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Background: The impacts of climate change on surface water, waterborne disease, and human health remain a growing area of concern, particularly in Africa, where diarrheal disease is one of the most important health threats to children under 5 years of age. Little is known about the role of surface water and annual flood dynamics (flood pulse) on waterborne disease and human health nor about the expected impact of climate change on surface-water-dependent populations. Methods and findings: Using the Chobe River in northern Botswana, a flood pulse river—floodplain system, we applied multimodel inference approaches assessing the influence of river height, water quality (bimonthly counts of Escherichia coli and total suspended solids [TSS], 2011–2017), and meteorological variability on weekly diarrheal case reports among children under 5 presenting to health facilities (n = 10 health facilities, January 2007–June 2017). We assessed diarrheal cases by clinical characteristics and season across age groups using monthly outpatient data (January 1998–June 2017). A strong seasonal pattern was identified, with 2 outbreaks occurring regularly in the wet and dry seasons. The timing of outbreaks diverged from that at the level of the country, where surface water is largely absent. Across age groups, the number of diarrheal cases was greater, on average, during the dry season. Demographic and clinical characteristics varied by season, underscoring the importance of environmental drivers. In the wet season, rainfall (8-week lag) had a significant influence on under-5 diarrhea, with a 10-mm increase in rainfall associated with an estimated 6.5% rise in the number of cases. Rainfall, minimum temperature, and river height were predictive of E. coli concentration, and increases in E. coli in the river were positively associated with diarrheal cases. In the dry season, river height (1-week lag) and maximum temperature (1- and 4-week lag) were significantly associated with diarrheal cases. During this period, a 1-meter drop in river height corresponded to an estimated 16.7% and 16.1% increase in reported diarrhea with a 1- and 4-week lag, respectively. In this region, as floodwaters receded from the surrounding floodplains, TSS levels increased and were positively associated with diarrheal cases (0- and 3-week lag). Populations living in this region utilized improved water sources, suggesting that hydrological variability and rapid water quality shifts in surface waters may compromise water treatment processes. Limitations include the potential influence of health beliefs and health seeking behaviors on data obtained through passive surveillance. Conclusions: In flood pulse river—floodplain systems, hydrology and water quality dynamics can be highly variable, potentially impacting conventional water treatment facilities and the production of safe drinking water. In Southern Africa, climate change is predicted to intensify hydrological variability and the frequency of extreme weather events, amplifying the public health threat of waterborne disease in surface-water-dependent populations. Water sector development should be prioritized with urgency, incorporating technologies that are robust to local environmental conditions and expected climate-driven impacts. In populations with high HIV burdens, expansion of diarrheal disease surveillance and intervention strategies may also be needed. As annual flood pulse processes are predominantly influenced by climate controls in distant regions, country-level data may be inadequate to refine predictions of climate—health interactions in these systems. [ABSTRACT FROM AUTHOR]

Irrigated agriculture is a key activity in water resources management at the river basin level in arid and semi-arid areas, since this sector consumes the largest part of the water resources overall. The current study proposes a methodology to evaluate the water footprint (WF) of the irrigated agriculture sector at the river basin level, through a simulation of the anthropised water cycle combining a hydrological model and a decision support system. The main difference from the approaches that have already been used is that the new methodology includes the limitations of the system for the exploitation of water resources where the irrigated areas are located, and it considers the hydrological principles governed by the law of continuity of mass. Water footprint accounting was carried out for the Segura River Basin (South-eastern Spain), applying the methodology proposed and another that is usually applied. The results of the two methodologies were compared, revealing significant differences in the values of the WF, basically due to the blue component. The methodology that is usually applied overestimated the WF of the agriculture in the basin since supply deficits were not taken into account, providing results that would only be possible if there were no spatial or temporal restrictions to water use. So, in order to make the WF indicator useful in water resources management plans, it is necessary to adapt the computations to the main characteristics of the water exploitation system of the whole basin under study, respecting the hydrological principles of the water cycle: regulation and transport infrastructure, the real water resources available and the priority of access to water between concurrent water uses. [ABSTRACT FROM AUTHOR]

Research at the interface between terrestrial, riverine, estuarine and marine environments is frequently constrained by significant disciplinary and geographical boundaries. This article outlines an international initiative, DANUBIUS-RI, which aims to address these problems by facilitating biogeochemical monitoring and interdisciplinary research on river-sea systems. The scope of the project spans the environmental, social and economic sciences and was accepted into the European Strategy Forum on Research Infrastructures roadmap in 2016. When operational, DANUBIUS-RI will offer researchers access to interdisciplinary expertise, facilities and European river-sea systems, providing a comprehensive platform for multidisciplinary research and training. [ABSTRACT FROM AUTHOR]

The Ganjiang River has abundant fish resources, which plays a significant role in maintaining and replenishing the fish resources in Poyang Lake and the Yangtze River, and contains important habitat for migratory fish. However, fish diversity has rapidly declined in the Ganjiang River, especially migratory fish. In this study, 107 fish species (including 43 Chinese endemic species) were found in the middle and lower reaches of the Ganjiang River. However, only 91 fish species were found in the main channel of the Ganjiang River, which was lower than the 108 fish species historically found there. According to the Chinese Red List, 85 Least Concern, two Critically Endangered, three Vulnerable, one Near Threatened and 16 Data Deficient fish species were found in the Ganjiang River. In addition, the species number, diversity and CPUE in the channel were all greater than in the reservoir. The Bray-Curtis resemblance matrix and non-metric multidimensional scaling (NMDS) showed that the habitats of the Ganjiang River were divided into three areas. The analysis of RDA showed that turbidity, dissolved oxygen and water depth significantly affected fish distributions and assemblage composition. These results indicated that dam construction and other human activities have seriously destroyed the fish habitat and led to the decline in fish diversity. Therefore, the conservation of fish has become urgent in the Ganjiang River, and an integrated management plan should be developed and effectively implemented. [ABSTRACT FROM AUTHOR]

Environmental DNA (eDNA) sampling has emerged as a powerful tool to detect and quantify species abundance in aquatic environments. However, relatively few studies have compared the performance of eDNA-based abundance estimates to traditional catch or survey approaches in the field. Here, we have developed and field-tested a qPCR assay to detect eDNA from alewife and blueback herring (collectively known as ‘river herring’), comparing eDNA-based presence and abundance data to traditional methods of quantification (ichthyoplankton sampling and adult observations). Overall, the qPCR assay showed very high target specificity in lab trials, and was successful in detecting river herring for 11/12 Chesapeake Bay tributaries in spring 2015 and 2016, with 106 out of 445 samples exhibiting positive eDNA hits. We found a strong correlation between eDNA abundance and ichthyoplankton count data (Spearman’s Rho = 0.52), and Phi-tests (correlation of presence/absence data) showed higher correlation between eDNA and ichthyoplankton data (Phi = 0.45) than adult data (Phi = 0.35). Detection probability was significantly lower on western vs. eastern shore tributaries of Chesapeake Bay, and blueback herring and alewife were more likely detected on the western and eastern shores, respectively. Temporal patterns of eDNA abundance over the spring spawning season revealed that alewife were present in high abundances weeks ahead of blueback herring, which aligns with known differences in spawning behavior of the species. In summary, the eDNA abundance data corresponded well to other field methods and has great potential to assist future monitoring efforts of river herring abundance and habitat use. [ABSTRACT FROM AUTHOR]

While numerous studies have shown that floodplain habitat complexity can be important to fish ecology, few quantify how watershed-scale complexity influences productivity. This scale mismatch complicates population conservation and recovery strategies that evaluate recovery at regional or multi-basin scales. We used outputs from a habitat status and trends monitoring program for ten of Puget Sound’s large river systems to examine whether juvenile Chinook salmon productivity relates to watershed-scale habitat complexity. We derived habitat complexity metrics that quantified wood jam densities, side and braid to main channel ratios, and node densities from a remote sensing census of Puget Sound’s large river systems. Principal component analysis revealed that 91% of variance in these metrics could be explained by two principal components. These metrics revealed gradients in habitat complexity across Puget Sound which were sensitive to changes in complexity as a result of restoration actions in one watershed. Mixed effects models revealed that the second principle component term (PC2) describing habitat complexity was positively related to log transformed subyearling Chinook per spawner productivity rates from 6–18 cohorts per watershed. Total subyearling productivity (subyearlings per spawner) and fry productivity (subyearling fry per spawner) rates were best described by models that included a positive effect of habitat complexity (PC2) and negative relationships with log transformed peak flow recurrence interval, suggestive of reduced survival due to egg destruction during floods. Total subyearling productivity (subyearlings per spawner) and parr productivity (subyearling parr per spawner) rates were best described by models that included a positive effect of habitat complexity (PC2) and negative relationships with log transformed spawner density, suggestive of density dependent limits on juvenile rearing habitat. We also found that coefficient of variation for log transformed subyearling productivity and subyearling fry productivity rates declined with increasing habitat complexity, supporting the idea that habitat complexity buffers populations from annual variation in environmental conditions. Therefore, we conclude that our watershed-scale census-based approach provided habitat complexity metrics that explained some of the variability in productivity of subyearling juveniles among Chinook salmon populations. Furthermore, this approach may provide a useful means to track and evaluate aggregate effects of habitat changes on the productivity of Endangered Species Act (ESA) listed Chinook salmon populations over time. [ABSTRACT FROM AUTHOR]

