Karine Borges Machado

Using lower taxonomic resolution and ecological approaches as a surrogate for plankton species

Abstract The use of lower taxonomic resolutions and ecological classifications can function as a strategy to minimize difficulties in plankton identification. To assess this issue, we evaluated the concordance of the spatial ordering of lakes in a floodplain using phytoplankton and zooplankton densities scaled at three taxonomic levels (species, genus, and family) and two exclusive ecological classifications for phytoplankton [Reynolds functional groups (RFGs) and morphology-based functional groups]. Furthermore, we evaluated the concordance of environmental variables with each taxonomic resolution/ecological classification. Procrustes and Mantel tests (simple and partial) were used for the concordance analysis. The correlations between species and higher taxonomic levels were found for phytoplankton and zooplankton. For the ecological classifications, significant r values, greater than 0.70, were obtained only for the Mantel test between species and RFGs. The relationship between species and genus and between species and family for phytoplankton can be explained by the environmental structure. For zooplankton, only species were related to environmental variables. These results indicate that it is possible to adopt a lower taxonomic resolution for identification of phytoplankton and zooplankton without a significant loss of information. However, the use of ecological classifications for phytoplankton is not recommended for this purpose.

Do traditional scientometric indicators predict social media activity on scientific knowledge? An analysis of the ecological literature

Traditional citation-based indicators and activities on Online Social Media Platforms (OnSMP; e.g. Twitter) have been used to assess the impact of scientific research. However, the association between traditional indicators (i.e., number of citations and journal impact factor) and the new OnSMP metrics still deserve further investigations. Here, we used multivariate models to evaluate the relative influence of collaboration, time since publication and traditional indicators on the interest of 2863 papers published in five ecological journals from 2013 to 2015 as given by nine OnSMP. We found that most activities were concentrated on Twitter and Mendeley and that activities in these two OnSMP are highly correlated. Our results indicate that traditional indicators explained most of the variation in OnSMP activity. Considering that OnSMP activities are high as soon as the articles are made available online, contrasting with the slow pace in which the citations are accumulated, our results support the use of activities on OnSMP as an early signal of research impact of ecological articles.

Environmental factors affecting chlorophyll-a concentration in tropical floodplain lakes, Central Brazil.

Chlorophyll-a (Chl-a) has been widely used in the assessment and monitoring of aquatic environments. Local and regional factors can influence Chl-a concentrations; moreover, the connection between terrestrial and aquatic ecosystems is a major paradigm within aquatic ecology. Here, we investigate the spatial distribution of Chl-a concentrations in a tropical savannah floodplain in Central Brazil using a broad spatial data set (a 900-km north-south transect; 30 lakes). We determine the relative importance of local environmental variables (limnological and morphometric) and regional (land use) and spatial distances (spatial eigenvector) on Chl-a concentrations using partial linear regression. We evaluate the direct and indirect effects of local and regional variables on Chl-a with a path analysis. Our results indicate spatially autocorrelated patterns wherein lakes in closer proximity showed more similar levels of Chl-a than more distant lakes. Local environmental factors explained most variance in Chl-a (R2adj = 0.28; P = 0.02); more specifically, both lake area and total nitrogen significantly (P < 0.05) explained Chl-a concentrations (direct effects). Meanwhile, regional factors neither directly nor indirectly predicted Chl-a. Thus, internal processes, such as the resuspension of sediment (which is frequent in tropical floodplains), rather than external influences, were the main factors that explained Chl-a concentrations in this study. The importance of local variables in structuring Chl-a concentration may be used to guide the conservation of the aquatic ecosystems in these tropical floodplain lakes.

Trends and biases in the scientific literature on Brazilian watersheds

Brazilian watersheds have a high species and natural resources biodiversity. To know the features of scientific production on these regions is important to adjust study focus and to determine publication biases. This study aims at characterizing the scientific literature about Brazilian watersheds on scientometric grounds. For this purpose, we performed a search of articles in the ISI Web of Science database of the Institute for Scientific Information (ISI). The search returned 2,945 articles: 1,613 on the Amazon basin, 584 on the La Plata basin, 262 on the Sao Francisco basin, 190 on the Tocantins basin, 117 on the Southeast Coastal basin, 70 on the Eastern Northeast Coastal basin, 48 on the Parnaiba basin, 45 on the South Coastal basin, 14 on the North Coastal basin and two on the Western Northeast Coastal basin. The highest number of articles, journal diversity and impact factor was for the Amazon basin. Generally, the increase of the number of articles on the coastal basins over the years is lower. A keyword analysis shows that the study of most basins deals with similar subjects. However, researches on the Amazon and La Plata basins follow lines that are very different both from each other and from the other basins. In view of such results, incentives for new studies must focus on coastal basins. It is also recommended to submit works to good quality journals.