Although species distribution pattern is a widely discussed topic, understanding the mechanisms that drive it in time and space is still one of the central goals of ecology. Moreover, it is of the most importance to discuss the maintenance of this biodiversity and the services it provides. Therefore, our aim is to test the following hypotheses: 1) Preserved environments have higher beta-diversity than environments with lower preservation values, since beta-diversity is determined by environmental variations between habitats; 2) Beta-diversity will be better than species richness to detect changes in community regarding environmental integrity gradients. This will occur because richness is not sensitive to changes in composition and this might mask results when sensitive species are lost and generalist species are introduced into the altered environments. In order to test these hypotheses, 20 points were sampled in five streams of the Brazilian Cerrado with different integrity conditions. Environmental change did not affect Heteroptera richness; however, it affected the beta-diversity of the group as a whole and of Nepomorpha, also negatively affecting both Gerromorpha beta-diversity and richness. Moreover, there was difference in variation of Gerromorpha composition in altered and degraded sites, but there was no effect on Nepomorpha. These results show that Gerromorpha is more sensitive to physical changes in streams caused by the loss of environmental integrity. Therefore, environmental changes with no regard to riparian vegetation boundaries causes shifts in stream conditions and changes aquatic communities, which places at risk the ecosystems services provided by these communities.
Os morcegos apresentam grande diversidade de hábitos alimentares, o que faz com que possam ser utilizados como indicadores de qualidade ambiental, além de prestarem serviços ecossistêmicos, como dispersão de sementes, estruturação de comunidade de plantas e controle de insetos. Além disso, o estudo da interação de morcegos com ectoparasitas pode possibilitar melhor compreensão dos processos ecológicos e evolutivos associados. Dessa forma, o objetivo desse estudo é contribuir para o conhecimento de algumas espécies de morcegos e suas moscas ectoparasitas no Parque Nacional da Serra do Pardo, interflúvio Xingu-Tapajós, estado do Pará, Brasil. A captura dos morcegos foi realizada em quatro pontos amostrais, através de redes de neblina e busca ativa. Em cada indivíduo capturado foi realizada inspeção da pelagem e das asas para retirada das moscas ectoparasitas. Foram amostrados 13 indivíduos de morcegos, representados por duas famílias (Phyllostomidae e Molossidae), seis gêneros e seis táxons, sendo C. perspicillata a mais amostrada. Quanto à guilda trófica, observamos espécies insetívoras e frugívoras, sendo a última a mais abundante. Para moscas ectoparasitas, observamos apenas a família Streblidae. Todos os ectoparasitas estavam relacionados aos indivíduos de C. perspicillata.
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