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Historic land degradation is an ongoing threat to the Sky Islands of southern Arizona, US, and northern Sonora, Mexico, an area designated as a globally significant biodiversity hotspot. Land degradation has reduced ecosystem services provisioning, released carbon from disturbed soils into the atmosphere, and significantly diminished resilience to climate change. Private land managers in the region have developed methods to reverse degradation and restore biodiversity and ecosystem function. Land managers have used rock detention structures (RDS), technology adapted from traditional Indigenous practices in the region, as a tool for reversing desertification and watershed degradation. The structures were installed primarily for erosion control and water management, but they have had positive impacts on multiple biophysical systems. In this study, we analyze watershed-scale installation of RDS as a nature-based solution for climate change mitigation and adaptation. Case studies include four properties that offer examples of structures that have been in place over a period ranging from 1 to 40 years. We reviewed journal articles and other studies conducted at the four sites, supplemented with interviews, to catalogue the nature-based solutions provided by RDS. This study documents positive impacts on overall stream flow, reduction in peak runoff during inundation events, and increased sedimentation, which increase resilience to drought, erosion, and flooding. Data suggest potential impacts for climate change mitigation, though further research is needed. In addition, results suggest that watershed restoration with RDS offers a host of co-benefits, including an increase in biodiversity and wildlife abundance, an increase in vegetative cover, and increased surface water provisioning over time to support the land-based livelihoods of downstream neighbors. In the discussion, we consider barriers to replication and scalability using the strategy of the UN Decade on Ecosystem Restoration as a guiding framework, discussing issues of awareness, legislation and policy, technical capacity, finance, and gaps in knowledge.

The conservation of threatened elasmobranchs in tropical regions is challenging due to high local reliance on aquatic and marine resources. Due primarily to fishing pressure, river sharks (Glyphis) and sawfishes (Pristidae) have experienced large population declines in the Indo-Pacific. Papua New Guinea (PNG) may offer a refuge for these species, as human population density is low, and river shark and sawfish populations are thought to persist. However, few data are available on these species in PNG, and risk posed by small-scale fishers is poorly understood. This study observed elasmobranch catches in small-scale fisheries in riverine and coastal environments in the East Sepik (northern region), Gulf, and Western Provinces (southern region) of PNG. Surveys were conducted over a period of weeks to months in each region, during the dry season across seven field trips from 2017 to 2020. We observed a total of 783 elasmobranchs encompassing 38 species from 10 families. River sharks made up 29.4% of observations in the southern region, while sawfishes made up 14.8 and 20.3% in the northern and southern regions, respectively. River sharks were commonly caught by small-scale fishers in lower riverine environments in southern PNG, while sawfishes were generally less common and mainly observed through dried rostra. The primary threat to river shark and sawfish populations is their capture by small-scale fishers targeting teleosts for swim bladder. Persisting populations of river sharks and sawfishes indicate that PNG is the second known nation with viable populations of multiple species in the Indo-Pacific. However, populations are declining or at high risk of decline, and fisheries management and conservation are required to realize the potential of PNG as a long-term refuge.

The species composition of a community is driven by the dispersal capacity of the species forming that community and their ecological niche. While the ecological niches of EPTs (Ephemeroptera, Plecoptera and Trichoptera) are well-studied due to their wide use as indicators for the ecological status of freshwater ecosystems, their dispersal capacity has not yet been accurately characterized. Dispersion of the merolimnic EPT species during the terrestrial aerial adult stage is of special importance because the distance dispersed by active flight or passive wind drift is usually much larger compared to dispersion during the aquatic larval stage by active crawling or by drifting downstream.The aerial dispersal distance has been directly measured for only a small number of EPT species. For most other species, the dispersal capacity is assessed indirectly using species’ traits that are mainly based on expert judgement and dispersal indices derived from trait information. In this study, we compiled a database of European EPTs’ aerial dispersal distances reported in empirical studies and compared them to the dispersal capacity of the species as described by five different dispersal indices (original and modified versions of Li’s Dispersal Capacity Metric DCM and Sarremejane’s Species Flying Propensity SFP as well as relative wing length).The database included empirical data on 180 species, comprising 9.3% of European EPT species. Most data came from trap experiments with traps located at different distances from the assumed emergence point. Since the distance classes differed between studies and had to be translated to a fixed set of four distance classes here, several species had to be assigned to more than one class. To account for this uncertainty, five ordered logistic regression models, each one with a dispersal index as predictor and the ordinal-scaled aerial dispersal distance as response, were bootstrapped 10,000 times. In each run, species belonging to several distance classes were randomly assigned to a single class out of all possible classes. Since wing length had no significant effect on aerial dispersal distance in any of the 10,000 bootstrap runs, we question the use of this anatomical trait as an indicator for the aerial dispersal capacity. In contrast, a modified version of the DCM index was consistently related to the aerial dispersal distances (96%). The original SFP index had a significant effect in 100% of the model runs, indicating that this index is very well-suited as an indicator for the aerial dispersal capacity of European EPT species.This study facilitates the assessment of European EPT flying distances by providing a compilation of empirical data on the topic and by recommending an accurate indirect method when empirical data is not available.

To investigate the composition variation of planktonic fungal communities, and their relationship with water physical and chemical parameters in the Xijiang River in China, the compositions of planktonic fungal communities in the high-water and low-water period of the Xijiang River were studied in this paper by high-throughput sequencing of fungal internal transcribed spacer amplicons. Ascomycota, Basidiomycota, Chytridiomycota, Glomeromycota, Rozellomycota, and Zygomycota were detected from the planktonic fungal communities. However, most high-quality sequences (59.58 ± 0.03%) could not accurately identify fungal phyla. Alpha-diversity indexes of the fungal communities and the relative abundances of Phoma brasiliensis, Pseudozyma sp., Psathyrella sp., Haematonectria haematococca, Podoscypha sp. in the high-water period were significantly higher than those in the low-water period, while the relative abundances of Basidiobolus sp., Rhizophydium littoreum, Teratosphaeria jonkershoekensis, Malassezia globosa, Malassezia restricta, Malassezia sp., Alternaria eichhorniae, Knufia epidermidis, and Scedosporium prolificans were significantly lower. No significant correlation has been found between the fungal community distance and geographical distance along the river. Water temperature and dissolved oxygen significantly influenced the fungal community structure in the high-water period. These results provide information for us to understand the composition and influencing factors of the planktonic fungal community in rivers. [ABSTRACT FROM AUTHOR]

