function and
iii. What is the evidence for linking the enhancement of a
particular species to ongoing dredging activities and under what
circumstances might these occur?