Within-year Variations Research Articles

Running the gauntlet; flyway-wide patterns of pollutant exposure in blood of migratory shorebirds

Shorebirds (order Charadriiformes) are among the world's most threatened avian taxa. Within the East Asian-Australasian Flyway (EAAF), a major threat to shorebirds' survival may be the gauntlet of pollution along the flyway. Metals, persistent organic pollutants (POPs), and per-/polyfluoroalkyl substances (PFASs) persist in the environment to the detriment of wildlife. In this study, we analysed element and PFAS concentrations in blood from 142 individuals across six species of Arctic-breeding migratory shorebirds with contrasting population trends, to discern species- and site-specific pollution differences, and determine how pollution correlated with population trends of EAAF shorebirds. Potential within-year pollution variations were investigated by blood-sampling birds at two sites, representing different points in the birds' annual migrations: staging in Taiwan on southward migrations and at non-breeding grounds in Western Australia (WA). Species' pollutant concentrations were compared to established population trends. Concentrations of potentially toxic elements were low in most individuals regardless of species. PFASs (range: <0.001–141 ng/g), Hg (<0.001–9910 ng/g) and Pb (<0.01–1210 ng/g) were higher in Taiwan than in WA (PFAS Taiwan median: 14.5 ng/g, WA median: 3.45 ng/g; Hg Taiwan: 338 ng/g, WA: 23.4 ng/g; Pb Taiwan: 36.8 ng/g, WA: 2.26 ng/g). Meanwhile As (range <0.001–8840 ng/g) and Se (290–47600 ng/g) were higher in WA than Taiwan (As Taiwan median: 500 ng/g, WA median: 1660 ng/g; Se Taiwan: 5490 ng/g, Se WA: 23700 ng/g). Nevertheless, pollutant concentrations in a subset of individuals may exceed sublethal effect thresholds (As, Se and PFASs). Finally, we found no consistent differences in pollution among species and demonstrated no correlation between pollution and population trends, suggesting pollution is likely not a major driver for population declines of EAAF shorebirds. However, ongoing and locally heavy environmental degradation and exposure to other contaminants not investigated here, such as POPs, warrants continued consideration when managing EAAF shorebird populations.

MATHEMATICAL MODELING OF THE TRANSFORMATIONS OF NUTRIENT COMPOUNDS IN THE VISTULA LAGOON ECOSYSTEM, BALTIC SEA

The article describes the general structure of the simulation model, the most important principles for describing the processes of bio-hydrochemical transformation of nutrient (C, N, P, Si) compounds, and the dynamics of dissolved oxygen in the ecosystem of the Vistula Lagoon (VL), Baltic Sea. Based on the results of long-term observations, tuning of the model parameters was performed, its adequacy and sensitivity to changes in parameter values were checked, within-year variations of nutrient compounds, components of the planktic and benthic parts of the VL ecosystem, turnover periods, as well as fluxes (balances) of dissolved and suspended solids between the selected components of the model were calculated and analyzed. Model calculations showed fairly good qualitative and quantitative correspondence of the simulated results to observed data for all variables of the simulation model. Practical implementation of computational procedures for model tuning proves that with the proposed algorithms for finding the parameters for the bio-hydrochemical block of the simulation model the optimization problem can be solved effectively even where the amount of observed data is insufficient and their variance is rather high. Attention should be given to statistically significant among-year variations in the values of the empirical parameters of the model. One should be cautious using the same values of model parameters in running computational experiments for different years of observations and in predicting VL ecosystem development in response to changes in external conditions. We quantified turnover times for the model components of the VL ecosystem. In a vast majority of cases there existed significant among-year variations in the turnover times for the model variables. Calculations of the balances of dissolved organic substances, as well as detrital nitrogen, phosphorus, and silicon have led us to an important conclusion that heterotrophic bacterioplankton and protozoa play a significant role in the processes of nutrient compound transformation in the lagoon ecosystem.

