Search

Recent advances in soft materials and nano-microfabrication have enabled the development of flexible wearable electronics. At the same time, printing technologies have been demonstrated to be efficient and compatible with polymeric materials for manufacturing wearable electronics. However, wearable device manufacturing still counts on a costly, complex, multistep, and error-prone cleanroom process. Here, we present fully screen-printable, skin-conformal electrodes for low-cost and scalable manufacturing of wearable electronics. The screen printing of the polyimide (PI) layer enables facile, low-cost, scalable, high-throughput manufacturing. PI mixed with poly(ethylene glycol) exhibits a shear-thinning behavior, significantly improving the printability of PI. The premixed Ag/AgCl ink is then used for conductive layer printing. The serpentine pattern of the screen-printed electrode accommodates natural deformation under stretching (30%) and bending conditions (180°), which are verified by computational and experimental studies. Real-time wireless electrocardiogram monitoring is also successfully demonstrated using the printed electrodes with a flexible printed circuit. The algorithm developed in this study can calculate accurate heart rates, respiratory rates, and heart rate variability metrics for arrhythmia detection.

The hydrological variability of intermittent streams means that the spatial distribution of dry-season aquatic refuges within river networks and the temporal dynamics of hydrological connectivity between them are critical for the persistence of aquatic biodiversity. Here, a new approach is demonstrated to identify surface water bodies as priority refuges for efficient conservation management of freshwater biodiversity in intermittent stream networks. Recently developed models of surface water extent and daily streamflow were used to represent spatio-temporal variations in hydrological connectivity and surface water persistence within river networks of eastern Australia over a 107-yr period. Using this information, systematic conservation planning was applied to prioritize aquatic areas for conservation of 25 fish species under two scenarios. One scenario identified priority refuges to complement those already occurring in protected areas, whereas the other did not consider protected area status. The priority networks identified concentrated on the main stems of river catchments where surface water was more likely to be persistent and aquatic refuges were more likely to be connected, but also included headwaters for rare fish species. All three set conservation targets for the 25 fish species can be met in the best solution of priority networks. Although the second scenario achieved the targets with a smaller size of priority network overall, it required more new aquatic refuges and was thus less efficient than the first scenario. The newly developed datasets are useful for freshwater conservation prioritization because they account for hydrological variability of intermittent streams. The systematic prioritization approach applied is transferable to other regions and freshwater taxa to identify aquatic refuges for biodiversity conservation within intermittent stream systems.

Extracellular vesicles (EVs) are secreted lipid-enclosed particles that have emerged as potential biomarkers and therapeutic agents in lung disease, including bronchopulmonary dysplasia (BPD), a leading complication of preterm birth. Many unanswered questions remain about the content and cargo of EVs in premature infants and their role in lung development. To characterize EVs during human lung development, tracheal aspirates were collected from premature neonates between 22 and 35 wk gestational age and analyzed via nanoparticle tracking analysis, electron microscopy, and bead-based flow cytometry. EVs were detectable across late canalicular through saccular stages of lung development, demonstrating larger sizes earlier in gestation. EVs contained an abundance of the EV-enriched tetraspanins CD9, CD63, and CD81, as well as epithelial cell and immune cell markers. Increases in select surface proteins (CD24 and CD14) on EVs were associated with gestational age and with the risk of BPD. Finally, query of expression data obtained from epithelial cells in a single-cell atlas of murine lung development found that epithelial EV marker expression also changes with developmental time. Together, these data demonstrate an association between EV profile and lung development and provide a foundation for future functional classification of EVs, with the goal of determining their role in cell signaling during development and harnessing their potential as a new therapeutic target in BPD.

