Publications by authors named "Jean C G Ortega"

Estimates of dark diversity, species that belong to a given species pool but are not present locally, can help to understand how environmental conditions influence species distribution. However, it remains uncertain whether dark diversity can predict the absence of indicator species in preserved environments after environmental changes. We explored the sensitivity of dark diversity (the set of species absent from a particular area), in detecting the absence of Zygoptera (Odonata) indicative of preserved forest environments in altered habitats, and the influence of sample coverage on the detected patterns.

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The Amazon floodplain is home to an extremely high diversity of fish, with lakes playing an important role in the establishment of this biological richness. These lacustrine environments are subject to constant fluctuations caused by the annual flood pulse, with local factors and other regional patterns also contributing to the variation in fish community structure. The present study verified how local (depth and transparency of the water, the size and species composition of the macrophyte stands) and regional factors (spatial distribution of the stands and the hydrological phase) influence the structure of the fish community of the floodplain lakes of the Môa River, in northern Brazil.

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Solitary bees and wasps that nest in cavities in tree trunks are important components of terrestrial ecosystems, providing pollination services, and in the case of wasps, the regulation of their prey populations. However, little is known about the vertical strata where bees and wasps build their nests. This is especially the case of urban forest remnants in the Amazon, which is relevant in the context of the global crisis in insect losses.

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Article Synopsis
  • Traditional chemical controls for plant diseases harm the environment and conflict with sustainable development goals.
  • This study conducted a meta-analysis of the biocontrol potential of Bacillus bacteria, finding they reduce disease by 60% compared to control groups, with greater efficacy linked to higher concentrations and protective inoculation methods.
  • The research indicates that newly tested Bacillus strains are more effective than commercial products, offering important insights for sustainable plant disease management for researchers and policymakers.
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Dung removal by macrofauna such as dung beetles is an important process for nutrient cycling in pasturelands. Intensification of farming practices generally reduces species and functional diversity of terrestrial invertebrates, which may negatively affect ecosystem services. Here, we investigate the effects of cattle-grazing intensification on dung removal by dung beetles in field experiments replicated in 38 pastures around the world.

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Ecological communities are structured by several mechanisms, including temporal, spatial and environmental factors. However, the simultaneous effects of these factors have rarely been studied. Here, we investigated their role on water beetle assemblages sampled over a period of 18 years.

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Turbidity plays an important role in aquatic predator-prey interactions. Increases in turbidity are expected to reduce prey capture rates, especially for visually oriented predators. However, there is also evidence indicating that turbidity may have little or no effect on predation rates.

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Ecological Niche Models (ENMs) have different performances in predicting potential geographic distributions. Here we meta-analyzed the likely effects of climate change on the potential geographic distribution of 1,205 bird species from the Neotropical region, modeled using eight ENMs and three Atmosphere-Ocean General Circulation Models (AOGCM). We considered the variability in ENMs performance to estimate a weighted mean difference between potential geographic distributions for baseline and future climates.

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Environmental heterogeneity (EH) plays a central role in hypotheses used to explain distributions of species diversity. Here, we conducted a meta-analysis of species richness-EH (S-EH) relationships reported for experimental or quasi-experimental studies. We controlled for the lack of independence among effect sizes and additionally performed a cumulative meta-analysis.

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The expansion of agriculture causes habitat loss and fragmentation that negatively affects biodiversity. We analyzed the species richness, composition and habitat preferences of anuran species in aquatic habitats in mesophytic semideciduous Atlantic Forest remnants and surrounding agricultural landscapes in southern Brazil, between April 2011 and March 2013. Nineteen anuran species, belonging to 11 genera and 5 families, were recorded.

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