Monitoramento da microtopografia do solo em trilhas de uso público no litoral do Parque Nacional da Serra da Bocaina

Abstract

A erosão hídrica superficial é um dos processos responsáveis pela degradação dos solos, especialmente em áreas tropicais, devido aos elevados índices pluviométricos. A análise da microtopografia do solo é um dos métodos de mensurar a evolução e desenvolvimento deste processo, principalmente em áreas sob uso intensivo, como trilhas em unidades de conservação. O litoral do Parque Nacional da Serra da Bocaina, no estado do Rio de Janeiro, apresenta diversos pontos de interesse geoturístico, que atraem inúmeros visitantes diariamente, desencadeando vários impactos ambientais nas trilhas que dão acesso a estes atrativos. Sendo assim, esta pesquisa teve como objetivo avaliar a evolução espaço-temporal dos processos erosivos no leito de duas trilhas deste parque, através do monitoramento da microtopografia do solo em dois períodos distintos. Posteriormente, os resultados foram correlacionados com os dados das precipitações pluviométricos e com as características fisiográficas da área. Constatou-se que ambos os pontos monitorados estão sofrendo com a perda de solo devido, principalmente, aos elevados índices pluviométricos, que se concentram nos meses de dezembro e janeiro. A visitação intensa e desordenada, a cobertura vegetal e quantidade de serrapilheira foram fatores que possivelmente influenciaram a evolução destes processos no leito das trilhas, gerando dinâmicas distintas entre os pontos monitorados.

Water Erosion Processes on the Geotouristic Trails of Serra da Bocaina National Park Coast, Rio de Janeiro State, Brazil

“…Soil trampling on trails for public use, for example, is a human activity that causes soil degradation and occurrence of these processes, especially when these actions are carried out in an intensive and disorderly way. These activities corroborate with the alteration of the characteristic physicochemical and biological changes in the soil, which, in turn, modify the hydraulic and edaphic dynamics, since, in addition to reducing organic matter levels, porosity values, and water infiltration rates, they cause an increase in bulk density, runoff volume, and soil loss due to erosion [7][8][9][10].…”

“…When jointly considering the obtained data, it was possible to identify that these factors are related to each other, since certain physical-chemical parameters, for example, when subjected to certain dynamics of use and precipitation, tend to condition the evolution of erosive features such as those that were evidenced during the soil microtopography monitoring period (Figures 9-13) [9,14,17,18].…”

“…The determination of the soil physicochemical properties (e.g., granulometry, porosity, bulk density, pH, and organic matter content) were chosen because they are related to erodibility and soil use and management, given that their values are influenced and/or modified by intensive trampling of the ground, mainly by the flow of tourists where the surveyed trails are located [9,10,17,22].…”

“…The soil microtopography was determined through the installation of erosion bridges (PDE) with stakes from one edge to the other in the cross sections of sites and on the beds of the trails that presented water erosion processes, following the method developed by Shakesby [30] and adopted by Ferreira [31] in studies on water erosion in soils and subsequently applied to trails [9,22,32]. Thus, the evolution of erosion features was monitored between August 2021 and March 2022 and between August 2022 and March 2023.…”

“…These classes, as well as Litholic Neosols, also occur in the mountainous region of the PNSB, on the escarpments and on the coastal strip between Serra do Mar escarpment and the plains. Oxisols, on the other hand, occur at the top and on smoother slopes [9,23,26].…”