Regional-based within-year seasonal variations in influenza-related health outcomes across mainland China: a systematic review and spatio-temporal analysis

BackgroundChina experiences large variations in influenza seasonal activity. We aim to update and improve the current understanding of regional-based within-year variations of influenza activity across mainland China to provide evidence for the planning and optimisation of healthcare strategies.MethodsWe conducted a systematic review and spatio-temporal meta-analysis to assess regional-based within-year variations of ILI outpatient consultation rates, influenza test positivity rates amongst both ILI outpatients and SARI inpatients, and influenza-associated excess mortality rates. We searched English and Chinese databases for articles reporting time-series data on the four influenza-related outcomes at the sub-national and sub-annual level. After synthesising the data, we reported on the mean monthly rate, epidemic onset, duration, peak and intensity.ResultsWe included 247 (7.7%) eligible studies in the analysis. We found within-year influenza patterns to vary across mainland China in relation to latitude and geographic location. High-latitude provinces were characterised by having short and intense annual winter epidemics, whilst most mid-latitude and low-latitude provinces experience semi-annual epidemics or year-round activity. Subtype activity varied across the country, with A/H1N1pdm09 and influenza B occurring predominantly in the winter, whereas A/H3N2 activity exhibited a latitudinal divide with high-latitude regions experiencing a winter peak, whilst mid and low-latitude regions experienced a summer epidemic. Epidemic onsets and peaks also varied, occurring first in the north and later in the southeast. We found positive associations between all influenza health outcomes. In addition, seasonal patterns at the prefecture and county-level broadly resembled their wider province.ConclusionsThis is the first systematic review to simultaneously examine the seasonal variation of multiple influenza-related health outcomes at multiple spatial scales across mainland China. The seasonality information provided here has important implications for the planning and optimisation of immunisation programmes and healthcare provision, supporting the need for regional-based approaches to address variations in local epidemiology.

Water stream heating dynamics around extreme temperature events: An innovative method combining GAM and differential equations

The highlighting and study of extreme water temperatures, which endanger numerous species, is of particular interest for river managers planning for future thermal conditions. Extreme water temperatures, defined as temperatures outside the normal range, are predicted to occur more frequently. This range includes seasonality and other trends in temperature time series.First, extreme water temperatures were highlighted using generalized additive modeling (GAM) to extract within-year variations (seasonality) and long-term changes (trend). Second, the temporal dynamics of water temperature around extremes were modeled using specific differential equations. The period considered was 15 days, 7 days before and after each extreme considered day. The data were water temperatures measured every 10 min for 7 years (2012–2018) at 94 measurement sites. Sites were located evenly throughout the Walloon (southern Belgium) hydrological network.Results showed that GAM was robust for capturing seasonality and trend, and highlighting extreme water temperatures. GAM had already been used in water temperature studies but not yet to detect extremes. The thermal dynamics of water temperature around extremes was successfully modeled using differential equations. Several equations expressing heat flux processes between air and water interface were tested. Two correlations were analyzed: (i) between the model coefficients and the number of extreme days, and (ii) between the model coefficients and the number of days above a fixed thermal threshold. Significant positive correlations were found in both cases. Considering the value ranges of the model coefficients, it is thus possible to describe rivers’ thermal sensitivity. With our approach, river’s managers can now better address the important issue of extreme water temperature in the context of climate change.

Agent-based modelling of water balance in a social-ecological system: A multidisciplinary approach for mountain catchments

