Freshwater Conservation Research Articles

Spatial relationships between fishes and amphibians: implications for conservation planning in a Neotropical Hotspot.

Species distribution patterns are widely used to guide conservation planning and are a central issue in ecology. The usefulness of spatial correlation analysis has been highlighted in several ecological applications so far. However, spatial assumptions in ecology are highly scale-dependent, in which geographical relationships between species diversity and distributions can have different conservation concerns. Here, an integrative landscape planning was designed to show the spatial distribution patterns of taxonomic and functional diversity of amphibians and fishes, from multiple species traits regarding morphology, life history, and behavior. We used spatial, morphological, and ecological data of amphibians and fishes to calculate the functional diversity and the spatial correlation of species. Mapping results show that the higher taxonomic and functional diversity of fishes is concentrated in the West Atlantic Forest. Considering amphibians, are located in the East portion of the biome. The spatial correlation of species indicates the regions of the Serra do Mar and the extreme southern part of the Central Corridor as the main overlapped species distribution areas between both groups. New key conservation sites were reported within the Brazilian Atlantic Forest hotspot, revealing cross-taxon mismatches between terrestrial and freshwater ecosystems. This study offers useful spatial information integrating suitable habitats of fishes and amphibians to complement existing and future research based on terrestrial and freshwater conservation. New priorities for biodiversity conservation in rich-species regions highlight the importance of spatial pattern analysis to support land-use planning in a macroecological context.

The dynamics of mature and emerging freshwater conservation programs

Conservation programs range from small, place-based initiatives to large, bureaucracy-heavy systems. The dynamics of these programs vary greatly. New initiatives may experience exponential growth, but participation and spending in mature programs may rise and fall in response to a number of factors. Here, we analyze historical patterns of participation and spending across five freshwater conservation programs in the United States. Our analysis highlights fundamental differences between emerging programs, which may experience exponential or logistic growth, and mature programs with slower growth, in which changes in participation may be driven by a number of internal and exogenous factors. We propose that changes in the number and spatial distribution of conservation projects are associated with four key factors: changes in legislation that open new funding streams; shifting priorities of actors; changes in the policies or management of a program that align it with new funding opportunities; and increases in individuals’ willingness to participate in a program as it grows. These programmatic shifts represent windows of opportunity for strategically reorienting conservation programs to leverage newly-available resources. Given that large, mature conservation programs support biodiversity and ecosystem services worldwide, comparison of their dynamics with those of emerging programs may reveal key opportunities for maximizing the benefits of investments in these programs.

Identifying priority aquatic refuges to sustain freshwater biodiversity in intermittent streams in eastern Australia

AbstractThe 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.

Enabling a low-carbon electricity system for Southern Africa

<h2>Summary</h2> Southern Africa faces the dual challenge of providing affordable energy to meet rapidly growing electricity demand while limiting carbon emissions and socio-environmental impacts. We combined open-source geospatial, hydrological, and electricity grid-investment models to develop cost-optimal low-carbon electricity pathways for Southern Africa. If technology and fuel prices continue to follow current trends, wind and solar technologies can become the dominant sources of electricity in the region by 2040. Importantly, no new coal capacity is built in any scenario except when inter-regional transmission is constrained. Furthermore, despite the abundant hydropower potential in the region, nearly half of the planned hydropower capacity is not cost competitive, thus supporting freshwater conservation efforts. An 80% clean energy target can halve annual greenhouse gas emissions by 2040, as compared with 2020, with only a modest 6% cost premium. Alternatively, retiring coal plants 20 years earlier could result in even greater emission reductions but could incur 12% higher annual costs.

Risk of Legionellosis in residential areas around farms irrigating with municipal wastewater.

