scholarly journals Ecology of Laridae under conditions of unstable hydrological regime: colony sizes and synchronization of reproduction

2021 ◽  
Vol 29 (4) ◽  
pp. 399-406
Author(s):  
Y. I. Melnikov
Keyword(s):  
Hydrological Regime ◽  
Egg Laying ◽  
Timing Of Reproduction ◽  
High Loss ◽  
Large Colony ◽  
Bird Breeding ◽  
Long Time ◽  
Total Variability ◽  
Frequent Failure ◽  
Severe Flooding

The problem of criteria for distinguishing colonies from similar socio-demographic structures (mainly in terms of nesting density) is highly relevant and has remained in the focus of attention of ornithologists for a long time. The synchronization of reproduction in a colony is one of the criteria which require special development. Based on particular works (1972–2005), I present synchronization of the reproduction of gulls in colonies of different sizes. In contrast to previous studies, this paper uses a specially developed Index of Synchronization of Bird Breeding (Isr) to study this phenomenon, making it relatively easy to determine its level. The index distinguishes between different species of birds of this group: 75.7% (white-winged black tern) and 97.6% (black-headed gull) of the total variability of synchronization of breeding birds in colonies. Frequent failure of nesting attempts often causes repeated (compensatory) reproduction, which in the case of a mass manifestation significantly reduces the synchronization of the nesting period in colonies and thus significantly reduces this indicator. It is proved that a higher synchronization of reproduction characterizes small colonies (up to 50 nests). In all species of gulls, the beginning of reproduction in different colonies differs in terms of the appearance of the first eggs by 1–10 days and at the beginning of mass egg-laying – by 1–18 days. To the same extent, they differ in the timing of the hatching of eggs. In small colonies, the total egg-laying period is shorter by 34.9–49.7% compared to larger colonies. My observations show that large colonies are formed by the nesting of several small colonies on one plot. This phenomenon is noticeable during periods of mass re-nesting of birds after a high loss of nests (up to 69.5% or more) because of severe flooding. Differences in the breeding periods of colonies that differ in size appear when several small colonies with different breeding periods of birds are combined into one larger colony. This phenomenon is well detected in the formation of several sub-colonies and in the differences in the timing of reproduction of different parts of a large colony.

Surface Water Management and Modelling in the Sakia El Hamra Hydraulic Basin (Southern Morocco)

2020 ◽  
Author(s):  
Nafia El-alaouy ◽  
Aicha Moumni ◽  
Badr-eddine Sebbar ◽  
Abdeljalil Gouzrou ◽  
Aberrahman Lahrouni
Keyword(s):  
Flash Flood ◽  
Hydrological Regime ◽  
Shape Index ◽  
Flash Floods ◽  
Drainage Density ◽  
Agricultural Lands ◽  
Surface Water Management ◽  
Short Period ◽  
Long Time ◽  
Log Normal

<p>Due to its arid to semi-arid climate, Morocco often faces significant intense rainfall periods that can generate flash floods and raging torrents causing serious damage in a very short period of time. In this context, these recent years, the watershed corresponding to the SAKIA EL HAMRA wadi has known devastating downpours and excessive heavy rains that caused severe floods in Laayoune city and its regions.</p><p>The watershed of Sakia El Hamra covers an area of 82000 km<sup>2</sup>, that drains to Sakia El Hamra wadi, a stream of about 447 km long, crosses the basin in its northern part in the East-to-West direction, to discharge into the Atlantic Ocean at the outlet called Foum El Oued. This zone often experiences dangerous torrents of water and violent flash floods, specifically in the northern part of Laayoune city. For example, a flash flood has occurred at the end of October 2016. The peak flow was far in excess of the average (3000 m<sup>3</sup>/s against 410m<sup>3</sup>/s). This river flood, lasted for about 10 h, caused damage to the infrastructure and destruction of agricultural lands near Foum El Oued.</p><p>The objective of this study is to investigate, through modelling, the hydrological regime of SAKIA EL HAMRA watershed to prevent the floods in the future and improve warning systems. The hydrological parameters of the watershed were determined by WMS software, namely: zone extent, perimeter, slope, basin’s average elevation, Gravelius compactness index, Horton shape index, average altitude, drainage density and concentration time.</p><p>Flood flow return was simulated using the Log-normal distribution, using a long time-series of flow and maximum daily and annual precipitation data, recorded between 1985 and 2016, at the Airport station in Laayoune city. The results showed that during flash floods with known flows, water level can reach up to 13 meters, with high flow velocities flooding hundreds of hectares of surrounding plains at the northern part of the city of Laayoune and agricultural lands near Foum El Oued.</p>

scholarly journals Analysis of reproductive traits and laying egg rhythm of maize weevil sitophilus zeamais (motschulsky)