Rivers are a key site of human-nonhuman connection in the work of Kathleen Dean Moore and Rebecca Solnit. Reading this connection against the backdrop of the current climate crisis, this article considers how both writers offer ways of interacting with and thinking about changing landscapes that counter what Timothy Morton calls the 'information dump' of climate communication. I argue that by privileging conflicting emotions and uncertainty instead, Moore and Solnit use rivers and riverine forms to advocate for alternative, meaningful relationships to and understandings of shifting environments. With a dual focus on the physical and metaphorical resonances of rivers, this article unpacks the ways rivers might figure in our understanding of climate change, and what it might mean to read about rivers in this context. Ultimately, I suggest that Moore and Solnit's works demonstrate encounters with joy and despair that not only characterise of twenty-first century relationships to the nonhuman, but are in fact vital to combatting ecological damage. [ABSTRACT FROM AUTHOR]

Antibiotics released into the environment through anthropogenic activities exert selective pressure, driving bacteria towards increasing antimicrobial resistance. The prevalence of antibiotics and the ecological risks posed in the riverine estuarine of Larut River and Sangga Besar River, which included wastewater effluents from hospital, zoo, and poultry slaughterhouse sources were investigated. Solid phase extraction (SPE) followed by high-performance liquid chromatography tandem mass chromatography (HPLC-MS/MS) were used to extract and quantify the antibiotic residues from 22 antibiotics belonging to six major antibiotic classes (sulfonamide, macrolide, fluoroquinolone, phenicol, trimethoprim, and tetracycline). Sixteen antibiotic residues were detected with concentrations ranging from limit of detection (LOD) to 1 262.3 ng/L. Fluoroquinolones and macrolides were the most frequently detected compounds. Erythromycin, clarithromycin, and ofloxacin detected in hospital and zoo effluents posed a high risk to algae while tetracycline had low to medium ecological risks toward all the relevant organisms from aquatic environments (algae, invertebrate Daphnia magna, and fish). [ABSTRACT FROM AUTHOR]

In 2015, professional diver and amateur archaeologist A. Matiukas discovered an extraordinarily rich and well-preserved underwater multiperiod archaeological site, Kaltanėnai, at the point where the Žeimenys Lake feeds into the Žeimena River in East Lithuania. Over the duration of 3 years of multiple diving expeditions, he collected ca. 800 archaeological finds made of wood, bone, antler, flint, stone, iron and glass. Moreover, in eroded places of the river bed, he observed numerous wooden piles of potential constructions. These initial finds attested the newly discovered site’s great scientific value and potential, and therefore a scientific investigation of the site was initiated. This paper presents the first results of underwater survey at this site and analyses of its various finds. These include the site’s plan with a mapping of stationary fishing gear, a geological profile made from boreholes, 23 14C dates of various artefacts and wooden constructions, wood and animal taxa determinations including ZooMS, and traceological analysis of osseous tools. Our research demonstrates that the site was intensively used for fishing via various methods starting from the Late Mesolithic to the modern era, while most of the finds date to the Subneolithic and the Bronze Age. Further research at the site, including underwater excavations of stratified archaeological layers, will shed even more light onto the history of inland fishing in the East Baltic. [ABSTRACT FROM AUTHOR]

A faunistic survey was made to assess the tiger beetle fauna from the Chakrashila Wildlife Sanctuary and adjacent rivers for the first time from the western part of Assam, India. A total of 15 species of tiger beetles (subfamily Cicindelinae) belonging to seven genera were recorded from forest, moist and dry riverine ecosystem using an occasional night trap. Eight species belonging to five genera were recorded from the riverine ecosystem. Two species, viz., Cylindera spinolae and Calochroa assamensis, were strictly restricted to the forest and Cosmodela virgula was recorded from both forest and riverine areas. Cylindera (Eugrapha) minuta, Calochroa flavomaculata, and Lophyra (Spilodia) vittigera were collected using a night trap from the forest area. The study revealed that habitat degradation due to human interference is the major threat to the tiger beetles in the study area. [ABSTRACT FROM AUTHOR]

Lateral transport of organic carbon (OC) to the coastal ocean is an important component of the global carbon cycle because rivers transport, mineralize, and bury significant amounts of OC. Glaciers drive water and sediment export from many high‐elevation and high‐latitude ecosystems, yet their role in watershed OC balances is poorly understood, particularly with regard to particulate OC. Here, we evaluate seasonal water, sediment, and comprehensive OC budgets, including both dissolved and particulate forms, for three watersheds in southeast Alaska that vary in glacier coverage. We show that glacier loss will shift the dominant size fraction of riverine OC from particulate toward dissolved and potentially alter the provenance of particulate OC. Glacier coverage also controls whether OC export is source (C stock) or transport (runoff) limited at the watershed scale. These findings provide insight into the future trajectory of riverine OC export in glacierized regions. Plain Language Summary: Rivers transport large quantities of organic carbon from the land to the ocean; however, the role that glaciers play in this process is not well understood. We measured organic carbon leaving three watersheds in coastal Alaska that vary in their relative amount of glacier cover to understand how glacier shrinkage will impact the amount and type of organic carbon in rivers. We found that changes in glacier coverage will increase transport of dissolved organic carbon in rivers and decrease transport of particulate organic carbon. Sources of particulate organic carbon in rivers may also change as glaciers shrink. In watersheds, glaciers also appear to influence whether transport of OC in rivers is controlled by the availability of carbon in the watershed versus the availability of water to move that carbon. These findings provide insight into how the loss of glaciers will change the transport of organic carbon in rivers. Key Points: Heavily glacierized watersheds can have high organic carbon yields driven largely by elevated levels of particulate organic carbon exportWatershed glacier coverage influences the importance of C availability and hydrological transport for controlling watershed OC balancesGlacier shrinkage will increase riverine DOC:POC yield ratios and likely alter the balance of petrogenic and biogenic POC in rivers [ABSTRACT FROM AUTHOR]

The parasite Chonopeltis australis Boxshall, 1976 has been recorded from tributaries of the Orange-Vaal River System. It is host-specific, preferring the cyprinids Labeo capensis (Smith, 1841) and Labeo umbratus (Smith, 1841). Sampling was conducted between spring 2016 and autumn 2019 at various sites on the main stream of the Vaal River. The current study considers current ecological data and compares these to historic data. The species produces a single cohort, with overwintering eggs and adults. The infection of L. capensis peaks in autumn. Parasites aggregate on larger hosts that occur in riverine habitats, but can succeed in shallow impoundments with suitable hard surfaces for egg deposition. This parasite exploits changes in ecological conditions and host biology in order to survive, but will only choose between these two host species where they aggregate on larger hosts. The increased pollution in the Vaal River Barrage and downstream has had an impact on the occurrence of C. australis and it is possibly extirpated in polluted parts of the river. [ABSTRACT FROM AUTHOR]