Highlights • Runoff forcing impact is examined in ocean simulations over the Western Mediterranean. • A validation is done using sea surface observations collected during HyMeX SOP1. • River plumes extend is increased using runoff observations over climatological data. • The use of runoff observations change the sea surface salinity and temperature. • A vertical distribution of runoff modifies the stratification close to river mouths. Abstract The Western Mediterranean Sea is often affected by heavy precipitation which frequently generates floods or even flash floods. These events generally produce brief but major freshwater inputs in the ocean. In order to evaluate the sensitivity to the representation of river freshwater input, three different runoff forcing dataset are used to drive the NEMO ocean model: a monthly climatology, an observational dataset with a daily or a hourly frequency. The sensitivity is investigated over the first Special Observation Period (SOP1) of the HyMeX program that took place in autumn 2012, in two configurations of NEMO: the first is WMED36 over the Western Mediterranean Sea at 1/36°-resolution and the second is a new configuration covering the North-Western Mediterranean Sea with a 1/72°-resolution named NWMED72. With NWMED72, the impact of the representation of the river freshwater flux, i.e. moving from a surface flux to a vertical distribution of the flux, is also evaluated. The results show that the ocean stratification is significantly modified locally in simulations where runoff observations are used compared to those using the climatology. The sea surface salinity is modified as well as the mixed layer which is thinner as bounded by a well marked halocline. The sea surface temperature is also impacted by the change in runoff frequency. Moreover, the current intensity in river plume during flood is increased. Vertical profiles of salinity and temperature and thus the mixed layer depth are changed when the runoff forcing is distributed over a depth. Those changes are limited and very local but the realism of the river runoff input is improved. [ABSTRACT FROM AUTHOR]

Morphometric differences were investigated among five fish species of subfamily Barbinae from the Ganga river system through traditional morphometrics and the truss network system. Species taken into account were Puntius chola (Hamilton 1822), Puntius sophore (Hamilton 1822), Pethia ticto (Hamilton 1822), Pethia conchonius (Hamilton 1822) and Systomus sarana (Hamilton 1822). Although, taxonomists carefully examine external body features to discriminate these species, there is still a risk of misidentification during a visual assessment. In the present study, the traditional morphological analysis included 22 morphometric measurements and 10 meristic counts. Truss network system of 14 landmarks was interconnected to yield 91 distance variables. The principal component analysis (PCA), discriminant function analysis (DFA) and cluster analysis (CA) were employed in order to determine morphometric variations. In traditional analysis, 29 characters out of 32 were found significant (p<0.05). Eight principal components were extracted through PCA explaining 85.30% of the total variance in samples, DFA correctly classified 100.0% of original grouped cases and 100.0% of cross-validated grouped cases. Truss analysis showed that all the 90 characters were significant (p<0.05). PCA extracted four principal components explaining 96.45% of the total variance. DFA correctly classified 96.1% of original grouped cases and 92.1% of cross-validated grouped cases. The results acquired from the traditional as well as truss analyses indicate significant morphometric heterogeneity. However, variations are not the same for the two different methods (traditional and truss) employed for the analyses. Shape differences among species were evident from relative warps (RW) supporting truss network analysis. Geometric morphometric methods (GMM), but limited use of Procrustes methods revealed even very small dissimilarity between groups. In spite of determining the morphometric differentiation among species, the present study also provides a useful insight on the application and complementary role of truss analysis with traditional morphometric analysis in the correct classification of the selected species. [ABSTRACT FROM AUTHOR]

Background: Onchocerciasis control in Côte d’Ivoire started with aerial insecticide spraying in 1974 and continued with community directed treatment with ivermectin (CDTi) from 1992 to the present. Onchocerciasis and lymphatic filariasis (LF) are co-endemic in 46 of the 81 health districts in the country. Fourteen and 12 districts are endemic for only LF or onchocerciasis, respectively. This paper aims to review the impact of past interventions on onchocerciasis in Côte d’Ivoire between 1975 and 2013, and review plans for disease elimination. Methods: We reviewed microfilaria (MF, skin snip) prevalence and community microfilarial load (CMFL) data from published reports from 53 health districts during two major epidemiological assessment periods. Data from 1975 through 1991 provided information on the impact of vector control, and data from 1992 through 2016 provided information on the impact of CDTi. Results: Weekly aerial insecticide spraying in 8 endemic districts between 1975 and 1991 reduced the overall MF prevalence by 68.1% from 43.5% to 13.9%. The CMFL also decreased in 7 out of 8 surveyed communities by 95.2% from 9.24 MF/snip to 0.44 MF/snip. Ivermectin distribution started in 1992. The coverage targets for control (65% of the total population) was reached in most endemic districts, and some areas achieved 80% coverage. Two sets of surveys were conducted to assess the impact of CDTi. Results from the first repeat surveys showed a significant decrease in overall MF prevalence (by 75.7%, from 41.6% to 10.1%). The second follow-up evaluation showed further improvement in most endemic districts and also documented major reductions in CMFL compared to baseline. Conclusions: Extensive data collected over many years document the very significant impact of interventions conducted by the National Onchocerciasis and other Eyes Diseases Control Programme during challenging times with periods of civil unrest. The Health Ministry has now integrated efforts to control neglected tropical diseases and adopted the goal of onchocerciasis elimination. [ABSTRACT FROM AUTHOR]

Objective: Tick-borne encephalitis (TBE) caused by the tick-borne encephalitis virus (TBEV) is the most important tick-borne arboviral disease in Europe and Asia. The Upper Rhine Valley is thought to be the very western border of TBEV distribution in Europe. The aim of our study was to identify natural foci and isolate TBEV from ticks, to determine the prevalence of TBEV in local tick populations and to study the phylogenetic relatedness of circulating TBEV strains in this region. Material and methods: Ticks were collected between 2016, 2017 and 2018 by flagging. TBEV was isolated from collected ticks and phylogenetic analyses were performed. Minimal infection rates (MIR) of the collected ticks were calculated. Results: At 12 sampling sites, a total of 4,064 Ixodes ticks were collected in 2016 and 2017 –(and one single collection 2018). 953 male, 856 female adult ticks and 2,255 nymphs were identified. The MIR rates were 0,17% (1/595) for Schiltach (Germany) and 0,11% (1/944) for Foret de la Robertsau (France), respectively. Overall, the three newly described TBEV strains, isolated in the years 2016 and 2017 from the Upper Rhine Valley have no close phylogenetic relation and show a genetic relationship with strains from eastern Europe. The 2018 TBEV strain from Aubachstrasse (Germany), however, is closely related to the TBEV found in Schiltach (Germany). Conclusion: In conclusion, we demonstrate, to our knowledge for the first time, the phylogenetic relations of the newly isolated TBEV strains on both sides of the upper Rhine river. [ABSTRACT FROM AUTHOR]

The primary objective of this study was to examine the status of woody species composition and diversity along the Walga River of Wonchi, Southwestern Ethiopia. Fifty quadrats of 10 m x 50 m were laid at 500 m interval through systematic sampling method along the river line. Vegetation height (≥2.5 m) and DBH (≥2.5 cm) of only tree species were measured and altitude, ecological disturbances such as, grazing intensity and human impacts were included as main environmental variables at each of the sampled plots. The data was analyzed using different R statistical packages. Ninety-nine woody vascular plant species belonged to 81 genera and 45 familieswere recorded in Walga riparian vegetation. Only 10% of specieswere endemic to the Flora area. Asteraceae and Fabaceae had the highest number of species. Majority of the species (52.5%) were shrubs. Four major plant community types were identified: Euclea divinorum-Maytenus arbutifolia (1), Pterolobium stellatum- Calpurnia aurea (2), Brucea antidysenterica-Prunus africana (3), Erica arborea-Hagenia abyssinica (4). Species richness, true diversity and importance values were highestin community type 2(the lowest altitude ranges between 1976–2212 m a.s.l.) while evenness was highestin community type 3(mid altitude ranges between 2359–2676 m a.s.l.). Both community typeswere comprised of 56% of all recorded species and all endemic taxa except two. The highest percentage of species in lower frequency classes indicates a higher degree of floristic heterogeneity. There was a strong negative correlation (r = -0.65, p<0.001) between species richness and altitude with 42% of the variation in species richness per plot being explained by altitude. Our findings suggest that human disturbances and excessive livestock grazing are the main threats in community types1 and 2. We conclude that identifying major plant community types and underlying environmental conditions may help to manage and conserve forest resources in the area. [ABSTRACT FROM AUTHOR]