The European Alps are known as the ‘water towers of Europe’. However, climatic and socioeconomic changes influence both water supply and demand, increasing the need to manage this limited and valuable resource properly to avoid user conflicts and water scarcity. Two major challenges emerge when assessing water scarcity in the Alps: Firstly, mountainous regions are very heterogeneous regarding water availability and demand over space and time, and therefore water scarcity assessments need to be done at low temporal and spatial scales. Secondly, the tight coupling of the natural and the social sphere necessitate an integrative approach considering dynamics and interactions of the social-ecological system. Hence, we applied the agent-based water supply and demand model Aqua.MORE, which is designed for catchment scale and sub-daily temporal resolution, to a case study site in the Italian Alps. In the model, the water supply, the local water managers and water users are represented by interacting model agents. We estimated the water supply by refining the annual runoff data provided by the InVEST water yield model for within-year variations. Local stakeholders contributed to the development of quantitative and spatially-explicit scenarios for land use and tourism evolution. To evaluate water supply and demand dynamics, we assessed six scenarios for the period of 2015 to 2050: three different socio-economic policy pathways, both alone and in combination with a climate change scenario. In all six scenarios, the water demand:supply (D:S) ratio continuously rises from 2015 to 2050.The highest D:S ratio values are prognosed at the beginning of the irrigation period in May. In all scenarios considering climatic changes, the D:S ratio exceeds 20% for several days, indicating potential water scarcity. The simulation results reinforce the importance of analysing water balances at a high temporal resolution and can support management processes and stakeholder dialogues for sustainable watershed management.

A Machine Learning Analysis of Seasonal and Cyclical Sales in Weekly Scanner Data

This paper analyzes weekly scanner data collected for 108 groups at the county level between 2006 and 2014. The data display multi-dimensional weekly seasonal effects that are not exactly periodic but are cross-sectionally dependent. Existing univariate procedures are imperfect and yield adjusted series that continue to display strong seasonality upon aggregation. We suggest augmenting the univariate adjustments with a panel data step that pools information across counties. Machine learning tools are then used to remove the within-year seasonal variations. A demand analysis of the adjusted budget shares finds three factors: one that is trending, and two cyclical ones that are well aligned with the level and change in consumer confidence. The effects of the Great Recession vary across locations and product groups, with consumers substituting towards home cooking away from non-essential goods. The adjusted data also reveal changes in spending to unanticipated shocks at the local level. The data are thus informative about both local and aggregate economic conditions once the seasonal effects are removed. The two-step methodology can be adapted to remove other types of nuisance variations provided that these variations are cross-sectionally dependent. Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.

Evidence for sensitivity of dune wetlands to groundwater nutrients

Dune slacks are seasonal wetlands, high in biodiversity, which experience considerable within-year and between-year variations in water-table. They are subject to many pressures including climate change, land use change and eutrophication. Despite their biological importance and the threats facing them, the hydrological and nutrient parameters that influence their soil properties and biodiversity are poorly understood and there have been no empirical studies to date testing for biological effects in dune systems resulting from groundwater nutrients at low concentrations. In this study we examined the impact of groundwater nutrients on water chemistry, soil chemistry and vegetation composition of dune slacks at three distance classes (0–150m, 150–300m, 300–450m) away from known (off-site) nutrient sources at Aberffraw dunes in North Wales, whilst accounting for differences in water-table regime. Groundwater nitrate and dissolved inorganic nitrogen (DIN) and soil nitrate and nitrite all had significantly higher concentrations closest to the nutrient source. Multivariate analysis showed that although plant species composition within this site was primarily controlled by water table depth and water table fluctuation, nitrogen from groundwater also influenced species composition, independently of water table and soil development. A model containing all hydrological parameters explained 17% of the total species variance; an additional 7% was explained following the addition of NO3 to this model. Areas exposed to elevated, but still relatively low, groundwater nutrient concentrations (mean 0.204mg/L+/−0.091 of DIN) had greater abundance of nitrophilous species and fewer basipholous species than in areas with lower concentrations. This shows that clear biological impact occurs below previously suggested DIN thresholds of 0.20–0.40 (mg/L).

