Áreas de Preservação Permanente e seus serviços ambientais

The Permanent Preservation Areas (APP), along watercourses, are determined based on the width of these. However, it is believed that there are more relevant factors, such as environmental services offered by APPs. The present study sought to compile studies that address environmental services from the APPs, such as subsidies for a better understanding on the subject. It was observed that, although there are equations for estimating the minimum width of APPs, some authors argue that the lack of a definitive method for establishing this width that allows for satisfactory protection of the watercourse. Some claim that without studies of the dynamics that occur in the riparian area, there is no way to conclude the distances expressed numerically for APPs are consistent with the principles of preservation for which they propose. Due to different methodologies and parameters involved in the delimitation of APP, are distinct bands of width settings for the same function in the same section of river. Thus, it is considered that one can only make widths indicative of areas to be kept vegetated or revegetated depending on the type of environmental service than expected, without, however, having to determine the proper width to serve simultaneously to all the services.As Áreas de Preservação Permanente (APPs), ao longo dos cursos d’água, são determinadas em função da largura destes. Contudo, acredita-se que há outros fatores que devem ser considerados, entre quais se destacam os serviços ambientais oferecidos pelas APPs. O presente trabalho buscou compilar estudos que tratam dos serviços ambientais oriundos das APPs, a fim de fornecer subsídios para melhor entendimento sobre o assunto. Observou-se que, embora haja equações de estimativa da largura mínima de APPs, há autores que defendem a inexistência de um método definitivo para o estabelecimento desta largura que possibilite uma proteção satisfatória do curso d'água. Alguns autores afirmam que, sem os estudos da dinâmica que ocorre na área ripária, não há como concluir se as distâncias expressas numericamente para APPs são compatíveis com os princípios da preservação para os quais se propõem. Em virtude de diferentes metodologias e dos parâmetros envolvidos na delimitação da APP, encontram-se distintas definições de largura de faixas para uma mesma função, em uma mesma seção de rio. Deste modo, considera-se que se pode apenas fazer indicativos de larguras de áreas a serem mantidas vegetadas ou revegetadas em função do tipo de serviço ambiental que se espera, sem, entretanto, ter a determinação da largura adequada para atender, simultaneamente, a todos os serviços

PROTOCOL OF FACTORS ASSESSMENT INFLUENTIAL IN SUSCEPTIBILITY TO EROSION OF RIVER SLOPES

ABSTRACT Actions to conserve rivers must be preceded by an environmental diagnosis, however, beyond the body of water, the adjacent atmosphere must also be characterized by ability of recognizing the human impacts and differentiate them of the natural variation of these ecosystems. This study aimed to develop a rapid assessment protocol (PAR), composed of seven parameters - vegetation, soil texture, part of the river, slope inclination slope gradient, soil depth in slope, stroke width of water course, use and land cover -, assigning them weights 0-4, in order to assess the influence of their categories in susceptibility to erosion of the river slope. The PAR was applied in 40 sampling unities (UA) in the watershed of Arroio Val de Buia in Silveira Martins, RS. From the final result of the PAR it was created erosion susceptibility classes, "stable", "susceptible" and "instable". The t test showed significant differences between the evaluated units and the Hierarchical Cluster Analysis (AHA) distinguished two classes of UA, according to the categories of susceptibility to erosion resulting from PAR. The basic parameters that determined the groupings were: soil, soil depth in slope, vegetation, the stretch of water course and, land use and land cover. We conclude that the PAR is presented as a good rapid assessment tool river, similar to the studied stream, being useful to the environmental planning considering the regional characteristics