2019 ◽  
Vol 41 (2) ◽  
Author(s):  
Nguyen Van Duong ◽  
Khuat Dang Long ◽  
Le Xuan Que
Keyword(s):  
Reproductive Traits ◽  
Egg Laying ◽  
Sitophilus Zeamais ◽  
Cereal Crops ◽  
Maize Weevil ◽  
Development Stages ◽  
Wide Range ◽  
Long Time ◽  
Cubic Polynomials

The maize weevil, Sitophilus zeamais (Motschulsky), is a serious pest affecting a wide range of cereal crops, such as maize, rice, beans and other stored dried grains. As a S. zeamais female can keep laying eggs for a long time throughout its life after chewing its way into the grains, most development stages of the maize weevil, such as eggs, larvae and pupae, can always be found in stored maize grains. Our experiment with S.  zeamais on long grain rice showed that 10 days after eclosion and mating, maize weevil females started laying eggs for a period of 145 days. On average, a S.  zeamais female laid 38.67 eggs, of which, up to 62.81% were laid in the first 7–8 weeks (with the remaining 37.19% in the latter half of the 145 day period), and 55.07%  were laid within day 55–95. The egg laying pattern of S. zeamais was modeled using cubic polynomials, which described the maximum percentages of eggs laid at day 15, 35, 75, 95 and 105.   

scholarly journals Long Time-Scale Teleconnection Patterns in the Northern Atlantic and Pacific

2012 ◽  
Vol 25 (1) ◽  
pp. 414-422
Author(s):  
George J. Boer
Keyword(s):  
Time Scale ◽  
Climate Model ◽  
Potential Predictability ◽  
Teleconnection Patterns ◽  
Statistical Robustness ◽  
Model Control ◽  
Long Time ◽  
Total Variability ◽  
Northern Atlantic ◽  
Hadley Centre

Abstract Long time-scale teleconnection patterns, with common features in both the northern Atlantic and Pacific regions, are identified. The teleconnection patterns arise in an investigation of the internally generated variability in a multimodel ensemble of coupled climate model control simulations. The large amount of data involved offers statistical robustness and the benefits of combining results across models. Maxima of decadal potential predictability identify regions where long time-scale variability is an appreciable fraction of the total variability and serve as index regions for the teleconnection analysis. Annual, 5-yr, and decadal mean temperatures over these Atlantic and Pacific index regions are correlated with corresponding temperatures and precipitation rates over the globe. The resulting teleconnection patterns are reasonably similar despite the different long time-scale variability mechanisms thought to exist in the two ocean basins. Although lacking statistical robustness, some aspects of the temperature teleconnection patterns are obtained based on the Hadley Centre Sea Ice and Sea Surface Temperature (HadISST) dataset. The similarity of the teleconnection patterns in the two northern ocean regions suggests that common variability mechanisms may be involved.

scholarly journals Modelling burned area in Africa

2010 ◽  
Vol 7 (3) ◽  
pp. 4385-4424 ◽  
Author(s):  
V. Lehsten ◽  
P. Harmand ◽  
I. Palumbo ◽  
A. Arneth
Keyword(s):  
Linear Models ◽  
Model Performance ◽  
Performance Model ◽  
Burned Area ◽  
Climate Data ◽  
Wet Season ◽  
High Loss ◽  
Global Circulation Models ◽  
Data Driven Approach ◽  
Total Variability