Background: Climate change is affecting food systems globally, with implications for food security, nutrition, and the health of human populations. There are limited data characterizing the current and future consequences of climate change on local food security for populations already experiencing poor nutritional indicators. Indigenous Amazonian populations have a high reported prevalence of nutritional deficiencies. This paper characterizes the food system of the Shawi of the Peruvian Amazon, climatic and non-climatic drivers of their food security vulnerability to climate change, and identifies potential maladaptation trajectories. Methods and findings: Semi-structured interviews with key informants (n = 24), three photovoice workshops (n = 17 individuals), transect walks (n = 2), a food calendar exercise, and two community dissemination meetings (n = 30 individuals), were conducted within two Shawi communities in Balsapuerto District in the Peruvian Loreto region between June and September of 2014. The Shawi food system was based on three main food sub-systems (forest, farming and externally-sourced). Shawi reported collective, gendered, and emotional notions related to their food system activities. Climatic and non-climatic drivers of food security vulnerability among Shawi participants acted at proximal and distal levels, and mutually reinforced key maladaptation trajectories, including: 1) a growing population and natural resource degradation coupled with limited opportunities to increase incomes, and 2) a desire for education and deforestation reinforced by governmental social and food interventions. Conclusion: A series of maladaptive trajectories have the potential to increase social and nutritional inequities for the Shawi. Transformational food security adaptation should include consideration of Indigenous perceptions and priorities, and should be part of Peruvian food and socioeconomic development policies. [ABSTRACT FROM AUTHOR]

Restoration efforts with native eastern oyster, Crassostrea virginica, in Chesapeake Bay and elsewhere have been limited by shell availability, necessitating the use of alternative structures as subtidal reefs, yet these have rarely been evaluated quantitatively. We quantified population structure, density, abundance and biomass of eastern oyster and hooked mussel, Ischadium recurvum, on a concrete modular reef (75 m2 surface area over 5 m2 of river bottom) deployed subtidally at 7 m depth in the Rappahannock River, Virginia during October, 2000. After nearly 5 y (May 2005), we took 120 stratified random samples over the reef. The reef was heavily colonized by 28-168 oysters and 14-2177 mussels m-2 surface area. These densities translate to 1085 oysters and 8617 mussels m-2 river bottom, which are the highest recorded for artificial oyster reefs. Size structure of oysters reflected four year classes, with over half of oysters more than 1 y old and of reproductive age. Oyster biomass (1663 g dry mass m-2 river bottom) and condition index were equally high, whereas parasite prevalence and intensity were low. Oyster density correlated positively in a sigmoid fashion with mussel density up to high densities, then declined. This modular reef is one of the most successful artificial reefs for eastern oyster and hooked mussel restoration, and details features that are conducive for successful settlement, growth and survival in subtidal habitats. [ABSTRACT FROM AUTHOR]

Two distinct microtidal estuarine systems were assessed to advance the understanding of the coastal dynamics of sea level rise in salt marshes. A coupled hydrodynamic-marsh model (Hydro-MEM) was applied to both a marine-dominated (Grand Bay, Mississippi) and a mixed fluvial/marine (Weeks Bay, Alabama) system to compute marsh productivity, marsh migration, and potential tidal inundation from the year 2000 to 2100 under four sea level rise scenarios. Characteristics of the estuaries such as geometry, sediment availability, and topography, were compared to understand their role in the dynamic response to sea level rise. The results show that the low sea level rise scenario (20 cm) approximately doubled high-productivity marsh coverage in the marine-dominated estuary by the year 2100 due to an equilibrium between the rates of sea level rise and marsh platform accretion. Under intermediate-low sea level rise (50 cm), high-productivity marsh coverage in the year 2100 increased (doubled in the marine-dominated estuary and a seven-fold increase in the mixed estuary) by expanding into higher lands followed by the creation of interior ponds. The results also indicate that marine-dominated estuaries are vulnerable to collapse as a result of low, relatively uniform topography and lack of sediment sources, whereas mixed estuaries are able to expand due to higher elevations and sediment inputs. The results from the higher sea level rise scenarios (the intermediate-high (120 cm) and high (200 cm)) showed expansion of the bays along with marsh migration to higher land, producing a five-fold increase in wetland coverage for the mixed estuary and virtually no net change for the marine-dominated estuary. Additionally, hurricane storm surge simulations showed that under higher sea level rise scenarios, the marine-dominated estuary demonstrated weaker peak stage attenuation indicating that the marsh’s ability to dissipate storm surge is sensitive to productivity changes and bay expansion / marsh loss. [ABSTRACT FROM AUTHOR]

Dissolved organic carbon (DOC) released from glaciers has an important role in the biogeochemistry of glacial ecosystems. This study focuses on DOC from glaciers of the southeastern Tibetan Plateau, where glaciers are experiencing rapid shrinkage. We found that concentrations of DOC in snowpits (0.16±0.054 μg g−1), aged snow (0.16±0.048 μg g−1), and bare ice (0.18±0.082 μg g−1) were similar across the southeastern Tibetan Plateau, but were slightly lower than those in other glaciers on the Tibetan Plateau. Vertical variations of DOC, particulate organic carbon, black carbon, and total nitrate in snowpit showed no systematic variations in the studied glaciers, with high values of DOC occurring in the ice or dusty layers. We estimated the export of DOC and particulate organic carbon from glaciers to be 1.96±0.66 Gg yr–1 and 5.88±2.15 Gg yr–1 in this region, respectively, indicating that organic carbon released from glacier meltwater may be affecting downstream ecosystems. Potential sources of the air masses arriving at the southeastern Tibetan glaciers include South Asia, Central Asia, Middle East, and northwest China. Emissions from biomass burning of South Asia played an important role in the deposition of DOC to the glacier, which can be evidenced by backward trajectories and fire spot distributions from MODIS and CALIPSO images. Our findings suggest that anthropogenic aerosols contribute abundant DOC to glaciers on the southeastern Tibetan Plateau. The pronounced rate of glacial melting in the region may be delivering increased quantities of relic DOC to downstream rivers. [ABSTRACT FROM AUTHOR]

Biogeochemical maps of coastal regions can be used to identify important influences and inputs that define nearshore environments and biota. Biogeochemical tracers can also track animal movement and their diet, monitor human coastal development, and evaluate the condition of habitats and species. However, the beneficial applications of spatial biogeochemical analysis are hindered by a limited understanding of how tracer distribution is affected by different land and ocean–based influences. To help address these knowledge gaps, we determined the spatial trends of three stable isotopes (δ13C-carbon, δ15N-nitrogen, δ34S-sulfur) and 13 major and trace elements in an urbanized coastal embayment (Moreton Bay, Australia), as incorporated into the muscle tissue of a marine consumer, the eastern king prawn Melicertus plebejus. Results were used to identify unique biochemical regions within the bay and to discuss how spatial patterns in tracers could be used to indicate the relative importance of catchment, urban and offshore drivers in coastal bays. Discriminant analysis identified seven biogeochemical regions that were likely distinguished by variation in catchment, urban, and offshore input, and habitat type. δ13C and δ15N patterns suggested nearshore areas could be distinguished by increased sediment resuspension and higher wastewater inputs from catchments. High inshore lead (Pb) and copper (Cu) concentrations were likely the result of urban input. Arsenic (As) and cadmium (Cd) increased further from shore. This trend implied oceanic influences were a significant control over As and Cd bioavailability. Cobalt (Co) and rare earths were also used to differentiate some nearshore areas, but incongruent distribution patterns in Co suggested it may be less reliable. Overall, results indicated that δ15N, δ13C, Cd, Cu, Pb and rare earth elements were the most reliable tracers to differentiate nearshore and offshore environments, and catchment–based effects. We encourage future studies to consider using a similar multivariate approach in coastal spatial analysis, and to include unrelated tracers that reflect distinct coastal influences. [ABSTRACT FROM AUTHOR]

Seagrass meadows are among the most important coastal/ marine ecosystems for long-term carbon storage and conditioning of coastal waters. A combined air-water flux of CO2 and CH4 from the seagrass meadows was studied for the first time from Asia’s largest brackish–water lagoon, Chilika, India. Ecosystem-based comparisons were carried out during two hydrologically different conditions of dry and wet seasons in the seagrass dominated southern sector (SS); macrophyte-dominated northern sector (NS); the largely un-vegetated central sector (CS) and the tidally active outer channel (OC) of the lagoon. The mean fluxes of CO2 from SS, NS, CS and OC were 9.8, 146.6, 48.4 and 33.0mM m-2d-1, and that of CH4 were 0.12, 0.11, 0.05 and 0.07mM m-2d-1, respectively. The net emissions (in terms of CO2 equivalents), considering the global warming potential of CO2 (GWP: 1) and CH4 (GWP: 28) from seagrass meadows were over 14 times lower compared to the macrophyte-dominated sector of the lagoon. Contrasting emissivity characteristics of CO2 and CH4 were observed between macrophytes and seagrass, with the former being a persistent source of CO2. It is inferred that although seagrass meadows act as a weak source of CH4, they could be effective sinks of CO2 if land-based pollution sources are minimized. [ABSTRACT FROM AUTHOR]

Lebbiea grandiflora (Podostemaceae), a rheophytic herb from the Sewa River rapids in Sierra Leone, is described as a new species. It is the first new African genus of Podostemaceae published for 30 years. First collected in May 2017, the species is assessed as Critically Endangered using the IUCN 2012 standard. It is on the edge of extinction with a small population at a single site threatened by deposition of gravel and sand from alluvial gold and diamond mining upstream, and a planned hydro-electric dam. The new genus is unique in Podostemaceae in a) its highly developed and robust style-stigma structure in which the bases of the two style-stigmas unite to form a bifurcate funneliform-cylindrical structure, with a reflexed, blade-like apex that extends half-way around the perimeter of the ovary-fruit towards the base of the ovary-fruit, b) a specialised andropodium, with robust, self-supporting capacity, having differentiated thickened central, and angled, thinner marginal areas (in other Podostemaceae the andropodial structures are undifferentiated), c) the pillar-like haptera which completely elevate the crustose root above the substrate. Lebbiea is placed in Podostemoideae, necessitating amplification of the delimitation of that subfamily in which it is additionally unique in having the foliose tepals characteristic of the basal subfamilies Weddellinoideae and Tristichoideae. [ABSTRACT FROM AUTHOR]

