Tatiana Nascimento Docile

Urbanisation alters the flow of energy through stream food webs

Anthropogenic changes in the aquatic environment can influence macroinvertebrate communities, interfering with species richness and diversity. Few studies have investigated the effect of urbanisation in streams using a food web approach. The aim of this study was to describe the food webs of aquatic macroinvertebrates in streams located in urban and preserved areas of the Atlantic Rainforest domain. Sampling was conducted in the state of Rio de Janeiro, Brazil, at 10 urban and 10 preserved streams during the dry season (August–September) of 2012. The streams were characterised with respect to their environmental conditions. Macroinvertebrates were sorted and identified in the laboratory and gut contents were examined. Trophic relationships were plotted in consumer–resource food webs and network properties were used to compare the two sets of streams. Food webs in urban streams had higher linkage density and connectance, but consumers had fewer items in their guts, which may indicate reduced flow of energy and more unstable food webs. The base of the food webs in each land‐use type were also quite different, with higher amounts of plant detritus in preserved streams and fine detritus in urban streams. This study shows that preserved areas offer better conditions for the development of macroinvertebrates, resulting in more stable trophic structures when compared with environments under higher anthropogenic influence.

Macroinvertebrate diversity loss in urban streams from tropical forests

The increase of human activities in recent years has significantly interfered and affected aquatic ecosystems. In this present study, we investigate the effects of urbanization in the community structure of aquatic macroinvertebrates from Atlantic Forest streams. The sampling was conducted in the mountainous region of the State of Rio de Janeiro, Brazil in 10 urban and 10 preserved streams during the dry season (August–September) of 2012. The streams were characterized for its environmental integrity conditions and physico-chemical properties of water. The macroinvertebrates were sampled on rocky substrates with a kicknet. A total of 5370 individuals were collected from all streams and were distributed among Ephemeroptera, Odonata, Plecoptera, Hemiptera, Megaloptera, Coleoptera, Trichoptera, Lepidoptera, and Diptera. In urban sites, all those orders were found, except Megaloptera, while only Mollusca was not found in preserved streams. We performed a non-metric multidimensional scaling (NMDS) analysis that separated two groups distributed among sites in urban communities and another group outside this area. The dominance was significantly higher at urban sites, while the α diversity and equitability were greater in preserved sites. A canonical correspondence analysis (CCA) was also performed, indicating that most taxa associated with high values of the Habitat Integrity Index (HII) and a few genus of the order Diptera with the high values of ammonia, total nitrogen, associated to streams in urban sites. Urban and preserved streams differ by physical-chemical variables and aquatic macroinvertebrates. In urban streams, there is most dominance, while α diversity and equitability are higher in preserved streams.

FREQUÊNCIA DOS CASOS DE DENGUE NOS DISTRITOS DO MUNICÍPIO DE DUQUE DE CAXIAS, RIO DE JANEIRO, BRASIL

Dengue, zika e chikungunya sao doencas transmitidas por vetores, cujo detectar os criadouros dos mosquitos torna-se vital para medidas de controle. O objetivo desse estudo foi avaliar os casos notificados de dengue no municipio de Duque de Caxias (Rio de Janeiro, Brasil) em seus quatro Distritos Sanitarios, durante oito anos, compreendendo o periodo de 2007 a 2014. Essa regiao apresenta inumeros problemas relacionados a processo de ocupacao desordenada, densidade demografica e altos indices de violencia urbana e o municipio e organizado em quatro distritos. Os casos de dengue notificados a Secretaria Municipal de Saude de Duque de Caxias e registrados na base municipal do SINAN (Sistema Nacional de Agravos de Notificacao), referentes ao periodo de 2007 a 2014 foram utilizados neste estudo. Em 2008, 2011 e 2013, observou-se uma epidemia no municipio, que em 2008 tomou magnitude ainda maior e alcancou incidencia de mais de mil casos a cada 100 mil habitantes. No periodo de 2009 e 2014, houve uma queda das incidencias observadas, caracterizando-o como interepidemico. Em relacao aos casos de dengue em cada distrito, o primeiro e segundo distritos foram os que tiveram maior numero de casos da doenca, enquanto o quarto distrito foi o que teve menor numero de casos em todos os anos estudados. Possivelmente, pelo fato do 1o distrito (Centro) ter a maior parte das habitacoes e o 2o distrito (Campos Eliseos), abrigar as industrias. Enquanto o 3o distrito (Imbarie) e 4o distrito (Xerem) sao considerados muito mais arborizados e com poucos nucleos habitacionais.