Abstract. The simulation of current and projected wildfires is crucial for predicting vegetation as well as pyrogenic emissions in the African continent. This study uses a data-driven approach to parameterize burned area models applicable to dynamic vegetation models (DVMs) and global circulation models (GCMs). Therefore we restricted our analysis to variables for which either projections based on climate scenarios are available, or which are calculated by DVMs and the spatial scale to one degree spatial resolution, a common scale for DVMs as well as GCMs. We used 9 years of data (2000–2008) for the variables tree and herb cover, precipitation over the last dry season, wet season and averaged over the last 2 years, a fire-danger index (the Nesterov index), population density and an annual proportion of area burned derived from the MODIS MCD45A1 product. Since the effect of fires on vegetation depends strongly on burning conditions, the timing of wildfires is of high interest too. We related the seasonal occurrence of wildfires to the Nesterov index and found a lognormal relationship with a maximum at a value of 104. We parameterized two generalized linear models, one with the full variable set (model I) and one (model II) considering only climate variables. All introduced variables resulted in an increase in model performance. Model I correctly predicts the spatial distribution and extent of fire prone areas though the total variability is underrepresented. Model II has a much lower performance in both aspects (correlation coefficient of predicted and observed ratio of burned area: 0.71 model I and 0.58 model II). An application of the models with simulated climate data ranging from 1980 to 2060 resulted in a strong decrease of burned area of ca. 20–25%. Since wildfires are an integral part of land use practices in Africa, this indicates a high loss in areas favourable for food production.

scholarly journals Influence of the river floodplain on the regime of the upper Lužnice River

Geografie ◽  
2015 ◽  
Vol 120 (3) ◽  
pp. 354-371
Author(s):  
Pavel Svoboda ◽  
Miroslav Šobr ◽  
Bohumír Janský ◽  
Tomáš Vlasák
Keyword(s):  
Statistical Evaluation ◽  
Hydrological Regime ◽  
Physical Geography ◽  
Data Series ◽  
Oxbow Lakes ◽  
Flood Events ◽  
Time Data ◽  
The Past ◽  
Long Time ◽  
Anthropogenic Modifications

The aim of this study is an evaluation of the hydrological regime of the upper part of the Lužnice River basin with respect to anthropogenic modifications. The Lužnice River is located in the south of Czechia. A larger part of the river exhibits a low intensity of modification - meandering stream with many pools and oxbow lakes in the floodplain where a safe retention of water during the flood event remains possible. The main part of the study concentrates on the hydrological regime. The methodology is based on statistical evaluation of a long-time data series from the Pilař water gauging station. Flood events and dry periods were analysed during the past 46 years. Discharge measurements (conducted by the Faculty of Science, Department of Physical Geography and Geoecology) are used for recent flood evaluations.

scholarly journals Predictive Maintenance Implementation In Reach Stacker Kalmar Type Drd To Reduce Component Failure

2018 ◽  
Vol 3 (1) ◽  
pp. 29
Author(s):  
Ponidi Ponidi ◽  
Ali Makhfud
Keyword(s):  
Fault Tree Analysis ◽  
Standard Operating Procedure ◽  
Predictive Maintenance ◽  
Effect Analysis ◽  
Failure Data ◽  
Long Time ◽  
History Of ◽  
Frequent Failure ◽  
Lifting Equipment ◽  
Load Handling

The Reach Stacker lifting tool is the most productive lifting tool for container lifting today. It can move container till 20 container box in every hour, it means that in 3 minutes it can lift and lower 1 box container. In operation the lifting equipment will surely experience a stop operation due to the failure of a component. The purpose of this study was to determine critical and important components of the history of failure data for a year (2016) in PT meratusline, by using tools Fault Tree Analysis, Failure Mode and Effect Analysis and Pareto. From the analysis, it obtained Load Handling component as the most critical component based on the most frequent failure and required a long time to repair. The cause of the failure itself was inconsistent greasing maintenance / Predictive maintenance was not executed and there was no loose handling of Load Handling chain components. From the result of research, it was suggested to make standard rule by adding greasing item in worksheet Predictive maintenance and Standard Operating Procedure Predictive Maintenance for chain replacement on Load Hadling component if already entering 12000 Hour life.

scholarly journals Morphological features of eggs depending on the chicken genotype by mutations T+3737C and A+3971G in insulin locus

