Efeitos do sombreamento e eutrofização no desenvolvimento de uma macrófita invasora.

Abstract

Aquatic macrophytes are essential for the maintenance and balance of aquatic ecosystems as they play important roles. Eutrophication is a process that occurs especially through human interventions that allow changes in the amount of nutrients in water courses that can favor the excessive growth of aquatic macrophytes, especially invasive species. Shading on plant development can trigger strategic responses according to the amount of light that is offered to them. The riparian forest plays an important role in the protection, conservation and recovery of biotic and abiotic factors in riparian environments. Urochloa arrecta is a Poaceae from Africa with high regeneration potential and can be aggressive in aquatic environments. The objective of this work was to evaluate experimentally the effect of different levels of shading and eutrophication on the growth of the species under study, Urochloa arrecta. For this, structures and all the necessary material were assembled to start the experiment in the year 2021 with a duration of 98 days, when the shoots were established. The shading simulation was done through the levels of the shade nets (0%, 30%, 60% and 80%) and the eutrophication simulation through the concentration of nutrients (S- no addition Control, M- Moderate with 5g of nutrient addition and B- High with 10g of nutrient addition). At the end of the experiment, the plants that developed were extracted, washed, measured, oven dried and weighed. The response variables measured were the number of shoots, height, aerial biomass and root biomass. To answer our objective, the Generalized Linear Model was used to perform the statistical test. Our results showed that for the number of shoots, mean shoot height, root biomass, there was a significant effect on nutrient concentration.. While in aerial biomass there was a significant interaction between treatments (shading and nutrient concentration). In this work, we identified that nutrient concentration plays a very important and significant role in the clonal growth of propagules of the Urochloa arrecta species. The information from this study is relevant for the regulation of the invasive potential of the species under study in the aquatic environment to avoid its proliferation and future damages in ecological interactions and to conserve aquatic biodiversity.