Changes In Water Regime Research Articles

Confronting Climate Change Challenges to Dryland Cereal Production: A Call for Collaborative, Transdisciplinary Research, and Producer Engagement

Semi-arid cereal systems face challenges worldwide that are driven by ongoing and projected climate change. These challenges include ensuring cropping system resilience and productivity under changing water and temperature regimes while reversing soil degradation, reducing crop susceptibility to pests, pathogens and weed competition, and exploiting genetic resources to develop cultivars with resilience to climate stresses and improved compatibility with cropping system innovations. Meeting these interdependent challenges requires transdisciplinary efforts that integrate knowledge across many scientific domains. The USDA-NIFA-funded coordinated agricultural project, “Regional Approaches to Climate Change for Pacific Northwest Agriculture” (REACCH), employed this transdisciplinary approach to address climate change and sustainability challenges for rain-fed cereal-based systems in the semi-arid intermountain Pacific Northwest. To engage with and contribute to similar efforts globally, REACCH sponsored a workshop “Transitioning Cereal Systems to Adapt to Climate Change” (TCSACC) in November 2015. Participants from 17 countries and five continents with expertise in agronomy, crop physiology, crop modeling, crop protection, breeding and genetics, sociology and economics shared their perspectives, successes, and challenges to achieving transdisciplinary research integration for semi-arid cereal systems under changing climates. Conference goals were to: (1) strengthen the global network of researchers addressing climate change effects on semi-arid cereal-based systems, (2) share the approaches to achieving transdisciplinary collaboration to advance climate change resilience in cereal systems, and (3) identify the elements of a collaborative research agenda that are needed to advance global food security in the 21st century. This paper distills the conference themes and summarizes the calls to action that were discussed.

Effect of cement on the stability and the wearrance of soils in earthworks

The technique of soil treatment is known for a long time, currently, during the big motorway programs this technique is experiencing important to reach zero imprints and zero deposit in a context of sustainable development or the socio-economic and environmental challenges incite during the work of earthworks. Our work puts highlights the treatment of fine soils in westerns region of Algeria (wilaya of Tlemcen, a project to construct a payment station for the entry of the wilaya (sample n°1), electrical post 400/200 KVA in the locality Ain Fetah (sample n°2)), belonging to the class A3h (very plastic clay) according to the Technical Guide for Earthworks (GTR), whose use in the raw state would involve great risks of stability because of their plasticity (Ip > 20%) and their low capacity (CBR < 25) according to the Specification of the Algerian Loads, Technical Clauses (CSDCA-CT) by the incorporation of the stabilizing agents, for example the variant of locally manufactured CEM II / A42.5N composite cement, in order to define their behaviours by examining the variation of their characteristics determined according to the Algerian standards and at a ambient temperature according to the additive dosage and to contribute to the deduction of the interest of the method demonstrated previously. The results obtained clearly show a tendency the rearrange classification of the soils studied according to the unified system en proportion whit to the additive dosage (0 to 14%) in view of the appreciable change in the plasticity behaviour, which results in a decrease in the plasticity index, going up to 37.7% and the 11% of the maximum dry density accompanied by a satisfactory increase in the suitability of the materials to be supported a load with different moisture content and changes in water regime exceeds 100%. Given the unavailability of other exploitable deposits near the site and the experimental results obtained, the variant of the treatment seems feasible.

The dikes of the sub-lakes change soil carbon cycle in the littoral wetland in Poyang Lake

