ICES CM 2010/Q :14
Baseline benthic biodiversity of the Belgian part of the North Sea: lessons learned and the way
forward with ecological restoration goals
J-S. H ouziaux, ƒ. H aelters, F. Kerckhof, S. D egraer, and T. Jacques
The determ ination of "baselines" is a necessary step in the im plem entation of ecological "restoration". A
baseline can be defined as th e ecosystem state u n d e r levels of anthropogenic pressu re th at do not
negatively affect its functioning. H istorical situations p ro v id in g us w ith inform ation on m arine
ecosystem stru ctu re and functioning p rio r to anthropogenic im pacts are th u s invaluable to determ ine the
extent of h u m an -in d u ced environm ental change and to set targets for the future. The ecology of the
Belgian Part of th e N o rth Sea, n o w subject to intensive hum an-induced disturbance, has been intensively
stu d ied since th e 1970s. Earlier, in th e first decade of the tw entieth century, ecological surveys w ere also
conducted by G ustave Gilson, an early contributor to ICES science. The resulting un p u b lish ed archive
(specim ens an d w ritten records), kept at the Royal Belgian Institute of N atural Sciences, w as researched
betw een 2003 an d 2009, an d w as su p p lem ented w ith an analysis of the pre-1900 literature. The d a ta w ere
com pared w ith th e recent situation, targeting subtidal sedim ents and th eir benthos. H istorical
"baselines" w ere d ra w n for benthic habitats located offshore (Ostrea edulis beds; gravels) and nearshore
(coastal sedim ents) an d w ere placed in their context of anthropogenic pressure. O bserved long-term
(>100 years) biodiversity shifts are consistent w ith the expected im pact of h u m a n activities d u rin g the
tw en tieth century. H ow such detailed historical d ata alter our perception of "ecosystem health", thus far
m ainly b ased on post-1970 know ledge, is discussed and has im plications for the definition of m eaningful
an d achievable m arine ecological restoration goals (e.g. u n d e r the EC "H abitat" and "M arine Strategy"
fram ew ork directives).
Keywords: baselines, benthos, ecological restoration, environmental management, long-term changes, seabed
integrity.
Contact author: J.-S. Houziaux, Royal Belgian Institute o f Natural Sciences (RBINS), Management Unit o f the North Sea
Mathematical Models (M U M M ), Gulledelle 100, 1200 Brussels, Belgium [e-mail: js.houziaux@mumm.ac.be].