Experimental Approaches to Sediment Communities
349
that there was no significant difference in species richness between treatment (Osmocote) and control HUs (F 1 ,lS=2.744, P>O.1, Fig. 16.5 c), although
more species were identified from enriched HUs than controls during the
20-week period (Fig. 16.5b). However, enriched HUs had a significantly lower
diver-sity (Shannon-Weiner measure) than control HUs (Fl,1s=4.99,
P 2
1.6
Gi c
~ 1.2
c
o
:§ 08
. .
ill
0.4
NS
o .~t-.-~~IJC--a
III 30
.!!!
~ 25
1/1
.! 20
~ 15
z
.~ 10
1 ::I
E
::I
U
b
III
III
5
o
12
10
~ 8
.c
~ 6
III
.!!!
~ 4
1/1 2
o
5
o
5
NS
NS
p 2
t-test resu~s
1.6
>1.2 ~
:a ..
8 ~
o. .B'
0.4
-----------+----------40
10
Time (weeks)
10
Time (Weeks)
15
15
20
20
__ Treatment
____ Control
o+---------~~--------_+----------~--------~
o
5
10
15
20
c
Time (weeks)
Fig.16.5. Species diversity (richness and Shannon-Wiener measure) on artificial habitat
units (pan scourers), with and without slow-release fertiliser, placed in Ythan estuary,
Scotland, for 20 weeks. (Emmerson 2000)