Natural Hydrological Regime Research Articles

Examining gradients in ecosystem novelty: fish assemblage structure in an invaded Everglades canal system

AbstractNovel ecosystems result from a combination of altered historical abiotic regimes and new species assemblages. In freshwater systems, novel environmental conditions often result from large‐scale changes to hydrological connectivity as well as species invasions. Novel environmental conditions may affect the survival of aquatic fauna by altering dispersal patterns and resource fluctuations, and/or may impose physiological constraints on native species evolutionarily adapted to particular environments. Further, novel systems can provide insight into processes driving community structure because re‐sorting or filtering of regional biota is a likely consequence of decoupling from historical conditions. Although several studies document the presence of novel conditions, few examine variation or gradients in novelty. The Florida Everglades is a highly invaded and hydrologically altered system characterized by a large network of canals that compartmentalize the ecosystem and act to both increase and decrease connectivity. Little is known about how canals in this region function as habitat for native and nonnative fishes, the extent to which these canals may function as novel habitats, and how these habitat characteristics may influence distribution, abundance, and assembly patterns. In this study, we examined native and nonnative fish assemblages along a gradient of novelty, defined as the loss of wetland connectivity, influence of the natural hydrological regime, and habitat complexity (well connected to leveed canals). As novelty increased, native species richness and abundance strongly declined and the contribution of nonnatives increased to nearly 50%. Vast differences in community structure across the novelty gradient were strongly influenced by spatial factors and secondarily by hydrological factors, while habitat and abiotic factors were of very low relevance. Natives and nonnatives had opposing responses to key hydrological and habitat characteristics. Abundance of native fishes declined with decreased connectivity to adjacent marshes and canal littoral zone width, while nonnative fishes increased significantly in the most novel canals. Our results suggest that the inherent loss of natural environmental conditions and subsequent replacement by novel ones can lead to extensive changes in fish community structure. Success or failure at maintaining native assemblages will rely heavily on natural resource manager's ability to incorporate natural environmental characteristics with ecosystem restoration.

Водные ресурсы озера Байкал и возможные стратегии управления его уровенным режимом

Over the recent years the Lake Baikal basin and the lake itself face the developing complicated water/economic situation due to the long-term low water period and inadequately substantiated limitations of the water level fluctuations. The Lake Baikal water resources are used for purposes of power production and water supply, therefore negative environmental phenomena are often associated with probable disturbances of natural hydrological regime. Existing approaches to the Lake Baikal water resources management and recommendations on intensification of its environment-protective aspects have been considered. Dates of the maximal and minimal level periods starting, the level fluctuations amplitude, the lake filling speed, and other parameters significant changing of those can affect the Baikal ecosystem status were used as a set of ecological indicators (limitations). The choice of the Baikal level regime control strategy has been done on the basis of analysis of water/economic ecological indicators-based calculations results. Results of calculations of the water resources availability for different water users and fulfilling of ecosystem requirements expressed as distribution of probabilities of respective indicators of the Lake Baikal level fluctuations are presented. Conclusions on the preference of one of the discussed schemes of the runoff regulation have been made.

Fine-scale determinants of conservation value of river reaches in a hotspot of native and non-native species diversity

Global freshwater biodiversity is declining at unprecedented rates while non-native species are expanding. Examining diversity patterns across variable river conditions can help develop better management strategies. However, many indicators can be used to determine the conservartion value of aquatic communities, and little is known of how well they correlate to each other in making diagnostics, including when testing for the efficacy of protected areas. Using an extensive data set (99,700km2, n=530 sites) across protected and unprotected river reaches in 15 catchments of NE Spain, we examine correlations among 20 indicators of conservation value of fish communities, including the benefits they provide to birds and threatened mammals and mussels. Our results showed that total native fish abundance or richness correlated reasonably well with many native indicators. However, the lack of a strong congruence led modelling techniques to identify different river attributes for each indicator of conservation value. Overall, tributaries were identified as native fish refugees, and nutrient pollution, salinization, low water velocity and poor habitat structure as major threats to the native biota. We also found that protected areas offered limited coverage to major components of biodiversity, including rarity, threat and host-parasite relationships, even though values of non-native indicators were notably reduced. In conclusion, restoring natural hydrological regimes and water chemical status is a priority to stem freshwater biodiversity loss in this region. A complementary action can be the protection of tributaries, but more studies examining multiple components of diversity are necessary to fully test their potential as fluvial reserves in Mediterranean climate areas.