Intercellular communication is a critical process that ensures cooperation between distinct cell types and maintains homeostasis. EVs, which were initially described as cellular debris and devoid of biological function, are now recognized as key components in cell–cell communication. EVs are known to carry multiple factors derived from their cell of origin, including cytokines and chemokines, active enzymes, metabolites, nucleic acids, and surface molecules, that can alter the behavior of recipient cells. Since the cargo of EVs reflects their parental cells, EVs from damaged and dysfunctional tissue environments offer an abundance of information toward elucidating the molecular mechanisms of various diseases and pathological conditions. In this review, we discuss the most recent findings regarding the role of EVs in the progression of cancer, metabolic disorders, and inflammatory lung diseases given the high prevalence of these conditions worldwide and the important role that intercellular communication between immune, parenchymal, and stromal cells plays in the development of these pathological states. We also consider the clinical applications of EVs, including the possibilities for their use as novel therapeutics. While intercellular communication through extracellular vesicles (EVs) is key for physiological processes and tissue homeostasis, injury and stress result in altered communication patterns in the tissue microenvironment. When left unchecked, EV-mediated interactions between stromal, immune, and parenchymal cells lead to the development of disease states Video Abstract Supplementary Information The online version contains supplementary material available at 10.1186/s12964-021-00787-y.

Human activities have increasingly impacted rivers globally and influence environmental factors at multiple scales: proximal factors (e.g., light and nutrients) and distal controls (e.g., riparian cover and forest area in the basin) that affect benthic metabolism or algal assemblage structure. Function and structure have been studied separately and thus the linkage between them is not well understood. Furthermore, how much of the variability of benthic metabolism can be explained by changes in the environmental variables is inconclusive. We measured the structural and metabolism of epilithic algae in streams across gradients of catchment forest cover (3.5 to 88.6%) and riparian zone canopy cover (0 to 91.0%) in South East Queensland, Australia. Overall net daily metabolism (NDM) on cobbles was positive (gross primary production, GPP exceeded respiration, R) for all but three of the 34 sites. Chl a biomass of benthic algae on cobbles ranged from 1.37 to 178.05 mg m−2. Shaded streams had the highest percentage of diatoms (95.4%), while the least shaded streams were dominated by cyanobacteria (82.2%). Partial least squares (PLS) regression modeling showed that most of the variation in GPP, R, and NDM was explained by light intensity (photosynthetic photon flux density, PPFD), phosphorus concentration in water, water temperature, and the percentage of mid-dense forest upstream of the site. Path analysis (structural equation modeling, SEM) indicated that, as a surrogate for metabolism, diatom (Bacillariophyta) density was the best predictor of GPP and NDM when we assessed the environmental process in the streams. In comparison, Chl a, which has been traditionally used as a surrogate for measurements of GPP or NDM, performed well only when the percentage of diatoms in the epilithic algal community exceeded 75%. Our results also indicated that both the structure and function of benthic algal communities were sensitive to anthropogenic modifications, including riparian vegetation and forest cover in the catchment in river ecosystems.

Coastal wetlands are essential for regulating the global carbon budget through soil carbon sequestration and greenhouse gas (GHG – CO2, CH4, and N2O) fluxes. The conversion of coastal wetlands to agricultural land alters these fluxes' magnitude and direction (uptake/release). However, the extent and drivers of change of GHG fluxes are still unknown for many tropical regions. We measured soil GHG fluxes from three natural coastal wetlands – mangroves, salt marsh, and freshwater tidal forests – and two alternative agricultural land uses – sugarcane farming and pastures for cattle grazing (ponded and dry conditions). We assessed variations throughout different climatic conditions (dry–cool, dry–hot, and wet–hot) within 2 years of measurements (2018–2020) in tropical Australia. The wet pasture had by far the highest CH4 emissions with 1231±386 mgm-2d-1, which were 200-fold higher than any other site. Dry pastures and sugarcane were the highest emitters of N2O with 55±9 mgm-2d-1 (wet–hot period) and 11±3 mgm-2d-1 (hot-dry period, coinciding with fertilisation), respectively. Dry pastures were also the highest emitters of CO2 with 20±1 gm-2d-1 (wet–hot period). The three coastal wetlands measured had lower emissions, with salt marsh uptake of -0.55±0.23 and -1.19±0.08 gm-2d-1 of N2O and CO2, respectively, during the dry–hot period. During the sampled period, sugarcane and pastures had higher total cumulative soil GHG emissions (CH4+N2O) of 7142 and 56 124 CO2-eqkgha-1yr-1 compared to coastal wetlands with 144 to 884 CO2-eqkgha-1yr-1 (where CO2-eq is CO2 equivalent). Restoring unproductive sugarcane land or pastures (especially ponded ones) to coastal wetlands could provide significant GHG mitigation.

