Efeitos da adição de nutrientes e da invasão por Megathyrsus maximus, na ecofisiologia de plantas nativas, em uma área da Caatinga em regeneração natural

Abstract

Caatinga, the largest and most populous Seasonally Dry Tropical Forest in the world, is located predominantly in the Northeast of Brazil. This unique ecosystem is characterized by highly endemic vegetation, adapted to semi-arid climatic conditions and soils with low nutrient concentrations. However, it faces several threats, including the unsustainable use of resources by the population, the intensification of drought due to climate change and the invasion of exotic species. Such threats compromise local biodiversity and favor desertification processes. This study aims to evaluate the biochemical behavior of pioneer native plants in response to soil changes and increasing competition due to invasion by Megathyrsus maximus. We observed that plants with shorter roots tend to react more efficiently to changes in acidity and the accumulation of Al3+ in sandy soils in the Caatinga. Although the addition of NPK prior to the growing season, coupled with the invasion of M. maximus, did not cause significant changes to the soil over the course of a year, we suggest that these nutrients may have been leached or that the initial soil conditions may have been altered. restored due to high soil activity and absorption by the invasive plant. Even without detectable changes in soils, native plants showed signs of nitrogen reduction, especially in areas invaded by exotic species, indicating an increase in competition for resources. These results provide important insights into the responses of native plants to anthropogenic changes, which can be exacerbated by climate change, threatening the natural regeneration of the Caatinga and the survival of pioneering endemic species. For a more complete understanding of the effects of environmental fluctuations on these species, we recommend long-term studies, given the slow nature of responses to fertilization and invasion by exotic plants.