Long-term environmental drivers of DOC fluxes: Linkages between management, hydrology and climate in a subtropical coastal estuary

Urban and agricultural development of the South Florida peninsula has disrupted historic freshwater flow in the Everglades, a hydrologically connected ecosystem stretching from central Florida to the Gulf of Mexico, USA. Current system-scale restoration efforts aim to restore natural hydrologic regimes to reestablish pre-drainage ecosystem functioning through increased water availability, quality and timing. Aquatic transport of carbon in this ecosystem, primarily as dissolved organic carbon (DOC), plays a critical role in biogeochemical cycling and food-web dynamics, and will be affected both by water management policies and climate change. To better understand DOC dynamics in South Florida estuaries and how hydrology, climate and water management may affect them, 14 years of monthly data collected in the Shark River estuary were used to examine DOC flux dynamics in a broader environmental context. Multivariate statistical methods were applied to long-term datasets for hydrology, water quality and climate to untangle the interconnected environmental drivers that control DOC export at monthly and annual scales. DOC fluxes were determined to be primarily controlled by hydrology but also by seasonality and long-term climate patterns and episodic weather events. A four-component model (salinity, rainfall, inflow, Atlantic Multidecadal Oscillation) capable of predicting DOC fluxes (R2 = 0.84, p < 0.0001, n = 155) was established and applied to potential climate change scenarios for the Everglades to assess DOC flux response to climate and restoration variables. The majority of scenario runs indicated that DOC export from the Everglades is expected to decrease due to future changes in rainfall, water management and salinity.

Variant restoration trajectories for wetland plant communities on a channelized floodplain

AbstractRestoration efforts are typically based on an assumption that reestablishment of altered determinants of ecological structure and function will lead to a predictable reestablishment of populations and reassembly of communities. Dechannelization and reestablishment of natural hydrologic regimes provide the basis for the ongoing restoration of the Kissimmee River in Central Florida, United States. The expected reestablishment of historically dominant broadleaf marsh (BLM) and buttonbush shrub (BB) communities was evaluated over a 10‐year period following implementation of the first phase of the restoration project. Plant species composition and cover were assessed during dry (spring) and wet (summer) season sampling periods at five sites on the restored floodplain, and four “control” sites on the channelized floodplain. Mean daily stage data from nearby gauges indicated hydroperiods and depths on the reflooded floodplain were within the range of historic hydrologic conditions that selected for BLM and BB communities on the pre‐channelization floodplain. After reflooding, pasture grass and upland shrub communities rapidly transitioned to a fluid mix of obligate and facultative wetland species. Although signature BLM and BB species, Sagittaria lancifolia (bulltongue arrowhead), Pontederia cordata (pickerel weed), and Cephalanthus occidentalis (buttonbush), recolonized all study sites, the expected reestablishment of dominant cover of these species did not occur. Results indicate that restoration of BLM and BB communities has been impeded by deep flood pulse disturbances, establishment of invasive wetland grasses, and mineralized soil characteristics of the drained floodplain.