水文节律是影响湖泊湿地土壤碳循环的重要因素.堑秋湖是鄱阳湖传统的渔业生产方式，对鄱阳湖碟形湖水文节律具有显著影响.因此，本文研究了堑秋湖对鄱阳湖洲滩土壤碳循环的影响.结果表明，堑秋湖围堤内外洲滩土壤总有机碳含量无显著差异，但围堤内土壤轻组有机碳含量比围堤外低35.03%.围堤内土壤有机碳（SOC）矿化速率明显高于围堤外.围堤内SOC矿化的平均Q₁₀为2.72，比围堤外低4.83%，但两者SOC矿化的水分敏感性没有显著差异.围堤内外SOC矿化速率分别与土壤可溶性有机碳和土壤轻组氮含量相关关系最为显著.综上所述，堑秋湖围堤已经改变了鄱阳湖洲滩的土壤碳循环过程.模拟湖泊湿地土壤碳循环时需要充分考虑当地渔业生产的影响.;Water regime changes caused by natural and anthropogenic activities can significantly affect soil carbon cycle in wetland ecosystem. Some fishery activities could greatly impact on wetland water regime, but, till now, their influences on wetland soil carbon cycle are still not fully understood. In this paper, we investigated the effects of the dike of Lake Dahuchi, which was used to restrain the fish at the low water period, on soil carbon cycle in the littoral wetland. Our results showed that soil total organic carbon (TOC) was not changed by the dike, but soil light fraction of organic carbon inside the dike was significantly lower than that outside the dike by 35.03%. Meanwhile, the littoral wetland soil inside the dike had higher soil organic carbon (SOC) mineralization rate, but lower temperature sensitivity. The Q₁₀ of SOC mineralization inside and outside the dike were 2.72 and 2.85, respectively. The dike did not significantly change the moisture sensitivity of SOC mineralization. In addition, the determining factors of SOC mineralization rates inside and outside the dike were dissolved organic carbon and light fraction of total nitrogen, respectively. In summary, soil carbon cycle in littoral wetland in Poyang Lake could be modified by fishery activities. Scientists should take account of the effects of fishery in simulating soil carbon cycle of the wetland ecosystem in future.

Cучасні тенденції зміни клімату, водних ресурсів та екосистем у середньо-нижній частині річки Південний Буг, Україна

Статтю присвячено аналізу особливостей змін клімату та водності в нижній частині басейну Південного Бугу, в регіоні розташування ЮУАЕС, в другій половині ХХ ст. та на початку ХХІ ст., оцінці впливів від діяльності ЮУАЕС на мікрокліматичні умови, а також визначенню можливих загроз для біотичного різноманіття природних екосистем, які пов’язані зі змінами довкілля.

Causes of changing stock of the Amur pike <i>Esox reichertii</i>

Retrospective data on catches of fine-mesh fishes in the Amur collected by Khabarovsk branch of the Pacific Fish. Res. Center (TINRO) since 1937 are analyzed. The main factors influencing on stock and catches of the Amur pike Esox reichertii (Dybowski, 1869) are revealed by methods of multiple regression and variance analyses, as the water level and preceding withdrawal by fishery. Dependence of the pike annual catch on these factors in preceding year (annual landing and the water level in June-September) and in current year (the water level in June) describes about 80 % of the catches variation. The tendency to both stock and landings decreasing since in the late 20 th century is caused by the Amur water regime change. Ways of the stock recovery in conditions of low water level are discussed.

Copper Pollution Increases the Resistance of Soil Archaeal Community to Changes in Water Regime.

Increasing efforts have been devoted to exploring the impact of environmental stresses on soil bacterial communities, but the work on the archaeal community is seldom. Here, we constructed microcosm experiments to investigate the responses of archaeal communities to the subsequent dry-rewetting (DW) disturbance in two contrasting soils (fluvo-aquic and red soil) after 6years of copper pollution. Ten DW cycles were exerted on the two soils with different copper levels, followed by a 6-week recovery period. In both soils, archaeal diversity (Shannon index) in the high copper-level treatments increased over the incubation period, and archaeal community structure changed remarkably as revealed by the non-metric multidimensional scaling ordinations. In both soils, copper pollution altered the response of dominant operational taxonomic units (OTUs) to the DW disturbance. Throughout the incubation and recovery period, the resistance of archaeal abundance to the DW disturbance was higher in the copper-polluted soils than soils without pollution. Taken together, copper pollution altered the response of soil archaeal diversity and community composition to the DW disturbance and increased the resistance of the archaeal abundance. These findings have important implications for understanding soil microbial responses to ongoing environmental change.

Transformation of estimated characteristics of the annual and maximal runoff in the major tributaries of Lake Baikal

Hydrometric data of recent years were used to evaluate the parameters of distribution of the annual and maximal runoff in the major tributaries of Lake Baikal: the Selenga, Upper Angara, and Barguzin. The estimates of the mean water content, maximal water discharges of spring flood and rain freshets were obtained. The comparison with analogous data of an earlier period often shows significant difference. Variations of the characteristics under consideration are taking place against the background of warming in the region since the early 1970s. The results of the current transformation of river runoff variations is a change in Baikal water regime, which determines the restructuring of hydrological processes in the lake.