Understanding how past communities have been shaped by environmental alterations can provide insight into the impacts of future climate change. Local climate and river systems have changed significantly over the last glacial maximum, but little is known about the communities of the Georgian Coastal Plain earlier in the period. Plant fossils from Coffee Bluff, a Quaternary organic river deposit of the Ocmulgee River in southeastern Georgia, were used to determine past environmental and climatic conditions. The paleoflora were found imbedded in a mud matrix and were removed by a slaking method; they were later identified and separated to respective ecological environments. Of the eleven species identified, one was a wetland species (marsh sedges), while the remaining ten were woodland species. From using the coexistence approach with the plant fossils and aligning their growing conditions, we suggest that Coffee Bluff was a stream/riverine habitat with loamy and well-drained soils; local climate was humid, with temperatures and annual precipitation ranging from 10 to 210C and 1016 to 1524 mm, respectively. Few gymnosperm specimens were recovered in the material, though groups like conifers were dominant in the coastal plain environment during the late Pleistocene. It is most likely that there were fewer conifer trees near the collection area. [ABSTRACT FROM AUTHOR]

Present study was conducted to assess the haematological profile of Channa marulius from hatchery and riverine populations. Blood samples were collected by caudal vein puncture. Significantly higher values (p ≤ 0.05) were recorded for various blood indices in hatchery populations as compared to those of riverine sources. Observed values of haematological parameters in hatchery populations were: Erythrocytes 4.90×106 cells µL-1, eosinophils 4.06 %, monocytes 5.53 %, haematocrit count 28.86 %, haemoglobin content 5.385 gdL-1, platelet distribution width 6.91 fL, red blood cell distribution width 23.83 fL, Procalcitonin 2.37 µL, mean corpuscular volume 7.87 fL and large platelet concentration ratio 14.64 %. In riverine populations, significantly higher values (p ≤ 0.05) for leucocytes count 5625×103 µL-1, mean cell haemoglobin 32.75 pg, mean corpuscular haemoglobin concentration 43.66 gdL-1 and mean cell volume 171.90 fL were observed as compared to those of hatchery populations. Conversely, non-significant (p ≥ 0.05) differences were observed with elevated values for neutrophils (14.042 %) in riverine fish populations as compared hatchery samples (13.896 %). Lymphocytes and platelets counts were 17.344 % and 33.742×103 µL-1, respectively in hatchery populations whereas in riverine populations these were 13.764 % and 33.896×103 µL-1, respectively. Physico-chemical parameters of sample water were observed to be in safe range throughout the study period. The observed variation in haematological profile between both groups is due to different inhabiting conditions that exert direct impacts on fish haematology. [ABSTRACT FROM AUTHOR]

Abstract Background This study aims to assess the role that Pleistocene refugia, rivers and local habitat conditions may have played in the evolutionary diversification of three central African duiker species (Cephalophus dorsalis, C. callipygus and Philantomba monticola). Genetic data from geo-referenced feces were collected from a wide range of sites across Central Africa. Historical patterns of population genetic structure were assessed using a ~ 650 bp fragment of the mitochondrial control region and contemporary patterns of genetic differentiation were evaluated using 12 polymorphic microsatellite loci. Results Mitochondrial analyses revealed that populations of C. callipygus and P. monticola in the Gulf of Guinea refugium are distinct from other populations in west central Africa. All three species exhibit signatures of past population expansion across much of the study area consistent with a history of postglacial expansion. There was no strong evidence for a riverine barrier effect in any of the three species, suggesting that duikers can readily cross major rivers. Generalized dissimilarity models (GDM) showed that environmental variation explains most of the nuclear genetic differentiation in both C. callipygus and P. monticola. The forest-savanna transition across central Cameroon and the Plateaux Batéké region in southeastern Gabon show the highest environmentally-associated turnover in genetic variability. A pattern of genetic differentiation was also evident between the coast and forest interior that may reflect differences in precipitation and/or vegetation. Conclusions Findings from this study highlight the historical impact of Pleistocene fragmentation and current influence of environmental variation on genetic structure in duikers. Conservation efforts should therefore target areas that harbor as much environmentally-associated genetic variation as possible in order to maximize species’ capacity to adapt to environmental change.

Abstract Background Malaria causes the greatest public health burden in sub-Saharan Africa where high mortality occurs mainly in children under 5 years of age. Traditionally, malaria has been reported mainly in the lowlands endemic regions of western Kenya, while the highlands of the Rift Valley have been relatively free except for the sporadic epidemics in some areas. Baringo County is located in the Kenyan highlands. The county generally experiences seasonal transmission of malaria. A few hotspots which experience continuous malaria transmission in the county do however exist. The objective of this study was to assess malaria infection status and identify areas with continuous transmissions with a view to mapping out probable transmission hot spots useful in mounting focused interventions within the county. Methods Systematic sampling was employed to identify 1668 primary school pupils from fifteen primary schools located in 4 ecological zones (lowland, midland, highland and riverine) of three sub-counties of Baringo. Finger prick blood sampling was done every 4 months (during the dry season in February/March, after the long rains in June/July and short rains in November 2015). Malaria occurrence was tested using rapid diagnostic test kit (CareStart HRP-2 Pf). Microscopic examination was done on all RDT positive and 10% of negative cases. Results A total of 268 (16.1%), out of 1668 pupils tested positive for Plasmodium falciparum by RDT; 78% had a single episode, 16.8% had 2 episodes, 4.9% had 3 episodes and 0.4% had 4 episodes. The riverine zone had the highest malaria cases (23.2%) followed by lowlands (0.9%). No malaria cases were detected in the midland zone while highland zone recorded only few cases during the third follow up. Up to 10.7% of malaria cases were reported in the dry season, 2.9% during the long rains and 5.7% in short rains season. Conclusions Malaria infection was prevalent in Baringo County and was mainly restricted to the riverine zone where transmission is continuous throughout the year. High malaria prevalence occurred in the dry season compared to the wet season. Even though malaria transmission is relatively low compared to endemic regions of Kenya, there is a need for continued monitoring of transmission dynamics under changing climatic conditions as well as establishing expanded malaria control strategies especially within the riverine zone which would include an integrated mosquito control and chemotherapy for infected individuals.