Ecosystem analysis of the degrading Vembanad wetland ecosystem, the largest Ramsar site on the South West Coast of India — Measures for its sustainable management

Vembanad wetland ecosystem — the largest Ramsar site on the South West Coast of India, located in the most populous coastal segments of Kerala, serves as the rice bowl of the state that forms a major hotspot of biological diversity. Alterations in natural hydrologic regime of Vembanad wetland started with the commissioning of Thanneermukkom barrage (TMB) across the backwater system in 1976, to prevent saline water intrusion, which adversely affected the eco-biology of the water body. The study was conducted during March 2011 to February 2012 on a monthly basis to evaluate the eco-hydrological status of this multifunctional ecosystem. Reclamation of estuarine areas for agriculture and other interventions has led to drastic decline in water holding capacity (2.4 to 0.6 km3) and depth (av. 4.02 m) of the estuary over the years. Water quality on an average reflects a neutral (7.11) and well oxygenated (7.4 mg L−1) nature; the salinity varying from 0.01 to 31.8 ppt. TMB plays a crucial role in influencing the salinity pattern of Vembanad wetland; with an oligohaline (0.5–5 ppt) in southern whereas meso and polyhaline (5–18 ppt) condition prevailing in northern stations. The estuary is nutrient rich with nitrate-nitrogen and phosphate-phosphorus ranging between 0.05–5.9 μmol L−1 and 0.18–6.49 μmol L−1 respectively. Trophic index (TRIX value 6.39 ± 0.75) indicated an impacted water quality condition leading to an accelerated eutrophication in the system. Bacillariophyceae (83.55%), Chlorophyceae (8.98%), Cyanophyceae (6.92%) and Zygnemophyceae (0.55%) were the major phytoplankton. Zooplankton community was composed of calanoids (63%), rotifers (22.5%), copepodites (2%), amphipoda (2%), crustacean naupli (1.5%) and cladocerans (1.2%) showing a declining trend in post barrage phase. Benthic polychaetes like Spionidae and Capitellidae were opportunistic bio-indicators of organic enrichment. Decline in fishery diversity and production (4387.31 t), reflects considerable ecological impacts on lower trophic levels. Thus the study presents an over view on a degrading coastal wetland system of India and signifies the need for enhanced restoration programmes for long term management and conservation objectives.

Hydrological alterations from water infrastructure development in the Mekong floodplains

AbstractThe Mekong floodplains, which encompasses the region from Kratie Township in Central Cambodia to the Vietnamese East Sea, is a region of globally renown agricultural productivity and biodiversity. The construction of 135 dams across the Mekong basin and the development of delta‐based flood prevention systems have caused public concern given possible threats on the stability of agricultural and ecological systems in the floodplains. Mekong dams store water upstream and regulate flow seasonality, while in situ flood prevention systems re‐distribute water retention capacity in the floodplains. The main aim of this paper is to evaluate possible impacts of the recent development of both hydropower dams and flood prevention systems on hydrological regimes in the Mekong floodplains. An analysis of measured daily and hourly water level data for key stations in the Mekong floodplains from Kratie to the river mouth in Vietnam was conducted. Hydropower dam information was obtained from the hydropower database managed by the Mekong River Commission, and the MODIS satellite imagery was used to detect changes in flooding extent related to the operation of flood prevention systems in the Vietnam Mekong Delta. Results indicate that the upper part of the floodplains, the Cambodian floodplains, may buffer upstream dam impacts to the Vietnam Mekong Delta. Flood prevention up to date has had the greatest effect on the natural hydrological regime of the Mekong floodplains, evidenced by a significant increase of water level rise and fall rates in the upper delta and causing water levels in the middle delta to increase. The development of flood prevention systems has also effected spatial distribution of flooding as indicated via a time series analysis of satellite imagery. While this development leads to increase localized agricultural productivity, our historical data analysis indicates that development of one region detrimentally affects other regions within the delta, which could increase the risk of future conflicts among regions, economic sectors and the ecological value of these important floodplains. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Resilience changes in watershed systems: A new perspective to quantify long-term hydrological shifts under perturbations