This study was initiated to document information on the levels of sediment contamination with organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Moreover, it was intended to identify compounds which impose major ecological risks to aquatic organisms. Surficial sediments were collected from 46 locations within the streams and rivers of the Awash River Basin. In total 30 compounds were included in this study: 16 OCPs, 7 PCBs and 7 PBDEs. The total concentrations of OCPs, PCBs, and PBDEs ranged from 6.63 to 206.13 ng g-1- dry weight (dw), 0.85 to 26.56 ng g-1-dw and 3.71 to 18.95 ng g-1-dw respectively. Out of all the tested OCPs, heptachlor, heptachlor epoxide, p,p′-dichlorodiphenyltrichloroethane (p,p′-DDT) and β-hexachlorocyclohexane (β-HCH) were the most abundant in the study area. The ratio of (β-HCH/∑HCHs) indicated that HCHs were originally from earlier usage of HCH in the area whereas the ratio of (p,p’-DDT/p,p’-DDE) showed that the majority of DDT components were recently introduced into most of the sampling locations. Even though there were relatively low concentrations of PBDEs and PCBs across the sampling sites, substantial amounts of PCBs were observed in Addis Ababa City. According to the established ecological risk indices, p,p’-DDT and γ-HCH are the major concerns for potential adverse ecological impacts. This study provided the first comprehensive information on organohalogenated compounds’ (OCs’) occurrences, spatial distributions, and ecological risks in sediments of the Awash River Basin. Thus, the report will be very useful background information for further studies on sediment contamination with OCs’ in the region. It also adds important first-hand data to the field of fresh water ecology and provides useful empirical evidence for setting pollution control priorities for an ecologically important, yet largely understudied region. [ABSTRACT FROM AUTHOR]

Background: Intestinal parasite infections are major public health problems in resource-limited countries that adversely affect the well-being of millions. Among these, intestinal schistosomiasis is a serious public health problem in tropical and sub-tropical countries. Methods: A Community based cross sectional study was conducted from February to April 2017 in Addiremets town, Ethiopia. Socio-demographic associated risk factors and knowledge, attitude and practices of individuals regarding intestinal parasite infection including schistosomiasis were collected from 411 study participants using pretested structured questionnaires. From each study participant, a fresh stool sample was collected and direct microscopy, formol-ether concentration and Kato- Katz techniques were performed. Snails were checked and collected from the nearby study area river. The collected data was entered and analyzed using SPSS version 20. Bi-variant and multiple logistic regressions were used for correlation analysis. A P <0.05 was considered as statistically significant. Result: The overall intestinal parasite prevalence was 51.3% (211/411). The most prevalent parasites were S. mansoni 26.3%(108/411) and Hookworm 23.1%(95/411). The prevalence of intestinal parasites among males and females were 54.1%(131/242) and 47.3%(80/169) respectively. The highest proportion of parasite infection was reported among the age group of 5–9 year old participants, at 70.6%(36/51). The prevalence of S. mansoni was 26.3% (108/411) with mean infection intensity of 218 eggs per gram (range: 24 to 1728). Among study participants, 94.4% had good knowledge while 35.9% of them had poor practices towards intestinal parasite and Schistosomes infection prevention. Conclusion: High prevalence of intestinal parasitic infection was observed in Addiremets town and the most common parasites identified were S. mansoni and Hookworm. Most study participants had light infection intensity of Schistosomiasis, Ascariasis and Hookworm infection. Majority of the participants in the study area had good knowledge and positive attitude about intestinal parasitic infection and schistosomiasis control. Shells of Biomphalaria species, Bulinus species and Physa species were collected from the Mytsaeda river shore. [ABSTRACT FROM AUTHOR]

Rising river temperatures in western North America have increased the energetic costs of migration and the risk of premature mortality in many Pacific salmon (Oncorhynchus spp.) populations. Predicting and managing risks for these populations requires data on acute and cumulative thermal exposure, the spatio-temporal distribution of adverse conditions, and the potentially mitigating effects of cool-water refuges. In this study, we paired radiotelemetry with archival temperature loggers to construct continuous, spatially-explicit thermal histories for 212 adult Chinook salmon (O. tshawytscha) and 200 adult steelhead (O. mykiss). The fish amassed ~500,000 temperature records (30-min intervals) while migrating through 470 kilometers of the Columbia and Snake rivers en route to spawning sites in Idaho, Oregon, and Washington. Spring- and most summer-run Chinook salmon migrated before river temperatures reached annual highs; their body temperatures closely matched ambient temperatures and most had thermal maxima in the lower Snake River. In contrast, many individual fall-run Chinook salmon and most steelhead had maxima near thermal tolerance limits (20–22 °C) in the lower Columbia River. High temperatures elicited extensive use of thermal refuges near tributary confluences, where body temperatures were ~2–10 °C cooler than the adjacent migration corridor. Many steelhead used refuges for weeks or more whereas salmon use was typically hours to days, reflecting differences in spawn timing. Almost no refuge use was detected in a ~260-km reach where a thermal migration barrier may more frequently develop in future warmer years. Within population, cumulative thermal exposure was strongly positively correlated (0.88 ≤ r ≤ 0.98) with migration duration and inconsistently associated (-0.28 ≤ r ≤ 0.09) with migration date. All four populations have likely experienced historically high mean and maximum temperatures in recent years. Expected responses include population-specific shifts in migration phenology, increased reliance on patchily-distributed thermal refuges, and natural selection favoring temperature-tolerant phenotypes. [ABSTRACT FROM AUTHOR]

Autoradiography was used to detect 137Cs-enriched particles in sediment samples. The contributions of 137Cs-enriched particles to 137Cs concentrations in sediment samples ranged from 9% to 64%. These experiments revealed that the variability of 137Cs concentrations was due mainly to the heterogeneous distribution of 137Cs-enriched particles in the samples. Therefore, the heterogeneous distribution of 137Cs-enriched particles is probably one of the main factors responsible for the temporal and spatial variations of 137Cs concentrations in sediment samples. [ABSTRACT FROM AUTHOR]

Meaningful iteration between place-based knowledge of rivers and generalised, theoretically-framed understandings is a significant challenge in river science and management. How can we communicate knowledge of the inherent complexity of river systems in light of managerial quests for simple, easy-to-apply frameworks that can be used by a wide range of practitioners, such that we can meaningfully transfer experiences in river science and management from one situation to another? Identification, definition, classification and naming are vital parts of this process. In a sense, a name is like a ‘brand’, for which a consistency of product is expected. The River Styles Framework is a flexible, open-ended approach to river science and management. The Framework applies a set of hierarchical principles to differentiate reaches, interpret their process-based behaviour and examine interactions between patterns of reaches at the catchment scale. Here we outline an evolution and tightening of the Framework to better communicate how to identify and name types of river at the reach scale. Like the River Styles Framework itself, the naming convention applies hierarchical procedures, starting at the valley setting scale, and incorporating analyses of river planform, channel and floodplain landforms (geomorphic units) and bed material texture. Using a series of examples from around the world, we show how this naming convention can be applied to name river reaches and can be adapted to particular purposes in a consistent, readily communicable manner. We outline various challenges that are faced in managing the use of such a naming convention. [ABSTRACT FROM AUTHOR]

Several hypotheses are used to explain species richness patterns. Some of them (e.g. species-area, species-energy, environment-energy, water-energy, terrestrial primary productivity, environmental spatial heterogeneity, and climatic heterogeneity) are known to explain species richness patterns of terrestrial organisms, especially when they are combined. For aquatic organisms, however, it is unclear if these hypotheses can be useful to explain for these purposes. Therefore, we used a selection model approach to assess the predictive capacity of such hypotheses, and to determine which of them (combined or not) would be the most appropriate to explain the fish species distribution in small Brazilian streams. We perform the Akaike’s information criteria for models selections and the eigenvector analysis to control the special autocorrelation. The spatial structure was equal to 0.453, Moran’s I, and require 11 spatial filters. All models were significant and had adjustments ranging from 0.370 to 0.416 with strong spatial component (ranging from 0.226 to 0.369) and low adjustments for environmental data (ranging from 0.001 to 0.119) We obtained two groups of hypothesis are able to explain the richness pattern (1) water-energy, temporal productivity-heterogeneity (AIC = 4498.800) and (2) water-energy, temporal productivity-heterogeneity and area (AIC = 4500.400). We conclude that the fish richness patterns in small Brazilian streams are better explained by a combination of Water-Energy + Productivity + Temporal Heterogeneity hypotheses and not by just one. [ABSTRACT FROM AUTHOR]

