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changes in the numbers of P. elegans larvae settling. Furthermore, during April the
patch plots and non-patch plots can be more-or-less separated suggesting that in
addition to the seasonal effect, the effects of plot type can be observed. This was not
apparent for the August and December experiments when plot type differences were
not so pronounced (see Figures 6.8 and 6.10).
Figure 6.13 presents the ordination of the 'average' faunal communities in both azoic
and ambient (see Chapter 8) samples for both plot types. 'Average' communities,
which were calculated on PRIMER, were used since an MDS plot of all 108 replicates
would have been difficult to interpret. The dendrogram is not included here due to the
low stress value of 0.04. The ordination, which includes the results from both the
April, August and December experiments, allows an estimation of the similarity
between azoic and ambient communities after 3 weeks. There is very little overlap
between the cluster formed by the azoic communities and that of the control
communities. However, it can seen that the azoic patch and non-patch communities
from the April experiment are both located very near the cluster formed by the
ambient communities and conceivably form one larger cluster. Therefore, while
colonisation during August and December was either relatively slow, or produced
communities with different species composition to ambient communities, colonisation
of azoic sediments during April was relatively rapid and after 3 weeks a community
similar to ambient was present.
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