masterThesis
Caracterização da comunidade bentônica do recife raso de Pirangi/RN, Brasil, e avaliação do seu processo de estruturação sob impacto de pisoteio
Fecha
2014-04-30Registro en:
BARBOZA, Alina Rocha Pires. Caracterização da comunidade bentônica do recife raso de Pirangi/RN, Brasil, e avaliação do seu processo de estruturação sob impacto de pisoteio. 2014. 80f. Dissertação (Mestrado em Ecologia) - Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, 2014.
Autor
Barboza, Alina Rocha Pires
Resumen
Despite being areas of socioeconomic and ecological importance, the
reef environments in northeastern Brazil have been suffering with cluttered
tourism impacts, such as trampling, activity that leads to decrease in abundance
of organisms, especially benthic, and loss of biodiversity. The objectives of this
study were 1) to characterize the benthic community in the shallow sandstone
reef of Pirangi/RN, identifying patterns of zonation, and 2) evaluate its process
of structuring under different degrees of impact of trampling, providing
information to the proper use of the area. Data on abundance of organisms, the
percentage coverage of the substrate and physic-chemical parameters were
collected. The formation of two zones on the reef was observed: one that
considers submerged areas and ones with shorter time of exposure, lower
roughness and higher heterogeneity in the coverage of the substrate, with a
predominance of sand, foliose algae, rodolit, being related to organisms such as
gastropods, crabs and sea-urchin; the second zone comprises areas with
longer time of exposure, greater roughness and predominance of bedrock
uncovered, being associated with organisms such as barnacles, gastropods,
bivalves and crabs. It is concluded that the studied reef presents its own
zonation pattern, influenced by both the time of immersion and the substrate
characteristics, such as roughness and type of coverage. To answer the second
objective of this study, four experimental blocks were mounted on each of the
three areas of different intensities of trampling, containing the following
treatments: control (isolated from trampling), shaved isolated, trampling and
shaved trampling, with data collection by 11 months. The data in abundance,
diversity indices and living coverage of the substrate were compared between
areas and treatments. The results showed that at the trampling areas, at the
end of the experiment, differences were observed between the intensities of the
impact, where higher values of abundance and richness of mobile fauna and
richness of live coverage (ANOVA, p <0.05) were found in the area of higher
trampling intensity. For fauna withdrawal of trampled scraped treatments, it was
observed in the area of greatest impact that the abundance of small benthic
invertebrates is more than three times smaller than that at the area of
intermediate trampling (ANOVA, p <0.05). Initial isolated areas and final ones
differed only as to the percentage of live coverage, with an increase of 35% at
the end of this experiment. As for the areas that were completely scraped and
isolated at the end of the experiment was observed an increase in the
percentage of live coverage of 11.11% compared to the initial amount in the
area of intermediate impact and 37.5% in the area with greater impact,
indicating recovery of the area. It is suggested that the current use of the reef of
Pirangi be reviewed, with a decentralization of trampling, or a decrease in visits,
so that it does not occur at high intensities