Sclerolaena napiformis is an endangered chenopod with a disjunct distribution. Here, we report the complete genomes of two geographically isolated accessions. The two genomes, respectively, were 151,112 and 151,291 bp in length with a pair of inverted repeats (IRs) of 24,345 and 24,339 bp separated by a large single-copy region (LSC) of 83,893 and 84,113 bp and a small single-copy region (SSC) of 18,529 and 18,500 bp, and CG content 36.57% and 36.53%. In total, 130 genes were annotated, including 85 protein-coding genes. Phylogenetic analysis of up to 87 protein-coding genes from 22 plastomes placed the genome of S. napiformis as a sister taxon to the sub-family Salsoloidae within the family Amaranthaceae.

Introduction: Current research of fish locomotion is focused on creating better underwater vehicles and how environmental stress factors modify swimming. Objective: To study the relation of morphometric characteristics with burst swimming in six representative species of continental fishes from Costa Rica. Methods: We measured total length, standard length, height and area of the tail of 38 individuals from six species. We used a Kruskall-Wallis test and a Boxplot graphic to compare species; and a PCA test to identify body variables that influence swimming. A Non-Metric Dimensional Scaling (NMDS) test was done for species and position in the water column. Results: The fastest swimming corresponded to A. nigrofasciata (9,29cm/s), while S. salvini (1,65cm/s) was the slowest. Burst swimming speed is influenced by body size and tail type, and differed with position in the water column, being surface species the fastest. Conclusions: Morphological and ecological characteristics determine differences in burst swim.

Attention towards microplastic (MP) pollution in various environments is increasing, but relatively little attention has been given to the freshwater-riverine environment. As the biggest city in the eastern Indonesia region, Makassar can be a potential source of MP pollution to its riverine area. This study aimed to determine the spatial trends, seasonal variation, and characteristics of MPs in the water and sediment of Tallo River, as the main river in Makassar. Water samples were collected using a neuston net and sediment samples were collected using a sediment corer. The samples collected contained MPs with an abundance ranging from 0.74 ± 0.46 to 3.41 ± 0.13 item/m3 and 16.67 ± 20.82 to 150 ± 36.06 item/kg for water and sediment samples, respectively. The microplastic abundance in the Tallo River was higher in the dry season and tended to increase towards the lower river segment. Fragments (47.80–86.03%) and lines (12.50–47.80%) were the predominant shapes, while blue (19.49–46.15%) and transparent (14.29–38.14%) were the most dominant color. Polyethylene and polypropylene were the common MP polymers found in the Tallo river. Actions to prevent MP pollution in the Makassar riverine area are needed before MP pollution becomes more severe in the future.

Anthropogenic activities can cause serious negative effects on ecosystems. Despite the ecological significance of bacterial communities, the integrated biogeography of planktonic and sedimentary bacterial communities in response to anthropogenic activities is not adequately understood. Here, we examined environmental parameters and the composition of planktonic and sedimentary bacteria in the Yulin River, a tributary of Three Gorges Reservoir, in response to changes in land use and dam construction. The results revealed that human-induced land use changes enhanced the nutrient concentrations in surface water and dam construction reduced the content of carbon and nitrogen in immediately downstream sediments. Intensified human-dominated land use showed a slight impact on sedimentary bacterial communities but largely reduced the diversity of planktonic bacterial communities. Moreover, human-induced land use changes increased the abundance of genes associated with denitrification, nitrification, and anammox in planktonic bacterial communities by 19.04%, 32.40% and 30.45%, respectively. In dam construction regions, the diversity and nutrient-related metabolic activity of sedimentary bacterial communities immediately downstream of the dam were decreased, whereas these changes were not observed in planktonic bacterial communities. Additionally, bacterial community composition was significantly related to nutrient concentrations variability and followed a distance-decay pattern. Furthermore, environmental effects explained more of the variation in planktonic bacterial community composition as compared with spatial effects did, whereas, sedimentary bacterial communities were more closely related to spatial effects. Our results demonstrated the distinct responses of planktonic and sedimentary bacterial communities to anthropogenic activities, and offered new insight for understanding their potential ecological influence on rivers. Unlabelled Image • The impacts of anthropogenic activities on bacterial communities were studied. • Planktonic bacterial communities were sensitive to land use changes. • Construction of the dam reduced the diversity of sedimentary bacterial communities. • Planktonic bacterial communities were more associated with environmental effects. • Sedimentary bacterial communities were more closely related to spatial effects. [ABSTRACT FROM AUTHOR]

This paper reports the assessment of the ecological integrity of streams in Bregalnica River Basin with emphasis on river Bregalnica as the biggest and most important watercourse in Eastern Macedonia. The results have principally been derived from remote sensing data and set up in a model build up on Watershed Habitat Evaluation and Stream Integrity Protocol (WHEBIP). WHEBIP effectiveness in predicting ecological integrity of streams has been assessed by correlation analyses derived upon data on macroinvertebrate biotic indices and physico-chemical parameters on 35 localities throughout the basin. The statistical analyses confirmed the capacity of WHEBIP to predict stream site-specific features with great accuracy in the case of Bregalnica. The results obtained in this study contribute towards the improvement of the WHEBIP protocol and in general, promotes applicability of stream integrity assessment tools in setting priorities for integrated watershed management. [ABSTRACT FROM AUTHOR]

The patterns of zooplankton community structural attributes were evaluated with reference to water quality in Teluk Bahang Reservoir, Penang, Malaysia over an annual cycle (March 2014–March 2015) and spatial gradients. Four sampling stations located at the lacustrine (Stations 1, 2 and 3) and riverine (Station 4) zones of the reservoir were designated to gather data. Samples were collected vertically at 5 m, 10 m and 15 m depth. Zooplankton samples were collected by filtering forty litres of lake water using plankton net with 30 µm mesh size. A total of 28 taxa from three major groups of zooplankton (Rotifera, Cladocera and Copepoda) were recorded. Pearson's correlation showed that the abundance of zooplankton is directly correlated with most environmental variables including water transparency, temperature, dissolved oxygen, conductivity, total dissolved solids, pH, chlorophyll a, ammonium-nitrogen, nitrite-nitrogen and rainfall. In a similar vein, the Canonical Correspondence Analysis (CCA) also revealed that zooplankton abundances were influenced by the combined effects of water quality variables. This was further proven by the fact that the zooplankton diversity, when measured by Shannon-Weiner index, was low probably due to short water retention time and fluctuations in water levels. The results of this study indicated that the occurrence of zooplankton was characterised by the reservoir water conditions based on the value of species-environment correlations (0.66–0.84) in CCA analysis. [ABSTRACT FROM AUTHOR]