China's water sustainability in the 21st century: a climate-informed water risk assessment covering multi-sector water demands

Abstract. China is facing a water resources crisis with growing concerns as to the reliable supply of water for agricultural, industrial and domestic needs. High inter-annual rainfall variability and increasing consumptive use across the country exacerbates the situation further and is a constraint on future development. For water sustainability, it is necessary to examine the differences in water demand and supply and their spatio-temporal distribution in order to quantify the dimensions of the water risk. Here, a detailed quantitative assessment of water risk as measured by the spatial distribution of cumulated deficits for China is presented. Considering daily precipitation and temperature variability over fifty years and the current water demands, risk measures are developed to inform county level water deficits that account for both within-year and across-year variations in climate. We choose political rather than watershed boundaries since economic activity and water use are organized by county and the political process is best informed through that unit. As expected, the risk measures highlight North China Plain counties as highly water stressed. Regions with high water stress have high inter-annual variability in rainfall and now have depleted groundwater aquifers. The stress components due to agricultural, industrial and domestic water demands are illustrated separately to assess the vulnerability of particular sectors within the country to provide a basis for targeted policy analysis for reducing water stress.

Assessment of the Azerbaijan Arid Territories’ Rivers Hydro/chemical State

Assessment of the Azerbaijan arid territory rivers’ water mineralization variations has been carried out with the linear trend method. Analysis of many-year rows of river mineralization has shown very complicated and ambiguous character of its variation tendency. Hydro/chemical regime of the arid territories’ rivers of Azerbaijan is characterized by small within-year variations of concentration and close ties of concentration with water discharge rate for Са2+, Мg2+, НСО3 ions and mineralization (С).

Effect of regional climate variations and economic activity on changes in the hydrological regime of watersheds and small-river runoff

Regularities of long-term within-year and between-zone variations in climate characteristics (air temperature and precipitation) were identified, and estimates were obtained for the response time of the factors of hydrothermal state of watersheds at the beginning of snow-melting (maximal snow storage, freezing depth, and soil moisture content), spring surface slope runoff, annual and spring river runoff of small rivers in different natural zones of Russian Plain.

Mathematical modeling of marine environment pollution processes by petroleum hydrocarbons and their degradation in Caspian Sea ecosystem

The available observational data on the pollution of tributaries and areas of the Caspian Sea by petroleum hydrocarbons and products are examined. The possible petroleum input from sources in the sea is assessed using up-to-date data of satellite observations of sea surface pollution by oil films. The hydroecological CNPSi-model is applied to studying water pollution processes by petroleum hydrocarbons in ten areas chosen in the Caspian Sea and the subsequent biodegradation of those pollutants. The model calculations of the within-year dynamics of petroleum hydrocarbon concentrations use mean annual observational data on within-year variations in water mediium characteristics (water temperature, light intensity, and transparency), as well as the morphometric parameters of sea areas (the area, mean depth, and water volumes). The characteristics of water exchange between the areas were evaluated using a hydrodynamic model. The model calculations were used to characterize the within-year variations in petroleum hydrocarbon concentrations, the biomasses of petroleum-oxidizing bacteria, the characteristics of their oxidation activity and bioproduction, and the internal fluxes of petroleum hydrocarbons (their input from various sources, horizontal and vertical transport, and biotransformation) in different sea areas. Calculation results were used to compile annual balances for the processes of input and consumption of petroleum hydrocarbons in the chosen and aggregated sea areas.

Petroleum hydrocarbons in the waters of major tributaries of the White Sea and its water areas: A review of available information

The White Sea is a natural analogue of arctic seas. The pollution of the sea by petroleum hydro� carbons is not high now. However, the load on sea ecosystem can increase in the nearest future because of the anticipated industrial development in its watershed, including an increase in oil, coal, and diamond produc� tion. The specific features of the nature of arctic marine systems (hydrological, ice, hydrobiological, hydro� chemical, and radiation regimes), and the poor knowledge of the conditions of dispersion, transformation, and utilization of petroleum hydrocarbons in such seas make their ecological studies especially important. Petroleum hydrocarbon concentrations in the waters of tributaries and water areas of the White Sea (for 1980-2006 and 1989-2006, respectively) were evaluated using literary and authors' data. Analysis of the col� lected materials shows that the majority of petroleum hydrocarbons enter the sea's water areas with river run� off. Petroleum hydrocarbon concentrations were evaluated in major tributaries of the sea, including the rivers of Northern Dvina, Onega, Mezen, Niva, Kem, and Keret, delivering petroleum hydrocarbons into the bays of Dvina, Onega, Mezen, and Kandalaksha, water area near the Solovetskie Islands, and Chupa Bay, respec� tively (BayGulf). Model calculations should yield withinyear variations in petroleum hydrocarbon con� centrations in different part of the sea (under a correctly specified load) and the conditions of their biotrans� formation and horizontal transport through the boundaries between areas within the sea.

