RESUMO

Interactions between terrestrial and aquatic systems influence the structure of river habitats and, consequently, affect their benthic macroinvertebrate composition. The aim of this study was to evaluate the effects of spatial and environmental variables (local physical and chemical variables of water and regional landscape characteristics) on the benthic macroinvertebrate community of the Pandeiros River Basin. Biotic and abiotic variables were evaluated at 20 sampling sites distributed across the primary sub-basins of the Pandeiros River Basin. We found that the macroinvertebrates were primarily affected by environmental variables. The most important environmental variables were pebble proportion and water conductivity at the local scale (7.2% of explained variation) and elevation and nonforest areas at the regional scale (6.9% of explained variation). The spatial variables were representative only in shared explained variation with the environmental matrices (local-spatial = 0.2% and regional-spatial = 2%; all matrices combined = 4.4%). Sampling sites with higher non-forest areas, lower elevations, and steeper slopes presented low pebble fractions and higher electrical conductivities. Habitat diversity was lower when the percentage of pebbles decreased, resulting in decreased taxonomic richness and diversity in macroinvertebrate communities. High electrical conductivities and non-forest areas also had negative effects on macroinvertebrate density due to the loss of habitat diversity. We conclude that higher proportions of pebbles in the substrate and higher altitudes were likely the primary variables for positive effects on the taxonomic richness and density of macroinvertebrate communities.

Assuntos

RESUMO

Interactions between terrestrial and aquatic systems influence the structure of river habitats and, consequently, affect their benthic macroinvertebrate composition. The aim of this study was to evaluate the effects of spatial and environmental variables (local physical and chemical variables of water and regional landscape characteristics) on the benthic macroinvertebrate community of the Pandeiros River Basin. Biotic and abiotic variables were evaluated at 20 sampling sites distributed across the primary sub-basins of the Pandeiros River Basin. We found that the macroinvertebrates were primarily affected by environmental variables. The most important environmental variables were pebble proportion and water conductivity at the local scale (7.2% of explained variation) and elevation and nonforest areas at the regional scale (6.9% of explained variation). The spatial variables were representative only in shared explained variation with the environmental matrices (local-spatial = 0.2% and regional-spatial = 2%; all matrices combined = 4.4%). Sampling sites with higher non-forest areas, lower elevations, and steeper slopes presented low pebble fractions and higher electrical conductivities. Habitat diversity was lower when the percentage of pebbles decreased, resulting in decreased taxonomic richness and diversity in macroinvertebrate communities. High electrical conductivities and non-forest areas also had negative effects on macroinvertebrate density due to the loss of habitat diversity. We conclude that higher proportions of pebbles in the substrate and higher altitudes were likely the primary variables for positive effects on the taxonomic richness and density of macroinvertebrate communities.(AU)

Assuntos

RESUMO

A qualitative and quantitative analysis of the environmental damages occurrences was conducted through the lawful documents established for charging at the State Prosecution Service of São Carlos city, State of São Paulo, during 1991 - 2000, to understand the relationship between environmental problems and the current development actions. The environmental damage identified were grouped into nine classes, where deforestation was prevailing in each year along the period of study. Of the total number of deforestation occurrences, 180 was related to areas smaller than 5 ha. It corresponded to 110.35 ha of the total deforested area. The other 37 were associated with areas higher than 5 ha, equivalent to 1,013.27 ha. The registers of environmental damages in the period in a rough estimate, corresponded to a mediam loss of 5.91 ± 4.14 ha/occurrence and of 112.36 ± 91.73 ha/year of deforested area.

Foi realizada a análise qualitativa e quantitativa das ocorrências de danos ambientais através dos instrumentos jurídicos instaurados pelo Ministério Público Estadual da cidade de São Carlos, SP, para a compreensão da interação entre os problemas ambientais e as ações desenvolvimentistas na paisagem local. no período de 1991-2000. Os danos ambientais foram agrupados em nove classes, sendo desmatamento o de maior ocorrência em cada ano e ao longo do período de estudo. Cerca de 180 ocorrências de desmatamento estão relacionadas com áreas menores que 5 ha, com predomínio da atuação de Pessoas Físicas, correspondendo a 110,35 ha de área desmatada no período. As 37 ocorrências restantes estão associadas com áreas maiores que 5 ha, totalizando 1.013,27 ha de área desmatada. Em uma estimativa grosseira estes valores correspondem às perdas médias de 5,91 ± 4,14 ha/ocorrência e de 112,36 ± 91,73 ha/ano de área desmatada.

RESUMO

Foram realizados a análise e o zoneamento ambiental com a finalidade do manejo do Parque Municipal Longines Malinowski (PMLM). Com 24,85 ha, este parque urbano inclui um fragmento de floresta sub-tropical úmida, completamente cercado por áreas residenciais e comerciais na cidade de Erechim, Rio Grande do Sul. As características da paisagem, obtidas de cartas aerofotogramétricas, com base no uso de Sistemas de Informações Geográficas (SIG-IDRISI), resultaram em diversas cartas temáticas, pelas quais foi efetuada uma proposta do zoneamento ambiental, observando a definição de cinco zonas de uso. O diagnóstico ambiental identificou diversos tipos de atividades potencialmente prejudiciais à biodiversidade do PMLM e à qualidade ambiental da cidade. A implementação de um plano de manejo é essencial à manutenção e à conservação deste parque urbano, assegurando sua participação na qualidade de vida urbana.