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polychaetes on the initial successional dynamics and colonisation mode of the most
abundant invertebrate taxa are addressed.
Chapter 7 considers the micro-scale spatial heterogeneity of P. elegans. Specifically,
the spatial distribution of P. elegans within small-scale patches was monitored
through the year and the importance of adult-juvenile interactions, interspecific
interactions and abiotic variables in determining micro-scale patterns are discussed.
In Chapter 8, the ecological significance of the small-scale P. elegans patches were
investigated. In particular, the structures of patch and non-patch communities were
compared using univariate and multivariate analyses using data from samples taken at
various times during this study. In this chapter, the community structure during the
decline of these patches are studied, giving an insight into the possible causes of their
demise.
Chapter 9 is a general discussion in which the findings of all the preceding chapters
are brought together.
PYGOSPIO ELEGANS
Pygospio elegans Claparede is a small, sedentary, tube-building polychaete. This
species is particularly interesting to study since various studies have suggested that it
possesses a wide habitat tolerance, a variety of feeding mechanisms and displays a
remarkable diversity of reproductive strategies (Morgan, 1997), in addition to its
ability to form patches of increased density, or tube-beds.
Pygospio elegans has been found in a wide range of habitats from vertical rock
crevices (Gudmundsson, 1985) to hard sand and gravel, but reaches its highest
densities in sandy or mixed sediments (Smidt, 1951; Muus, 1967). The species is
common in both marine and brackish waters although the highest densities are found
in the latter, being abundant at salinities as low as 2ppt (Hempel, 1957).
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