Implications of Scientific Collaboration Networks on Studies of Aquatic Vertebrates in the Brazilian Amazon.

The quantity of wildlife extracted from the Amazon has increased in the past decades as a consequence of an increase in human population density and income growth. To evaluate the spatial distribution of studies on subsistence and/or commercial hunting conducted in the Brazilian Amazon, we selected eight mid-sized and large-bodied aquatic vertebrate species with a history of human exploitation in the region. We used a combination of searches in the gray and scientific literature from the past 24 years to provide an updated distributional map of studies on the target species. We calculated the distances between the study sites and the locations of the research institutes/universities that the first and last authors of the same study were affiliated to. For the period of 1990 to 2014, we found 105 studies on the subsistence and/or commercial hunting of aquatic vertebrates in the Brazilian Amazon in 271 locations that involved 43 institutions (37 Brazilian and 6 international). The spatial distribution of the studies across the Brazilian Amazon varied, but over 80% took place in the northeast and central Amazon, encompassing three States of the Legal Brazilian Amazon (Amazonas, 51.42%; Pará, 19.05%; and Amapá, 16.19%). Over half of the research study sites (52.91%) were within 500 km of the research institute/university of the first or last authors. Some research institutes/universities did not have any inter-institutional collaborations, while others collaborated with eight or more institutes. Some research institutes/universities conducted many studies, had an extensive collaboration network, and contributed greatly to the network of studies on Amazonian aquatic vertebrates. Our research contributes to the knowledge of studies on the subsistence and/or commercial hunting of the most exploited aquatic vertebrates of the Brazilian Amazon, illustrates the impact that collaboration networks have on research, and highlights potential areas for improvement and the generation of new collaborations.

Variability and uncertainty in water demand and water footprint assessments of fresh algae cultivation based on case studies from five climatic regions.

Using case studies from five typical climatic locations, this study revealed that current quantification of water demand (WD) and water footprint (WF) of freshwater algae cultivation in raceway ponds suffer from uncertainty and variability in the methodologies and assumptions used. Of particular concern, the WF metric had an intrinsically poor geographical resolution and could be biased towards high-productivity arid locations because local levels of water stress are not accounted for. Applying current methodologies could therefore cause the selection of locations that are neither economically viable nor environmentally sustainable. An improved methodology should utilize more accurate evaporation models, determine realistic limits for the maximum hydraulic retention times and process water recycling ratios, and apply weighting to the WF to reflect localized water stress or use an alternative metric such as the equivalent years of rainfall required to support a productivity of 1G J m(-2).

[Nonparametric methods for comparative assessment of species diversity as applied to riverine macrozoobenthic communities].

Models for relationship between sampling effort and estimates of species number and other characteristics of species diversity are considered and evaluated. In the analysis, different randomization algorithms and other statistical methods of monitoring data processing are used including jackknife and bootstrap procedures, algorithms ICE and Chao2, Colwell-Mao interpolation model, Mikhaelis-Menten curves, and others. A comparative analysis of overall species richness in macrozoobenthic communities using streams of the Lower Volga basin as a case study is performed with the aid of different extrapolation models, and the resulting estimates are discussed. The relationships are analyzed between sampling effort (number of hydrobiological samples) and cumulative estimates of species richness and basic indices of species diversity. The means towards improvement of conclusions substantiation when ranking riverine communities by species diversity are considered.