Abstract: Relief generation in non‐glaciated regions is largely controlled by river incision into bedrock but datable fluvial terraces that allow quantifying incision rates are not always present. Here we suggest a new method to determine river incision rates in regions where low‐relief surfaces are dissected by streams. The approach consists of three steps and requires the 10Be concentrations of a stream sediment sample and a regolith sample from the low‐relief surface. In the first step, the spatial distribution of 10Be surface concentrations in the given catchment is modelled by assuming that denudation rates are controlled by the local hillslope angles. The slope–denudation rate relation for this catchment is then quantified by adjusting the relation between slope angle and denudation rate until the average 10Be concentration in the model is equal to the one measured in the stream sediment sample. In the second step, curved swath profiles are used to measure hillslope angles adjacent to the main river channel. Third, the mean slope angle derived from these swath profiles and the slope–denudation relation are used to quantify the river incision rate (assuming that the incision rate equals the denudation rate on adjacent hillslopes). We apply our approach to two study areas in southern Tibet and central Europe (Black Forest). In both regions, local 10Be denudation rates on flat parts of the incised low‐relief surface are lower than catchment‐wide denudation rates. As the latter integrate across the entire landscape, river incision rates must exceed these spatially averaged denudation rates. Our approach yields river incision rates between ~15 and ~30 m/Ma for the Tibetan study area and incision rates of ~70 to ~100 m/Ma in the Black Forest. Taking the lowering of the low‐relief surfaces into account suggests that relief in the two study areas increases at rates of 10–20 and 40–70 m/Ma, respectively. Copyright © 2018 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Bivalves are one of the most representative groups in the Phylum Mollusca, with over 1,100 freshwater species around the world except Antarctica. About 900 of these species belong to the Order Unionida Gray, 1854. In South America, the distributional range of the Unionida includes all countries in the region and extends as far south as the lakes and rivers of Argentinean-Chilean Patagonia. With the aim of generating distribution maps for the different genera of Unionida in Argentina, we consulted the databases of the nation’s main official malacological collections. The data were analyzed and georeferenced using the point-radius method. Spatial analyses were performed with the software Q-GIS 2.16.3 Nødebo using vector layers under the 2007 Argentinean Geodesic Positions reference system. A total 1,833 lots were analyzed, of which it was possible to georeference 1,503. The distribution of Unionida in Argentinean territory was analyzed according to political provinces, Surface Drainage Basins and the Argentinean Protected Areas. Species richness was analyzed using the surface drainage basins of Argentina. We generate distribution maps for each genus and discuss the species threat status and conservation degree in the region. Only six (18%) of the Unionida present in Argentina have been classified by the IUCN, four are Least Concern and two are Data Deficient. This pattern is also valid for all of South America. More than 95% of the distributional range of the Unionida has no protected area. Conservation management is necessary for the preservation of Unionida diversity in southern South America. [ABSTRACT FROM AUTHOR]

While many studies on tribal water resources of individual tribal lands in the United States (US) have been conducted, the importance of tribal water resources at a national scale has largely gone unrecognized because their combined totals have not been quantified. Thus, we sought to provide a numerical estimate of major water budget components on tribal lands within the conterminous US and on USGS hydrologic unit codes (HUC2) regions. Using existing national-scale data and models, we estimated mean annual precipitation, evapotranspiration, excess precipitation, streamflow, and water use for the period 1971–2000. Tribal lands represent about 3.4 percent of the total land area of the conterminous US and on average account for 1.9 percent of precipitation, 2.4 percent of actual evapotranspiration, 0.95 percent of excess precipitation, 1.6 percent of water use, and 0.43 percent of streamflow origination. Additionally, approximately 9.5 and 11.3 percent of US streamflow flows through or adjacent as boundaries to tribal lands, respectively. Streamflow through or adjacent to tribal lands accounts for 42 and 48 percent of streamflow in the Missouri region, respectively; and for 86 and 88 percent in the Lower Colorado region, respectively. On average, 5,600 million cubic meters of streamflow per year was produced on tribal lands in the Pacific Northwest region, nearly five times greater than tribal lands in any other region. Tribal lands in the Great Lakes, Missouri, Arkansas-White-Red, and California regions all produced between 1,000 and 1,400 million cubic meters per year. [ABSTRACT FROM AUTHOR]

The distributions of two bitterling fish (subfamily: Acheilognathinae), Tanakia lanceolata and T. limbata, overlap in western Japan. Acheilognathinae fish lay their eggs in the gills of freshwater bivalves, and the early juvenile stage develops in the gills. Populations of freshwater bivalves are declining worldwide, which has limited the number of spawning substrate for bitterlings. T. limbata has been artificially introduced to some rivers in Ehime, Japan, where it coexists with native T. lanceolata, and some hybrids have been observed. We collected both species from several sites in western Japan, and from the Kunichi River system in Ehime, and analyzed genetic population structure based on six microsatellite loci and sequences of the mitochondrial cytochrome b gene. Structure analysis identified three genetically distinct populations: T. lanceolata, T. limbata “West Kyushu”, and T. limbata “Setouchi”. Two clades of T. limbata were also supported by molecular phylogenetic analyses based on cytochrome b. Hybrids in Ehime originated mostly from interbreeding between male T. lanceolata and female T. limbata “West Kyushu”, and made up 10.2% of all collected fish, suggesting that hybrids occurred frequently between females of colonizing species and males of native species. On the other hand, interspecific hybrids were detected at rates of 40.0%, 20.0%, and 17.6% in the Ima River (Fukuoka), Midori River (Kumamoto), and Kase River (Saga), respectively, which are naturally sympatric regions. We found a few T. limbata “Setouchi” in the Midori and Kase Rivers, which were supposed to be introduced from other regions, coexisting with native T. limbata “West Kyushu”, and this cryptic invasion may have triggered the interspecific hybridization. These results suggest that artificial introduction of a fish species, a decline in the unionid population, and degradation of habitat have caused broad hybridization of bitterlings in western Japan. [ABSTRACT FROM AUTHOR]

Environmental and spatial factors are known as the main determinants of community variation in aquatic organisms. However, historical factors may interact with local processes to regulate community structure patterns. Here we compared historical, environmental, and spatial factors in a multi-scale approach in order to identify the main drivers structuring species composition and functional diversity of fish communities in forest enclaves across three hydrographic basins in semiarid Brazil Caatinga biome. We initially modeled spatial structure within each basin using asymmetric eigenvector maps (AEM). We then partitioned the explanation of the variation in local community structure into three groups of predictor variables: (1) environmental variables, (2) spatial variables, and (3) phylogenetic history. Biogeographical bias was assessed using a basin identity matrix as covariable. The combination of 1, 2, and 3 explained the variation in species composition, while pure spatial, phylogenetic, and environmental components explained the distribution of functional groups and their nested patterns. Our findings confirmed the importance of phylogenetic history, as well as the usefulness of robust methods in community studies in refining explanations of the processes determining variation in species composition and functional groups. [ABSTRACT FROM AUTHOR]

The influence of groynes in large rivers on caddisflies has been poorly studied in the literature. Therefore, we carried out an investigation on the 420-km stretch of the River Oder equipped with groynes. At 29 stations, we caught caddisflies in four habitats: current sites, groyne fields, riverine control sites without groynes and in the river’s oxbows. We found that groyne construction increased species richness, diversity, evenness, and altered the structure of functional groups into more diversified and sustainable ones compared to the control sites. The groyne field fauna is similar to that of natural lentic habitats, but its composition is largely governed by the presence of potential colonists in the nearby oxbows. We distinguished three of the river’s caddisfly assemblages. The distribution of Trichoptera was governed inter alia by the plant cover and the amount of detritus, and consequently, the food resources. Oxygen, nitrates, phosphates and electrolytic conductivity were important as well. Groynes have had positive effects for caddisflies—not only those in the river itself, but also those in its valley. They can therefore be of significance in river restoration (although originally they served other purposes), especially with respect to the radically transformed ecosystems of large rivers. [ABSTRACT FROM AUTHOR]

Background: Onchocerciasis a neglected tropical disease that historically has been a major cause of morbidity and an obstacle to economic development in the developing world. It is caused by infection with Onchocerca volvulus, which is transmitted by black flies of the genus Simulium. The discovery of the potent effect of Mectizan (ivermectin) on O. volvulus microfilariae and the decision by its manufacturer to donate the drug for onchocerciasis spurred the implementation of international programs to control and, more recently, eliminate this scourge. These programs rely primarily on mass distribution of ivermectin (MDA) to the afflicted populations. However, MDA alone will not be sufficient to eliminate onchocerciasis where transmission is intense and where ivermectin MDA is precluded by co-endemicity with Loa loa. Vector control will likely be required as a supplemental intervention in these situations. Methodology/Principal findings: Because biting by the black fly vectors is often a major nuisance in onchocerciasis afflicted communities, we hypothesized that community members might be mobilized to clear the breeding sites of the vegetation that represents the primary black fly larvae attachment point. We evaluated the effect of such a community based "slash and clear" intervention in multiple communities in Northern Uganda. Slash and Clear resulted in 89–99% declines in vector biting rates. The effect lasted up to 120 days post intervention. Conclusions/Significance: Slash and clear might represent an effective, inexpensive, community- based tool to supplement ivermectin distribution as a contributory method to eliminate onchocerciasis and prevent recrudescence. [ABSTRACT FROM AUTHOR]

