Water Stocks Research Articles

Identifying risk factors associated with White Spot Disease outbreaks of shrimps in the Gulf of California (Mexico) through expert opinion and surveys

AbstractWhite spot disease is one of the most serious problems in the shrimp‐farming industry in Mexico. An assessment of risk of an outbreak of the disease could be useful for farmers making decisions concerning early harvest to minimize economic losses. A group of researchers identified the most important risk factors, classified in four broad categories: management variables at the regional level, environmental variables at the regional level, management variables at the farm and population variables at the farm. For each variable, categories were defined and a risk score assigned. To validate these scores, a survey was carried out with 65 stakeholders. A semi‐quantitative risk assessment model was proposed and implemented as a questionnaire containing 21 risk variables with weighted scores. The most important risk factors were the period of fallowing within farm's region and health quality of larvae. Also important were estimated level of viral load and virus detection in wild hosts in the surrounding area, pond water temperature, length of fallowing period of pond, vector control at water intake and stocking density. The overall estimated risk was calculated as the sum of all scores with a further adjustment, according to maximum and minimum total scores. Three risk levels for white spot disease outbreak at ponds are based on estimated risk: low (≤0.2), moderate (0.2–0.4) and high (≥0.4).

Dynamics of European eel landings and stocks in the coastal waters of Estonia

AbstractEuropean eel stocks are in a decline all over Europe. In Estonia, we analysed three different dataseries (commercial landings 1969–2014, scientific eel monitoring 1998–2014, and recreational catches 2005–2012). In the commercial fishery, the biggest drop in landings occurred in the 1980s, with a small recovery in the end of the 1990s. We also interviewed fishers to evaluate the quality of the official catch figures. In the monitoring dataseries, gathered by the use of special eel fykenets, the steepest cpue decline occurred in the last 5 years. Finally, recreational eel fishery has almost stopped: in 2012, catches were only 3% of that in 2005. In conclusion, both professional and recreational eel catches have declined in all the coastal areas of Estonia. The number of professional and recreational fishers specialized to eel fishing has decreased and the number of licences for eel-specific fishing gear has been reduced.

How to assess urban development potential in mountain areas? An approach of ecological carrying capacity in the view of coupled human and natural systems

How to assort with the relationship between mountain development and ecological protection is a key issue during the process of mountainous urban construction. Ecological carrying capacity (ECC), as the key to measuring regional sustainable development in terms of society, economy and ecology, provides an approach to assess urban development potential in mountain areas. Taking Dali Bai Autonomous Prefecture in Yunnan Province, China as a study area, this study has explored the conceptual framework for ECC in view of coupled human and natural systems (CHANS), and has constructed an index system using aspects of ecosystem vigor (EV), resources and environmental carrying capacity (RECC), and social development ability (SDA). The results at the county level showed that: (1) Dali City had the highest EV and SDA, with a relatively good ecological background, stable geological environment, and more concentrated population and flourishing urbanization. Yunlong County occupied the best RECC for its relatively abundant stock of water and land resources. Due to well-balanced ecosystem stability maintenance, resource utilization, and human development, Yunlong County possessed the highest ECC all over the prefecture; (2) the study area can be grouped into five categories considering trade-offs between mountain development and ecological protection. That is, priority areas for conservation, priority areas for development, areas suitable for short-term conservation but long-term development, areas suitable for short-term development but long-term conversation, and areas reserved for future appropriate development. This research could help to identify the approach to sustainable mountain development from the perspective of CHANS, and to make effective contribution to urban development decision-making in mountainous areas.

