Interações macrófitas-invertebrados aquáticos: rede de interação e variação temporal

Abstract

Macrophytes are important structural components of tropical aquatic ecosystems. They play crucial roles in the dynamics of these ecosystems and serve as storage and cycling of nutrients, food for various organisms, colonization, a hideaway from predators and even a nursery. This dissertation has two chapters addressing the interaction between macrophytes and invertebrates. Chapter 1 verified the structure and temporal variation of interactions between floating macrophytes and invertebrates associated with the submerged part of macrophytes. This study carried out six samplings between November 2016 and April 2018 at 10 points in Lake Itaipu on the shores of the Santa Helena Area of Relevant Ecological Interest (ARIE-SH), PR, Brazil. For this study, two individuals of each plant species were sampled at each sampling point. These plants were packed and their submerged parts washed in the laboratory to remove the invertebrates for later sorting and identification at the lowest possible taxonomic level. A total of eight species of macrophytes and 85 invertebrate taxa distributed in five phyla were evidenced. The study found 129.818 invertebrates associated with the 363 macrophytes collected. The samples showed abundance and richness of invertebrates associated with macrophytes, which varied within collections and macrophyte species. The macrophyteinvertebrate interaction network had median connectance, nested pattern and modularity no significative in all samples. This study presents the relationship between the mass of the submerged part of the roots as well as the richness of the invertebrate taxa. Chapter 1 demonstrates that the macrophyte-invertebrate interaction is complex and varies over time. Chapter 2 verified the existence of bioindicator invertebrates in the submerged parts of macrophytes. This chapter used the same sampling methodology used in Chapter 1. From 129.818 invertebrates sampled, 1.271 are bioindicators, equivalent to 0,97%. The results show that checking the submerged parts of the macrophytes is a methodology for biomonitoring studies, acting as a complementary method to reach more precise conclusions about water quality. This work contributed to the survey of the aquatic invertebrate fauna associated with macrophytes.