Salmonella enterica serovar Napoli (serovar Napoli) is an emerging cause of human salmonellosis in Northern Italy. No specific reservoirs of serovar Napoli have been identified in Italy, so far. However, the environment, especially surface waters, has been hypothesized as an important source of infection based on the observation that genotypically different clusters of serovar Napoli are detected in different geographical macro-areas. To further support the hypothesis of a spatially-restricted pattern of serovar Napoli diffusion, a spatial segregation of serovar Napoli lineages should be observed also at smaller geographical scale. However, classical genotyping techniques used for Salmonella, such as pulsed-field gel electrophoresis (PFGE), did not possess enough discriminatory power to highlight spatial clustering of serovar Napoli within the macro-areas. To this purpose, we performed phylogeographical analyses based on genome-wide single nucleotide polymorphisms to test whether spatio-temporal evolution patterns of serovar Napoli in Northern Italy could be recognized with high geographical resolution, i.e. at local level. Specifically, we analyzed the local spread of the main PFGE clonal group, responsible for more than 60% of human infections in the study area, that did not show any geographical differentiation by PFGE within Northern Italy, i.e. the macro-area considered in the study. Both discrete and continuous phylogeography highlighted the existence of two main geographically-restricted clades: a Southern clade corresponding to the Po Valley and a Northern clade corresponding to the Pre-Alps area. Furthermore, the phylogeographical analyses suggested that the most probable site of origin of the clone was in an area of the Po Valley at the confluence of the Po and Ticino rivers, one of the most important Italian wetlands. These findings provide further support to the hypothesis that environmental transmission may play an important role in the ecology of serovar Napoli. [ABSTRACT FROM AUTHOR]

Climate change will affect stream systems in numerous ways over the coming century. Globally, streams are expected to experience changes in temperature and flow regime. Previous work has indicated that these changes will likely affect fish distributions, but little work has been conducted examining population level effects of climate change on warmwater fish at the warmest portion of their range. We model several potential climate change-related stressors and the resulting effects on smallmouth bass Micropterus dolomieu populations in the Buffalo National River, Arkansas, USA, located near the southern extent of smallmouth bass range. Smallmouth bass are a popular recreational fish in the region and angler harvest likely contributes substantially to annual mortality. We created a simulation model parameterized with data collected from the Buffalo National River to evaluate the relative importance of climate stressors and angler harvest on smallmouth bass populations. Our simulations suggest that increases in springtime temperature and reductions in river discharge during the spawning period could increase recruitment, resulting in increases in adult abundance (8% higher). However, when increased flooding and drought probabilities are considered, our model indicates the Buffalo National River could experience large reductions in adult smallmouth bass abundance (≥50% decline) and increased probability of extinction compared to present levels. Simulations showed that harvest reduction could be a viable strategy to reduce the negative effects of climate change, but that even with complete closure of harvest, smallmouth bass population levels would still be well below present abundance (46% lower than present). Efforts to reduce flooding and drought effects related to climate change in the Buffalo National River could help offset the predicted reduction in the smallmouth bass population. [ABSTRACT FROM AUTHOR]

Metabarcoding allows the genetic analysis of pooled samples of various sources. It is becoming popular in the study of animal diet, especially because it allows the analysis of the composition of feces without the need of handling animals. In this work, we studied the diet of the Pyrenean desman (Galemys pyrenaicus), a small semi-aquatic mammal endemic to the Iberian Peninsula and the Pyrenees, by sequencing COI minibarcodes from feces using next-generation sequencing techniques. For the identification of assembled sequences, we employed a tree-based identification method that used a reference tree of sequences of freshwater organisms. The comparison of freshly collected fecal samples and older samples showed that fresh samples produced significantly more sequencing reads. They also rendered more operational taxonomical units (OTUs), but not significantly. Our analyses of 41 samples identified 224 OTUs corresponding to species of the reference tree. Ephemeroptera, Diptera excl. Chironomidae, and Chironomidae were the most highly represented groups in terms of reads as well as samples. Other groups of freshwater organisms detected were Plecoptera, Trichoptera, Neuropteroida, Coleoptera, Crustacea, and Annelida. Our results are largely in line with previous morphological and genetic studies on the diet of the Pyrenean desman, but allowed the identification of a higher diversity of OTUs in each sample. Additionally, the bioinformatic pipeline we developed for deep sequencing of fecal samples will enable the quantitative analysis of the diet of this and other species, which can be highly useful to determine their ecological requirements. [ABSTRACT FROM AUTHOR]

With an estimate of around 9,000 species, the Neotropical region hosts the greatest diversity of freshwater fishes of the world. Genetic surveys have the potential to unravel isolated and unique lineages and may result in the identification of undescribed species, accelerating the cataloguing of extant biodiversity. In this paper, molecular diversity within the valuable and widespread Neotropical genus Hoplias was assessed by means of DNA Barcoding. The geographic coverage spanned 40 degrees of latitude from French Guiana to Argentina. Our analyses revealed 22 mitochondrial lineages fully supported by means of Barcode Index Number, Automatic Barcode Gap Discovery and phylogenetic analyses. This mtDNA survey revealed the existence of 15 fully supported mitochondrial lineages within the once considered to be the continentally distributed H. malabaricus. Only four of them are currently described as valid species however, leaving 11 mitochondrial lineages currently “masked” within this species complex. Mean genetic divergence was 13.1%. Barcoding gap analysis discriminated 20 out of the 22 lineages tested. Phylogenetic analyses showed that all taxonomically recognized species form monophyletic groups. Hoplias malabaricus sensu stricto clustered within a large clade, excluding the representatives of the La Plata River Basin. In the H. lacerdae group, all species but H. curupira showed a cohesive match between taxonomic and molecular identification. Two different genetic lineages were recovered for H. aimara. Given the unexpected hidden mitochondrial diversity within H. malabaricus, the COI sequence composition of specimens from Suriname (the type locality), identified as H. malabaricus sensu stricto, is of major importance. [ABSTRACT FROM AUTHOR]

Rivers are a vital resource for human wellbeing. To reduce human impact on water bodies, the European Union has established an essential regulatory framework for protection and sustainable management (WFD; 2000/60/EC). In this strategy, reliable and economic bioindicators are a fundamental component. Benthic macroinvertebrates are the group most commonly used as bioindicators through all European countries. However, their conventional assessment currently entails serious cost-efficiency limitations. In this study, we have tested the reliability of metabarcoding as a tool to record river macroinvertebrates using samples from a mock community (in vitro validation) and eDNA extracted for field validation from water from six sites within a north Iberian river (River Nalón, Asturias, Spain). Two markers (V4 region within the nuclear 18S rDNA and a fragment of the mitochondrial COI gene) were amplified and sequenced using an Illumina platform. The molecular technique has proven to be more sensitive than the visual one. A cost-benefit analysis shows that the metabarcoding approach is more expensive than conventional techniques for determining macroinvertebrate communities but requires fewer sampling and identification efforts. Our results suggest metabarcoding is a useful tool for alternative assessment of freshwater quality. [ABSTRACT FROM AUTHOR]

Garnets from disparate geographical environments and origins such as oxidized soils and river sediments in Thailand host intricate systems of microsized tunnels that significantly decrease the quality and value of the garnets as gems. The origin of such tunneling has previously been attributed to abiotic processes. Here we present physical and chemical remains of endolithic microorganisms within the tunnels and discuss a probable biological origin of the tunnels. Extensive investigations with synchrotron-radiation X-ray tomographic microscopy (SRXTM) reveal morphological indications of biogenicity that further support a euendolithic interpretation. We suggest that the production of the tunnels was initiated by a combination of abiotic and biological processes, and that at later stages biological processes came to dominate. In environments such as river sediments and oxidized soils garnets are among the few remaining sources of bio-available Fe2+, thus it is likely that microbially mediated boring of the garnets has trophic reasons. Whatever the reason for garnet boring, the tunnel system represents a new endolithic habitat in a hard silicate mineral otherwise known to be resistant to abrasion and chemical attack. [ABSTRACT FROM AUTHOR]

Eelgrass (Zostera marina) forms extensive beds in coastal and estuarine environments and provides various ecosystem functions. The aboveground part of eelgrass provides habitats for other types of primary producers such as epiphytic microalgae and for epifaunal invertebrate grazers. Because of the different sizes, generation times and resource requirements, these different types of producers and consumers may be affected by different sets of biotic/abiotic factors over multiple spatial scales. We examined the spatial variations in three functional groups of eelgrass beds (eelgrass, epiphytic microalgae and epifaunal invertebrates) and the abiotic/biotic factors responsible for these variations in three lagoons with different environmental properties at the eastern region of Hokkaido Island, Japan. The spatial scale responsible for the variation in the biomasses of the three functional groups varied, where within-lagoon variation was important for eelgrass and epifauna but among-lagoon variation was important for microalgae. The environmental predictors for the observed spatial variations also differed among the different functional groups, with variation in eelgrass biomass related to depth, nutrient and salinity, epiphytes to water temperature, eelgrass biomass and water column chlorophyll and epifauna mainly to eelgrass biomass. These results revealed that the level of importance of among- and within-lagoon environmental gradients vary in the different functional groups of the eelgrass bed community. The large-scale variation in pelagic productivity, which is tightly related to the ocean current regimes, is likely responsible for the great among-lagoon variation in microalgae. The local variations in environmental factors such as salinity and nutrients, which change with alterations in terrestrial river inputs, are likely related to the great variations in eelgrass and epifauna within the ecosystem. The observed relationship of epifauna with eelgrass biomass indicates the importance of non-trophic plant-animal interactions because epifauna utilize eelgrass as habitat. We therefore emphasize the importance of evaluating spatial variations at multiple scales to further understand the functions of coastal and estuarine ecosystems. [ABSTRACT FROM AUTHOR]