Length at maturity as a potential indicator of fishing pressure effects on coastal pikeperch (Sander lucioperca) stocks in the northern Baltic Sea

In the Baltic Sea, the pikeperch is one of the commercially important coastal fish species. Most of the local pikeperch stocks in this area can be classified as data-limited. There is an increasing need to monitor the state of all commercial fish stocks in European waters due to the EU Marine Strategy Framework Directive (MSFD). Proper stock assessment is not required in all cases, and alternative and less data demanding approaches and indicators can also be applied. In this study, we combined data on three of the best-studied coastal pikeperch stocks in the northern Baltic Sea to evaluate the performance of length at maturity indicators. A connection was found between intensive selective fishing and the length at maturity (TL50) of female pikeperch. Power analysis indicated that a sample size of 200–400 females, or around 35–70 samples per year, produces reasonable and almost maximal precision when determining the six-year mean TL50 for a stock. Our analysis also demonstrated that in cases where a monitored parameter is annually variable, an increase in the annual sample size does not continuously yield higher precision in the long-term mean, but it is crucial that samples are collected annually. We conclude that TL50 is a promising and cost-efficient indicator of the effects of fisheries on the maturation of coastal pikeperch stocks. This indicator could be further tested after a few years when more data become available.

The new assessment of soil loss by water erosion in Europe

Soil erosion by water is one of the major threats to soils in the European Union, with a negative impact on ecosystem services, crop production, drinking water and carbon stocks. The European Commission's Soil Thematic Strategy has identified soil erosion as a relevant issue for the European Union, and has proposed an approach to monitor soil erosion. This paper presents the application of a modified version of the Revised Universal Soil Loss Equation (RUSLE) model (RUSLE2015) to estimate soil loss in Europe for the reference year 2010, within which the input factors (Rainfall erosivity, Soil erodibility, Cover-Management, Topography, Support practices) are modelled with the most recently available pan-European datasets. While RUSLE has been used before in Europe, RUSLE2015 improves the quality of estimation by introducing updated (2010), high-resolution (100m), peer-reviewed input layers. The mean soil loss rate in the European Union's erosion-prone lands (agricultural, forests and semi-natural areas) was found to be 2.46 t ha−1 yr−1, resulting in a total soil loss of 970 Mt annually.A major benefit of RUSLE2015 is that it can incorporate the effects of policy scenarios based on land-use changes and support practices. The impact of the Good Agricultural and Environmental Condition (GAEC) requirements of the Common Agricultural Policy (CAP) and the EU's guidelines for soil protection can be grouped under land management (reduced/no till, plant residues, cover crops) and support practices (contour farming, maintenance of stone walls and grass margins). The policy interventions (GAEC, Soil Thematic Strategy) over the past decade have reduced the soil loss rate by 9.5% on average in Europe, and by 20% for arable lands. Special attention is given to the 4 million ha of croplands which currently have unsustainable soil loss rates of more than 5 t ha−1 yr−1, and to which policy measures should be targeted.

Satellites provide the big picture.

INSIGHTS Mountain range formation p. 687 Rethinking vascular therapy for cancer p. 694 ▶ PERSPECTIVES WATER Downloaded from www.sciencemag.org on September 14, 2015 Watching water: From sky or stream? Monitoring and management of freshwater resources has long depended upon on-the-ground measurements. Satellite remote sensing has brought new complementing capabilities. In this final of three debates, Science invited arguments about the appropriate roles for, and balance between, each approach. By J. S. Famiglietti, 1, 2, 3 * A. Cazenave, 4, 5 A. Eicker , 6 J. T. Reager, 1 M. Rodell , 7 I. Velicogna 1 ,2 Satellite observations have revolutionized our understanding of hydrology, water availability, and global change, while catalyzing modern advances in weather, flood, drought, and fire prediction in ways that would not have occurred with relatively sparse POLICY ground-based measurements alone. Earth-observing satellites provide the necessary “big-picture” spatial coverage, as well as the regional-to-global understanding essential for improving predictive models and informing policy-makers, re- source managers, and the general public. Sustained investments in a robust satellite hydrology program have enabled a plethora of discoveries, along with modernization of water management, that have increased the human, economic, and water security of many nations. We now recognize distinct human- and climate-driven fingerprints on the water landscape that are dramatically changing the distribution of freshwater on Earth ( 1). Improved understanding and heightened societal aware- ness of the global extent of sea-level rise ( 2), ice sheet and glacial melt ( 3), changing rainfall patterns ( 4), declining snow cover ( 5), groundwater depletion ( 6), and the changing extremes of flooding ( 7) and drought ( 8) simply would not have occurred without satel- lite observations. As we look ahead, ongoing and near-future missions will soon provide routine global monitoring of the stocks of soil moisture ( 9), surface water ( 10), and total water storage ( 11)—which will im- prove estimates of groundwater storage changes ( 12)—and of the fluxes of precipitation ( 4) and evapotranspiration ( 13). Taken to- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA. Department of Earth System Science, University of California, Irvine, CA, USA. 3 Department of Civil and Environmental Engineering, University of California, Irvine, CA, USA. 4 Centre National d’Etudes Spatiales–Laboratoire d’Etudes Geophysique et Oceanographique Spatiales (CNES/ LEGOS), Toulouse, France. 5 International Space Science Institute, Bern, Switzerland. 6 Institute of Geodesy and Geoinformation, University of Bonn, Germany. 7 NASA Goddard Space Flight Center, Greenbelt, MD, USA. *Corresponding author. E-mail: james.famiglietti@jpl.nasa.gov. sciencemag.org SCIENCE 14 AUGUST 2015 • VOL 349 ISSUE 6249 Published by AAAS ILLUSTRATION: DAVIDE BONAZZI Satellites provide the big picture

