Estrutura e dinâmica das interações entre invertebrados e macrófitas aquáticas

Abstract

Ecological interactions are associations between organisms, which interfere on survival in at least one of those involved. These interactions have been responsible for structure and maintenance of biodiversity in natural communities. Aquatic plants adapted to lentic environments whose roots remain submerged, being able to inhabit from flood areas to deep aquatic environments. These plants are important structural components of the tropical aquatic ecosystems, playing crucial roles in the dynamics of these ecosystems, serving as storage and cycling of nutrients, food for various organisms, colonization, refuge of predators and even nursery. This study aimed to contribute to the knowledge of the interaction between macrophytes and invertebrates aquatics on the banks of the Santa Helena Biological Reserve in the reservoir of the Itaipu Hydroelectric Power Plant, as well as to verify the structure and complexity of these interactions. A survey was made of the macrophites species and invertebrate associated with the aquatic macrophyte roots at reservoir, in months of November 2016, April, June and September 2017. Two individuals of each plant species were collected from 10 macrophyte banks on the margin of the Santa Helena Biological Refuge. The plants were collected, stored in plastic bags and their roots washed in laboratory for the removal of invertebrates, which were separated and identified at the lowest possible taxonomic level. Were collected 72.535 associated invertebrates associated with 230 roots of eight plant species. The interaction network macrophyteinvertebrate had a low pattern nested and specialization in the four collections. The invertebrates interacted on average with 2.7 plant species in Collection 1, 2.29 in Collection 2, 3.09 in Collection 3, 3.7 in Collection 4. Plant species had on average 21.66 invertebrate taxa associated in their roots in Collection 1, 29.25 in Collection 2,23.42 in Collection 3, 32.85 in Collection 4. The most abundant interaction was established between Mytilidae (Mollusca) and Eichhornia crassipes (Ponteriaceae), totaling 33.433 individuals in 45 roots. This study is a structural structure of the macrophyte-invertebrate interactions and their temporal variation. Aquatic macrophytes are ideal biological components for studying the relationship between habitat areas and the structure of the invertebrate community. These plants increase physical purity in the landscape and, as a result, tend to influence the positive capacity and richness of the resident fauna.