Interstitial lung disease (ILD) represents a significant cause of morbidity and mortality in systemic sclerosis (SSc). The purpose of this study was to examine recirculating lymphocytes from SSc patients for potential biomarkers of interstitial lung disease (ILD). Peripheral blood mononuclear cells (PBMCs) were isolated from patients with SSc and healthy controls enrolled in the Vanderbilt University Myositis and Scleroderma Treatment Initiative Center cohort between 9/2017–6/2019. Clinical phenotyping was performed by chart abstraction. Immunophenotyping was performed using both mass cytometry and fluorescence cytometry combined with t-distributed stochastic neighbor embedding analysis and traditional biaxial gating. This study included 34 patients with SSc-ILD, 14 patients without SSc-ILD, and 25 healthy controls. CD21lo/neg cells are significantly increased in SSc-ILD but not in SSc without ILD (15.4 ± 13.3% vs. 5.8 ± 0.9%, p = 0.002) or healthy controls (5.0 ± 0.5%, p lo/neg B cells can be identified from a single biaxial gate, tSNE analysis reveals that the biaxial gate is comprised of multiple distinct subsets, all of which are increased in SSc-ILD. CD21lo/neg cells in both healthy controls and SSc-ILD are predominantly tBET positive and do not have intracellular CD21. Immunohistochemistry staining demonstrated that CD21lo/neg B cells diffusely infiltrate the lung parenchyma of an SSc-ILD patient. Additional work is needed to validate this biomarker in larger cohorts and longitudinal studies and to understand the role of these cells in SSc-ILD.

Length–mass relationships for macroinvertebrates are used in many ecological studies; however, few length–mass relationships are available for Australian freshwater macroinvertebrates. In this study, we generated 22 new length–mass relationships from 2148 specimens spread across four orders, nine families, three subfamilies, 12 genera and two species. We also qualitatively compare our length–mass equations with others from Australia, New Zealand, North America and Europe.

With the introduction of the 5th generation of wireless systems and communications (5G) comes new risks and challenges. This paper explores the potential security challenges of 5G communication compared with legacy cellular networks and prior generations of communication standards. This paper defines what 5G is and how it affects our lives on a daily basis. It further discusses the new security features involving different technologies applied to 5G, such as heterogeneous networks, device-to-device communications, massive multiple-input multiple-output, software-defined networks, and the internet of things, including autonomous cars, healthcare, automated manufacturing, and more.

Anthropogenic changes to river flows can alter hydrological connectivity and cues necessary for the movement of fish to complete their life cycles. Quantifying flow-related movement ecology of fish and understanding how this varies between species and river systems is important for effective environmental flow management. This study aimed to determine hydroecological factors that influence fish movements in an unregulated, perennial river and to compare these findings to fish from regulated river systems. Broad-scale movements of the endangered Maccullochella ikei and Tandanus tandanus were recorded over 3 years in the unregulated, perennial Nymboida River, Australia. The limited movements both species exhibited were infrequent and over short distances. Although M. ikei movements appeared mostly unrelated to environmental changes, T. tandanus moved on flow pulse peaks and were more likely to move during the breeding season. These findings contrast with previous studies of the same or similar species in differing flow regimes, suggesting that fish in perennial, highly connected rivers may not need to move as frequently as those in more regulated or intermittent systems. Should these disparate behaviours be present in other species occurring among contrasting flow regimes, it will be challenging to define generalisable environmental flow rules to inform river management.