Background: Being aware of consumption patterns of antimicrobials is the first step in designing and implementing strategies to change behaviors and, thus, to reduce the occurrence of antimicrobial resistance. The present survey was carried out to identify and describe the use of antimicrobials without prescription in riverside dwellers of the Brazilian Amazon Basin. Methods: A cross-sectional study was carried out from a conglomerate stratified sample in the rural municipality of Coari, Amazonas State, Brazil, between April and July 2016. The survey was conducted in the riverside dwellers’ homes, and information was collected on all antimicrobials taken with and without medical or dental prescription for a 30-day period, together with indications of their use before the interview. Results: A total of 492 riverside dwellers were included in the present survey; 346 (70.3%) had taken at least one medication during the previous month, and 74 (21.3% of those taking a medicine) used an antimicrobial. Two-thirds of the patients treated with an antimicrobial (49; 66.2%) obtained it without a prescription. Additionally, one-third of the antimicrobials consumed by the study sample (25) were used for non-infectious or non-bacterial conditions. Discussion: The present survey showed not only that inappropriate use of antimicrobials is present in remote places such as the Amazon Basin, but also that one-third of those antimicrobials were taken to treat non-infectious or non-bacterial conditions. In addition to an unnecessary risk of adverse effects to the exposed populations, the inappropriate use of antibiotics without prescription helps to increase antibiotic-resistant strains. In the present case, this was happening near one of Latin America’s most important water supplies, which could contribute to the global impact of antimicrobial resistance. [ABSTRACT FROM AUTHOR]

Turtle shell rattles are percussion instruments used by Indigenous peoples of the Americas in ceremonial contexts to keep rhythm. Archaeological investigations in the southeastern United States produced several complete and partial Eastern box turtle (Terrapene carolina) shell rattles from mortuary contexts dating from the Archaic (ca. 8000–1000 BC) through Mississippian periods (ca. AD 800–1500). Fragmentary turtle remains, some identified as Eastern box turtle, are frequently recovered from non-mortuary contexts. Traditionally, these fragmentary remains are attributed to food waste. Given the archaeological and ethnographic evidence for turtle shell rattles, we need to consider how fragmentary remains might fit into the chaîne opératoire of rattle production. This paper presents the results of an experimental study designed to identify one such chaîne opératoire of rattle production. During this experiment, the data on taphonomic processes such as manufacturing marks, use-wear, and breakage patterns, were recorded. We then tested the taphonomic findings from the experimental study and an object trait list we compiled from known rattle specimens and documentary sources with archaeological turtle remains recovered from non-mortuary contexts at two Mississippian period (ca. AD 1000–1450) sites in Middle Tennessee. Historic indigenous groups are known to have, and still do into the present-day, make and use turtle shell rattles in the region. Ultimately, we determined that “food refuse” should not be the default interpretation of fragmentary box turtle remains, and instead the taphonomic history and contextual associations must be considered in full. The experimental process of crafting turtle shell rattles enhances our understanding of an ancient musical instrument and the success rate of identifying musical artifacts and distinguishing between other modified turtle remains in the archaeological record. This study expands our knowledge of ancient music in North America and prompts re-analysis of curated turtle remains in museums for rattle-related modifications. [ABSTRACT FROM AUTHOR]

Background: An understudied disease, little research thus far has explored responses to Buruli ulcer and quests for therapy from biosocial perspective, despite reports that people seek biomedical treatment too late. Methods and findings: Taking an inductive approach and drawing on long-term ethnographic fieldwork in 2013–14, this article presents perspectives on this affliction of people living and working along the River Nile in northwest Uganda. Little is known biomedically about its presence, yet ‘Buruli’, as it is known locally, was and is a significant affliction in this region. Establishing a biosocial history of ‘Buruli’, largely obscured from biomedical perspectives, offers explanations for contemporary understandings, perceptions and practices. Conclusions/Significance: We must move beyond over-simplifying and problematising ‘late presentation for treatment’ in public health, rather, develop biosocial approaches to understanding quests for therapy that take into account historical and contemporary contexts of health, healing and illness. Seeking to understand the context in which healthcare decisions are made, a biosocial approach enables greater depth and breadth of insight into the complexities of global and local public health priorities such as Buruli ulcer. [ABSTRACT FROM AUTHOR]

Knowledge about the population size and trends of common bird species is crucial for setting conservation priorities and management actions. Multi-species large-scale monitoring schemes have often provided such estimates relying on extrapolation of relative abundances in particular habitats to large-scale areas. Here we show an alternative to inference-rich predictive models, proposing methods to deal with caveats of population size estimations in habitat-specialist species, reed warblers (Acrocephalus scirpaceus and Acrocephalus arundinaceus). Reed warblers were only found in pure reedbeds within riparian woodlands or in riparian vegetation scattered within or around reedbed patches, as expected according to their habitat specialization. The proportion of individuals located in reedbed associated with lotic and lentic waters differed between species, and no reed warbler was recorded in reedbed located along dry streams. This indicates that microhabitat features or their effects on reedbed structure and other factors made a proportion of the apparently available habitat unsuitable for both warbler species. Most warblers detected were males performing territorial singing (females seldom sing and do not perform elaborate territorial song, and are undistinguishable from males by plumage). The regional population sizes of the warbler species (~4000 individuals of A. scirpaceus and ~ 1000 individuals of A. arundinaceus) were much smaller than those estimated for the same area by transforming relative abundance obtained at a national scale to population size through extrapolation by habitat at a regional scale. These results highlight the importance of considering the habitat actually used and its suitability, the manner of sex-related detection, population sex-ratio and their interactions in population estimates. Ideally, the value of predictive methods to estimate population size of common species should be tested before conducting large-scale monitoring, rather than a posteriori. Although logistically challenging, this can be achieved by designing monitoring programs including an intensive sampling of abundance in ad hoc reference areas of variable size. [ABSTRACT FROM AUTHOR]

Southwestern Amazonia is considered an early centre of plant domestication in the New World, but most of the evidence for this hypothesis comes from genetic data since systematic archaeological fieldwork in the area is recent. This paper provides first-hand archaeobotanical evidence of food production from early and middle Holocene (ca. 9,000–5000 cal. BP) deposits at Teotonio, an open-air site located on a 40 m-high bluff on the south bank of the Madeira river. Such evidence includes the presence of local and exotic domesticates such as manioc (Manihot esculenta), squash (Cucurbita sp.) and beans (Phaseolus sp.), alongside edible fruits such as pequiá (Caryocar sp.) and guava (Psidium sp.) that point to the beginnings of landscape domestication. The results contribute to an ever-growing number of studies that posit southwest Amazonia as an important centre for early crop domestication and experimentation, and which highlight the longue-durée of human impacts on tropical forest biodiversity around the world. [ABSTRACT FROM AUTHOR]

Background: Past studies have demonstrated an association between waterborne disease and heavy precipitation, and climate change is predicted to increase the frequency of these types of intense storm events in some parts of the United States. In this study, we examined the linkage between rainfall and sewage contamination of urban waterways and quantified the amount of sewage released from a major urban area under different hydrologic conditions to identify conditions that increase human risk of exposure to sewage.Methods and Findings: Rain events and low-flow periods were intensively sampled to quantify loads of sewage based on two genetic markers for human-associated indicator bacteria (human Bacteroides and Lachnospiraceae). Samples were collected at a Lake Michigan estuary and at three river locations immediately upstream. Concentrations of indicators were analyzed using quantitative polymerase chain reaction (qPCR), and loads were calculated from streamflow data collected at each location. Human-associated indicators were found during periods of low flow, and loads increased one to two orders of magnitude during rain events from stormwater discharges contaminated with sewage. Combined sewer overflow (CSO) events increased concentrations and loads of human-associated indicators an order of magnitude greater than heavy rainfall events without CSO influence. Human-associated indicator yields (load per km2 of land per day) were related to the degree of urbanization in each watershed. Contamination in surface waters were at levels above the acceptable risk for recreational use. Further, evidence of sewage exfiltration from pipes threatens drinking water distribution systems and source water. While this study clearly demonstrates widespread sewage contamination released from urban areas, a limitation of this study is understanding human exposure and illness rates, which are dependent on multiple factors, and gaps in our knowledge of the ultimate health outcomes.Conclusions: With the prediction of more intense rain events in certain regions due to climate change, sewer overflows and contamination from failing sewer infrastructure may increase, resulting in increases in waterborne pathogen burdens in waterways. These findings quantify hazards in exposure pathways from rain events and illustrate the additional stress that climate change may have on urban water systems. This information could be used to prioritize efforts to invest in failing sewer infrastructure and create appropriate goals to address the health concerns posed by sewage contamination from urban areas. [ABSTRACT FROM AUTHOR]