Direct and indirect effects of climate on agriculture: an application of a spatial panel data analysis to Tunisia

North African countries (NACs) are particularly concerned with climate change because of their geographical position (close to deserts) and their economic dependence on agriculture. We aim to provide additional insight into the impact of climate on agriculture for NACs, through the example of Tunisia. We first use disaggregated data, both at the geographical level (for 24 regions in Tunisia) and at the product level (cereals, olives, citrus fruit, tomatoes, potatoes and palm trees). Second, through spatial panel data analysis, we explore both the time and spatial dimensions of the data. This makes it possible to consider spatial interactions in agricultural production and the role of climate in these spatial spillover effects. Finally, the model not only includes direct climate variables, such as temperature and precipitation, but also indirect climate-related variables such as the stock of water in dams and groundwater. Results show that Tunisian agriculture is strongly dependent on the direct effects of temperature and precipitation for all the products considered at the regional level. The presence of dams and groundwater generally has a positive effect on agricultural production for irrigated crops with interesting spillover effects with neighboring regions. However, this impact is still considerably lessened in the case of detrimental climate conditions (indirect effect). These results raise the question of the sustainability of the growth in agricultural production in Tunisia in the case of significant climate change.

Hedging Supply Risks: An Optimal Water Portfolio

Although water supply diversification has been proposed as a solution to dwindling water reserves, the optimal mix of natural and manufactured sources of water remains largely unexplored. We develop a dynamic portfolio model of water supply that hedges against the supply risks from all potential water sources, by taking into account the size of water reserves, uncertainties of water flows as well as differences in supply costs. The optimal portfolio shares for an existing water supply system are derived and compared with the observed contributions to total water stock, revealing unexploited hedging opportunities between various naturally occurring water sources as well as a general over‐reliance on manufactured water. The optimal solution implies that future supply augmentations should target natural sources of water ahead of manufactured water. It is estimated that the optimization of the water supply portfolio for a medium‐sized city results in annual cost‐savings of up to $463 million.

Rapid assessment of the water–energy–food–climate nexus in six selected basins of North Africa and West Asia undergoing transitions and scarcity threats

Existing strategies for management of water scarcity in the Middle East and North Africa negotiate a complex system of trade-offs between water, energy, and food production. The effects of rural households' green water management practices on basin-level water, energy, food and carbon stocks and flows are sketched qualitatively in six basin agro-ecosystems. The case for increased strategic support for green agricultural water management practices appears stronger when weighed from the nexus perspective, rather than purely from the point of view of water balance and food production. Trade-offs under critical transitions affecting agricultural water use are explored, and the scope for quantitative monitoring is discussed.