The conservation of freshwater is of both global and national importance, and in the United States, agriculture is one of the largest consumers of this resource. Reduction of the strain farming puts on local surface or groundwater is vital for ensuring resilience in the face of climate change, and one possible option is to irrigate with a combination of freshwater and reclaimed water from municipal wastewater treatment facilities. However, this wastewater can contain pathogens that are harmful to human health, such as Legionella pneumophila, which is a bacterium that can survive aerosolization and airborne transportation and cause severe pneumonia when inhaled. To assess an individual adult's risk of infection with L. pneumophila from a single exposure to agricultural spray irrigation, a quantitative microbial risk assessment was conducted for a scenario of spray irrigation in central Illinois, for the growing seasons in 2017, 2018, and 2019. The assessment found that the mean risk of infection for a single exposure exceeded the safety threshold of 10-6 infections/exposure up to 1km from a low-pressure irrigator and up to 2km from a high-pressure irrigator, although no median risk exceeded the threshold for any distance or irrigator pressure. These findings suggest that spray irrigation with treated municipal wastewater could be a viable option for reducing freshwater consumption in Midwest farming, as long as irrigation on windy days is avoided and close proximity to the active irrigator is limited.

DNA metabarcoding unravels unknown diversity and distribution patterns of tropical freshwater invertebrates

Abstract Tropical freshwater invertebrate species are becoming extinct without being described, and effective conservation is hampered by a lack of taxonomic and distribution data. DNA metabarcoding is a promising tool for rapid biodiversity assessments that has never been applied to tropical freshwater invertebrates across large spatial and taxonomic scales. Here we use DNA metabarcoding to comprehensively assess the benthic freshwater invertebrate fauna of the Perak River basin, Malaysia. Specific objectives were to: (1) assess performance of two DNA metabarcoding protocols; (2) identify gaps in reference databases; (3) generate new data on species diversity and distribution; and (4) draw conclusions regarding the potential value of DNA metabarcoding in tropical freshwater conservation. Organisms were collected by hand and net at 34 sites and divided into small (retained in 0.5‐mm but passing through 1‐mm mesh) and large (retained in 1‐mm mesh) fractions, and a 313‐bp cytochrome c oxidase subunit I fragment amplified and sequenced using general Metazoa primers. Bioinformatic analysis resulted in 468 operational taxonomic units (~species) from 12 phyla. Only 29% of species could be assigned binominal names through matches to public sequence libraries, indicating varying levels of library completeness across Orders. Extraction of small‐fraction DNA with a soil kit resulted in a significantly higher species count than with a general kit, but this was not even across taxa. Metabarcoding (amplification) success rate, estimated via comparison to morphological identifications of the large‐fraction specimens, was high in most taxa analysed but low, for example, in ampullariid and viviparid gastropods. Conversely, a large proportion of species‐site records for Decapoda and Bivalvia came from metabarcoding only. Species richness averaged 29 ± 16 species per site, dominated by Diptera, Annelida, and Odonata, and was particularly high in tributaries of the mountainous Titiwangsa Range. At least eight species are new records for Malaysia, including the non‐natives Ferrissia fragilis (Gastropoda) and Dugesia notogaea (Platyhelminthes). Our study showed that DNA metabarcoding is generally more effective in detecting tropical freshwater invertebrate species than traditional morphological approaches, and can efficiently improve knowledge of distribution patterns and ranges of native and non‐native species. However, current gaps in reference databases, particularly for bioindicator taxa, such as the Plecoptera, Ephemeroptera, and Coleoptera, need to be addressed urgently.

Assessing placement bias of the global river gauge network.

Knowing where and when rivers flow is paramount to managing freshwater ecosystems. Yet stream gauging stations are distributed sparsely across rivers globally and may not capture the diversity of fluvial network properties and anthropogenic influences. Here we evaluate the placement bias of a global stream gauge dataset on its representation of socioecological, hydrologic, climatic and physiographic diversity of rivers. We find that gauges are located disproportionally in large, perennial rivers draining more human-occupied watersheds. Gauges are sparsely distributed in protected areas and rivers characterized by non-perennial flow regimes, both of which are critical to freshwater conservation and water security concerns. Disparities between the geography of the global gauging network and the broad diversity of streams and rivers weakens our ability to understand critical hydrologic processes and make informed water-management and policy decisions. Our findings underscore the need to address current gauge placement biases by investing in and prioritizing the installation of new gauging stations, embracing alternative water-monitoring strategies, advancing innovation in hydrologic modelling, and increasing accessibility of local and regional gauging data to support human responses to water challenges, both today and in the future.