Natural hydrological regimes are essential to the stability of river basins. While numerous efforts have been put forth to characterize flow regime alterations driven by climate change and human activities, few approaches have been proposed to explore changes in watershed resilience. The present study attempted to introduce a systematic approach that can be used to identify the resilience change of river basins based on annual river discharge through the application of a convex model and the principle of critical slowing down. Specifically, a resilience indicator (pi) that reflects streamflow autocorrelation at a given time was proposed to represent the temporal variation of the system resilience, and annual water discharge at representative hydrological stations located in upstream, midstream, and downstream regions of a river basin was used to reflect alterations in long-term hydrological processes and the stability of river basins. The application of this method to the Yellow River basin and Yangtze River basin indicated that the system resilience was lower in downstream regions compared to upstream regions. The Yellow River basin has suffered a decrease in resilience in its lower reaches since 1971, which extended to the middle reaches in 1987 and upper reaches in 1990. Similarly, recent observation of the resilience change in the Yangtze River basin indicated that resilience in its lower reaches has likely decreased since 2002, and this low resilience extended to the middle reaches in 2005. Overall, our study presents a new method to predict potential decreases of resilience in complex large scale watershed systems where mechanistic insight is insufficient to build reliable basin-scale hydrological, climate, ecosystem integrated models.

Application of benthic diatoms to assess efficiency of conservation management: a case study on the example of three reconstructed soda pans, Hungary

The number of shallow soda pans decreased drastically all over the world and their conservation needs to be urgently forced. Due to their unique physical and chemical features, the lack of appropriate management plans has been a worldwide issue. The aim of present paper was to study the efficiency of the applied water management in three Central European reconstructed soda pans based on their benthic diatom communities, physical and chemical parameters in the years 2012 and 2014. The diatom composition and the diversity metrics indicate unequivocally a worse ecological status of Borsodi-dűlő and Nyeki-szallas than it is characteristic for their natural conditions, which is attributable to their irregular water level modifications. The ecological status of the Legeny-to was far from the required because its conductivity was constantly low, diversity was high and the flora was dominated by mainly freshwater diatom species due to the lack of the natural hydrological cycle. However, these pans have significant conservation values; their good ecological status should be completely reached by restoring their natural hydrological and disturbance regimes.

Effects of high water discharge from Alcalá dam on fish larval stages of Guadalquivir estuary

Event Abstract Back to Event Effects of high water discharge from Alcalá dam on fish larval stages of Guadalquivir estuary Juan Miguel Miró1*, César Megina1, Iñigo Donázar-Aramendía1, Emilio Sánchez-Moyano1, Isabel García-Asencio1 and J. Carlos García-Gómez1 1 Facultad de Biología, Universidad de Sevilla, Departamento de Zoología, Spain Estuaries are unstable systems, generally with a limited number of species. However, they support a high productivity, frequently being important nursery zones where postlarvae and juvenile fishes find some good conditions for its development. Most of estuaries have the freshwater input regulated by dams, altering estuarine natural hydrological regime. Nevertheless, high discharges can modify sharply column water structure, influencing organisms that live inside by eliminating salinity gradient or increasing turbidity and flow velocity. These changes affect nursery function of estuaries. In this study, we analyse the effects of freshwater input episode, which come from Alcalá Dam after a high rainfall, on larval stages of Guadalquivir estuary (Southwestern Spain). Sampling were carried out before (24 m3/s), during (151 m3/s) and after (14 m3/s) a high dam discharge. Samples were taken with a zooplankton net with 1 meter mouth diameter and 1000 µm mesh size. Double oblique tows were performed from surface to bottom during flood tide, in the main channel. Samples were taken along the estuarine section where larval stages had been detected, including some external marine areas (~35‰). In every sampling area 3-5 replicated tows were done. Physiochemical data of the water column were also recorded in all water masses with a multi-parameter probe (salinity, temperature, turbidity, HDO, depth and pH). First preliminary results were analysed. Data from probe showed relevant changes in water column parameters and, even if this is a well-mixed estuary, we observed a salinity stratification up until 15 grades from the bottom to the surface during high discharge episode. Abundance of fish juvenile phases decreased markedly during high fresh water inputs episode, although it recovered partially after a short period. Still, this effect was not equal for all species. Additional episodes of high dam discharge will be sampled and analysed to obtain a more general pattern and to propose management strategies related to river discharges. Acknowledgements We thank to Autoridad Portuaria de Sevilla (APS) for financial support. This work was partially supported by the V Plan Propio Universidad de Sevilla via a pre-doctoral grant. Keywords: Fish larval stages, Dam discharge, Water column structure, Nursery area, Guadalquivir estuary Conference: XIX Iberian Symposium on Marine Biology Studies, Porto, Portugal, 5 Sep - 9 Sep, 2016. Presentation Type: Poster Presentation Topic: 1. ECOLOGY, BIODIVERSITY AND VULNERABLE ECOSYSTEMS Citation: Miró J, Megina C, Donázar-Aramendía I, Sánchez-Moyano E, García-Asencio I and García-Gómez J (2016). Effects of high water discharge from Alcalá dam on fish larval stages of Guadalquivir estuary. Front. Mar. Sci. Conference Abstract: XIX Iberian Symposium on Marine Biology Studies. doi: 10.3389/conf.FMARS.2016.05.00118 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 29 Apr 2016; Published Online: 03 Sep 2016. * Correspondence: PhD. Juan Miguel Miró, Facultad de Biología, Universidad de Sevilla, Departamento de Zoología, Sevilla, Sevilla, 41012, Spain, jmmiro@us.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Juan Miguel Miró César Megina Iñigo Donázar-Aramendía Emilio Sánchez-Moyano Isabel García-Asencio J. Carlos García-Gómez Google Juan Miguel Miró César Megina Iñigo Donázar-Aramendía Emilio Sánchez-Moyano Isabel García-Asencio J. Carlos García-Gómez Google Scholar Juan Miguel Miró César Megina Iñigo Donázar-Aramendía Emilio Sánchez-Moyano Isabel García-Asencio J. Carlos García-Gómez PubMed Juan Miguel Miró César Megina Iñigo Donázar-Aramendía Emilio Sánchez-Moyano Isabel García-Asencio J. Carlos García-Gómez Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Determination of daily eco‐hydrographs by the fish spawning habitat suitability model and application to reservoir eco‐operation