Critical appraisal of assumptions in chains of model calculations used to project local climate impacts for adaptation decision support—the case of Baakse Beek

In order to enable anticipation and proactive adaptation, local decision makers increasingly seek detailed foresight about regional and local impacts of climate change. To this end, the Netherlands Models and Data-Centre implemented a pilot chain of sequentially linked models to project local climate impacts on hydrology, agriculture and nature under different national climate scenarios for a small region in the east of the Netherlands named Baakse Beek. The chain of models sequentially linked in that pilot includes a (future) weather generator and models of respectively subsurface hydrogeology, ground water stocks and flows, soil chemistry, vegetation development, crop yield and nature quality. These models typically have mismatching time step sizes and grid cell sizes. The linking of these models unavoidably involves the making of model assumptions that can hardly be validated, such as those needed to bridge the mismatches in spatial and temporal scales. Here we present and apply a method for the systematic critical appraisal of model assumptions that seeks to identify and characterize the weakest assumptions in a model chain. The critical appraisal of assumptions presented in this paper has been carried out ex-post. For the case of the climate impact model chain for Baakse Beek, the three most problematic assumptions were found to be: land use and land management kept constant over time; model linking of (daily) ground water model output to the (yearly) vegetation model around the root zone; and aggregation of daily output of the soil hydrology model into yearly input of a so called ‘mineralization reduction factor’ (calculated from annual average soil pH and daily soil hydrology) in the soil chemistry model. Overall, the method for critical appraisal of model assumptions presented and tested in this paper yields a rich qualitative insight in model uncertainty and model quality. It promotes reflectivity and learning in the modelling community, and leads to well informed recommendations for model improvement.

Rainwater harvesting in Dry Chaco: Regional distribution and local water balance

Rainwater harvesting (RWH) has been essential for the establishment of human settlements in many dry regions of the world that lacked suitable surface or groundwater resources. A vast fraction of the South American Dry Chaco ecoregion still relies on RWH to support, not only livestock production, but domestic and industrial uses as well. As a result, water capture and storage infrastructure is widely disseminated throughout the region. In this paper we characterized the most typical RWH systems in two contrastingly developed sub-regions of Dry Chaco, ranging from extensive ranching to intensive beef and dairy production (central Argentina and western Paraguay, respectively). In each sub-region, we quantified RWH systems density, spatial distribution and associations with landscape features; furthermore, we illustrated how the daily dynamic of water stock in a typical RWH system contributes to assess their capture and storage efficiency. We found that randomly distributed low sophisticated RWH systems prevailed in central Argentina, while clustered distributed high sophisticated ones were more common in western Paraguay. RWH systems density was ten times higher in western Paraguay (0.94 vs. 0.098 units/km2), showing an exponential association with land cleared fraction and proximity to villages. The daily dynamic of water stock of the RWH impoundment showed that water harvest events were exponentially associated with precipitation magnitude events (R2 = 0.86), while annual water losses were explained by infiltration and evaporation fluxes (59 vs. 41%, respectively). Across both sub-regions, RWH accounts for less than 1% of the annual precipitation, playing a minor role on the regional water balance; however at a local level, they can affect several hydrological fluxes including the onset of groundwater recharge and the mitigation of extreme runoff events.

Effect of water temperature, stocking density and feeding cycle on growth of juvenile Poecilobdella manillensis

The effect of water temperature, stocking density and feeding cycle on the growth of Poecilobdella manillensis juvenile was conducted P. manillensis was conducted respectively under different conditions: water temperatures(18, 22, 26, 30,34, 38 degrees C and CT), stocking density (75, 125, 200, 275, 350 individual/L) and feeding cycle(2, 4, 6, 8, 12, 16 d). After 30 days, survival rate, weight gain rate, specific growth rate were measured. There was a significant correlation between water temperature and specific growth rate (γ = -0.066x2 + 3.543 1x -38.09, R2 = 0.837 9). Based on the regression equation, the specific growth rate of P. manillensis achieved the maximum (9.461 4) at 26.84 degrees C. And the most optimal water temperature was 26-30 degrees C. Meanwhile, the survival rates of P. manillensis was 0 at 38 degrees C in 3 d. There was significant negative correlation between density and specific growth rate (γ = -0.005 7x + 9.197 3, R2 = 0.998 3) and between feeding cycle and specific growth rate (γ = -0.468 2x + 10.574, R2 = 0.998 8).

