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

63.
SECTION 5
DISCUSSION
5.1 The significance of the results
I~ would appear from the results of both the
recurrent groups analysis and, the multiple discriminal,t
t
function analysis that assemblages of animals do occuc
in Lyttelton Ilarbour. It has been suggested in Section 4
that there is also a continuum composed of species that
are not tied to one region but exist over a range of
bottom types.
Generally these have been found to show
an affinity with one substrate, either muddy or sandy,
where they are more successful.
This type of study is investigating community
structures on a small scale in a region that would
norma~ly
be classified as a muddy-bottomed harbour and
the fauna present lumped into one community.
The communities have been identified in relation
to the substrate t~xture
and organic carbon content.
Towards these ends the substrate had to be categorized
into sands, sandy muds, and muds.
There are rather
indefinite, and certainly arbitrary, distinctions but
are necessary to reduce some of the variables and
facilitate handling of the datao
This type of approach·
is very common among benthic ecologists and was used
extensively by Sanders (1958) in stUdies in Buzzards
Bay.
He found a very marked correlation between the
amount of fine material, the concentration of chemical
nutrients and the density of faunae
Fager (1968) found
a strong relationship between a stable fine sand substrate
'and a well established epifaunal community off La Jolla,
California. Rhoads and Young (1970) have gone further