-Landscape is important in determining the composition of aquatic assemblage, and benthic invertebrates, particularly Chironomidae, are often used as bioindicators of environmental quality because their occurrence and distribution are influenced by different land uses. The objective of this study was to evaluate the influence of different land uses, considering three landscape scales (drainage basins, riparian buffer and streams), on chironomid assemblage. We sampled streams located in an agricultural matrix by collecting chironomid larvae and water samples and performed a landscape analysis using Geographical Information System techniques. The drainage basins had a high percentage of agricultural land use; in all of the drainage basins studied, 79% of the riparian buffer was not in accordance with Brazilian law. Cricotopus proved to be a good indicator of the agricultural conditions, whereas Thienemanniella and Rheotanytarsus proved to be indicators of exposed soil. Lopescladius was more sensitive to disturbance and was positively correlated with the presence of riparian vegetation. Although the variables at the local scale (stream) were responsible for a major change in the assemblage, the landscape attributes at large scales (drainage basin and riparian buffer) generated significant effects on Chironomidae fauna. Our results suggest the importance of the conservation of two larger landscape scales to support the equilibrium and maintenance of aquatic assemblage.

RESUMO(Padrões espaciais e ecológicos de espécies arbóreas refletem a estrutura em mosaicos de uma floresta subtropical). A abundância e distribuição espacial das espécies podem ser reflexos das necessidades do seu nicho ecológico, além de reflexos das variações ambientais no tempo e espaço. Os objetivos do presente trabalho foram analisar a distribuição espacial e grupos ecológicos das espécies arbóreas em um remanescente de floresta subtropical e avaliar a interferência destes padrões sobre métricas de riqueza e diversidade. Os padrões espaciais foram avaliados considerando uma área amostral de 1 ha dividida em unidades amostrais contíguas de 10 x 10 m, onde todos os indivíduos com perímetro à altura do peito ≥ 15 cm foram amostrados. A descrição dos padrões foi obtida por meio de correlogramas (índice I de Moran), considerando diversas classes de distância, índices de agregação e diagramas de superfície. A co-ocorrência entre espécies foi analisada por meio de índices de associação espacial. A maioria das espécies apresentou distribuição agrupada e com autocorrelação espacial positiva, sobretudo para as menores classes de distância, indicando a formação de pequenos grupos de indivíduos. Da mesma forma, 17 espécies apresentaram associações espaciais (co--ocorrências), formando densos agrupamentos e, embora não tenham interferido sobre a riqueza específica, Casearia sylvestris e Ocotea diospyrifolia diminuíram a equabilidade em alguns setores da área. Espécies tolerantes à sombra apresentaram-se associadas, bem como, espécies dependentes de luz, indicando que a dinâmica de mosaicos pode interferir diretamente sobre a distribuição das espécies, sobretudo pela limitação de dispersão.Palavras-chave: autocorrelação espacial, correlogramas, índices de distância, limitação de dispersão, riqueza de espécies ABSTRACT (Spatial and ecological patterns of tree species reflect patch dynamics of a subtropical forest). The abundance and spatial distribution of species may reflect on niche requirements, interactions among individuals and across as time and space. In this way, the aims of this work were to analyze tree species distribution and ecological groups in a remnant of subtropical forest to evaluate the interference of such patterns over richness and diversity metrics. We evaluated the spatial patterns of a 1 ha area divided into 10 x 10 m sampling units where we surveyed all living trees with perimeter at breast height ≥ 15 cm. Pattern descriptions were obtained by using correlograms (Moran's I) over several distance classes, aggregation indices and surface diagrams. The co-occurrence among species was obtained by using spatial association indices. Furthermore, 17 species showed aggregated distribution and positive spatial autocorrelation, mainly in the shorter distance classes, which indicated the occurrence of several small groups of individuals. In addition, many species were spatially associated with dense groups and although such groups do not influence species richness, Casearia sylvestris and Ocotea diospyrifol...

Aim This work aimed to analyze the effectiveness of protected areas (PA) as maintainers of the fauna of benthic macroinvertebrates and the use of these in the water management of these areas. We tested the hypothesis that in streams located within the PA there will be greater abundance and diversity of organisms. Methods We collected macroinvertebrates in streams located inside and outside two PA in Southern Brazil: (Fritz Plaumann State Park, Santa Catarina, Teixeira Soares Municipal Natural Park, Rio Grande do Sul). In each stream we measured physical and chemical variables of the water. Three sub-samples of macroinvertebrates were collected on stony substrate with a Surber sampler and calculated abundance of organisms, rarefied richness, Shannon diversity and Evenness. Results The streams located in the interior of the PA presented well oxygenated waters and slightly basic pH. The electrical conductivity was higher in the external sections than the UC. We observed that rarefied richness, Shannon diversity and equitability were higher in the streams located inside the PA. PerMANOVA indicates that the composition was different between streams sections (p = 0.03) and PA (p = 0.01). Conclusions The use of organisms as bioindicators showed a potential response to the environmental integrity of streams. Thus, these organisms have potential for use by PA managers for monitoring and decision making on the maintenance of protected areas.

O conhecimento da maneira pela qual a arborização urbana é planejada contribui para a compreensão da sociedade e de sua relação com o ambiente, sendo fundamental para a organização e manejo eficiente da arborização contemporânea. Em vista disso, o presente trabalho buscou responder a duas questões principais: como a arborização urbana foi conduzida em Erechim, Rio Grande do Sul, ao longo de sua história e quais fatores influenciaram nesta condução. Para responder a estas questões, realizou-se uma revisão bibliográfica da história do município e uma análise de fotografias de diversos pontos da cidade desde a época da colonização até os dias atuais. Os primeiros registros fotográficos relacionados à arborização urbana de Erechim datam da década de 1920. Verificou-se que nas décadas de 1920 a 1970 predominaram o uso de espécies exóticas e de formas simétricas e lineares, com estilo paisagístico fortemente associado à colonização europeia. A partir da década de 1980, verificou-se maior uso de espécies da flora regional, culminando com a maior valorização de espécies nativas no final do período.

The effects of land use and cover changes and the application of the Urbanity Index were analyzed to identify critical or non-critical naturalness scenery in the Northern Region of Rio Grande do Sul (Brazil), over a period of 30 years. Between 1986 and 2016, the main significant land use change was the reduction of the agricultural anthropic and the increase of the natural vegetation land use areas. About 90%-80% of the total study areas were characterized by anthropic pattern features, with a predominantly agricultural matrix. The conversion of agricultural anthropic into natural areas resulted in increased naturalness landscape and a gain in the stock of natural capital. The increase in the natural vegetation area, mainly to the north and east of the region, set in a steep relief, became remarkable after 1990. The Urbanity Index values evidenced a highest naturalness condition (natural vegetation areas) to the northern and eastern, while a smaller naturalness condition (agricultural and non-agricultural areas) to the southern and western and central of the Northern Region of Rio Grande do Sul. These changes are related to a non-impaired (northern and eastern) and a impaired scenery (southern, western and central portion) of the ecological sustainability of the Northern Region of Rio Grande do Sul, after a 30-year period (1986-2016). These results pointed out that land use transitions resulted in a consolidated farming scenario in which agricultural intensification coincided with the reduction of farming area and increased naturalness as a reverse trend to the agricultural frontier dynamics.