The benthic ecology and community structure in Lyttelton Harbour ...

53.
communities.
among workers
The extremes of splitting are usually found
cribing diverse, rocky, substrates where
the living s available increase greatly but m~y ~lso
be found in descriptions of level, soft-bottomed areas.
"There can be no rules from which to define limits in
this respect and the outcome is very much a matter of
tact, sociological training and experience" (Braun
Blanquet, 1964) ..
The next logical step from this somewhat confused
situation is to consider the possibility of a continuum.
It has been defined as that state where the fauna changes
continuously and is not differentiated, except arbitrarily,
into sociological entities (McIntosh, 1958)Q Brown and
Curtis (1152) described it as a gradient of communities,
in w~ich spec were distributed in a continuously
shiftio9 s of combinations, in a definite sequence
or pattern. Therefore the continuum is a construction
based on studies, within a specified faunistic region.
It is not an assorted mass of animals, with no plan or
cohesion.
Marine biologists traditionally have recognised
discret~
communities of benthic and littotal organisms,
but the continuum aspect is supported by many recognised
workers iM the field, (Tischler, 1950: Sanders, 1960:
Wieser, 1960: Kilbur~, 1961: Margalef, 1962: and Udvardy,
1964). Sanders (1960) in discussing the sediments of
'Buzzards , suggested a continuum changing with the
variation in sediment quality.
A problem that is common to all of these situations
is the subjective conclusion, that although adequate
when describing obvious cases of dominance, does not hold
up so well when ,a group of animals, although closely
integrated, has no indicator species. These are not