Fe/P concentration ratio in Mozhaisk reservoir deposits as an indicator of phosphate sorption

A relationship is established between within-year variations in Fetot/Ptot ratio in pore solution and the concentration of organic P compounds in solid phase. The passage of the FeOOH-P system in the silts of the Mozhaisk Reservoir from the aerobic conditions to aerobic is generally accompanied by dissolution of FeOOH and desorption of phosphates. The change from anaerobic conditions to aerobic during the spring and autumn seasons exhibits hysteresis in oxidation of Fe compounds in silts, such that variations in Fe/P ratio in the solid phase of silt do not agree with those in the pore solution.

Yield and Price Forecasting for Stochastic Crop Decision Planning

The primary objective of this paper is to develop yield and price forecasting models employed in informed crop decision planning—a key aspect of effective farm management. For yearly yield prediction, we introduce a weather-based regression model with time-dependent varying coefficients. In order to allow for within-year climate variations, we predict yearly crop yield using weekly temperature and rainfall summaries resulting in a large number of correlated predictors. To overcome this difficulty, we reduce the space of predictors to a small number of uncorrelated predictors using Functional Principal Component Analysis (FPCA). For detailed price forecasting, we develop a futures-based model for long-range cash price prediction. In this model, the cash price is predicted as a sum of the nearby settlement futures price and the predicted commodity basis. We predict the one-year commodity basis as a mixture of historical basis data using a functional model-based approach. In both forecasting models, we estimate approximate prediction confidence intervals that are further integrated in a decision planning model. We applied our methods to corn yield and price forecasting for Hancock County in Illinois. Our forecasting results are more accurate in comparison to predictions based on existing methods. The methods introduced in this paper generally apply to other locations in the US and other crop types. The supplemental materials for this article are available online.

Fe(II)/Fe(III) ratio in silt pore solution in the Mozhaisk Reservoir

Relationships between within-year variations in Fe(II)/Fe(III) ratio in silt pore solution were obtained. The samples to be examined were taken from silts of the channel zone of the Krasnovidovo Pool, the Mozhaisk Reservoir. Specific features of the within-year redistribution of Fe forms in the pore solution of the sediment column were identified.

Waterbird dynamics at the shallow Lake Krankesjön, southern Sweden: a long-term study

This paper reports the within-year and between-year variations in the number of waterbirds at Lake Krankesjön, southern Sweden based on counts carried out during 1985 to 2007. The background to these counts was a dramatic decrease in the number of Great Crested Grebe Podiceps cristatus, Mute Swan Cygnus olor and Common Coot Fulica atra from 1974 to 1976, concurrent with a deterioration of water transparency and a nearly total disappearance of submerged vegetation. In 1985, when the regular counts of waterbirds started, the lake had just begun to recover. Numbers of moulting and staging waterbirds increased rapidly as the conditions improved. Numbers of grebes, swans and coots over the two decades correlated with limnological variables, and it is concluded that their numbers depend on the amount of submerged vegetation, in turn determined by water transparency.

