Diagnóstico da mata ciliar e qualidade do solo nas margens do córrego Água Turva na microbacia hidrográfica do Rio Jirau Alto, Dois Vizinhos - PR

Abstract

Riparian forests are characterized as native vegetation bordering water bodies, playing important environmental benefits such as soil stability, water quality and biodiversity conservation. However, the advancement of agricultural activities and uncontrolled urbanization has caused great pressure on the riparian areas, leading to loss of ecological functions. Based on this, this study aimed to evaluate the impacts of urbanization on soil and vegetation in riparian stream Água Tuva, city of Two Dois Vizinhos - PR. For this sample were allocated ten points along the stream, which assessed the diversity and phytosociological structure of trees and regeneration, as well as the conflict in the use and occupation of land, erosion, erosion potential and accumulated litter. In addition, we evaluated the physical and chemical properties of the soil, in order to correlate the influence of impacts on the soil quality. Thus, in urban riparian forests was possible to verify that the Shannon Diversity Index, Maximum Diversity, evenness index and Wealth were low and lower than in rural areas, which indicates that there is greater pressure and anthropogenic interference with the riparian urban, which is reflected in the loss of plant biodiversity. Moreover, the great biological invasion, especially Hovenia dulcis and Ligustrum lucidum, reinforces the need for practices to environmental restoration of riparian forests. As the vegetation, urban areas showed higher values in conflict with the use and occupation of land, existing erosion, erosion potential, which reinforces the idea that cities cause major impacts when compared to agricultural areas. In relation to the ground, the density showed adequate in all sampling points, even in locations with high-conflict, which indicates that the environmental influences exerted no significant effect on this variable. In relation to the chemical characteristics of the soil, organic matter had a higher content in preserved areas, revealing itself as an important indicator of environmental quality. In addition, there was a great influence of litter stocked on the content of soil organic matter, being the only factor between environmental impacts and phytosociological parameters that have an influence on the variable. Other chemical attributes, such as phosphorus, calcium, magnesium, pH and base saturation were higher in urban areas, which indicates that the external input of nutrients in these areas has been higher than that generated by the mineralization of litter in preserved areas. Due to the irregular behavior of these attributes were not considered effective indicators of environmental quality.