Integrating downscaled CMIP5 data with a physically based hydrologic model to estimate potential climate change impacts on streamflow processes in a mixed-use watershed

Climatic changes have altered surface water regimes worldwide, and climate projections suggest that such alterations will continue. To inform management decisions, climate projections must be paired with hydrologic models to develop quantitative estimates of watershed scale water regime changes. Such modeling approaches often involve downscaling climate model outputs, which are generally presented at coarse spatial scales. In this study, Coupled Model Intercomparison Project Phase 5 (CMIP5) climate model projections were analyzed to determine models representing severe and conservative climate scenarios for the study watershed. Based on temperature and precipitation projections, output from GFDL-ESM2G (RCP2.6) and MIROC-ESM (RCP8.5) were selected to represent conservative (ΔC) and severe (ΔS) change scenarios, respectively. Climate data were used as forcing for the Soil and Water Assessment Tool (SWAT) to analyze the potential effects of climate change on hydrologic processes in a mixed-use watershed in central Missouri, USA. Results showed annual streamflow decreases ranging from -5.9% to -26.8% and evapotranspiration (ET) increases ranging from +7.2% to +19.4%. During the mid-21st century, sizeable decreases to summer streamflow were observed under both scenarios, along with large increases of fall, spring, and summer ET under ΔS. During the late 21st century period, large decreases of summer streamflow under both scenarios, and large increases to spring (ΔS), fall (ΔS) and summer (ΔC) ET were observed. This study demonstrated the sensitivity of a Midwestern watershed to future climatic changes utilizing projections from CMIP5 models, and presented an approach that used multiple climate model outputs to characterize potential watershed scale climate impacts.

Quantitative genetic differentiation and phenotypic plasticity of European beech in a heterogeneous landscape: Indications for past climate adaptation

Tree growth and species distributions are expected to be altered by climate change. European beech (Fagus sylvatica), one of the major tree species in Central Europe, is considered to be particularly threatened by the expected changes in local water regimes. Basic knowledge on the species⬢ genetic variation, environmental adaptation, and phenotypic plasticity is required to assess its potential for climate change adaptation, but sufficient information is lacking. Here, we describe a seedling common garden study at two field sites incorporating 77 natural populations of European beech from an environmentally heterogeneous mountain region in the center of its distribution. We aimed to identify patterns of genetic variation and phenotypic plasticity in growth and phenology, and to associate these with seed source environments. Population differentiation was greater for phenology than for growth (Qst=0.18⬜0.32 vs. 0.00⬜0.16), but within-population genetic variation was large for all seedling traits. The phenotype-environment associations indicated adaptive divergence in phenology and growth with respect to temperature and water availability, but not to soil characteristics, latitude, longitude, or topography of the seed source locations. Phenotypic plasticity was detected in growth and leaf duration, the magnitude of which differed among populations with different seed source temperatures. We conclude that seedling phenology is key to temperature and drought adaptation in European beech. Changes in local temperature and water regimes might result in local phenological maladaptation of European beech populations, although within-population genetic variation, gene flow, and phenotypic plasticity might mitigate the negative effects of climate change.

Conservation at a slow pace: terrestrial gastropods facing fast-changing climate.