AbstractGlobal conflict over water has become increasingly problematic. To meet water demands for economic growth in China, a large number of hydro‐projects have been developed and operated, which have significantly altered the natural hydrological regime of many rivers and imposed profound impact on aquatic ecosystems. Conservation of appropriate ecological flow is essential to balance river ecosystem health and economic development. We proposed an innovative method for river eco‐hydrograph determination based on the protection of fish spawning habitat. An integrated hydro‐environmental‐habitat model was developed and applied in de‐watered channels in the middle of Yalong River, China, where water was diverted for hydropower generation. Schizothorax chongi (S. chongi), the dominant and commercial indigenous fish, was selected as the target species. Different from previous research, the impacts of fragmentation and water level variation on fish habitat were analysed in the spawning period. Eco‐hydrographs for different preservation levels of S. chongi spawning habitat were estimated using the developed model, and the suitable one was recommended. Compared with traditional hydrologic and hydraulic methods, the improved habitat method not only determined the ecological water demand of the species more meaningfully but also increased water use efficiency. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Tailwater habitat stability after dam removal and return to a natural hydrological regime

Abstract The study was conducted from 2000 to 2003 in the tailwater of the Drzewieckie Lake, an artificial reservoir in Central Poland. Short-term peaks in water flow were generated for the purpose of the operation of a whitewater slalom canoeing track built just downstream of the dam. In 2002, the reservoir was drawn down. The patterns in habitat samples were recognized with a Kohonen’s unsupervised artificial neural network (SOM). The SOM spatial gradient was stronger than the SOM temporal gradient, which shows that the removal of the studied dam did not have a destructive impact on habitats’ features, as shown in other studies, and that the patchy nature of the riverbed has been maintained. The complete emptying of the Drzewieckie Lake took place at the beginning of the vegetation season, which allowed plants to cover the exposed bottom of the reservoir and, consequently, reduce the downstream flow of organic matter accumulated there. Patterns in the displacement of aquatic macrophytes, inorganic substratum and different fractions of particulate organic matter are discussed. The amount of dissolved oxygen decreased because of the lack of intensive water discharge from the reservoir into the river, which would result in high water turbulence. Results of this study are important for planning the ecologically sound dam removals.