Quantifying water footprint of winter wheat – summer maize cropping system under manure application and limited irrigation: An integrated approach

Recycling of livestock manure in agroecosystems can promote resource utilization and reduce negative environmental consequences from intensive crop-livestock systems. However, the interaction effect of manure application and irrigation strategy on the water footprint (WF) of crop production still remains incomplete. Here, we estimated the WF of the winter wheat – summer maize cropping system based on a three-year field experiment under limited irrigation and manure application by combining the hydrological water balance and the life-cycle assessment. Four fertilization strategies were chemical fertilizer (Fc), manure (Fm), the combination of chemical fertilizer and manure (Fc+m), and no fertilizer input (F0). Two irrigation regimes were irrigation (W1) and no irrigation (W0) at the jointing stage of wheat. W1 increased the blue WF (groundwater consumption per unit of grain yield) of the wheat-maize system by 46–95% compared to W0. The annual blue WF of Fm was 6% lower than that of Fc+m under W0 in 2016–2017, while that of Fc+m was lowest under W1 in 2016–2017 and 2017–2018. Fm had a higher annual yield under W0, while Fc+m yielded better under W1. Notably, the combination of limited irrigation and manure application decreased annual blue WF by benefitting annual grain yield through improving soil water storage. The indirect water consumption per unit grain yield of Fc+m and Fm were 57% and 17% of Fc for wheat and maize, respectively. Our findings highlight the great reductions in blue water footprint and indirect water consumption through limited irrigation and manure application, suggesting an effective way to balance freshwater conservation and crop production.

Multi-scale threat assessment of riverine ecosystems in the Colorado River Basin

Freshwater ecosystems are facing a deepening biodiversity crisis. Developing robust indicators to assess ecological integrity across large spatial scales and identifying the specific threats and pathways of impairment are thus critically needed if we are to inform freshwater conservation strategies. Here we present the first comprehensive threat assessment across the Colorado River Basin – one of the largest and most endangered river basins in North America – using a spatial framework accounting for the wide range of human activities (land uses, transportation infrastructure, exploitative activities, water withdrawals), pathways (local footprint, overland runoff, upstream cumulative effects), and spatial extent of influence (valley bottom, catchment and river network) known to affect the ecological integrity of riverine ecosystems. We quantified and mapped 69 individual threat indices with geospatial tools for each permanent, ephemeral, and intermittent stream segment within the Basin, encompassing a total of >1,067,700 river kilometers. We further aggregated these indices into components of water quality (diffuse and point-source pollution), hydrology (flow regulation/uses and climate change), and physical system (connectivity and geomorphology). To demonstrate the potential of our framework to inform spatial planning decision processes, we examined the typical combinations of threats experienced by different hydrologic areas and stream segment types, identified candidate watersheds for habitat restoration and enhancement where hotspots of biodiversity and threat overlapped, and assessed the associations between threat indices and in situ measurements of ecological integrity describing a suite of biological (benthic macroinvertebrate, fish), chemical (total nitrogen load, water conductivity), hydrological (flow alteration) and physical indicators (streambed stability, instream habitat complexity). Our assessment highlights clear disparities in term of overall degree of threat that result from different combinations and contributions of individual stressors, with different priorities emerging for perennial versus intermittent or ephemeral stream segments, and between the upper and lower parts of the Basin. Importantly, we showed that our threat indices were generally correlated with biological, chemical, hydrological and physical indicators of ecological integrity they were intended to capture. In addition to its implications for the conservation and management of the highly imperiled Colorado River Basin, our case study illustrates how multi-faceted threat mapping can be used to assess the ecological integrity of riverine ecosystems in the absence of spatially extensive in situ measurements.