2018 ◽  
Vol 20 (84) ◽  
Author(s):  
L. V. Shulika
Keyword(s):  
Rhode Island ◽  
Marker Assisted Selection ◽  
Molecular Genetic ◽  
Egg Laying ◽  
Morphological Features ◽  
Shell Weight ◽  
Chicken Population ◽  
Long Time ◽  
Speed Up ◽  
Animal Metabolism

Quality of eggs, including morphological features, affect on their dietary properties, incubatory and trade characteristics. This gives background to affirm necessity of selection work in direction of improving these features additionally to chicken egg-laying qualities. But selection by complex of traits requires long time and significant resources. To increase effectiveness and speed up the process of selection molecular genetic markers are used. Such approach is named marker-assisted selection. One of genes, that is of interest in the context of marker-assisted selection, is insulin gene, which product takes part in the regulation of animal metabolism. The gene is polymorphic in chicken, particularly, there were found mutations T+3737C and A+3971G, located within second intron and 3'-UTR-region, respectively. The current work is devoted of studying of morphological features of eggs depending on the genotype by above-mentioned mutations. The research was conducted on the chicken population of line 38 of Rhode Island Red breed. The following features were studied as yolk weight, glair weight, shell weight, yolk percent, shell percent, mean shell thickness, egg form index. Measuring was made on 30th and 52th weeks of layer age. Comparison of groups with different genotypes was conducted using t-criterion or U-criterion depending on the distribution normality. There was no significant associations between genotype by T+3737C mutation and egg morphological features within investigated line. By mutation A+3971G it was shown, that eggs of layers with AA genotype differ significantly (P ≤ 0.05) from eggs that received from chickens with AG and GG genotypes by egg form index on 30th week. Also, significant (P ≤ 0.01) association was revealed for yolk percent on 52th week of life and genotype on this mutation. Namely, chickens with AA genotype layed eggs with lower yolk percent than chickens with AG and GG genotypes. Similar situation was observed relatively to yolk weight but difference was reliable (P ≤ 0.05) only between homozygotes AA and GG. According to the results, it is possible to consider mutation A+3971G as the molecular genetic marker of morphological features of chicken eggs.

scholarly journals Climate warming may affect the optimal timing of reproduction for migratory geese differently in the low and high Arctic

Oecologia ◽  
2019 ◽  
Vol 191 (4) ◽  
pp. 1003-1014 ◽  
Author(s):  
Thomas K. Lameris ◽  
Margje E. de Jong ◽  
Michiel P. Boom ◽  
Henk P. van der Jeugd ◽  
Konstantin E. Litvin ◽  
...  
Keyword(s):  
Climate Warming ◽  
High Arctic ◽  
Egg Laying ◽  
The Arctic ◽  
Laying Date ◽  
Optimal Timing ◽  
Negative Effects ◽  
Barnacle Goose ◽  
Timing Of Reproduction ◽  
Low Arctic

Abstract Rapid climate warming is driving organisms to advance timing of reproduction with earlier springs, but the rate of advancement shows large variation, even among populations of the same species. In this study, we investigated how the rate of advancement in timing of reproduction with a warming climate varies for barnacle goose (Branta leucopsis) populations breeding at different latitudes in the Arctic. We hypothesized that populations breeding further North are generally more time constrained and, therefore, produce clutches earlier relative to the onset of spring than southern populations. Therefore, with increasing temperatures and a progressive relief of time constraint, we expected latitudinal differences to decrease. For the years 2000–2016, we determined the onset of spring from snow cover data derived from satellite images, and compiled data on egg laying date and reproductive performance in one low-Arctic and two high-Arctic sites. As expected, high-Arctic geese laid their eggs earlier relative to snowmelt than low-Arctic geese. Contrary to expectations, advancement in laying dates was similar in high- and low-Arctic colonies, at a rate of 27% of the advance in date of snowmelt. Although advancement of egg laying did not fully compensate for the advancement of snowmelt, geese laying eggs at intermediate dates in the low Arctic were the most successful breeders. In the high Arctic, however, early nesting geese were the most successful breeders, suggesting that high-Arctic geese have not advanced their laying dates sufficiently to earlier springs. This indicates that high-Arctic geese especially are vulnerable to negative effects of climate warming.