Reservoir-Induced Changes in Flow Fluctuations at Monthly and Hourly Scales: Case Study of the Qingyi River, China

AbstractReservoirs play an important role in modifying the natural hydrological regime. Reservoir-induced changes in flow fluctuations at monthly and hourly scales were analyzed through a case study of a tributary of the Yangtze River (China), the Qingyi River, where the Chencun reservoir is located at the upper reaches. Monthly and hourly flow data were collected from two flow gauging stations monitoring the inflow and outflow regimes, respectively. The flow fluctuations were characterized by coefficient of variation (CV) and concentration degree (Cd). Continuous Morlet wavelet transform was applied to detect diurnal period. The influence of the reservoir was revealed comparing the postdam with the predam conditions by and comparing the affected with the natural conditions. The results indicate two opposite change patterns. Reservoir impoundment may mitigate flow fluctuations at both of the monthly and the hourly scales. At a monthly scale, reservoirs usually impound water in the flood season for the dry...

High-resolution distributed analysis of climate and anthropogenic changes on the hydrology of an Alpine catchment

Summary A fully distributed hydrological analysis at scales significant for water management for present-day, and projected future climate conditions is presented for a catchment in the Alps. We selected the upper Rhone basin (Switzerland) as a test case for understanding anthropogenic impacts including climate change on water resources and flood risk in the Alpine area. The upper Rhone basin contains reservoirs, river diversions and irrigated areas offering the opportunity to study the interaction between climate change effects and hydraulic infrastructure. Anthropogenic disturbances of the flow regime were implemented in detail in the hydrological analysis. We downscaled climate model realizations using a methodology that accounts for the uncertainty in climate change projections related to the stochastic variability of precipitation and air temperature. We showed how climate change effects on streamflow propagate from high elevation headwater catchments to the river in the main valley by analyzing changes in several hydrological metrics and at various temporal scales across 297 control sections. Changes in the natural hydrological regime imposed by the existing hydraulic infrastructure are likely larger than climate change signals expected by the middle of the 21st century in most of the river network. Despite a strong uncertainty induced by stochastic climate variability, we identified an elevational dependence of climate change impacts with a severe reduction in streamflow due to the missing contribution of water from ice melt at high-elevation and a dampened effect downstream. Reduced ice cover and ice melt are likely to have significant implications for hydropower production. The impacts can emerge without any additional climate warming. A decrease of August–September discharge and an increase of hourly and daily maximum flows appear as plausible projected change for the most part of the catchment. However, it is unlikely that major changes in total runoff for the entire upper Rhone basin will occur in the next four decades.

REI: riparian ecosystem index to assess the impact of hydrologic regime changes on riparian ecosystems

AbstractWe developed a geographic information systems (GIS)‐based multi‐metric assessment tool using model‐simulated long‐term vegetation data to assess changes in riparian ecosystems due to altered hydrologic regimes. This allowed us to estimate spatial changes in a riparian system over several decades at annual resolution, to study system trends through time, and the effect of multiple and time‐distributed human activities. We applied the tool to assess human and hydrologic impacts, for two scenarios, pre‐dam versus post‐dam periods and pre‐levee versus post‐levee periods on the Kootenai River. The pre‐dam versus post‐dam scenario considers two distinct hydrologic regimes as a result of dam operation, whereas the pre‐levee versus post‐levee scenario has one single natural hydrologic regime. We compared riparian ecosystem, community composition and native woody riparian vegetation index scores within the two scenarios. Our results showed that all three time‐averaged index scores (riparian ecosystem, community composition and native woody vegetation) were statistically higher for the pre‐dam than the post‐dam period. In contrast, differences in index scores were small and were not statistically significant between pre‐levee and post‐levee periods. Thus, our GIS‐based assessment tool can detect the impact of human‐induced changes in the natural hydrologic regime on riparian ecosystems both temporally and spatially. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Avaliação das modificações hidrológicas ocorridas na Estação de Porto São José, situada em um trecho do rio Paraná regulado por Usinas Hidrelétricas