The climate is changing rapidly, and terrestrial ectotherms are expected to be particularly vulnerable to changes in temperature and water regime, but also to an increase in extreme weather events in temperate regions. Physiological responses of terrestrial gastropods to climate change are poorly studied. This is surprising, because they are of biodiversity significance among litter-dwelling species, playing important roles in ecosystem function, with numerous species being listed as endangered and requiring efficient conservation management. Through a summary of our ecophysiological work on snail and slug species, we gained some insights into physiological and behavioural responses to climate change that we can organize into the following four threat categories. (i) Winter temperature and snow cover. Terrestrial gastropods use different strategies to survive sub-zero temperatures in buffered refuges, such as the litter or the soil. Absence of the insulating snow cover exposes species to high variability in temperature. The extent of specific cold tolerance might influence the potential of local extinction, but also of invasion. (ii) Drought and high temperature. Physiological responses involve high-cost processes that protect against heat and dehydration. Some species decrease activity periods, thereby reducing foraging and reproduction time. Related costs and physiological limits are expected to increase mortality. (iii) Extreme events. Although some terrestrial gastropod communities can have a good resilience to fire, storms and flooding, an increase in the frequency of those events might lead to community impoverishment. (iv) Habitat loss and fragmentation. Given that terrestrial gastropods are poorly mobile, landscape alteration generally results in an increased risk of local extinction, but responses are highly variable between species, requiring studies at the population level. There is a great need for studies involving non-invasive methods on the plasticity of physiological and behavioural responses and the ability for local adaptation, considering the spatiotemporally heterogeneous climatic landscape, to allow efficient management of ecosystems and conservation of biodiversity.

Factor Analysis of Influence of Parameters of Water Regime and Hydrological Changes on Pastures

According to basic tabular data (DEFRA-commissioned project BD1310. Final report to the Department for Environment, Food and Rural Affairs) steady regularities between biochemical substances of the soil of pastures and hydrological parameters of their water mode are revealed shows the ranking methodology affecting and dependent factors and identification of deterministic models of the relationship between the 10 factors according to the general equation consisting of the sum of two biotechnical laws.

Effects of water-saving irrigation on weed infestation and diversity in paddy fields in East China

The purpose of the article is to investigate the effects of water-saving irrigation on weed infestation and diversity in paddy fields; a two-year field experiment was conducted in Gaoyou Irrigation District, China. The responses of two irrigation treatments, controlled irrigation (CI) and traditional irrigation (TI), were observed and compared. The irrigation water use, yield, weed density, coverage ratio, height, species richness, density, dominant species, Shannon–Wiener index, and Pielou index were examined to analyze the water productivity, weed infestation, and diversity in paddy fields under the two treatments. The results showed that the water conditions were similar before the late tillering stage, and thereafter the CI fields were alternatively dry and wet with shallow standing water and low soil water content, while the TI fields were mostly continuously flooded by deep standing water and high soil water content. Irrigation water use for CI was 46.8% lower than TI. The CI treatment reduced weed density by 38.0%, decreased coverage ratio by 13.8%, and resulted in a 39.0% increase in weed height. Fewer species were found in CI fields than TI fields. The Shannon–Wiener index decreased by 11.5%, and the Pielou index increased by 3.2%. The changed water regime under CI not only impeded the growth of dominant species but also placed the whole weed community at a relatively stable level with reduced weed density. Meanwhile, aquatic weeds were well controlled; however, semi-aquatic weeds became the dominant species. In general, CI effectively reduced the risk of weed outbreaks, and weed diversity also decreased when it reduced irrigation water use.

Breeding avifauna of mature forest stands in the Borki Forest and its dynamics at the turn of the 21stcentury

AbstractThe composition and structure of the breeding bird community in the Borki Forest in north-eastern Poland were investigated during two separate periods: 1994–1996 and 2012–2014. Bird censuses were carried out in three plots located in mature oak-hornbeam, ash-alder and mixed coniferous forest stands. A standard combined mapping technique for estimating the number of breeding birds was applied. A total of 74 bird species bred at least once within any plot during 1994–1996 or 2012–2014. The structure of the bird assemblages on particular plots displayed a high degree of similarity, exceeding 75%, which means that they represent essentially the same bird community. However, the investigated assemblages have changed substantially over the 20 years. Both, the number of breeding bird species and the population densities on all plots, were much higher in 2012–2014 than in 1994–1996. The mean number of breeding species on all plots was over 50% higher in 2012–2014 than in 1994–1996, whereas the mean total density of breeding pairs increased by more than 60%. Total population densities on the plots increased as a result of an increase in population densities of individual bird species combined with an increase in the number of breeding species. Due to different rates of population growth for certain species, also the composition of dominating species group have changed. The observed changes in the avifauna of the Borki Forest were most probably due to an enrichment of the forest habitats structure, which was caused by natural factors, such as ageing of forest stands, forest succession and a change in water regime by beaver dams, as well as by forest management, including group felling within or in the vicinity of plots and uncovering of the forest edge.

