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1
C N
W
4----111"
1.5m
2
NW
C
Control (C)-->
Weed (W)
..
v
3
C N
A
W
0.5m
3.5m
4
NW
C
.11
E-- Net (N)
5
WC
N
6
C N
W
Figure 4.2 : Experimental layout of weed implantation experiment showing positions
of the three treatments; unmanipulated control (C), net plot (N) and weed treatment
plot (W) within blocks 1-6. Block 3 has been expanded to show layout of plots in
more detail.
On June 1st, 1997, sediment and faunal samples were taken, together with redox
potential measurements from each plot to represent the initial values at the start of the
experiment. The fauna was sampled by taking 3 cores (each 6x6cm in area, 10cm
depth), located within each plot by random numbers, sieved on a 500jim mesh sieve
and preserved using 10% neutralised, saline formaldehyde solution with 0.01% Rose
Bengal. The three cores were pooled to prevent pseudoreplication (Hurlbert, 1984).
The preserved samples were later washed with freshwater, sorted with the aid of a
magnifying lens, and the organisms identified to the lowest possible taxonomic level.
P. elegans individuals were then stored in 70% ethyl alcohol for size measurements.
The sediment samples were taken by 3 randomly located cores (2.4cm internal
diameter, 3cm depth). The 3 cores were pooled to avoid pseudoreplication. The
samples were later frozen at -20°C for storage. Later in the experiment, weed was
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