The effects of water temperature and stocking density on survival, feeding and growth of the juveniles of the hybrid yellow catfish from Pelteobagrus fulvidraco (♀) × Pelteobagrus vachelli (♂)

In this study, we aimed to investigate the effects of water temperature and stocking density on the survival, feeding and growth of the juveniles of the hybrid yellow catfish from Pelteobagrus fulvidraco (♀) × Pelteobagrus vachelli (♂) using the parameters as follows: survival rate (%), feeding rate (% day−1), feed conversion ratio, specific growth rate (% day−1), coefficient of variation (%), productivity (P, g m−3 day−1) and condition factor. We reared the juvenile fish (3.25 ± 0.21 g) at 12 water temperature levels and six stocking density levels (each level included three aquaria in two batches of experiments). The results showed that all groups survived at a temperature range of ≤35°C during a 46-day experimental period, and they could achieve a high growth at a water temperature range of 26–32°C. The optimal temperature for growth was 29.8°C. Productivity peaked at a stocking density of 1.9 kg m−3. Our results indicated that the hybrid is very suitable for commercial aquaculture.

A Multivariate Assessment of Factors Influencing Survival of Red Drum in Earthen Outdoor Rearing Ponds

Abstract.Extensive culture of larval Red Drum Sciaenops ocellatus in outdoor ponds occasionally results in low survival, thereby stifling stock enhancement goals. Mortality is probably tied to multiple environmental influences rather than to any singular factor. We assessed factors influencing Red Drum mortality and survival in the context of an extensive aquaculture operation in Texas. Larvae were stocked into 120 rearing ponds of various sizes in the spring, summer, and fall of 2012 and 2013. Water quality variables (temperature, salinity, dissolved oxygen, and pH) were assessed throughout culture. A principal components analysis of water quality, pond size, stocking density, and zooplankton density (number of organisms/L) was used to determine how each variable related to survival (measured as a ratio of the total number of Red Drum harvested to the total number of Red Drum stocked). Temperature, salinity, dissolved oxygen, and pH all loaded significantly onto the first ordination axis, suggesting correlations among water quality variables. Survival loaded significantly on the second and third ordination axes and was positively associated with larger ponds, lower stocking density, higher zooplankton density, and lower pH. Stepwise regression of observed variables in ponds pooled by year suggested that pH and stocking density were important in both 2012 (r2 = 0.452) and 2013 (r2 = 0.305, P < 0.05). These data indicate that ponds with moderate densities of Red Drum larvae will have a higher probability of survival than ponds with high larval densities; the results also confirm previous findings that pH is a significant mortality factor in extensive aquaculture of Red Drum.

Novel bottom-up urban water demand forecasting model: Revealing the determinants, drivers and predictors of residential indoor end-use consumption