Hydrological connectivity in river systems facilitates the movement of animals, nutrients, and energy across riverine landscapes but is threatened by climate change and water resource developments. These anthropogenic disturbances are expected to alter connectivity patterns in wet-dry tropical river systems that are driven by a highly variable seasonal flow regime. We studied the composition and functional diversity of fish assemblages across a large wet-dry tropical river system in northern Australia that is under consideration for new agricultural and water resource developments. We explored changes in the environment, species turnover, and relationships between environmental characteristics and fish species composition, quantifying how they were influenced by hydrological connectivity, to identify species and habitats at risk of impacts of reduced connectivity. Characteristics of the aquatic environment were significantly different between low connectivity, high connectivity, and off-channel sites, and these environmental characteristics were associated with changes in fish community composition. Fish species turnover occurred across the catchment, with unique assemblages in headwater sites. High turnover between adjacent sites of low connectivity suggested that reduced movement opportunity creates localized populations, and these differences in species presence/absence are likely to be exacerbated by reduced connectivity from water resource developments. Species turnover was also related to functional diversity, which itself varied across connectivity levels. Habitat specialists and species with functional traits that depend on hydrological connectivity, such as diadromous species, are most at risk from anthropogenic change. Protection of the flow regime and environmental characteristics that support these species is important for maintaining biodiversity.

Floodplain wetlands are among the most productive and biodiverse ecosystems on Earth and provide a major subsidy of food resources for consumers in river systems. The basal energy source for those ...

Supporting the recovery of large carnivores is a popular yet challenging endeavour. Estuarine crocodiles in Australia are a large carnivore conservation success story, with the population having extensively recovered from past heavy exploitation. Here, we explored if dietary changes had accompanied this large population recovery by comparing the isotopes δ 13 C and δ 15 N in bones of crocodiles sampled 40 to 55 years ago (small population) with bones from contemporary individuals (large population). We found that δ 13 C and δ 15 N values were significantly lower in contemporary crocodiles than in the historical cohort, inferring a shift in prey preference away from marine and into terrestrial food webs. We propose that an increase in intraspecific competition within the recovering crocodile population, alongside an increased abundance of feral ungulates occupying the floodplains, may have resulted in the crocodile population shifting to feed predominantly upon terrestrial food sources. The number of feral pigs consumed to sustain and grow crocodile biomass may help suppress pig population growth and increase the flow of terrestrially derived nutrients into aquatic ecosystems. The study highlights the significance of prey availability in contributing to large carnivore population recovery.

We present the design, manufacturing and performance of the horn-switch system developed for the technological demonstrator of QUBIC (the $Q$\&$U$ Bolometric Interferometer for Cosmology). This system is constituted of 64 back-to-back dual-band (150\,GHz and 220\,GHz) corrugated feed-horns interspersed with mechanical switches used to select desired baselines during the instrument self-calibration. We manufactured the horns in aluminum platelets milled by photo-chemical etching and mechanically tightened with screws. The switches are based on steel blades that open and close the wave-guide between the back-to-back horns and are operated by miniaturized electromagnets. We also show the current development status of the feedhorn-switch system for the QUBIC full instrument, based on an array of 400 horn-switch assemblies., 30 pages, 28 figures. Accepted for submission to JCAP

Accurately accounting for flows of energy through food webs is challenging because of the spatial and temporal variability associated with energy production and consumption. Wet–dry tropical rivers have a highly seasonal discharge regime where wet season flows allow access to energy sources (inundated wetlands) that are not available during the dry season when aquatic consumers are confined to disconnected waterholes. We combined measures of fish community biomass with previously published feeding guild specific stable isotope analyses to explore how opposing wet- and dry-season habitat templates influence spatial and temporal trends in the sources of energy supporting fish biomass throughout a river network in the wet–dry tropics of northern Australia. Accounting for the relative contribution of each feeding guild to fish community biomass was a critical component of our analyses, as a single feeding guild (invertivore/piscivore) influenced spatial and temporal patterns in the sources of energy supporting overall fish biomass. During the early dry season, the reliance of fish communities on autochthonous sources of energy (periphyton) decreased from the upper to lower reaches of the river network, which correlates with increasing floodplain area and wet season inundation times. These patterns disappeared by the late dry season as fish in both upper and lower reaches became increasingly reliant on autochthonous sources produced within waterholes over the course of the dry season, indicating that the large wet-season gains in fish biomass are maintained through the dry season by energy produced within waterhole refuges. Collectively these results indicate that a combination of autochthonous and allochthonous sources of energy work in unison to support fish community biomass throughout the Mitchell River catchment and that access to these sources of energy is dictated by seasonal patterns in discharge interacting with spatial variability in river geomorphology (channel geometry and floodplain area). Many rivers are experiencing decreased flows due to water resource development and more frequent and severe droughts. Thus, we suggest our study provides insight into how changes in discharge regime could influence food web energetics throughout river networks.