Perceptions of ecosystem services and disservices associated with open water swimming

Open water swimming is becoming an increasingly popular recreational activity. Understanding the human well-being benefits that open water swimmers derive from interaction with outdoor spaces is fundamental to environmental decision making, yet little is currently known about the benefits, threats and needs of open water swimmers in relation to the environments they swim in. In this study we provide a balanced assessment of the perceived cultural ecosystem services (CES) and ecosystem disservices (EDS) experienced by open water swimmers in the UK. Factor analysis based on an online questionnaire with 505 respondents revealed three distinct clusters of CES benefits that contribute to human well-being (‘spiritual value and interaction with nature’, ‘mental and physical health’, and ‘social bonds’). Swimming frequency, site type, gender and whether respondents were members of environmental groups affected response patterns towards CES benefits. There were five distinct clusters of EDS (‘natural hazards’, ‘security and safety (health)’, ‘security and safety (weather)’, ‘recreation’ and ‘material (biotic and abiotic)’. Key EDS ranked as an issue (by more than 50% of respondents) related to water quality, currents, rubbish and litter in water bodies and boat traffic. Swimming duration, age and swimming frequency in particular affected response patterns surrounding EDS, and to a small extent the site type. The results can be used to support the effective implementation of national and international policy, which aims to improve human well-being through encouraging use of outdoor spaces, whilst promoting the conservation and sustainable use of freshwater and marine ecosystems. The results of this study support effective ecosystem management of aquatic environments used by recreational open water swimmers through: - Facilitating the inclusion of cultural ecosystem services/ ecosystem disservices experienced by open water swimmers in management planning - Identifying the main human well-being benefits experienced by open water swimmers when interacting with waterbodies and demonstrating that these vary depending on the demographics of the recreational user, and characteristics of the recreational activity - Understanding the main ecosystem disservices experienced by open water swimmers and identifying management actions to address these - Providing a framework that can be used for similar assessments

Conservation of genetic resources for sustainable aquaculture

Conservation of genetic resources for sustainable aquaculture

Synthesis of large-scale total water network with multiple water resources under seasonal flow rate constraints

In recent decades, numerous studies have been conducted on freshwater conservation by improving industrial water networks. However, most previous industrial water networks utilize freshwater supplies without defining the freshwater origin; besides, they also ignore the practical issue of seasonal utility flow rate fluctuations. In practice, industrial freshwater supply can be obtained from many raw water resources, including municipal water, groundwater, surface water, municipally treated wastewater, and seawater. Each type of raw water resource with different properties can use a specific pre-treatment technology with fixed removal and production ratios to produce freshwater. These pre-treatment technologies directly impact the total annual cost (TAC) of the industrial water network. This paper proposes a superstructure-based mathematical model for the optimum synthesis of an integrated total water network, including multiple water resources, along with water pre-treatment technologies. A superstructure-based mathematical model is framed, considering relative equations of water reuse/recycling connections, including the pre-treatment system, utility system, water-using system, and wastewater treatment system. A large-scale coastal oil refinery is selected to implement the proposed approach. Different scenarios of individual and multiple water resources under seasonal utility flow rate constraints are developed to check the applicability of the proposed model. A significant reduction in freshwater demand in all seasons is achieved. The TAC for the individual water resource is reduced by 4.5% and 2.8% using the groundwater and surface water compared to the preliminary design. For multi-resourced water networks, the TAC increased due to the higher investment cost of the treatment system for municipal treatment water and seawater.

Native Fish Need A Natural Flow Regime

Water development has threatened the ecological integrity of riverine ecosystems. Increasing water demand, persistent drought, and climate change exacerbate the effects of habitat degradation and loss in altered systems such as the Colorado River basin. Today, biologists are challenged to identify management actions that benefit native fishes while not hindering water development or management. Herein, we discuss the importance of the natural flow regime for functioning riverine ecosystems and provide examples from four tributaries to the Green River, a major headwater branch of the Colorado River. These tributaries represent a gradient of impacts ranging from water abstraction to the point of complete seasonal desiccation to a relatively natural flow regime, and consequently have maintained different levels of instream habitat complexity and native fish persistence. Despite decades of management, endangered species lack self‐sustaining populations and other native species have been extirpated from over half their ranges, which begs the question: can water development and fish conservation be balanced under current water laws and climate change‐driven declines in runoff? Given the continued decline in freshwater biodiversity and abundance occurring across the globe, we contend that immediate designation of rivers with natural flow regimes as freshwater conservation areas will enhance native species recovery.