Observed degradation of aquatic systems at Big Stone National Wildlife Refuge, located in west-central Minnesota, have been associated with sediment-laden inflows from riverine systems. To support management, a study was conducted during 2013–2014 with overall goals of characterizing the aquatic invertebrate and vegetation communities of the Big Stone National Wildlife Refuge and exploring relations between these communities and various water-quality parameters. Sample sites were located along an observed vegetation gradient and assigned to three predetermined habitat zones for comparison purposes: upstream, transition, and downstream. Of the 12 species of aquatic vegetation that were identified, invasive narrowleaf cattail Typha angustifolia dominated the upstream zone (observed at >90% of sample locations), coontail Ceratophyllum demersum and narrowleaf cattail were most common in the transition zone (collected or observed at 100 and 83% of sample locations, respectively), and coontail and narrowleaf pondweed Potamogeton strictifolius were most common in the downstream zone (collected at 100 and 64% of sample locations, respectively). Measured values for the water-quality parameters varied among dates, reflecting the continually fluctuating nature of riverine systems. Based on general observations across sample dates, turbidity and dissolved oxygen concentrations were greatest in the upstream zone sample sites, while oxidation-reduction potential was greatest in the downstream zone sites. There were 115 unique aquatic invertebrate taxa identified to varying levels of taxonomic resolution. Results suggested that there were overall differences in invertebrate biomass among the sample dates, but that there were no strong trends among the sample zones. Aquatic invertebrates and vegetation communities, along with the water-quality parameters, varied temporally and showed irregular relations among the sample zones. These general observations emphasize the importance of temporally and spatially intensive sampling to account for natural variation. Moreover, short- and long-term streamflow and water-level information obtained for this study demonstrated substantial variability that must be considered when conducting biotic inventories and monitoring water quality, as well as when using such data to assess management options. Periodic monitoring of wetlands and associated streamflows, along with sediment loads and water quality of inflows, should allow Big Stone National Wildlife Refuge staff to identify habitat degradation and potential contributing factors, and to develop strategies to achieve specific management objectives and goals. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the physical habitat of spawning areas for Thynnicthys thynnoides (T. thynnoides) in the Rui River, Gerik, Perak. Five sampling sites of Rui River's foodplain were chosen. Sampling was conducted between May and October 2015 by using a visual-based habitat assessment developed for Rapid Bioassessment Protocols for Use in Streams and Wadeable Rivers: Periphyton, Benthic Macroinvertebrates and Fish. This study showed that T. thynnoides still migrated to the upper stream of Rui River during spawning season mainly in August. Habitat assessment scoring indicated that the physical habitat structure of Rui River fell into a suboptimal category, which was most likely able to support fsh populations and thus providing a suitable habitat for T. thynnoides during the spawning season. Conclusively, it was observed that the T. thynnoides population was dependent on environmental conditions. [ABSTRACT FROM AUTHOR]

Mercury is an element with potential risk to fish and those who consume it. Thus, this study aimed to determine the levels of total mercury (THg), carry out a health risk assessment related to the consumption of the freshwater stingrays Potamotrygon motoro , and determine the physical and chemical properties of the water where stingrays occur. Stingrays of the species P. motoro were obtained from the Amazon River, and samples of the animals' musculature were collected to determine THg levels. Risk assessment was conducted using pre-established formulas of estimated monthly intake (EMI), maximum monthly intake rate (IRmm), and hazard quotient (HQ). Three population scenarios were evaluated, considering both sexes and differences between rural and urban areas. There was no relationship between weight and THg concentration nor between total length and THg concentration. Higher EMI values were observed in rural children; for the IRmm, male children had the lowest consumption levels. For the hazard quotient, there was a similarity between the three age groups when comparing the male and female sexes. In addition, the representatives of the rural area always had lower values than the urban area. Freshwater stingrays, like other elasmobranchs, can be crucial animal species because they act as sentinels in studies that assess harmful chemicals like mercury.

Despite the many studies on Wolbachia in Coleoptera, data about the prevalence of this bacterium among ground and rove beetles are missing. This study describes Wolbachia distribution and diversity in predatory beetles co-habiting the same environment - submontane river channels. Three species of Paederini (Staphylinidae) and four Bembidiini (Carabidae) were collected from six river catchments of the Carpathians. Wolbachia was absent in three species: Paederidus rubrothoracicus (Goeze), Bembidion decorum (Zenker in Panzer), Bembidion modestum (F.) - but detected in four others. Paederus limnophilus Erichson and Paederidus ruficollis F. were infected at only some sites by different strains of supergroup A, Bembidion punctulatum Drapiez was infected at all sites by a single strain from supergroup B, and Bembidion varicolor F. was single or double infection by three strains from A and B supergroups. The patterns of infection prevalence and strain diversity were very complex and only in some cases support common Wolbachia infection and strain similarity among different species of predatory beetles sharing the same environment. Moreover, the similar genetic patterns observed in all examined beetles cannot be associated with the infection status of particular species (distinct mitochondrial and nuclear haplotypes fixed in distant populations; small diversity within populations). [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Circulating S100B protein was proposed as a biomarker of MeHg-related neurotoxicity. • We quantified blood mRNA as alternative to protein in isolated populations. • Approximately 20% of participants showed mercury levels above the recommended limit. • Rigorous exclusion criteria were aplied a posteriori to avoid confounding factors. • S100B mRNA in blood of exposed participants was over two times higher. Abstract Mercury is a heavy metal responsible for human intoxication worldwide and especially in the Amazon, where both natural and anthropogenic sources are responsible for exposure in riverine populations. Methylmercury is the most toxic specie of mercury with recognized neurotoxicity due to its affinity for the central nervous system. S100B protein is a well-established biomarker of brain damage and it was recently associated with mercury-related neurotoxicity. Accurate measurement is especially challenging in isolated/remote populations due to the difficulty of adequate sample conservation, therefore here we use S100B mRNA levels in blood as a way to assay mercury neurotoxicity. We hypothesized that individuals from chronically exposed populations showing mercury levels above the limit of 10 μg/g in hair would present increased levels of S100B mRNA, likely due to early brain damage. A total of 224 riverine individuals were evaluated for anthropometric data (age, body mass index), self-reported symptoms of mercury intoxication, c-reactive protein in blood, and mercury speciation in hair. Approximately 20% of participants showed mercury levels above the limit, and prevalence for most symptoms was not different between individuals exposed to high or low mercury levels. Rigorous exclusion criteria were applied to avoid confounding factors and S100B mRNA in blood was tested by RT-qPCR. Participants with ≥10 μg/g of mercury had S100B mRNA levels over two times higher than that of individuals with lower exposure. A significant correlation was also detected between mercury content in hair and S100B mRNA levels in blood, supporting the use of the latter as a possible candidate to predict mercury-induced neurotoxicity. This is the first report of an association between S100B mRNA and mercury exposure in humans. The combination of both exposure and intoxication biomarkers could provide additional support for the screening and early identification of high-risk individuals in isolated populations and subsequent referral to specialized centers. [ABSTRACT FROM AUTHOR]