Gender and household decision-making in a Lao Village: implications for livelihoods in hydropower development

Hydropower development with concomitant changes in water and land regimes often results in livelihood transformation of affected people, entailing changes in intra-household decision-making upon which livelihood strategies are based. Economic factors underlying gender dimensions of household decision-making have been studied rigorously since the 1970s. However, empirical data on gender and decision-making within households, needed for evidence-based action, remain scarce. This is more so in hydropower contexts. This article explores gender and livelihood-related decision-making within rural households in the context of hydropower development in Lao PDR. Based on a social well-being conceptual approach with data from a household survey and qualitative interviews, it focuses on household decisions in an ethnic minority resettlement site soon after displacement, from an interpretive perspective. The article, first, aims to assess the extent to which household decision-making is gendered and secondly, to understand the complex reasoning behind household decisions, especially the relevance of material, relational, and subjective factors. It argues that while most household decisions are ostensibly considered as ‘joint’ in the study site, the nuanced nature of gendered values, norms, practices, relations, attitudes, and feelings underlying these decisions are important to assessing why households might or might not adopt livelihood interventions proposed by hydropower developers.

Hydrological and Morphological Changes of the Lower Danube Near Mohács, Hungary

Abstract Various direct human impacts changed the hydro-morphology of the Danube during the last centuries. The aims of the present study are (1) to analyze the water regime of the Danube River using the data of Mohács gauging station (1900-2013), and (2) to study the channel development (1952-2014) in connection with water regime changes and human impacts at a section near Bogyiszló (upstream of Mohács). According to the results the height of low water stages decreased by approx. 136 cm (1.2 cm/year), and new, high record flood stages were measured too. The discharge values appertaining to the same low water stages doubled, thus nowadays almost twice as much water flows through the cross-section of the channel at a given stage as at the beginning of the studied period. As the duration of low stages increased, the sandbar development intensified, thus the channel became narrower (by 48% at some places) and deeper thalweg evolved. Therefore, a smaller cross-section for flood-waves evolved, affecting the height of flood. These changes affect shipping, as due to riverbed incision and decrease of low water stages, the lowest shipping water level has to be set repeatedly at lower stages. Besides water extraction from the channel will have difficulties, thus irrigation and industrial cooling water supply will be limited in the future.

Opportunities and challenges for water‐dependent protected area management arising from water management reform in the Murray–Darling Basin: a case study from the Macquarie Marshes in Australia

Abstract In dryland environments, freshwater ecosystems often suffer extensive degradation through habitat modification and water regime changes. The Macquarie Marshes are located in the Murray–Darling Basin in south‐eastern Australia. They are an example of an ecosystem that has experienced significant degradation in recent decades owing to upstream water diversions. Recent reforms of water management in the Murray–Darling Basin have attempted to balance environmental needs against consumptive uses of water. This paper examines the role a protected area has played in conserving the Macquarie Marshes freshwater ecosystem and discusses how Murray–Darling Basin water reform, together with social expectations of public land managers, have had impacts on the management of the Macquarie Marshes Nature Reserve. Protected areas may limit adverse impacts on habitat associated with local‐scale agricultural production but struggle without formal water management arrangements to protect water‐dependent ecosystems from threats operating at a catchment scale. Protected area managers balance demands from stakeholders to address local issues, such as fire management and geomorphic changes, against contributing to the achievement of environmental goals in a water planning system that operates at the catchment scale. European settlement and water resource development has marginalized local Aboriginal people from any role in land and water management activities. The water reforms have given them more opportunities for involvement in decision‐making processes, but opportunities for increased access to water for cultural and spiritual purposes remain limited. Protected areas offer a means of providing greater access for Aboriginal people to their ancestral lands. The strategies and processes developed to maintain and enhance the Macquarie Marshes exemplify the evolution in understanding of freshwater ecosystem protection in Australia, and are relevant globally to water resource management in complex social‐ecological systems. Copyright © 2016 John Wiley & Sons, Ltd.