It is often assumed that invertebrate consumers in small tropical streams are dependent on allochthonous sources, although recent studies indicate that algae can form the base of food webs in tropical streams. Fish in tropical streams can feed across several trophic levels and the origin and path of energy and nutrient flow is uncertain for many species. We collected fish, insects, periphyton, and leaf litter from 20 streams across four Atlantic Forest catchments. We analysed stomach contents of fish to define trophic guild and fish dietary trophic position. We also analysed stable isotopes of carbon and nitrogen of fish and their resources to identify the main basal resources of the food web and to estimate trophic positions and identify the path of energy flow. We found that autochthonous sources were the primary resource base for fish communities. Trophic positions estimated from diet and isotopes were similar and correlated for insectivore and algivore–insectivore fish, but not for algivore–detritivore or omnivore fish. Using path analysis, fish classified as algivore–detritivores appear to have derived their biomass through a diet of primary consumer insects and periphytic algae and thus, are more likely to play a trophic role as algivore–insectivores in these streams. However, omnivores probably derived much of their biomass from aquatic insects. Our findings support other studies of tropical systems in which the main basal resource is autochthonous, even in small streams. We also show that the assignment to a specific trophic guild for some fish species, based on gut contents, does not reflect what they assimilate into their bodies. In some species, food sources that are uncommon can make a disproportionately important contribution to their biomass. This study affirms the important role of inconspicuous algal resources in aquatic food webs, even in small forested streams, and demonstrates the effectiveness of taking a combined approach of diet analysis, isotopic tracing, and modelling to resolve food web pathways where the level of omnivory is high.

International audience; The Q & U Bolometric Interferometer for Cosmology (QUBIC) is a cosmology experiment that aims to measure the B-mode polarization of the cosmic microwave background (CMB). Measurements of the primordial B-mode pattern of the CMB polarization are in fact among the most exciting goals in cosmology as it would allow testing of the inflationary paradigm. Many experiments are attempting to measure the B-modes, from the ground and the stratosphere, using imaging Stokes polarimeters. The QUBIC collaboration developed an innovative concept to measure CMB polarization using bolometric interferometry. This approach mixes the high sensitivity of bolometric detectors with the accurate control of systematics due to the interferometric layout of the instrument. We present the calibration results for the Technological Demonstrator, before its commissioning in the Argentinian observing site and preparation for first light.

Freshwater ecosystems are highly vulnerable to global warming because 1) their chief drivers, water quality and flow regimes, are highly sensitive to atmospheric warming, and 2) they are already extremely threatened by a wide range of interacting anthropogenic pressures. Even relatively modest global warming of 1.5°C poses a considerable threat to freshwater ecosystems and the many critical services these provide to people. Shifts in the composition and function of freshwater ecosystems are widely anticipated with adverse consequences for ecosystem services, including those underpinning water and food security. While the extent and severity of effects is likely to be significantly reduced if global warming is limited to 1.5°C, concerted efforts to implement widely recognised priorities for policy and management are required to mitigate unavoidable impacts and reduce the likelihood of perverse outcomes of climate mitigation and adaptation efforts in other sectors—all of which rely on fresh water supply. Freshwater ecosystems and their services, including provision of fresh water, must therefore be considered first and foremost when developing and implementing any climate action.