The purpose of this comprehensive study was to explore the principal determinants of six residential indoor water end-use consumption categories at the household scale (i.e. namely clothes washer, shower, toilet, tap, dishwasher, and bath), and to find an overarching research design and approach for building a residential indoor water end-use demand forecasting model. A mixed method research design was followed to collect both quantitative and qualitative data from 210 households with a total of 557 occupants located in SEQ, Australia, utilising high resolution smart water metering technology, questionnaire surveys, diaries, and household water stock inventory audits. The principal determinants, main drivers, and predictors of residential indoor water consumption for each end-use category were revealed, and forecasting models were developed this study. This was achieved utilising an array of statistical techniques for each of the six end-use consumption categories. Cluster analysis and dummy coding were used to prepare the data for analysis and modelling. Subsequently, independent t-test and independent one-way ANOVA extended into a series of bootstrapped regression models were used to explore the principal determinants of consumption. Successively, a series of Pearson's Chi-Square tests was used to reveal the main drivers of higher water consumption and to determine alternative sets of consumption predictors. Lastly, independent factorial ANOVA extended into a series of bootstrapped multiple regression models was used for the development of alternative forecasting models. Key findings showed that the usage physical characteristics and the demographic and household makeup characteristics are the most significant determinants of all six end-use consumption categories. Further, the appliances/fixtures physical characteristics are significant determinants of all end-use consumption categories except the bath end-use category. Moreover, the socio-demographic characteristics are significant determinants of all end-use consumption categories except the tap and toilet end-use categories. Results also demonstrated that the main drivers of higher end-use water consumption were households with higher frequency and/or longer end-use events which are most likely to be those larger family households with teenagers and children, with higher income, predominantly working occupants, and/or higher educational level. Moreover, a total of 14 forecasting model alternatives for all six end-use consumption categories, as well as three total indoor bottom-up forecasting model alternatives were developed in this study. All of the developed forecasting model alternatives demonstrated strong statistical power, significance of fit, met the generalisation statistical criteria, and were cross-validated utilising an independent validation data set. The paper concludes with a discussion on the most significant determinants, drivers and predictors of water end-use consumption, and outlines the key implications of the research to enhanced urban water planning and policy design.

강도다리(Platichthys stellatus) 치어의 섭식, 성장 및 흑화 발현에 있어 온도와 밀도의 영향

To examine the influences of water temperature and stocking density on feeding, growth and blind-side hypermelanosis of the starry flounder Platichthys stellatus, we performed an experiment with fry at two densities: 2 and 8 fish/L. The fry had a total length of , body weight , and pigmented patches (pigmented ratio ) on the blind side. Duplicate experiments were conducted in 93.7 L glass tanks for 120 days, from July to November. We determined daily food intake (DFI), food efficiency (FE), growth, survival rate, ratio of hypermelanic fish, and pigmented area rate on the blind side at 60-day intervals. The DFI was less than 50 mg/fish/day, and growth was delayed from July to September (water temperature [WT]> ). After October, when WT , the DFI increased significantly and the growth was accelerated, suggesting that the rearing temperature of starry flounder in artificial facilities should be . While the FE, and survival did no differ between the two density groups, DFI and growth were significantly higher at 2 fish/L than at 8 fish/L. There was no difference in the pigmented area ratio between the two density groups. Although the hypermelanosis was not correlated with body size, the malpigmentation increased with growth. These results suggest that a high stocking density is not the main cause of blind-side hypermelanosis, although it can accelerate hypermelanosis in the starry flounder.

The UN System for Environmental-Economic Accounts for Water (SEEA-W) and groundwater management: the experience of the Arno River Basin Authority within the PAWA project

The Pilot Arno Water Accounts (PAWA) project was recently funded under the Call “Preparatory Action on Development of Prevention Activities to Halt Desertification in Europe” of the Directorate- General for the Environment of the European Commission to promote preventive actions to manage water scarcity and drought phenomena and to meet one of the main goals under European environmental legislation: the effective and sustainable management of water resources. The partners involved in the implementation of the PAWA project (ISPRA, Arno River Basin Authority, SEMIDE/EMWIS) will carry out a pilot initiative in the Arno River Basin, an area severely affected by water scarcity and droughts phenomena and characterized by water withdrawals and land use changes. In the area a large experience about water balance application was already performed, for example in the context of the Water Framework Directive Common Implementation Strategy. Moving from this knowledge, the objective of the project is the definition of water accounting processing based on the UN System of Environmental Economic Accounts for Water, with the final goal to optimize a list of effective measures to face water scarcity phenomena. By the end of project (March 2015) the PAWA partnership aims at preparing physical water stock accounts, using the best available data resulting from field measurements or models, on a monthly step for the period 1999–201. The quality of each dataset will be assessed; tables, maps and graphs will be produced as outputs of the projects in cooperation with local stakeholders and players of the water sector. Furthermore, water accounts will be used to assess the potential impact of various measures related to water resource efficient exploitation in the most vulnerable sub-basins; their tolerability will be tested during workshops with stakeholders. Finally, water efficiency targets for potential future integration into Arno River Basin Management Plan will be identified.