Adjustment of the methodological guidelines for establishing the permitted surface water abstraction and environmental flow for freshwater ecosystem conservation

Adjustment of the methodological guidelines for establishing the permitted surface water abstraction and environmental flow for freshwater ecosystem conservation

Mountain freshwater ecosystems and protected areas in the tropical Andes: insights and gaps for climate change adaptation

SummaryAlthough protected areas (PAs) play an important role in ecosystem conservation and climate change adaptation, no systematic information is available on PA protection of high-elevation freshwater ecosystems (e.g., lakes and watersheds with glaciers), their biodiversity and their ecosystem services in the tropical Andes. We therefore combined a literature review and map analysis of PAs of International Union for Conservation of Nature (IUCN) and national systems of PAs and freshwater ecosystems. We found that seven national parks were created for water resources protection but were not designed for freshwater conservation (i.e., larger watersheds). High-value biodiversity sites have not been protected, and new local PAs were created due to water resource needs. We quantified 31 Ramsar sites and observed that PAs cover 12% of lakes, 31% of glacial lakes and 12% of the total stream length in the tropical Andes. Additionally, 120 watersheds (average area 631 km2) with glaciers and 40% of the total glacier surface area were covered by PAs. Future research into the role of PAs in ecosystem services provision and more detailed freshwater inventories within and around PAs, especially for those dependent on glacier runoff, will fill key knowledge gaps for freshwater conservation and climate change adaptation in the tropical Andes.

The use of umbrella fish species to provide a more comprehensive approach for freshwater conservation management

Abstract Where freshwater species populations are in decline, conservation management requires rapid, cost‐effective approaches to develop recommendations, particularly at broad geographical scales or where species‐specific information is lacking. The umbrella species approach, typically applied to terrestrial taxa, is one potentially useful option to inform large‐scale freshwater management efforts. A quantitative, integrated approach is proposed for selecting suites of umbrella fish species over diverse spatial scales using a combination of species ranges, life‐history traits, and species vulnerability scores. The approach also uses expert opinion to validate methods and results. This approach was applied to native fishes in California, and results for two river basins are explored in the context of instream flow management. These examples illustrate how the results could help address two common instream flow management challenges in California: (i) the lack of information related to species‐specific flow requirements in basins with many species; and (ii) the need to move beyond a single species approach to flow management. In addition, the results indicate that the protection of native fishes in California would provide co‐benefits for other aquatic and riparian taxa. A key benefit of this approach is that the data used to select suites of umbrella species (e.g. species ranges, life‐history traits, climate vulnerabilities) are widely available at varying degrees of specificity for most freshwater fishes. Therefore, this flexible approach could be applied in other regions to aid managers in making freshwater conservation decisions, such as for instream flow strategies, in an efficient and cost‐effective manner.

Upstream migration of anadromous and potamodromous brown trout: patterns and triggers in a 25-year overview

River fragmentation and alterations in flow and thermal regimes are the main stressors affecting migrating fish, which could be aggravated by climate change and increasing water demand. To assess these impacts and define mitigation measures, it is vital to understand fish movement patterns and the environmental variables affecting them. This study presents a long-term (1995–2019) analysis of upstream migration patterns of anadromous and potamodromous brown trout in the lower River Bidasoa (Spain). For this, captures in a monitoring station were analyzed using Survival Analysis and Random Forest techniques. Results showed that most upstream movements of potamodromous trout occurred in October–December, whereas in June–July for anadromous trout, although with differences regarding sex and size. Both, fish numbers and dates varied over time and were related to the environmental conditions, with different influence on each ecotype. The information provided from comparative studies can be used as a basis to develop adaptive management strategies to ensure freshwater species conservation. Moreover, studies in the southern distribution range can be crucial under climate warming scenarios, where species are expected to shift coldwards.