Waterbirds have a major functional role in wetlands, and understanding how functional traits of waterbirds depend on environmental characteristics can facilitate management of ecosystems and their services. We investigate how the waterbird community in a Neotropical river-floodplain system responds to environmental gradients, identifying how they affect waterbird species richness, functional diversity (measured as functional dispersion) and functional composition (specific functional traits). We sampled 22 lakes in the Upper Paraná floodplain system in southern Brazil, and modelled avian functional diversity and species richness as a function of environmental variables. Then we used a unified RLQ and fourth-corner analysis to evaluate environment-trait relationships. Waterbird species richness and functional diversity varied according to different environmental variables. Lake area and diversity of aquatic vegetation were associated with avian species richness, while relative abundance of grass and emergent macrophytes and mean and variation of depth were related to functional diversity. Furthermore, changes in functional diversity seemed to be mainly driven by presence of species that depend on perches for foraging (e.g. kingfishers, cormorants, and kites), whose presence was mainly associated with deep water and emergent macrophytes. Nevertheless, changes in functional diversity and functional composition did not depend on exactly the same set of environmental variables, suggesting that trait combinations (e.g. below surface feeders who feed on fish), not only specific traits, are important drivers of the variation in functional diversity between lakes. Given the observed differences in responses of species richness and functional diversity, both these diversity metrics should be used as complementary tools in ecosystem management. Furthermore, our results show that functional diversity and composition are partially coupled, suggesting that although functional diversity is influenced by the environmental filtering of particular traits, it also reflects other ecological mechanisms (e.g. competitive interactions among species). [ABSTRACT FROM AUTHOR]

Background: Geological evolution of the African continent has been subject to complex processes including uplift, volcanism, desert formation and tectonic rifting. This complex geology has created substantial biogeographical barriers, and coupled with anthropogenic introductions of freshwater fishes, has influenced the genetic diversity, connectivity and sub-structuring of the teleost fauna. Nile perch, Lates niloticus, is an iconic fish in Africa and is of high commercial importance, both in the species’ native range and where it has been translocated. However, the species is in decline and there is a need to understand its population genetic structure to facilitate sustainable management of the fishery and aquaculture development. Methodology: Nile perch tissue samples were acquired from two West and four East (Lakes; Albert, Kyoga, Victoria and Turkana) African locations. Nineteen polymorphic microsatellite loci were used to study the genetic variation among populations across regions (West and East Africa), as well as between native and introduced environments within East Africa. Principal findings and their significance: Results revealed strong and significant genetic structuring among populations across the sampled distribution (divergence across regions, FCT = 0.26, P = 0.000). STRUCTURE analysis at a broad scale revealed K = 2 clusters, the West African individuals were assigned to one cluster, while all individuals from the East African region, regardless of whether native or introduced, were assigned to another cluster. The distinct genetic clusters identified in the current study between the West and East African Nile perch, appear to have been maintained by presence of biogeographic barriers and restricted gene flow between the two regions. Therefore, any translocations of Nile perch should be carefully considered across the regions of West and East Africa. Further analysis at a regional scale revealed further structuring of up to K = 3 genetic clusters in East African Nile perch. Significantly (P < 0.05) lower genetic diversity based on analysis of allelic richness (AR) was obtained for the two translocated populations of Lake Kyoga (AR = 3.61) and Lake Victoria (AR = 3.52), compared to Nile perch populations from their putative origins of Lakes Albert (AR = 4.12) and Turkana (AR = 4.43). The lower genetic diversity in the translocated populations may be an indication of previous bottlenecks and may also indicate a difficulty for these populations to persist and adapt to climatic changes and anthropogenic pressures that are currently present in the East African region. [ABSTRACT FROM AUTHOR]

Climate change projections show that temperature and precipitation increases can alter the exchange of greenhouse gases between the atmosphere and high latitude landscapes, including their freshwaters. Dissolved organic carbon (DOC) plays an important role in greenhouse gas emissions, but the impact of catchment productivity on DOC release to subarctic waters remains poorly known, especially at regional scales. We test the hypothesis that increased terrestrial productivity, as indicated by the normalized difference vegetation index (NDVI), generates higher stream DOC concentrations in the Stordalen catchment in subarctic Sweden. Furthermore, we aimed to determine the degree to which other generic catchment properties (elevation, slope) explain DOC concentration, and whether or not land cover variables representing the local vegetation type (e.g., mire, forest) need to be included to obtain adequate predictive models for DOC delivered into rivers. We show that the land cover type, especially the proportion of mire, played a dominant role in the catchment’s release of DOC, while NDVI, slope, and elevation were supporting predictor variables. The NDVI as a single predictor showed weak and inconsistent relationships to DOC concentrations in recipient waters, yet NDVI was a significant positive regulator of DOC in multiple regression models that included land cover variables. Our study illustrates that vegetation type exerts primary control in DOC regulation in Stordalen, while productivity (NDVI) is of secondary importance. Thus, predictive multiple linear regression models for DOC can be utilized combining these different types of explanatory variables. [ABSTRACT FROM AUTHOR]

The southern region of Brazil is characterized by high species diversity and endemism of freshwater fishes distributed across geographically isolated river basins. Microglanis cottoides has a widespread range across these river basins and occurs in sympatry with other endemic species of the genus (e.g. M. cibelae, M. eurystoma, and M. malabarbai). Herein we tested the monophyly of M. cottoides and presented for the first time information about the molecular phylogeny of species in the genus. The results suggest that M. cottoides currently forms a non-monophyletic group which includes populations endemic to the Uruguay River basin that are more closely related to M. malabarbai, and excludes M. cibelae, found to be nested within M. cottoides. Based on an integrative approach using morphological and molecular data, we propose M. cibelae as a junior synonym of M. cottoides, and the populations of the Uruguay River basin previously assigned to M. cottoides in fact belong to M. malabarbai. Our molecular phylogeny shows that M. cottoides is sister to M. parahybae, which is also a coastal species, and M. malabarbai is sister of M. garavelloi, both endemic to inland river basins. The time-calibrated phylogeny indicates that the separation between inland and the coastal clades occurred in the Tertiary period, and that the species within the coastal basins diverged in the Pliocene, which overlaps with the diversification times estimated for the two inland species as well. This pattern of diversification corroborates some previous studies with other fishes from the same region. [ABSTRACT FROM AUTHOR]

Describing the physical habitat diversity of stream types is important for understanding stream ecosystem complexity, but also prioritizing management of stream ecosystems, especially those that are rare. We developed a stream classification system of six physical habitat layers (size, gradient, hydrology, temperature, valley confinement, and substrate) for approximately 1 million stream reaches within the Eastern United States in order to conduct an inventory of different types of streams and examine stream diversity. Additionally, we compare stream diversity to patterns of anthropogenic disturbances to evaluate associations between stream types and human disturbances, but also to prioritize rare stream types that may lack natural representation in the landscape. Based on combinations of different layers, we estimate there are anywhere from 1,521 to 5,577 different physical types of stream reaches within the Eastern US. By accounting for uncertainty in class membership, these estimates could range from 1,434 to 6,856 stream types. However, 95% of total stream distance is represented by only 30% of the total stream habitat types, which suggests that most stream types are rare. Unfortunately, as much as one third of stream physical diversity within the region has been compromised by anthropogenic disturbances. To provide an example of the stream classification’s utility in management of these ecosystems, we isolated 5% of stream length in the entire region that represented 87% of the total physical diversity of streams to prioritize streams for conservation protection, restoration, and biological monitoring. We suggest that our stream classification framework could be important for exploring the diversity of stream ecosystems and is flexible in that it can be combined with other stream classification frameworks developed at higher resolutions (meso- and micro-habitat scales). Additionally, the exploration of physical diversity helps to estimate the rarity and patchiness of riverscapes over large region and assist in conservation and management. [ABSTRACT FROM AUTHOR]

The increase in human population and domestic pets, such as cats, are generating important consequences in terms of habitat loss and pathogen pollution of coastal ecosystems with potential to generate negative impacts in marine biodiversity. Toxoplasma gondii is the etiological agent of zoonotic disease toxoplasmosis, and is associated with cat abundance and anthropogenic disturbance. The presence of T. gondii oocysts in the ocean has negatively affected the health status of the threatened Southern sea otter (Enhydra lutris nereis) populations. The present study analyzed seroprevalence and presence of T. gondii DNA in American mink (Neovison vison), Southern river otters (Lontra provocax) and domestic cats (Felis silvestris catus) in four different areas in Southern Chile comprising studies in rivers and lakes in Andean foothills and mountains, marine habitat and island coastal ecosystems. Mean seroprevalence of T. gondii in the study was 64% of 151 total animals sampled: 59% of 73 American mink, 77% of 13 Southern river otters, 68% of 65 domestic cats and in two of two kodkods (Leopardus guigna). Toxoplasma gondii DNA was detected in tissues from one American mink and one Southern river otter. The present study confirms the widespread distribution of T. gondii in Southern Chile, and shows a high exposure of semiaquatic mustelids and domestic cats to the parasite. Cats and anthropogenic disturbance have a role in the maintenance of T. gondii infection in ecosystems of southern Chile. [ABSTRACT FROM AUTHOR]