Pakistan has experienced severe floods over the past decades due to climate variability. Among all the floods, the flood of 2010 was the worst in history. This study focuses on the assessment of (1) riverine flooding in the district Jhang (where Jhelum and Chenab rivers join, and the district was severely flood affected) and (2) south Asiatic summer monsoon rainfall patterns and anomalies considering the case of 2010 flood in Pakistan. The land use/cover change has been analyzed by using Landsat TM 30 m resolution satellite imageries for supervised classification, and three instances have been compared, i.e., pre-flooding, flooding, and post-flooding. The water flow accumulation, drainage density and pattern, and river catchment areas have been calculated by using Shutter Radar Topography Mission digital elevation model 90 m resolution. The standard deviation of south Asiatic summer monsoon rainfall patterns, anomalies and normal (1979-2008) has been calculated for July, August, and September by using rainfall data set of Era interim (0.75° × 0.75° resolution). El Niño Southern Oscillation has also been considered for its role in prevailing rainfall anomalies during the year 2010 over Upper Indus Basin region. Results show the considerable changing of land cover during the three instances in the Jhang district and water content in the rivers. Abnormal rainfall patterns over Upper Indus Basin region prevailed during summer monsoon months in the year 2010 and 2011. The El Niño (2009-2010) and its rapid phase transition to La Niña (2011-2012) may be the cause of severity and disturbances in rainfall patterns during the year 2010. The Geographical Information System techniques and model based simulated climate data sets have been used in this study which can be helpful in developing a monitoring tool for flood management. [ABSTRACT FROM AUTHOR]

Abstract: Increasing demand for benefits provided by riverine ecosystems threatens their sustainable provision. The ecosystem service concept is a promising avenue to inform riverine ecosystem management, but several challenges have prevented the application of this concept. We quantitatively assess the field of riverine ecosystem services’ progress in meeting these challenges. We highlight conceptual and methodological gaps, which have impeded integration of the ecosystem service concept into management. Across 89 relevant studies, 33 unique riverine ecosystem services were evaluated, for a total of 404 ecosystem service quantifications. Studies quantified between 1 and 23 ecosystem services, although the majority (55%) evaluated three or less. Among studies that quantified more than one service, 58% assessed interactions between services. Most studies (71%) did not include stakeholders in their quantification protocols, and 34% developed future scenarios of ecosystem service provision. Almost half (45%) conducted monetary valuation, using 16 methods. Only 9% did not quantify or discuss uncertainties associated with service quantification. The indicators and methods used to quantify the same type of ecosystem service varied. Only 3% of services used indicators of capacity, flow and demand in concert. Our results suggest indicators, data sources and methods for quantifying riverine ecosystem services should be more clearly defined and accurately represent the service they intend to quantify. Furthermore, more assessments of multiple services across diverse spatial extents and of riverine service interactions are needed, with better inclusion of stakeholders. Addressing these challenges will help riverine ecosystem service science inform river management. Synthesis and applications. The ecosystem service concept has great potential to inform riverine ecosystem management and decision‐making processes. However, this review of riverine ecosystem service quantification uncovers several remaining research gaps, impeding effective use of this tool to manage riverine ecosystems. We highlight these gaps and point to studies showcasing methods that can be used to address them. [ABSTRACT FROM AUTHOR]

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The Oryzias woworae species group, composed of O. asinua , O. wolasi , and O. woworae , is widely distributed in southeastern Sulawesi, an island in the Indo-Australian Archipelago. Deep-elongated body shape divergence is evident among these three species to the extent that it is used as a species-diagnostic character. These fishes inhabit a variety of habitats, ranging from upper streams to ponds, suggesting that the body shape divergence among the three species may reflect adaptation to local environments. First, our geometric morphometrics among eight local populations of this species group revealed that the three species cannot be separated by body shape and that riverine populations had more elongated bodies and longer caudal parts than lacustrine populations. Second, their phylogenetic relationships did not support the presence of three species; phylogenies using mitochondrial DNA and genomic data obtained from RNA-Seq revealed that the eight populations could not be sorted into three different clades representing three described species. Third, phylogenetic corrections of body shape variations and ancestral state reconstruction of body shapes demonstrated that body shape divergence between riverine and lacustrine populations persisted even if the phylogenies were considered and that body shape evolved rapidly irrespective of phylogeny. Sexual dimorphism in body shape was also evident, but the degree of dimorphism did not significantly differ between riverine and lacustrine populations after phylogenetic corrections, suggesting that sexual selection may not substantially contribute to geographical variations in body shape. Overall, these results indicate that the deep-elongated body shape divergence of the O. woworae species group evolved locally in response to habitat environments, such as water currents, and that a thorough taxonomic reexamination of the O. woworae species group may be necessary. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the influence of distance from surface water on riparian woodland communities in the Okavango Delta. Vegetation sampling was conducted in seven sites within the Okavango Delta in 20 m × 10 m belted plots placed perpendicular to the river bank. The plots were placed at 0-10 m, 10-20 m, 20-30 m, 30-40 m and 40-50 m distance classes increasing away from the river bank. Tree height, basal area, species richness, canopy cover and diversity were determined for each distance class. Indicator species analysis was used to determine the characteristic species at each distance class. Single-factor ANOVA and Tukey post hoc analysis were used to compare species diversity, mean tree height, cover and basal area between distance classes. Correlation between distance from surface water and vegetation parameters was sought using Spearman regression analysis. All parameters except for species richness varied significantly ( P < 0.05) along distance from surface water. Distance from surface water was positively correlated all vegetation parameters except for mean species richness/plot. These results show that distance from surface water influences riparian plant community composition and distribution in the Okavango Delta. This implies that riparian plant species can be indicators of long-term hydrologic conditions in the Delta. [ABSTRACT FROM AUTHOR]

