Índices de adequabilidade de habitat como subsídio ao gerenciamento dos recursos hídricos do Banhado do Taim

Abstract

The Taim Wetland, situated in the Ecological Station (ESEC) Taim, an important wetland in southern Brazil, is fundamental to maintain the ecological stability of the region. The main economic activity in the surroundings of ESEC is the practice of irrigated rice planting through flooding, a process that requires large amounts of water, which are captured in the region of the lakes in the summer months and causing a decrease of ponds levels and Wetland , which may be harmful to this species dependent wetland environment. One way to investigate how species are impacted by this activity is through the integration of information on required environmental conditions for the survival of the species and their interdependence through habitat suitability indices method (HSI). This method is considered a form of ecological niche modeling, which can assist in improvement or development of management strategies of water resources and conservation of biodiversity, being widely used in areas of wetlands. Thus, using this methodology, this study was conducted in order to add information to the survey prepared by Tassi for Wetland Taim in 2008, through the development and validation of HSI, which relate hydrological and habitat aspects, aimed at management proposals of water resources of the local. To do so, were developed five new HSIs for selected indicator species: totora (Scirpus californicus), the white-faced Ibis (Plegadis chihi) and wood stork (Mycteria americana), and reptiles broad-snouted caiman (Caiman latirostris) and the D'orbigny's slider (Trachemys dorbigni). The species designated as indicators of the Wetland were those that could be observed in the field, and were willing to hydrological information. The construction of the HSIs species was made through the water slide height information needed to ensure the conservation of species and area required to be maintained flood free in reproductive period, from the premise that if ideal conditions would be maintained, these assure its chemical processes, food availability and reproductive success. Through a spatial model of environmental quality, specially developed for the Wetland Taim, there was a reproduction of the information of HSIs through thematic maps with color scale, which reflect the environmental suitability to species facing different scenarios. Through the analysis of the HSIs and retention curves were obtained the minimum water level of dimensions and maximum ideal for indicator species for Wetland Taim, corresponding to 1.75 m and 3.10 m, respectively. Water levels in this range of values create an environment to ensure the reproduction of the species and a favorable environment for migratory species of warm season. This, on the other hand, restrict the withdrawal of irrigation water under conditions of lower water availability, but use of this feature could be increased in situations that exceed the maximum limit established for Wetland dimension of the MAH.