Many organisms living in temporary streams rely on remnant surface water to survive during extended dry periods and recolonize newly established habitats when flow resumes. However, research on the spatio‐temporal variations of surface water extent for entire river networks is scarce. In this study, we first present a new field method for rapid surface water assessment. Next, we develop predictive models relating observed water extent to environmental attributes at a large number of surveyed stream segments (n=241) in eastern Australian coastal catchments. We use the models to predict daily variations in surface water dynamics throughout entire river networks over the period of 1911‐2017, based on available long‐term environmental attributes influencing hydrological processes. We find descriptors of surface water extent can be accurately predicted based on robust internal and external validations. Environmental predictor variables representing water gaining processes were more important in predicting surface water extent than variables representing water losses. Simulated long‐term variations in surface water extent were highly dynamic through space and time, particularly in inland streams, which were predicted to be the driest on average. Total stream length with surface water ranged from 8,974 to 13,742 km across the study period. Our study presents a novel and practical approach to quantifying and predicting variations in surface water extent, with potential applicability to other parts of the world. The simulated surface water extent through space and time can be used to identify and prioritize potential aquatic refuge areas that sustain aquatic biodiversity in river networks during extended dry periods.

Systematic conservation planning has contributed to the spatial design of reserve networks in river ecosystems by recognizing the importance of maintaining longitudinal connectivity. In the complex and dynamic landscapes of river-floodplain systems, however, it is still challenging to account for the longitudinal and, especially, lateral connections that are relevant to their management. Adequate protection of floodplain ecosystems requires accounting for spatio-temporal connectivity among all waterbodies that compose the riverine landscape. In this study we present a new framework to account for both within-floodplain (lateral) and longitudinal river connectivity in freshwater systematic conservation planning. We run four prioritization scenarios comparing different rules of connectivity for the rivers and floodplains of the entire Amazon River basin. The scenarios involved the comparison of local protection only versus integrated upstream protection for floodplains. The spatial framework combined two types of planning units, with connectivity between them assessed using two distance-based measures for within-floodplain and upstream-downstream connectivity. We found different levels of protection afforded to floodplain wetlands across scenarios. The scenario including only within-floodplain connectivity failed to detect the propagation of impacts from the surroundings and upstream catchment. In contrast, the scenario that integrated within-floodplain and longitudinal river connectivity agglomerated subcatchments around the priority wetlands, generating catchment-integrated units that efficiently reduced impacts. We also demonstrate that the integrated connectivity can be manipulated to meet different conservation objectives. The new approach presented here offers more ecologically meaningful protection to floodplains because it considers local wetland boundaries and connectivity within wetland complexes together with connectivity with the upstream landscape. This framework can be applied to integrated wetland conservation and management throughout the world and provide a valuable tool to safeguard the ecosystem functioning of complex river-floodplain mosaics.

Translocation of individuals is a widely used tool in the conservation of threatened species. The movement behaviours of translocated individuals in their new environment are a key factor that can influence translocation success (i.e. survival and reproduction). In this study, eel‐tailed catfish (Tandanus tandanus ) and Murray cod (Maccullochella peelii ) movements were monitored using fine‐scale acoustic telemetry over a 5‐month period in two lowland rivers in eastern Australia. Fine‐scale movement and habitat selection were compared among translocated lacustrine and resident riverine T. tandanus and between species. We found no difference in fine‐scale movement behaviours between translocated and resident T. tandanus ; however, there was some variation in movement response to environmental variation between species. In contrast, habitat selection varied not only between the two species, but also between resident and translocated T. tandanus individuals. Notably, activity was significantly lower in the first day after release compared to the remainder of the study period. Although T. tandanus translocated from a reservoir had never experienced the environmental fluctuations of a riverine system, individuals still responded in the same way as resident riverine fish, suggesting an innate behavioural response. However, this was not the case for habitat selection, where translocated individuals preferred habitats more common in their source population's lacustrine environment. The findings of this study are important in guiding future conservation efforts involving the translocation of wild‐caught fish, primarily the importance of the suitable habitat at the release site to ensure the success and persistence of translocated populations.