Background: This study aims to assess the role that Pleistocene refugia, rivers and local habitat conditions may have played in the evolutionary diversification of three central African duiker species (Cephalophus dorsalis, C. callipygus and Philantomba monticola). Genetic data from geo-referenced feces were collected from a wide range of sites across Central Africa. Historical patterns of population genetic structure were assessed using a ~ 650 bp fragment of the mitochondrial control region and contemporary patterns of genetic differentiation were evaluated using 12 polymorphic microsatellite loci. Results: Mitochondrial analyses revealed that populations of C. callipygus and P. monticola in the Gulf of Guinea refugium are distinct from other populations in west central Africa. All three species exhibit signatures of past population expansion across much of the study area consistent with a history of postglacial expansion. There was no strong evidence for a riverine barrier effect in any of the three species, suggesting that duikers can readily cross major rivers. Generalized dissimilarity models (GDM) showed that environmental variation explains most of the nuclear genetic differentiation in both C. callipygus and P. monticola. The forest-savanna transition across central Cameroon and the Plateaux Batéké region in southeastern Gabon show the highest environmentally-associated turnover in genetic variability. A pattern of genetic differentiation was also evident between the coast and forest interior that may reflect differences in precipitation and/or vegetation. Conclusions: Findings from this study highlight the historical impact of Pleistocene fragmentation and current influence of environmental variation on genetic structure in duikers. Conservation efforts should therefore target areas that harbor as much environmentally-associated genetic variation as possible in order to maximize species' capacity to adapt to environmental change. [ABSTRACT FROM AUTHOR]

Hydrologic exchange plays a critical role in biogeochemical cycling within the hyporheic zone (the interface between river water and groundwater) of riverine ecosystems. Such exchange may set limits on the rates of microbial metabolism and impose deterministic selection on microbial communities that adapt to dynamically changing dissolved organic carbon (DOC) sources. This study examined the response of attached microbial communities (in situ colonized sand packs) from groundwater, hyporheic, and riverbed habitats within the Columbia River hyporheic corridor to "cross-feeding" with either groundwater, river water, or DOC-free artificial fluids. Our working hypothesis was that deterministic selection during in situ colonization would dictate the response to cross-feeding, with communities displaying maximal biomass and respiration when supplied with their native fluid source. In contrast to expectations, the major observation was that the riverbed colonized sand had much higher biomass and respiratory activity, as well as a distinct community structure, compared with those of the hyporheic and groundwater colonized sands. 16S rRNA gene amplicon sequencing revealed a much higher proportion of certain heterotrophic taxa as well as significant numbers of eukaryotic algal chloroplasts in the riverbed colonized sand. Significant quantities of DOC were released from riverbed sediment and colonized sand, and separate experiments showed that the released DOC stimulated respiration in the groundwater and piezometer colonized sand. These results suggest that the accumulation and degradation of labile particulate organic carbon (POC) within the riverbed are likely to release DOC, which may enter the hyporheic corridor during hydrologic exchange, thereby stimulating microbial activity and imposing deterministic selective pressure on the microbial community composition. IMPORTANCE The influence of river water-groundwater mixing on hyporheic zone microbial community structure and function is an important but poorly understood component of riverine biogeochemistry. This study employed an experimental approach to gain insight into how such mixing might be expected to influence the biomass, respiration, and composition of hyporheic zone microbial communities. Colonized sands from three different habitats (groundwater, river water, and hyporheic) were "cross-fed" with either groundwater, river water, or DOC-free artificial fluids. We expected that the colonization history would dictate the response to cross-feeding, with communities displaying maximal biomass and respiration when supplied with their native fluid source. By contrast, the major observation was that the riverbed communities had much higher biomass and respiration, as well as a distinct community structure compared with those of the hyporheic and groundwater colonized sands. These results highlight the importance of riverbed microbial metabolism in organic carbon processing in hyporheic corridors. [ABSTRACT FROM AUTHOR]

Riparian zones are the interface between aquatic and terrestrial systems along inland watercourses. They have a disproportionate ecological role in the landscape considering their narrow extent, which makes them a good example of small natural features (sensu Hunter, 2017-inthisissue). Characteristically, riparian zones increase species richness in the landscape and provide key services to society, such as soil fertility, water purification, and recreation. Despite the recognized importance of riparian zones for ecological, economic and social reasons, and the vast amount of scientific literature exploring measures for their conservation, current management is still failing at enabling a proper ecological functioning of these areas. The best practices for conservation of riparian zones have mostly focused on manipulating biotic and physical components (e.g. renaturalizing flow regimes, improving channel mobility, and controlling invasions of exotic ecosystem engineer species). However, these strategies face important technical, socio-economic, and legal constraints that require a more integrative approach for effective conservation. In this paper we summarize the main problems affecting riparian zones and their current management challenges. Following Hunter et al. (2017-inthisissue), we review novel approaches to conservation of riparian zones, complementary to manipulating processes that reflect contemporary management and policy. These include (1) investing in environmental education for both local people and technical staff, (2) guaranteeing qualitative and long term inventories and monitoring, (3) establishing legislation and solutions to protect riparian zones, (4) framing economic activities in riparian zones under sustainable management, and (5) planning restoration of riparian zones at multiple and hierarchical spatio-temporal scales. [ABSTRACT FROM AUTHOR]

Background: Malaria causes the greatest public health burden in sub-Saharan Africa where high mortality occurs mainly in children under 5 years of age. Traditionally, malaria has been reported mainly in the lowlands endemic regions of western Kenya, while the highlands of the Rift Valley have been relatively free except for the sporadic epidemics in some areas. Baringo County is located in the Kenyan highlands. The county generally experiences seasonal transmission of malaria. A few hotspots which experience continuous malaria transmission in the county do however exist. The objective of this study was to assess malaria infection status and identify areas with continuous transmissions with a view to mapping out probable transmission hot spots useful in mounting focused interventions within the county. Methods: Systematic sampling was employed to identify 1668 primary school pupils from fifteen primary schools located in 4 ecological zones (lowland, midland, highland and riverine) of three sub-counties of Baringo. Finger prick blood sampling was done every 4 months (during the dry season in February/March, after the long rains in June/July and short rains in November 2015). Malaria occurrence was tested using rapid diagnostic test kit (CareStart HRP-2 Pf). Microscopic examination was done on all RDT positive and 10% of negative cases. Results: A total of 268 (16.1%), out of 1668 pupils tested positive for Plasmodium falciparum by RDT; 78% had a single episode, 16.8% had 2 episodes, 4.9% had 3 episodes and 0.4% had 4 episodes. The riverine zone had the highest malaria cases (23.2%) followed by lowlands (0.9%). No malaria cases were detected in the midland zone while highland zone recorded only few cases during the third follow up. Up to 10.7% of malaria cases were reported in the dry season, 2.9% during the long rains and 5.7% in short rains season. Conclusions: Malaria infection was prevalent in Baringo County and was mainly restricted to the riverine zone where transmission is continuous throughout the year. High malaria prevalence occurred in the dry season compared to the wet season. Even though malaria transmission is relatively low compared to endemic regions of Kenya, there is a need for continued monitoring of transmission dynamics under changing climatic conditions as well as establishing expanded malaria control strategies especially within the riverine zone which would include an integrated mosquito control and chemotherapy for infected individuals. [ABSTRACT FROM AUTHOR]