Visualizing the Large-Scale Patterns of ENSO-Related Climate Anomalies in North America

Abstract The variations of large-scale climatic controls and surface responses through the annual cycle during strong positive (El Niño) and negative (La Niña) phase ENSO events are analyzed to assess the within-year and among-year variations of climate anomalies. Data from the NCEP–NCAR reanalysis project are presented as small-multiple maps to illustrate the spatial and temporal variability in North American climate associated with extreme phases of ENSO. Temperature, mean sea level pressure, 500-mb geopotential heights, and 850-mb specific humidity have composite-anomaly patterns that exhibit the greatest degree of spatial and temporal coherence. In general, the composite-anomaly patterns for El Niño and La Niña events are of opposite sign, with stronger, more spatially coherent anomalies occurring during El Niño events than during La Niña events. However, the strength and coherency of the precipitation anomaly patterns are reduced in the interior intermountain west during both positive and negative phase of ENSO. The variations in precipitation anomalies are compared to the 500-mb omega and 850-mb specific humidity composite-anomaly patterns, which provide information on the controls of precipitation by large-scale vertical motions and moisture availability thus providing information on the specific mechanisms associated with precipitation variability during ENSO events.

Approaches for assessing some attributes of feed-base systems in mixed farming enterprises

Improving the feed-base to better balance livestock demands with the variation in feed supply can improve the sustainability and productivity of livestock enterprises. This paper outlines some approaches and tools that can be applied to the assessment of new feed options and/or potential changes to the feed-base in mixed farming systems. Demonstrations of strategic aspects of designing feed systems include: whole-farm feed planning using simple tools, such as the MLA Feed Demand Calculator, that enable iterative changes to the balance between feed supply and demand to be considered simultaneously; assessing production and environmental risks of different feed-base systems using simulation models (e.g. APSIM, GRAZPLAN); and using bio-economic models (e.g. MIDAS) to investigate the impact of a new feed source on whole-farm profitability and the optimal balance of other feed sources and livestock production system. Also included is an example of an approach to identifying opportunities and seasonal triggers for a tactical response for utilising an alternate feed source (e.g. grazing a grain crop). The importance of economics and risk as factors for assessing feed-base systems is demonstrated. In particular, the marginal value of extra feed supply is a critical element driving the whole-farm economics of the feed system. Some approaches consider seasonal averages, but the risk of year-to-year and within-year variations in the timing and amount of feed supply should also be assessed. Several tools of varying complexity exist to investigate attributes of the feed-base, but it is important that the correct approach is applied to the particular question in mind. A range of approaches could be applied concurrently to fully explore a range of aspects of the performance of a feed-base system.

Revisiting reservoir storage–yield relationships using a global streamflow database

Annual and monthly streamflows for 729 rivers from a global data set are used to assess the adequacy of five techniques to estimate the relationship between reservoir capacity, target draft (or yield) and reliability of supply. The techniques examined are extended deficit analysis (EDA), behaviour analysis, sequent peak algorithm (SPA), Vogel and Stedinger empirical (lognormal) method and Phien empirical (Gamma) method. In addition, a technique to adjust SPA using annual flows to account for within-year variations is assessed. Of our nine conclusions the key ones are, firstly, EDA is a useful procedure to estimate streamflow deficits and, hence, reservoir capacity for a given reliability of supply. Secondly, the behaviour method is suitable to estimate storage but has limitations if an annual time step is adopted. Thirdly, in contrast to EDA and behaviour which are based on time series of flows, if only annual statistics are available, the Vogel and Stedinger empirical method compares favorably with more detailed simulation approaches.

How to manage human-induced mortality in the Eagle Owl Bubo bubo

The Eagle Owl Bubo bubo, which feeds mainly on rabbits and partridges, has been persecuted widely for causing damage to game interests. Although it is a protected species throughout Europe, there is a noteworthy gap in the scientific literature on the causes of mortality in this top predator. Here, we assess the relative importance and the geographical and temporal variation of human-related causes of death by reviewing 1,576 files of individuals admitted to wildlife rescue centres in Spain, a stronghold for Eagle Owls. The main known cause of death was interaction with powerlines followed by persecution and collisions with game fences and cars. There were within-year variations in the distribution of persecution, electrocution and collisions with game fences. Some man-induced causes of mortality were seen to depend on both the geographical region and the period of the year; moreover, mortality within each region was also year-dependent. Since there are strong socio-economic and ethical components involved, management guidelines are discussed bearing in mind such points of view.