No abstract

Food web studies provide a useful tool to assess the organization and complexity of natural communities. Nevertheless, the seasonal dynamics of food web properties, their environmental correlates, and potential association with community diversity and stability remain poorly studied. Here, we condensed an incomplete 6‐year community dataset of a subtropical coastal lake to examine how monthly variation in diversity impacts food web structure over an idealized time series for an averaged year. Phytoplankton, zooplankton, macroinvertebrates, and fish were mostly resolved to species level (n = 120 trophospecies). Our results showed that the seasonal organization of the food web could be aggregated into two clusters of months grouped here as ‘summer’ and ‘winter’. During ‘winter’, the food web decreases in size and complexity, with the number of trophospecies dropping from 106 to 82 (a 22.6% decrease in the number of nodes) and the trophic interactions from 1,049 to 637 between month extremes (a 39.3% drop in the number of links). The observed simplification in food web structure during ‘winter’ suggests that community stability is more vulnerable to the impact of any change during this period.

A redução dos impactos ambientais e a melhoria da qualidade de vida estão diretamente relacionadas à maior consciência ambiental e atitude da população. Com este enfoque, o objetivo deste trabalho foi avaliar a percepção e o comportamento dos residentes quanto a alguns aspectos ambientais comumente vivenciados em seus domicílios. A coleta dos dados foi realizada mediante a aplicação de questionários diretamente a 89 famílias de Lages/SC, durante o período de agosto a dezembro de 2013. Os principais resultados encontrados indicam que a preocupação e o comportamento ambientalmente corretos são mais elevados nas classes da população com maior escolaridade. Verificou-se também um desconhecimento por significativa parte da população sobre medidas colaborativas eficazes que podem ser tomadas e das consequências socioambientais de atitudes incorretas. De maneira geral, a pesquisa verificou que, embora manifestem preocupação quanto ao tema, a população ainda não incorpora ações práticas significativas no seu cotidiano, principalmente por desconhecê-las.

This paper systematically assessed trends of aquatic ecology publications related to the urbanization growth during three decades (1990-2010) in Santa Catarina Island. The study was carried out in fifteen watersheds of Santa Catarina Island, located in Florianópolis city, Southern Brazil. Geoprocessing and scientometry tools were used to analyze the evolution of urban areas and publications, respectively, related to these watersheds during three decades. The QGIS software was used to delimitate the catchment area of each watershed and contrast those areas with the built-up area for each decade, therefore obtaining the percentage of area covered with buildings and impervious surfaces. A gradient was created allowing the classification of the watersheds related to the urbanized area percentage, resulting in 5 groups of urbanization (0-5%; 5-10%; 10-20%; 20-30%; >30% of urbanization). Aquatic ecology publications were obtained from several scientific and academic databases and used in the scientometric analysis. The number of publications by decade, document type, knowledge area and watershed of study were recorded. Growth of urbanized areas was mainly evidenced since the 2000s and showed a moderate positive relationship with the number of publications in ecology of aquatic systems in the Santa Catarina Island during the same period. However, differences between watersheds were observed, since the most urbanized watersheds were not necessarily the ones with the largest number of publications. Urban gradient evidenced in Santa Catarina Island offers an opportunity to investigate the impacts of human disturbance on aquatic ecology, water quality and stream communities. Furthermore, the low number of research projects might be contributing to the decline in biological integrity due to the lack of knowledge for evaluation and management in these environments.