Utilização de substratos artificiais para o monitoramento de macroinvertebrados aquáticos no açude Cachoeira II, Serra Talhada – PE

Abstract

The preservation of water bodies is an alternative to guarantee the sustainability of natural resources, being important in the elaboration of actions of preservation of the aquatic biodiversity and consequently ecological integrity of these water bodies. Periphyton is a group of great ecological importance in continental aquatic environments. Thus, these organisms have been used as bioindicators of water quality, as they respond to specific environmental conditions. For the observation of the colonization process and structuring of the community of this group within streams, it is recommended to use artificial substrates, allowing a greater control of variables such as area to be colonized, superficial substrate heterogeneity and time of colonization, providing a reliable and reliable analysis. of the tested effects on colonization, succession or even human impacts. This paper presents a chapter where the inventory of aquatic insects associated with artificial substrates and macrophytes Ludwigia helminthorrhiza and Egeria densa will be presented, comparing the composition of aquatic macroinvertebrates in the natural and artificial substrates in Cachoeira II, Serra Talhada, Pernambuco - PE reservoir, inferring about its use as instruments in the biomonitoring of water quality in this environment. To evaluate the composition of the community of aquatic insects monthly collections were carried out from September/19 to November/19. The insects were collected from the natural and artificial substrates manually and using aquatic entoological net at three collection points, with three treatments for each point (T1- Aquatic macrophytes freely present at the banks of the reservoir; T2 - PET bottle collectors containing inside it a polyethylene plant mime; T3 - Polyethylene plant mimes attached to the stakes). The samples were sorted in a sieve size (4.76 mm), fixed in 70% alcohol, and identified at species level through a magnifying glass. Subsequently, they were classified as to the degree of sensitivity to pollution using the BMWP (Biological Monitoring Working Party) index and to the trophic groups. Three 500 mL bottles of water were collected from each point in previously decontaminated containers and kept under refrigeration for further analysis of chemical parameters. In the vicinity of each collection point the abiotic water parameters were measured. The analysis of aquatic entomofauna data found on artificial and natural substrates was based on Margalef Biodiversity Index, Shannon-Wiener Diversity Index and Simpson Dominance Index. A total of 483 insects at different developmental stages (larva, nymph and adults) were collected throughout the research, distributed in 10 orders, 34 families, 38 genera and 15 species, besides the presence of ecdises, 857 mollusks, 11 shrimps and 5 spiders. Of this total, 266 insects were collected on artificial substrate distributed in 10 orders, 28 families, 29 genera and 10 species, in addition to 452 mollusks and 6 shrimps. Coleoptera and Hemiptera with eight families and Diptera with six were the most representative, being Hydrophilidae the most abundant family in both substrates. Predators will be more prominent among the aquatic insects found, which are bioindicators of good water quality because they require specific water parameters. The presence and dominance of Hydrophilidae can be justified by the fact that this family is among the most abundant in 9 lotic aquatic ecosystems and because they have disturbance sensitive species. Application of Margalef Biodiversity Index, Shannon-Wiener Diversity Index and Simpson Dominance Index indicated a high diversity and species richness. The BMWP Index characterized the environment with acceptable, dubious and polluted quality. Therefore, the results obtained indicate that the monitoring of aquatic environments provides extremely important information about the expansion of pollution in the environment, as well as evaluating the efficiency of measures taken to reduce or eliminate their source of contamination, in order to establish a biomonitoring program of this body of water, essential to supply the municipality of Serra Talhada-PE.