scholarly journals Colonial Larids (Charadriiformes): Breeding Synchrony and Determination of its Level

2020 ◽  
Vol 33 ◽  
pp. 3-25
Author(s):  
Yu. I. Mel’nikov ◽  
Keyword(s):  
Total Duration ◽  
Bird Species ◽  
Breeding Birds ◽  
Egg Laying ◽  
Breeding Cycle ◽  
Synchronization Index ◽  
Large Colony ◽  
Short Period ◽  
Mass Reproduction ◽  
Comparison Of The Results

Based on many years of research (1972–2018) on the biology, ecology, and behavior of gull birds, whose membership in colonial species is not in doubt, the features of the specific phenomenon of the colony – high reproduction synchronization – are examined. It consists in a very short period of mass egg laying (in small colonies 2-3, and very rarely 4 days), but at this time the main number of birds forming the colony begins to nest. It was shown that this trait varies quite significantly depending on its size and is most strongly and clearly expressed in small colonies. The latter is due to the fact that large colonies are formed from small ones, often differing in terms of reproduction. As a result, the seasonal breeding cycle of a large colony often covers the entire nesting period characteristic of a particular species. The features of synchronizing the breeding of birds in colonies as one of its main characteristics are considered in detail. The factors that most determine the degree of synchronization of reproduction of birds in colonies of different sizes were identified: a) the size of the colony and the total duration of egg laying, b) the size of the colony and the duration of mass egg laying, c) the size of the colony and the proportion of birds that formed clutches during the period of mass reproduction, d) the duration of the mass egg laying and the proportion of birds that formed the clutches during this period. The correlation relationships between all these signs of the colony are calculated. Of all the factors considered by us, the two most characteristic for the period of mass nesting of colonial birds are detected immediately and very simply. All colonies differ well in the length of the period of mass breeding and in the proportion of birds that started to nest at that time. These are interrelated factors, but the degree of their correlation is relatively small and they determine the level of synchronization of breeding birds in the colony. With an increase in the proportion of birds that formed clutches during the period of mass reproduction and a decrease in time of this period (mass egg laying), the synchronization of reproduction of birds in the colony increases. An ideal relationship between the level of synchronization and these factors - the entire colony is formed in one day. The case is quite rare, but, nevertheless, constantly found in small colonies of all species of gull birds. Since the index is always a relative indicator, and almost all of the signs that we have examined are related to the size of the colony, it is precisely it that should be included in the developed comprehensive indicator. Based on them, a special index has been developed and proposed for use, which allows us to assess the level of synchronization of bird breeding in colonies, nesting clusters and aggregations – Isr (breeding synchronization index). As a result of our work, this index has the following form: Isr = √(n / l) / N, 0 ≤ Isr ≤ 1, where: n is the number of clutches formed during the period of mass breeding of birds, in item (by the date of laying the first egg in the nest); l – the duration of the period of mass egg-laying, day and night (accurate to tenths); N is the size of the colony (number of nests or pairs); Isr is the synchronization index. The essence of this indicator can be formulated as follows: the index of reproduction synchronization, as a relative indicator indicates how many nests in the average are formed during one day of mass egg laying, depending on its duration and the size of a particular colony. Extraction of the square root increases the obtained value, sometimes very small (in very large colonies), which greatly facilitates the use of this index and improves its perception. The maximum estimate of the level of synchronization of breeding birds in the colony tends to 1.0 and sometimes reaches this value. The minimum value of this indicator tends to 0, but is unlikely to reach it. In any case, our minimum estimates of the level of synchronization of the entire breeding season of birds in a very large colony (about 5.0 thousand nests) did not fall below 0.05. Comparison of the results of his calculation with actual observational data shows that he clearly responds to changes in colony parameters used to determine the level of egg laying synchronization and its other reproductive indicators. In addition, according to the results of statistical analysis, its high relationship with the main reproductive parameters of the colonies was established, which allows us to consider the synchronization index as one of the most important and promising relative indicators. Its use allows us to discover new, still very poorly studied relationships of various parameters of the reproductive processes of colonial bird species with environmental factors.

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