참조기 유자망의 설 높이에 따른 어획특성

Small yellow croaker is one of the important stocks in Korean waters. In this study, we conducted sea trials to estimate optimum height of a drift gill net for effective fishing of small yellow croaker. In the trial using existing net which has 9.2m in height, there was 22 species (1,180 fishes, 99.9kg) caught. The catch (in individuals) of small yellow croaker, especially larger fishes (over 22cm in FL), was higher as part of net height is higher, while the number of species bycaught and the catch of those species were higher as part of net height is lower. In the trial using extension net which has 18.4m in height, there was 27 species (2,030 fishes, 151.7kg). It showed same pattern with existing net in the section I to III, however, in the section IV which is over 13.8m of net height, the catch sharply decreased. The number of species bycaught and the catch of those species using extension net were also same as results using existing net. It showed that section III (9.2-13.8m) where is upper-middle part of the net has caught most of catch and large fishes having over 22cm in length. Through these results, it is judged that the setting depth of the net where is 4.6-13.8m above the sea bottom is the best to reduce bycatch and catch much more large size fishes, and the catch per net is proportional to filtering area of net. Therefore the Fisheries Resource Management Act (the clause 1, article 10) on the amount of usage for offshore drift gill net need to be considered not only length of a net but also net height.

Подсолнечник в орошаемом севообороте степной зоны КБР

Исследованы условия образования остаточных запасов воды в двухметровом слое почвы поля орошаемого и богарного севооборотов. Представлены в динамике расход влаги из почвы за вегетацию подсолнечника и влияние объёма влагозапасов на урожайность гибридов, суммарный расход воды и коэффициент водопотребления гибридов подсолнечника при разных фонах водообеспеченности.

Monitoring decadal lake dynamics across the Yangtze Basin downstream of Three Gorges Dam

The Yangtze River Basin downstream of China's Three Gorges Dam (TGD) (thereafter referred to as “downstream” basin) hosts the largest cluster of freshwater lakes in East Asia. These lakes are crucial water stocks to local biophysical environments and socioeconomic development. Existing studies document that individual lakes in this region have recently experienced dramatic changes under the context of enduring meteorological drought, continuous population growth, and extensive water regulation since TGD's initial impoundment (i.e., June, 2003). However, spatial and temporal patterns of lake dynamics across the complete downstream Yangtze basin remain poorly characterized. Using daily MODIS imagery and an advanced thematic mapping scheme, this study presents a comprehensive monitoring of area dynamics in the downstream lake system at a 10-day temporal resolution during 2000–2011. The studied lakes constitute ~76% (~11,400km2) of the total downstream lake area, including the entire +70 major lakes larger than 20km2. The results reveal a decadal net decline in lake inundation area across the downstream Yangtze Basin, with a cumulative decrease of 849km2 or 7.4% from 2000 to 2011. Despite an excessive precipitation anomaly in the year 2010, the decreasing trend was tested significant in all seasons. The most substantial decrease in the post-TGD period appears in fall (1.1%yr−1), which intriguingly coincides with the TGD water storage season. Regional lake dynamics exhibit contrasting spatial patterns, manifested as evident decrease and increase of aggregated lake areas respectively within and beyond the Yangtze Plain. This contrast suggests a marked vulnerability of lakes in the Yangtze Plain, to not only local meteorological variability but also intensified human water regulations from both the upstream Yangtze main stem (e.g., the TGD) and tributaries (e.g., lakes/reservoirs beyond the Yangtze Plain). The produced lake mapping result and derived lake area dynamics across the downstream Yangtze Basin provides a crucial monitoring basis for continuous investigations of changing mechanisms in the Yangtze lake system.