Regional macrophyte diversity is shaped by accumulative effects across waterbody types in southern China

Studies on aquatic biodiversity in different waterbody types have attracted significant attention worldwide to achieve the goal of freshwater conservation. Different freshwater habitats can help maintain regional biodiversity by directly supporting aquatic plants and forming networks to promote aquatic dispersal across regions. However, few studies have conducted large-scale comparisons of macrophyte diversity among different waterbody types in China due to a lack of a national macrophyte dataset. Here, we compared species richness, species composition, beta diversity, and its components among ponds, ditches, disturbed ponds, lakes, rivers, and reservoirs in southern China. We found that macrophyte species composition overlapped in the different waterbody types, indicating similar regional species pools. Species composition was best explained by temperature, elevation, and flow velocity. For species richness, ponds supported the highest number of species, followed by lakes, ditches, rivers, and reservoirs, with disturbed ponds showing the lowest diversity. For beta diversity, the relatively low turnover and high nestedness in the lakes indicated high dispersal of macrophyte species throughout these water bodies or suggested that human disturbance in lakes may lead to a more uniform chemical environment and thus regional macrophyte community. This study emphasized the importance of maintaining the diversity of different waterbody types in the landscape and determining the most threatened freshwater habitats. Moreover, small water bodies (e.g., ponds) contribute more to the regional macrophyte species pool than permanent water bodies (e.g., lakes) due to their relatively high biodiversity value. Their stable hydrological environment may help maintain rare and uncommon species that do not appear in other waterbody types.

Do fishes enjoy the view? A MaxEnt assessment of fish habitat suitability within scenic rivers

Scenic rivers programs are a potential tool to conserve freshwater habitat but few studies have attempted to characterize fish habitat within scenic rivers. Using the Virginia Scenic Rivers Program as a case study, we built species distribution models for a representative set of Virginia freshwater fishes and tested whether model-predicted habitat suitability values for scenic rivers are consistently higher than the range-wide average values. We began by selecting 33 fish species that were broadly representative of the complete functional trait space comprised by Virginia's freshwater ichthyofauna. This subset included 11 state-listed imperiled species. Next, we built maximum entropy species distribution models for each of the 33 fishes and used the models to predict habitat suitability throughout each species' range. Habitat suitability within state-listed scenic rivers was then summarized and compared with the complete, state-wide distribution of habitat suitability for each species. For 21 of 33 species, model-predicted habitat suitability was significantly higher in currently listed Virginia scenic rivers than in the state-wide distribution; of these 21 species, 5 were imperiled taxa. Furthermore, habitat suitability within scenic rivers is predicted to exceed the range-wide average by a significant margin for 25 species, including eight imperiled species, if all pending scenic listing petitions are approved. We conclude that scenic rivers provide important conservation benefits to Virginia's freshwater fishes. We also note that our flexible, model-based process can be applied in other rivers and used to inform other types of freshwater conservation programs that seek to identify and protect the highest quality habitats.

A Role for Newly Developed Sorbents in Remediating Large‐Scale Oil Spills: Reviewing Recent Advances and Beyond

AbstractThe conservation of ocean and freshwater have been crucial issues over the past decades, and oil/water separation is a well‐known technology to restore polluted water systems. In the meantime, oil sorbents serve as a promising means of achieving water conservation to recover from oil spills, which require a multi‐factorial approach to review high selectivity, capacity, and rate of oil recovery. However, reusability is a critical component to consider in incidents with large‐scale spills. With the development of sorbent technology, some studies have progressed to explore surface engineering and material design for high oil sorption capacity and durability. Thus, this systemic review, a summary of sorbent developments, serves as a guide to understanding practical applications that can apply to large‐scale oil spills and recognize remaining issues. In this review, the oil weathering process and oil sorption mechanisms in relation to the characteristics of target pollutants are introduced. Then, this comprehensive review focuses on materials in advanced sorbents. These materials have properties including, aligned channels for fast sorption, self‐heating capabilities for viscous oil cleanup, and magnetic‐responsiveness to enhance a collection of final products. The perspective and challenges for the next generation of oil spills remediation technology‐based oil sorbents materials are finally presented in the last section.