Floodplain forest of the Upper Mississippi River provides habitat for an abundant and diverse breeding bird community. However, reed canary grass Phalaris arundinacea invasion is a serious threat to the future condition of this forest. Reed canary grass is a well-known aggressive invader of wetland systems in the northern tier states of the conterminous United States. Aided by altered flow regimes and nutrient inputs from agriculture, reed canary grass has formed dense stands in canopy gaps and forest edges, retarding tree regeneration. We sampled vegetation and breeding birds in Upper Mississippi River floodplain forest edge and interior areas to 1) measure reed canary grass cover and 2) evaluate whether the breeding bird assemblage responded to differences in reed canary grass cover. Reed canary grass was found far into forest interiors, and its cover was similar between interior and edge sites. Bird assemblages differed between areas with more or less reed canary grass cover (>53% cover breakpoint). Common yellowthroat Geothlypis trichas, black-capped chickadee Parus atricapillus, and rose-breasted grosbeak Pheucticus ludovicianus were more common and American redstart Setophaga ruticilla, great crested flycatcher Myiarchus crinitus, and Baltimore oriole Icterus galbula were less common in sites with more reed canary grass cover. Bird diversity and abundance were similar between sites with different reed canary grass cover. A stronger divergence in bird assemblages was associated with ground cover <15%, resulting from prolonged spring flooding. These sites hosted more prothonotary warbler Protonotaria citrea, but they had reduced bird abundance and diversity compared to other sites. Our results indicate that frequently flooded sites may be important for prothonotary warblers and that bird assemblages shift in response to reed canary grass invasion. [ABSTRACT FROM AUTHOR]

Two of the main mechanisms of bacterial resistance to sulfonamides in aquatic systems, spread of antibiotic resistance genes (ARG) among the microbial community and in-situ bacterial sulfonamide degradation, were studied in mesocosms experiments using water and cobble biofilms from upstream (pristine waters) and downstream (polluted waters) from the Llobregat river, NE Iberian Peninsula. Mesocosms were prepared at two different concentrations (5000 ng/L and 1000 ng/L) of sulfonamides antibiotics (sulfamethazine and sulfamethoxazole). Concentrations of ARG, nutrients, sulfonamides and their degradation products were measured during the time course of the experiments. Sulfonamides were efficiently degraded by the biofilms during the first four weeks of the experiment. The abundance of ARG in biofilms sharply decreased after addition of high concentrations of sulfonamides, but this was not observed in the mesocosms treated with low concentrations of sulfonamides. Sulfonamide degradation was faster in polluted waters and at high concentrations of sulfonamide (and lower ARG abundances), suggesting that both degradation and ARG are two complementary resistance strategies employed by the microbial community. This study shows that microbial degradation of antibiotics is an efficient resistance mechanism coupled with the presence of ARG, and suggests that in situ degradation prevails at high concentrations of antibiotics whereas physiological adaptation by ARG spread would be more important under relatively lower concentrations of antibiotics. [ABSTRACT FROM AUTHOR]

The Nanfei River is by many measures the most heavily polluted tributary to Lake Chaohu. In this study, the temporal occurrence and sources of four classes of persistent organic pollutants (POPs), including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs), in suspended particulate matter (SPM) from the river mouth were investigated monthly during 2014. Results show that concentrations of all four POPs in SPM were higher than those in the sediment of Lake Chaohu. PBDEs (26.7 ng g −1 dry weight (dw)) were originated mainly from commercial deca-BDE mixtures. PCB concentrations (1.336 ng g −1 dw) were lower than those of sediments in many other water bodies worldwide. PAHs (2597 ng g −1 dw) and OCPs (57.38 ng g −1 dw) were the most common POPs. PAHs mainly had high molecular weights and originated from pyrolytic sources, with a small proportion of petrogenic origin. The predominant OCPs were DDTs, heptachlorepoxides, dieldrin, hexachlorocyclohexanes, hexachlorobenzene, and chlordanes. Most OCPs originated from historical use, except lindane. Generally, of all the POPs studied, those of primary ecological concern should be acenaphthene, fluorene, DDTs, and chlordanes. Higher concentrations of POPs were detected during winter and spring than in summer and autumn, probably because of the high river flow during the rainy season. The high concentration of POPs in the riverine SPM and the fractionation of POPs in the water and SPM of the river should be a focal point in the future study of Lake Chaohu. [ABSTRACT FROM AUTHOR]

Since its launch in 2007, TerraSAR-X observations have been widely used in a broad range of scientific applications. Particularly in wetland research, TerraSAR-X’s shortwave X-band synthetic aperture radar (SAR) possesses unique capabilities, such as high spatial and temporal resolution, for delineating and characterizing the inherent spatially and temporally complex and heterogeneous structure of wetland ecosystems and their dynamics. As transitional areas, wetlands comprise characteristics of both terrestrial and aquatic features, forming a large diversity of wetland types. This study reviews all published articles incorporating TerraSAR-X information into wetland research to provide a comprehensive study of how this sensor has been used with regard to polarization, and the function of the data, time-series analyses, or the assessment of specific wetland ecosystem types. What is evident throughout this literature review is the synergistic fusion of multi-frequency and multi-polarization SAR sensors, sometimes optical sensors, in almost all investigated studies to attain improved wetland classification results. Due to the short revisiting time of the TerraSAR-X sensor, it is possible to compute dense SAR time-series, allowing for a more precise observation of the seasonality in dynamic wetland areas as demonstrated in many of the reviewed studies.