Hydroelectric Plants (UHE- Usinas Hidroeletricas) are importantly represented on the Brazilian energy scene, and provide the base for the National Interconnected System (SIN Sistema Interligado Nacional). However, one of the consequences of UHE operation is changes in the natural hydrological regimes of the river system both upstream and downstream from the dam. For this reason this paper analyzes the possible hydrological changes at a rivergauging station downstream from a hydropower plant, based on field campaigns with flow measurements carried out during the period from 1965 to 2014, bathymetric surveys and historical series of water levels The results obtained for Porto Sao Jose Station (PSJ) in Parana river, 30 km downstream from UJE Porto Primavera and UHE Rosana, indicate the occurrence of erosion in the PSJ section with a 28% increase in the wetted area and 20% reduction of mean velocity. Because of these changes a new rating curve was determined for the permanent flow condition, and the non-permanent flow condition (hysteresis) was identified and corrected for PSJ. Thus, taking the sum total of outflows from the UHEs as reference, the calibration table indicates monthly deviations of -500 m3 s-1, the rating curve for permanent flow deviations of - 90 m3 s-1, and the rating curve for non permanent flows deviations of -75 m3 s-1. Although the rating curve for permanent flows presents small monthly deviations (- 90 m3 s-1), because of the daily energy demands, the outflows from the UHE cause hourly deviations at PSJ of +640 to -610 m3 s-1 (mean of 17 m3 s-1). Thus flow regulation in this reach of Parana River caused alterations of hydrological and hydraulic variables at PSJ (e.g. area, velocity, runoff for non-permanent condition) which could be correctly represented by rating curves defined by continuous field campaigns

Russian

The Earth now is in a state of human-induced uncertainty of geospheres, biosphere, climate change, degradation of water systems. Water has become a global deficit, is required a review of the world water policy. Irrigation consumes 95% of fresh water. Irrigation for thousands years is imitated the natural hydrological regime, although the natural hydrological regime is oriented on biological diversity of the biosphere, not to obtain the desired maximum output at the lowest amount of water. This is a systemic defect of currently accepted worldwide as a standard the gravitational simulative frontal continuum-isotropic irrigation paradigm. Using this paradigm we do not solve the problem of transformation of concentrated water flow into the moisture continuum in the soil, dispersed in the soil continuum in the area of plant roots in an amount necessary for plant nutrition with high quality soil solution. Copying natural hydrological regime the obsolete irrigation technologies causes an uncontrollable mass-transfer in the soil continuum and vadose zone, violation of geochemical barriers, degradation of soil and landscape. The crisis is due to the inability to control irrigation biogeosystems. An old irrigation paradigm gives the long-term negative result. Due to systemic irrigation defects in the world ecological humanitarian disasters occur. Modernization of irrigation has been slow and is aimed at partial improvement technology within the old paradigm. Water consumption of standard irrigation is of 5-15 times more than empirically assessed need of plant, in its turn, this calculated water demand is overestimated for 2-3 times concerning the biologically based need of plants for water. Excess water consumption is dangerous because the standard methods of hydrological forecasting now reviewing a fall. The problem of hydrological regime of pedosphere managing as the main component of the Irrigation paradigm and Water Strategy of the world has not yet been solved. The synthesis requires of a new irrigation technology platform - delete the currently accepted range of iriigation thermodynamic potential of water from 0.0 to -0.03 MPa, providing a range of stomatal regulation of transpiration from -0.2 MPa to -0.5 MPa. For ecologically meaningful management of biosphere is proposed the biogeosystem technique. Within the framework of biogeosystem technique the new intra-soil pulse continuous-discrete irrigation paradigm is proposed, the configuration of artifacts for its implementation too. It provides a controlled dissipation of discrete water volumes inside the soil continuum. The new paradigm excludes irrigation mass-transfer, excessive soil moisture, evaporation, loss of water to the vadose zone, soil degradation, destruction of geochemical barriers. By providing the stomatal regulation of transpiration regime the demand for water for irrigation is less up to 10-30 times compared to standard irrigation. The new paradigm of

