The first sets produce uniform bands. In
contrast, coherent events generate idiosyncratic
spikes in species or site temperatures that are
much hotter than the overall matrix temperatures
(Atmar and Patterson(1995).(Fig. 2). The sites can
be reorganized in descending order(Atmar and
Patterson,1995) (Table 5 and Table 6).
Many of the genera selected as indicators of
organic pollution by Palmer (1969) are those which
were idiosyncratic or those that appeared
occasionally when the environmental conditions
were favourable. Probably these were
predominant during all seasons and each author
has reported based on their mere presence.
Therefore it is essential to select organisms that
are always present and indicate the level of
organic pollution. Nestedness software (Fig.2)
detects the algal species of autochthonous or
allocathonous origin which