Water regime change of surfactant polluted soils

Studies were made on the adsorption of a cationic surfactant, hexadecylpyridinium-chloride (CPC), on various soils and sediments. The aim was to determine how modify the adsorbed surfactant the soil physical characteristics, mainly water regime. Water retention were measured, pore size distribution curves were derived from water retention curves, modal suction, total porosity and rate of different pores (macro-, meso-, micro-, ultramicro- and cryptopores) were evaluated. Due to CPC treatment, samples became hydrophobic. Rate of cryptopores declined at all surfactant treated samples, while rate of micropores were raised most of the samples. Except for two samples total porosity was decreased, as well. Kind of these changes can depend on differences in particle size distribution, calcium carbonate content, aggregate stability, quantity and quality of clay minerals. As pore size changes, amount of retained water also changes.

Identification of processes controlling chemical composition of pit lakes waters located in the eastern part of Muskau Arch (Polish-German borderland) / Identyfikacja procesów kształtujących skład chemiczny wód zbiorników zlokalizowanych na obszarach pogórniczych we wschodniej części Łuku Mużakowa (pogranicze polsko-niemieckie)

Abstract Exploitation of lignite within the area of Muskau Arch, carried out from the mid-nineteenth century, contributed to the transformation of the natural environment and changes in water regime. In the post-mining subsidences pit lakes were formed. The chemical composition of waters is a consequence of the intensive weathering of pyrite (FeS2), which is present in Miocene lignite-bearing rock forming the embankments of the lakes. This process leads to the formation of Acid Mine Drainage (AMD) and finally acidification of lake waters. This paper presents results of the identification of hydrogeochemical processes affecting the chemistry of waters from these reservoirs carried out using the speciation and statistical (cluster and factor) analyses. Cluster analysis allowed to separate from the analyzed group of anthropogenic reservoirs 7 subgroups characterized by a similar chemical composition of waters. The major processes affecting the chemistry of waters were identified and interpreted with help of factor and speciation analysis of two major parameters (iron and sulfur).

Spatial and temporal variations of winter discharge under climate change: Case study of rivers in European Russia

Abstract. An important problem in hydrology is the re-evaluation of the current resources of surface and underground waters in the context of ongoing climate changes. The main feature of the present-day changes in water regime in the major portion of European Russia (ER) is the substantial increase in low-water runoff, especially in winter. In this context, some features of the spatial–temporal variations of runoff values during the winter low-water period are considered. Calculations showed that the winter runoff increased at more than 95% of hydrological gauges. Changes in the minimum and average values of runoff during winter low-water period and other characteristics are evaluated against the background of climate changes in the recent decades. The spatial and temporal variability of winter runoff in European Russia is evaluated for the first time.

Assessing climate change impacts on wetlands in a flow regulated catchment: A case study in the Macquarie Marshes, Australia

Globally wetlands are increasingly under threat due to changes in water regimes as a result of river regulation and climate change. We developed the Exploring CLimAte Impacts on Management (EXCLAIM) decision support system (DSS), which simulates flow-driven habitat condition for 16 vegetation species, 13 waterbird species and 4 fish groups in the Macquarie catchment, Australia. The EXCLAIM DSS estimates impacts to habitat condition, considering scenarios of climate change and water management. The model framework underlying the DSS is a probabilistic Bayesian network, and this approach was chosen to explicitly represent uncertainties in climate change scenarios and predicted ecological outcomes. The results suggest that the scenario with no climate change and no water resource development (i.e. flow condition without dams, weirs or water license entitlements, often regarded as a surrogate for ‘natural’ flow) consistently has the most beneficial outcomes for vegetation, waterbird and native fish. The 2030 dry climate change scenario delivers the poorest ecological outcomes overall, whereas the 2030 wet climate change scenario has beneficial outcomes for waterbird breeding, but delivers poor outcomes for river red gum and black box woodlands, and fish that prefer river channels as habitats. A formal evaluation of the waterbird breeding model showed that higher numbers of observed nest counts are typically associated with higher modelled average breeding habitat conditions. The EXCLAIM DSS provides a generic framework to link hydrology and ecological habitats for a large number of species, based on best available knowledge of their flood requirements. It is a starting point towards developing an integrated tool for assessing climate change impacts on wetland ecosystems.