Criteria definition for delimiting a buffer zone to a biosphere reserve in southern Brazil

Abstract

Taim Ecological Station (ESEC Taim) is a biosphere reserve (MAB) in southern Brazil located on the coastal plain of the state of Rio Grande do Sul, within a complex system of wetlands and lagoons. Although more than three decades have passed since its implementation in 1978, the situation of ESEC Taim is not well set yet. Among the main problems, there are the land issues, with pending expropriations, and the lack of a buffer zone (BZ) and a management plan, both instruments granted under the Brazilian law. Such is the context in which this study was developed, proposing the elaboration of an environmental study and the identification of criteria for the construction of BZ scenarios for ESEC Taim. The BZ proposals presented in this study were built based on aspects related to geology, landscape ecology, uses of the surroundings, adaptation of limits from Brazilian legislation and directions from the International Union for Conservation of Nature (IUCN). This information was inserted into a digital database in a geographic information system (GIS), where multi-criteria analysis was accomplished, and from which three scenario proposals resulted. Essentially, Scenario “zero” is the current situation of ESEC Taim, with the projection of the minimum distances specified in national decrees for the protection of the surroundings; Scenarios I and II present ecosystem proposals seeking to contemplate all the water system to which the ESEC Taim belongs, maintaining the ecological relationship with the adjacent landscape, with easily recognized boundaries in the field. Scenario II does not include some categories of areas safeguarded by the Brazilian law and under which there is the intention of creating new protected areas. Ideally, we believe that Scenario I, for covering most of the natural environments that are related to the ESEC, as well as the adjacent economic activities, is the one with the greatest potential to constrain threats and to improve the environmental quality of ESEC Taim and its surroundings through more cautious and oriented management of the uses of such territory.

Keywords: protected areas, GIS, wetlands, conservation, Taim.