Within studies of biological communities the search for occurrence and distribution
patterns is acquiring space in researches in recent decades. Knowledge of the
community structure and their relations, associated with interaction of these organisms
with the environment, give necessary subsidies for the maintenance of these
communities and relevant information for conservation and management plans. This
way, the aim of this work was analyze the effect of environment and space on the
structuration of the fish assemblage of rocky tidepools, describing the occupation
patterns of these species in this environment and testing the hypothesis of the space
having strong effect on the ichthyofauna organization. It was sampled 80 rocky
tidepools in Amazon coastal zone, being 40 of the rainy period and 40 of the dry period
of 2011. These pools are localized in five beaches of the Pará coastal zone and their
volume, distance of the margin and physical-chemical parameters of the water (as pH,
temperature and salinity) were measured. A total of 1.311 fishes were sampled, being
633 individuals of rainy season and 648 of dry season. The specimens represent nine
orders, 14 families and 21 species. Perciformes was the most abundant order, within B.
soporator and L. jocu as the most representative species. Obtained results in BioEnv
process showed that abiotic variables (pH, temperature and volume) are not responsible
for the organization of the community. Calculation of β diversity evidenced a wide
variation of the data, including since the total substitution of the species to identical
communities, considering the occurrence and abundance. DCA pointed that the
pluviometric period is not determinant on species distribution, as result of the lack of
difference in the composition among periods. The effect of space and environment on
the community was low, since the larger part of variation was not explained with
environmental variables, as the second analysis, where it was utilized the variables
defined with the BioEnv process. Following the same pattern, the partial RDA used
with the most correlated variables showed that: 6% explained by environment, 4% by
space, 2% by environment and space, and 88% by other factors. The obtained results in
these analyses prove that abiotic factors measured, likewise the distance among
samples, are not determinant in composition and distribution of tidepools ichthyofauna.
These data refute the hypothesis of the space having influence on the organization of the
ichthyofauna, since the environmental conditions experience constant disturbances
caused by tidal movement. In doing so, the species that occupy this environment
showed themselves adapted, and for this reason they would not have their distribution
affected by the variation of environmental parameters at this scale, responding only for
the space effect.
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