6 .. \ Rccol onwllion Arter Experimental Disturbances
181
Scoloplos armiger, and the molluscs Macoma balthica and Mytilus edulis. Ostracoda and the amphipod Urothoe poseidonis were among the first settlers as well.
Several stages of recolonization were distinguished in the spring experiment of
1994. Until August, the species composition quickly approximated the control
situation. Dominant species in the experimental plots were P. elegans, ostracods,
S. armiger, Poiydora sp. and C. capitata. Caused especially by the increase of
juvenile polychaetes (mainly P. elegans), abundances were not significantly different between experimental and control plots after three months and all plots
were similar with respect to species composition. Hardly any molluscs settled in
the experimental plots in spring. A storm at the end of August caused the end of
this stage and benthic abundances were reduced everywhere. In the following
year, a similar seasonal development of species composition and abundances prevailed in both the experimental and control plots. But in June and August, recruitment by P. elegans and Polydora sp. was much higher in the experimental than in
the control plots with abundances twice as high as control values (Fig. 6.3.3).
N
100
E
0
80
lO
co
~ 60
CIl
Cii 40
::)
'0
:~ 20
'0
.!: 0
N
100
E
0
80
lO
a::) 60
(")
.....
CIl
Cii 40
::J
'0
.:; 20
:c c
0
N
100
E
o 80
If!
co
~ 60
CIl
Cii 40
::)
'0
.:; 20
:c
.!: 0
n
147
disturbance
+
... ... ...
m m m
a. 'iij c:
~ ::l:
::J
....,
disturbance
+
... v v ... ...
m m m m m
'S '"
c. S; >
...., ::J Q> 0
0
« (f)
z
control
adult
r=J juvenile
spring experiment
autumn experiment
... It) It) It) It) It) It) It) It) It) It) It) It)
m m m m m m m
m m m m m
m
N
C
.0
<0 0.. '0; c: 'S '"
0. S; > N
Q>
'"
., ::l: « ~
::J
--, ::J Q) 0
0
Q>
0 ...., u..
....,
~
(f)
Z 0
Fig. 6.3.3 Mean individual den sities of small macrofauna in the course of the experiments opened for recolonization in spring and autumn 1994 (see text for details). The share o f juvenile
polychaetes is indicated by no shading. (Tecklenborg, unpublished data)
181
Scoloplos armiger, and the molluscs Macoma balthica and Mytilus edulis. Ostracoda and the amphipod Urothoe poseidonis were among the first settlers as well.
Several stages of recolonization were distinguished in the spring experiment of
1994. Until August, the species composition quickly approximated the control
situation. Dominant species in the experimental plots were P. elegans, ostracods,
S. armiger, Poiydora sp. and C. capitata. Caused especially by the increase of
juvenile polychaetes (mainly P. elegans), abundances were not significantly different between experimental and control plots after three months and all plots
were similar with respect to species composition. Hardly any molluscs settled in
the experimental plots in spring. A storm at the end of August caused the end of
this stage and benthic abundances were reduced everywhere. In the following
year, a similar seasonal development of species composition and abundances prevailed in both the experimental and control plots. But in June and August, recruitment by P. elegans and Polydora sp. was much higher in the experimental than in
the control plots with abundances twice as high as control values (Fig. 6.3.3).
N
100
E
0
80
lO
co
~ 60
CIl
Cii 40
::)
'0
:~ 20
'0
.!: 0
N
100
E
0
80
lO
a::) 60
(")
.....
CIl
Cii 40
::J
'0
.:; 20
:c c
0
N
100
E
o 80
If!
co
~ 60
CIl
Cii 40
::)
'0
.:; 20
:c
.!: 0
n
147
disturbance
+
... ... ...
m m m
a. 'iij c:
~ ::l:
::J
....,
disturbance
+
... v v ... ...
m m m m m
'S '"
c. S; >
...., ::J Q> 0
0
« (f)
z
control
adult
r=J juvenile
spring experiment
autumn experiment
... It) It) It) It) It) It) It) It) It) It) It) It)
m m m m m m m
m m m m m
m
N
C
.0
<0 0.. '0; c: 'S '"
0. S; > N
Q>
'"
., ::l: « ~
::J
--, ::J Q) 0
0
Q>
0 ...., u..
....,
~
(f)
Z 0
Fig. 6.3.3 Mean individual den sities of small macrofauna in the course of the experiments opened for recolonization in spring and autumn 1994 (see text for details). The share o f juvenile
polychaetes is indicated by no shading. (Tecklenborg, unpublished data)