Evaluation of Sustainable Environmental Flows Based on the Valuation of Ecosystem Services: a Case Study for the Baiyangdian Wetland, China

Using China's Baiyangdian Wetland as a case study, we evaluated the sustainable level of environmental flows for the wetland based on a statistical relationship between the ecosystem service values and hydrological data. We used canonical correlation analysis to reveal the relationships between seven major ecosystem services (gross production of agriculture, fish and reeds; water supply; recreation; culture; habitat protection; climate regulation; and water purification) and a hydrological dataset (annual inflows, annual outflows, mean annual water elevation, 7-day low elevation, duration of the flood pulse, and number of days of extreme drought) from 1980 to 2005. Using this approach, we established a gray relationship matrix to reveal the influence of the hydrological parameters on the ecosystem services value. Using the hydrological parameters shown to significantly influence the ecosystem services values as the set of environmental flows, we evaluated the sustainable environmental flows by mean of cubic spline interpolation between data points to identify the maximum wetland ecosystem services value. The results were justified by referring to the natural hydrological regime in the 1960s and 1970s. Based on the results of this comparison, our approach provides an effective way for managers to regulate the flows of water to satisfy the wetland’s environmental flow requirements while also obtaining the maximum socioeconomic benefit.

Change in agricultural land use constrains adaptation of national wildlife refuges to climate change

SUMMARYLand-use change around protected areas limits their ability to conserve biodiversity by altering ecological processes such as natural hydrologic and disturbance regimes, facilitating species invasions, and interfering with dispersal of organisms. This paper informs USA National Wildlife Refuge System conservation planning by predicting future land-use change on lands within 25 km distance of 461 refuges in the USA using an econometric model. The model contained two differing policy scenarios, namely a ‘business-as-usual’ scenario and a ‘pro-agriculture’ scenario. Regardless of scenario, by 2051, forest cover and urban land use were predicted to increase around refuges, while the extent of range and pasture was predicted to decrease; cropland use decreased under the business-as-usual scenario, but increased under the pro-agriculture scenario. Increasing agricultural land value under the pro-agriculture scenario slowed an expected increase in forest around refuges, and doubled the rate of range and pasture loss. Intensity of land-use change on lands surrounding refuges differed by regions. Regional differences among scenarios revealed that an understanding of regional and local land-use dynamics and management options was an essential requirement to effectively manage these conserved lands. Such knowledge is particularly important given the predicted need to adapt to a changing global climate.

Impacts of Changing Hydrology and Hurricanes on Forest Structure and Growth Along a Flooding/Elevation Gradient in a South Louisiana Forested Wetland from 1986 to 2009

Alterations to Louisiana’s coastal landscape during the last 200 years have resulted in major changes to the natural hydrologic regime. Hurricane and tornado winds further impact coastal forests by exacerbating conditions that affect community structure, growth, and regeneration. Twenty-three years of study of forested wetlands in the Lake Verret watershed provide an opportunity to relate changes in forest communities to precipitation, drought, storms, and rising water levels. The area had two communities in 1986, but four communities were present by 2009. A major change in community composition occurred in drier sites after Hurricane Andrew (1992), when Chinese tallow (Triadica sebifera) became established. Swamp plots were generally not affected by hurricanes, but composition continued to change as a result of flooding. After Hurricane Andrew, net primary productivity (NPP) declined dramatically until 2001. Subsequent hurricanes in 2004 and 2005 also caused reductions in NPP, but recovery was rapid. Low-lying and transition areas are trending from bottomland communities toward more of a deepwater swamp as baldcypress (Taxodium distichum) and water tupelo (Nyssa aquatica) increase their stature, likely due to the system-wide flooding. Natural ridges are flooded less often and have remained primarily bottomland, though Chinese tallow (Triadica sebiferum) numbers increased following Hurricane Andrew.