Hostens, K.

Van Hoey, G.

Ysebaert, T.

Open Marine Archive

EU Framework Directives 
(marine  environment)
• Water Framework Directive
• Marine Strategy Directive
• Habitat and Bird Directives
Evaluation of the 
environment
• Impact assessment
• Physical disturbance (fisheries, 
sand extraction, dredging)
• Pollution (chemicals, 
nutrients)
• Construction works (harbours
wind farms, coastal defense)
• Recovery assessment
Benthic Ecosystem 
Quality index (BEQI)
• Benthic indicator tool
• Scaled the deviation between 
control and impact data in 5 
classes
• Sampling effort based
• Evaluate  benthic parameters: 
density, biomass, number of 
species, similarity (species 
composition) 
Measuring the impact degree of different pressure types with the Benthic 
Ecosystem Quality Index (BEQI) H:25
CONCLUSION
 Indicators are evidence based tools which can be used for the evaluation of anthropogenic impacts in marine systems.
 The BEQI indicator tool is capable of measuring the impact degree of different pressure types. The different BEQI parameters
combined in the tool, however, may react differently (the degree of impact) on exerted pressures.
Gert Van Hoey1, Tom Ysebaert2 and Kris Hostens1
Institute for Agricultural and Fisheries Research, Animal Sciences – Fisheries
ILVO, Biological Environmental Research, Ankerstraat 1, 8400 Oostende, Belgium
 +32(0)59/569 847 gert.vanhoey@ilvo.vlaanderen.be
Dumping of dredged material (BE)
www.beqi.eu
The need for adequate control/reference areas Sampling strategy spatially and temporally adapted to impact type
Biological assessment has to coincide with detailed knowledge on 
impact frequency and intensity
Indicators summarize patterns, but they do not provide full explanations 
of observed patterns
Impact assessment: Points of attention !!
MEASURING IMPACT DEGREES: CASE STUDIES
Organic enrichment (Lake Veere, NL) Alien species (Ensis directus) (NL coast)
Evaluation of the impact at 5 dredge disposal
sites (2006-2008) in Belgian Coastal waters
 Benthic community impacted (EQR < 0.6)
from a dumping intensity of 1 to 2 million
tones dry matter per year
 Impact strongest on the parameter density
 Number of species less impacted
 Chronic dumping prevent the development
of a healthy, stable benthic community
 Ecological status in Lake Veere bad, mainly in
the deepest habitat (< 8m) due to oxygen
depletion as a consequence of eutrophication
and stratification
 Management action: again water exchange
through inlet in Oosterschelde dam
 Benthos recovery in deepest habitat
 Other habitats still affected, partly due
to changed salinity patterns
Due to the dominance of Ensis directus in fine 
sandy sediments at Wadden Coast (2002-2004):
Benthos species composition changed
 Similarity EQR moderate
 Biomass quadrupled in last 10 years
 Biomass EQR bad
 Number of species slightly decreased
 Number of species EQR moderate
Healthy ecosystems where 
anthropogenic influences 
are well-managed
Source Van Hoey et al., 2007. The  Benthic Ecosystem Quality Index, intercalibration and assessment of 
Dutch Coastal and transitional waters for the Water Framework Directive, NIOO-report 2007-02
Source: Van Hoey et al., 2007. The  Benthic Ecosystem Quality Index, intercalibration and assessment of 
Dutch Coastal and transitional waters for the Water Framework Directive, NIOO-report 2007-02
21
Average BEQI EQR value per habitat 
0,00
10,00
20,00
30,00
40,00
50,00
60,00
70,00
80,00
90,00
P
e
rc
e
n
ta
g
e
 s
u
rf
a
ce
zuurstof < 7 mg/l
zuurstof < 2 mg/l
0.0
0.2
0.4
0.6
0.8
1.0
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
B
E
Q
I-
s
c
o
re
Lake Veere, time serie
< 2m t.o.v NAP
2 - 8m t.o.v. NAP
> 8m t.o.v. NAP
Restoration measures
Oxygen < 7mg/l
Oxygen < 2mg/l
Source: Van Hoey, G., Hostens, K., Parmentier, K., Robbens, J., Bekaert, K., De Backer, A., Derweduwen, 
J., Devriese, L., Hillewaert, H., Hoffman, S., Pecceu, E., Vandendriessche, S., Wittoeck, J., 2010. Biological 
and chemical effects of the disposal of dredged material in the Belgian Part of the North Sea (period 
2007-2008). Report ILVO-Animal Science-Fisheries 1, pp. 97.
Evaluation “Wadden” 
coast (2002-2004)
0
0.2
0.4
0.6
0.8
1
0 2000000 4000000 6000000 8000000 10000000 12000000
E
Q
R
Dumping quantity (Tonnes Dry Matter) per year
BEQI  EQR scores versus dumping intensity
Similarity
Number of species
Density
Average EQR score
Average
EQR
0.39
(Poor)
Similarity EQR 0.43 
(Moderate)
Number of 
species EQR
0.53
(Moderate)
Density EQR 0.61
(Good)
Biomass EQR 0.0
(Bad)
0
50
100
150
200
250
0
0.2
0.4
0.6
0.8
1
ref 1993-1995 1996-1998 1999-2001 2002-2004
g 
A
FD
W
B
EQ
I b
io
m
as
s 
EQ
R
Ensis AFDW
Biomass EQR
Reference period 1983-1990
Species
“Holland” coast 1991-2001
“Holland” coast 2002-2004
“Wadden” coast 1991-2001
“Wadden” coast 2002-2004


Measuring the impact degree of different pressure types with the Benthic Ecosystem Quality Index (BEQI) [Poster]

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