LONG-TERM CHANGES (1979-89) IN THE INTERTIDAL MACROZOOBENTHOS OF THE OOSTERSCHELDE ESTUARY - ARE PATTERNS IN TOTAL DENSITY, BIOMASS AND DIVERSITY INDUCED BY THE CONSTRUCTION OF THE STORM-SURGE BARRIER
Jj. Seys et al., LONG-TERM CHANGES (1979-89) IN THE INTERTIDAL MACROZOOBENTHOS OF THE OOSTERSCHELDE ESTUARY - ARE PATTERNS IN TOTAL DENSITY, BIOMASS AND DIVERSITY INDUCED BY THE CONSTRUCTION OF THE STORM-SURGE BARRIER, Hydrobiologia, 283, 1994, pp. 251-264
To evaluate the effects of the construction of a storm surge barrier i
n the Oosterschelde, long-term patterns (1979-89) in abundance and bio
mass of the intertidal macrozoobenthos were studied at 14 permanent st
ations. Additionally, data of a large-scale survey in late summer 1985
and 1989 were analysed. In this paper, patterns in general parameters
are discussed. Late summer values of total biomass, total density, sp
ecies richness, diversity and abundance- and biomass ratio show no ove
rall significant trend during the study period. The changes in the hyd
rodynamics and the morphology of the Oosterschelde after the completio
n of the storm surge barrier do not seem to have influenced the normal
patterns in benthic populations. The observed patterns are determined
by the occurrence of severe versus mild winters, rather than by hydro
dynamic changes caused by the construction of the barrier. Low biomass
es, high densities (particularly of opportunistic species) and higher
''stress-values'' (abundance- and biomass ratio) in 1985(-87) indicate
a temporal disturbance by severe winter weather. At the elevated COST
-station 27, total biomass decreased sharply in 1985, due to a short-t
erm increase in exposure time, caused by the manipulation of the storm
surge barrier.