In many wetlands the timing and duration of inundation determine ecological characteristics and the provision of ecosystem services; however, wetland conservation decisions often rely on static maps of wetland boundaries that do not capture their dynamic hydrological variability and connectivity. The Amazon River basin contains some of the world's most extensive wetlands, many of which are floodplains where seasonal flood pulses result in a temporally varying inundation area and hydrological connectivity with river systems. This study classified Amazon wetlands according to the timing and duration (months per year) of inundation detected by remote sensing, and also investigated the contribution of precipitation regimes in affecting wetland distribution and hydrological dynamics. Permanently inundated wetlands account for the largest area and are mainly floodplains located in the lowlands of the catchment. Seasonally inundated wetlands varied greatly in the duration of inundation over the course of the year, ranging from 1 to 9 months. Distinct seasonal timing was detected among the large wetland complexes, reflecting rainfall regimes as well as time lags for drainage and drying. For example, inundation in the extensive Llanos de Moxos region of the southern Amazon was protracted and lasted well after the rainy season, compared with the Roraima region of the northern Amazon, where inundation was shorter and tracked the rainy season. The integration of inundation dynamics into wetland classification captures regional differences in timing and duration of inundation in the major wetlands of the basin that should be considered for conservation planning and other ecological applications. This information can aid regional wetland management and planning, especially with regards to minimizing the effects of dam and waterway construction that can directly affect the natural wetland dynamics. The use of global remotely sensed inundation data makes this approach easily transferable to other large tropical wetlands.

Closely related species may have different patterns of distribution and spatial population structure in common landscapes, which can have implications for conservation of the species if they are vulnerable. The Australian mountain galaxias species complex has recently been split into 15 described species, 11 of which are threatened. In this study, we assessed the distribution and landscape genetic structure of two mountain galaxias species (Galaxias olidus and Galaxias oliros) in the Goulburn–Broken catchment (Murray–Darling Basin) in relation to hydrographic descriptors of river terrain, network and hydrology. We also assessed small‐scale population structure in juvenile G. oliros in tributary streams of the Goulburn River (the Granite Creeks). Analyses of distribution revealed that G. olidus mostly occurs in smaller streams at high elevations with steep valley slopes and high stream gradients downstream, whereas G. oliros mostly occurs in larger downstream waterways with higher magnitude and variability of stream flow. Population genetic structure in G. olidus was much greater than for G. oliros, with 17 of the 19 sampled locations resolved as genetically distinct populations for G. olidus, but only a single population revealed for G. oliros. Results for both species did not reflect the expectations of the stream hierarchy model or isolation‐by‐distance model. However, small‐scale spatial population structure in juvenile G. oliros in the Granite Creeks reflected the expectations of both stream hierarchy and isolation‐by‐distance models, suggesting that population structure of juveniles of this species reflects some level of spatial aggregation of closely related individuals that probably diminishes as the population ages. Higher landscape genetic structure in G. olidus was correlated with steeper stream and valley slopes, whereas no population genetic correlations were significant for G. oliros. Genetic diversity in G. olidus was higher in areas of greater hydrological variability, suggesting that populations in hydrologically variable areas function as a metapopulation and have a more diverse gene pool than populations in areas with lower hydrological variability. In contrast, genetic diversity in G. olidus was lower in higher elevation areas with steep valley slopes, suggesting that smaller but more stable populations occur in high elevation streams with high perenniality and low interannual variability of flows. Our results are consistent with other studies that highlight the importance of supporting natural hydrological regimes and natural patterns of hydrological connectivity for conservation of vulnerable freshwater fish.

The economic development-environmental protection dichotomy is an out-dated construct. A 21st century approach to the world's water problems is progressively being developed by researchers and practitioners, who are combining traditional and ecosystem-based engineering systems to yield cost-effective solutions. Given the continuing and widespread loss of ecological services and functions, water security in a multi-generational, SDG context requires a meaningful, global commitment to redirect the current downward trajectory in both (i) the state of the world's ecosystems and the services they provide to society, and (ii) our collective level of stewardship of these important resources. Achieving sustainable water security will require overcoming strategic challenges related to protected areas, ecosystem-based solutions research, water observatories and expanded technical readiness. It also needs to address other limitations and demands related to water infrastructure, economies, human settlements and water quality, sanitation and health. Four globally significant actions can support the adoption of more efficient and sustainable water futures: green infrastructure watershed banks, an accelerated global research and solutions program, a new global water-ecosystem services observatory, and an improved technical capacity/workforce development initiative. Finally, the engagement of relevant stakeholders from academia, government, the private sector and civil society are needed to ensure that humankind will be able to meet its water security goals and commitments, including those expressed in the sustainable development agenda.