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capable of numerically dominating the early stages of succession following sediment
disturbance. Although the later stages of succession were not investigated in the
present study, Noji and Noji (1991) suggested that spionids such as P. elegans are
capable of persisting at very high densities for some time after numerically dominating
the early stages of succession. Sediment disturbance is most likely on Drum Sands
during the winter months and therefore it must coincide with the second recruitment
period if patches are to be formed. Sediment disturbance during periods of low P.
elegans larval availability results in an early community dominated by C. capitata, the
later successional stages of which were not investigated. Although this study showed
that P. elegans was capable of dominating after small-scale disturbances it did not
show this on the same scale as P. elegans patches, i.e., 1-1.5m2. Experiments in
which the area of sediment disturbance was equivalent to the size of P. elegans
patches, approximately 150-200 times larger than those in the present experiments,
were not performed.
The absence of asexual proliferation and benthic larval production suggested that the
maintenance of increased P. elegans densities within patches would have involved
increased larval/adult recruitment to patches and/or decreased larval/adult emigration.
Increased larval recruitment to defaunated sediments within patches compared to non-
patches were shown by the present experiments during periods of high P. elegans
larval availability. Without further studies it is not possible to suggest the mechanism
of this, but in view of the hydrodynamics of established patches, it is likely that
increased passive larval entrainment was an important factor. Similarly, adult
colonisation of defaunated sediments within patches was shown to be higher than in
non-patch areas. These results suggest that P. elegans patch maintenance was
possible without asexual proliferation and benthic larval production.
This thesis concentrated on the processes responsible for the generation of the small-
scale P. elegans patches and no explicit studies were carried out to investigate the
processes responsible for the presence of micro-scale patches of P. elegans. This
could form the basis of further research. A correlative approach, however, was used
to investigate whether intraspecific interactions (adult-larval interactions),
interspecific interactions or sediment heterogeneity were likely to affect P. elegans
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