No abstract

Mercury is a major pollutant in the Amazon River system, and its levels in fish and human hair are usually above the limit recommended by health agencies. The objective of this study was to analyze the methylmercury (MeHg) concentration in fish tissue from the Roosevelt River. The river’s water velocity, depth, pH, temperature, electrical conductivity, dissolved oxygen and substrate type were measured, and fifty specimens distributed in 14 fish species were collected. A total of 64.3% of the sampled species were of the order Characiform and 71.4% of the species were carnivores. Fifty percent of the species had MeHg concentrations above threshold limit (Hg-T 0.5 mg kg-1) established for food by the World Health Organization. Cichla monoculus had the highest value of MeHg (2.45 mg kg-1). The MeHg concentration in fish varied according to dietary habits. The study also found bioaccumulation of MeHg in fish tissue in the following descending order: carnivorous > detritivorous > frugivore. Low significant correlations were found between fish weight or length and MeHg. Further studies on MeHg contamination are recommended in tissues of fish consumed in human riverine communities in the Roosevelt River Basin.

Aim: The goal of this study was to analyze the effects of predation by nymphs of Erythemis Hagen, 1861 on Elmidae and Chironomidae and to check if the presence and the architecture of aquatic macrophytes may mediate this interaction. Methods: All prey as well as nymphs were captured near macrophytes in a small lagoon alongside a highway near Humaitá, Amazonas, Brazil. Twelve buckets were used in three different treatments: with Pistia stratiotes Linnaeus, 1753, with Salvinia auriculata Aublet and without macrophytes. Results: We found a mortality rate of 100% of Chironomidae and Elmidae larvae in the treatment without macrophytes. There was a greater survival of Elmidae compared to Chironomidae in the treatments with P. stratiotes and S. auriculata; however, there was a greater survival of both preys on treatment with P. stratiotes. Conclusions: We conclude that the presence of macrophytes decreased the efficiency of predation of Erythemis nymphs under experimental conditions. The architecture of macrophytes affected predation as macrophytes with longer roots and with greater habitat complexity promoted a greater survival of prey.

The Program for Biodiversity Research (PPBio) is an innovative program designed to integrate all biodiversity research stakeholders. Operating since 2004, it has installed long-term ecological research sites throughout Brazil and its logic has been applied in some other southern-hemisphere countries. The program supports all aspects of research necessary to understand biodiversity and the processes that affect it. There are presently 161 sampling sites (see some of them at Supplementary Appendix), most of which use a standardized methodology that allows comparisons across biomes and through time. To date, there are about 1200 publications associated with PPBio that cover topics ranging from natural history to genetics and species distributions. Most of the field data and metadata are available through PPBio web sites or DataONE. Metadata is available for researchers that intend to explore the different faces of Brazilian biodiversity spatio-temporal variation, as well as for managers intending to improve conservation strategies. The Program also fostered, directly and indirectly, local technical capacity building, and supported the training of hundreds of undergraduate and graduate students. The main challenge is maintaining the long-term funding necessary to understand biodiversity patterns and processes under pressure from global environmental changes.

No abstract

Hypothenemus hampei is the main coffee pest in the Amazon and worldwide. Although coffee cultivation exists in the State of Amazonas, there is no information regarding the behavior of this species population in this region of Brazil. Since the Amazon region is a favorable environment for H. hampei, the present study aimed to investigate this insect population in the following cultivation systems implanted in the municipality of Humaitá, Southern Amazonas: i) coffee in native forest (CNF), ii) coffee intercropped with cupuaçu and açaí (native Brazilian fruits) (CCA) and iii) coffee in monoculture (MC). Also, the climatic and phenological parameters of the plant were used in relation with the population dynamics of the insect. For that, ten baited traps were installed in each field for the monthly sampling of the H. hampei population from July/2018 to June/2019. The highest population abundance of the insect was observed during the coffee flowering season, mainly in monoculture crops, when compared to the other intercropped fields. The total mean value of the insect population observed in the three environments evaluated was highest in August/2018, with a recorded value of 1749. The increase in rainfall indexes occurred simultaneously with a decrease in the insect population; this coincides with the end of the flowering season (October/2018, 161.8 mm) and the beginning of grain formation (November/2018, 234.8 mm). The lowest abundance of the insect observed in the coffee fields in native forest, with an abundance of 83 (CNF), indicates that the local biodiversity disfavors the population size of the pest in the environment. These results suggest that phenological phases of conilon coffee and the influence of climatic conditions can result in changes in the population dynamics of the H. hampei. Coffee agroforestry systems are more promising to maintain this population at low levels.

<p>A bacia Amazônica abriga a maior diversidade de peixes de água doce do mundo. O objetivo deste estudo foi analisar as assembleias de peixes em igarapés de terra firme em duas sub-bacias do Médio Rio Madeira. O estudo foi realizado em duas sub-bacias no Médio Rio Madeira localizadas em terras indígenas. Foram coletados 475 indivíduos, distribuídos em 55 espécies. As curvas do coletor e de rarefação indicam esforço amostral satisfatório. A ordem Characiformes foi a mais abundante. A espécie mais abundante foi <em>Potamorhina latior</em> e a mais amplamente distribuída foi <em>Crenicichla lenticulata</em>. A cor da água estruturou a assembleia de peixes em igarapés na área de estudo com maior diversidade de espécies em igarapés de água preta. Diferenças entre águas pretas, brancas e claras são óbvias, mas mais estudos sobre assembleias de peixes nestes ambientes da bacia Amazônica são necessários.</p>

This study presents an inventory of the ichthyofauna of the lower Roosevelt River sub-basin and its associated tributaries. Fish sampling with fishing nets and measurements of environmental parameters of water occurred in November/2012 (rising water), February/2013 (flooding), May/2013 (falling water) and August/2013 (drought). Depth mean was 8.86 m, water transparency was 0.6 m, conductivity was 22.7 µS.cm-1, pH was 6.59, dissolved oxygen was 7.63 mg.l-1 and temperature was 28°C. The total estimated capture area was 68,829.6 m2 during 2,880 hours. The catch per unit Effort (CPUE) was 0.37 individuals m-2.day-1. Species were spatially aggregated in all sampling points and river water levels. A total of 5,183 individuals distributed in 7 orders, 29 families, 104 genders and 188 species were sampled in this survey. The diversity index was 4.121 and equitability index was 0.789. The Characiforms order was the most abundant with 106 species, followed by Siluriforms with 63 species and Cichliforms with 23 species. The most abundant species was Serrasalmus rhombeus (Linnaeus, 1766) with 327 individuals (5.9%), followed by Chalceus epakros (Cope, 1870) with 309 individuals (5.6%) and Acestrorhynchus microlepis (Schomburgk, 1841) with 250 individuals (4.5%). Trophicity was characterized by omnivorous (28.6%), piscivorous (14.3%), carnivorous (13.8%) and detritivorous (12.8%). According to IBAMA's regulation, 29.25% of captured species presents ornamental potential.