annual fluctuation
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Oryx ◽  
2021 ◽  
pp. 1-8
Author(s):  
F. Zino ◽  
M. Biscoito ◽  
A. Buckle

Abstract The largest colony of Cory's shearwater Calonectris borealis nests on the island of Selvagem Grande in the north-eastern Atlantic. In 2002, a programme of eradication was conducted to remove two alien invasive mammals, the house mouse Mus musculus and European rabbit Oryctolagus cuniculus. Preliminary studies recorded beneficial effects of the eradications for a variety of plant and animal species, including Cory's shearwater. We recorded fledging rates of shearwaters for 1982–2001, prior to the eradication, and for 2002–2020, after the eradication, from two quadrats, each containing 134–329 nest sites. Although there was annual fluctuation in fledging rates in the quadrats, the mean rate of 40.74 ±SD 3.92 fledglings per 100 nest sites for the two quadrats combined prior to the eradication of mammals increased significantly, to 52.88 ± SD 5.03 per 100 nest sites, after the eradications. Because the two mammals were removed synchronously it is difficult to know which factors depressed fledging of Cory's shearwaters on Selvagem Grande. However, the predatory behaviour of house mice on other oceanic islands, and the fact that increased fledging was seen soon after the eradications occurred, suggest predation by house mice on shearwater hatchlings was the main cause of losses.


2021 ◽  
Author(s):  
Huazu Liu ◽  
Qiu Jin ◽  
Ruijie Shi ◽  
Chengxu Lv ◽  
Junxiao Luo ◽  
...  

Abstract. Hydrological conditions drive the distribution of plant communities in wetlands to form vegetation zones where the material cycling varies with plant species. This mediation effect caused by the distribution of vegetation under hydrological conditions will affect the emission of N2O during the nitrogen migration in wetlands. In this study, five vegetation zones in the second largest wetland of China were investigated in situ during high and low water levels to elucidate the effect mediated by vegetation. With the increase in the rate of change of water levels, the zones of the mud flat, nymphoides, phalaris, carex, and reeds were distributed in sequence in the wetland, and the densities of carbon and nitrogen sequestrated by plants also increased. The carbon and nitrogen densities in each zone during low water level was significantly higher than that during high water level, while the organic carbon and the total nitrogen of sediments during high water level was higher. Sediments converted between source and sink for both carbon and nitrogen, during the annual fluctuation in water level. The flux in N2O emissions showed significant differences between the vegetation zones during each water level period. The emission flux decreased with the increasing C : N ratio in sediments, approximating the threshold at 0.23 μg m−2 h−1 when the C : N ratio > 25. The phylum abundance of Firmicutes, Proteobacteria, and Chloroflexi in sediments increased with flooding. The denitrifying nirS and nirK genes and anammox hzsB gene were significantly affected by water level fluctuation, with the maximal variations of these genes occurring in the mud flat and nymphoides zone. The results indicate that the distribution of plants under hydrological conditions modified the stoichiometric ratio of sediments, resulting in the variations of N2O emission fluxes and microbial communities in vegetation zones. Therefore, hydraulic regulation rather than direct planting would be an effective strategy to reduce greenhouse gas emissions in freshwater wetlands.


Separations ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 119
Author(s):  
Konstantina Pasvanka ◽  
Marios Kostakis ◽  
Maria Tarapoulouzi ◽  
Pavlos Nisianakis ◽  
Nikolaos S. Thomaidis ◽  
...  

Major, minor and trace elements in wines from Greece were determined by inductively coupled plasma–mass spectrometry (ICP–MS). The concentrations of 44 elements (Na, Mg, P, K, Ca, Cu, Co, Cr, Zn, Sn, Fe, Mn, Li, Be, B, V, Sr, Ba, Al, Ag, Ni, As, Sn, Hg, Pb, Sb, Cd, Ti, Ga, Zr, Nb, Pd, Te, La, Sm, Ho, Tm, Yb, W, Os, Au, Tl, Th, U) in 90 white and red wines from six different regions in Greece for two consecutive vinification years, 2017 and 2018, were determined. Results for the elements aforementioned were evaluated by multivariate statistical methods, such as discriminant analysis and cluster analysis, and the wines were discriminated according to wine variety and geographical origin. Due to the specific choice of the analytes for multivariate statistical investigation, a prediction rate by cross-validation of 98% could be achieved. The aim of this study was not only to reveal specific relationships between the wine samples or between the chemical variables in order to classify the wines from different regions and varieties according to their elemental profile (wine authentication), but also to observe the annual fluctuation in the mineral content of the studied wine samples.


2021 ◽  
Author(s):  
Kenshiro Arie ◽  
Chiyuki Narama ◽  
Ryohei Yamamoto ◽  
Kotaro Fukui ◽  
Hajime Iida

Abstract. In 2012, three perennial snow patches in the northern Japanese Alps were determined to be very small glaciers (VSGs: < 0.5 km2). These were soon followed by four more nearby. However, it had not been determined how such glaciers could be maintained in such a warm climate. In this study, we calculate annual and seasonal mass balances of five of these VSGs, covering 2015–2019 for four of them (2017–2019 for the fifth) using multi-period digital surface models (DSMs) based on structure from motion–multi-view stereo (SfM–MVS) technology and images taken from a small airplane. The results indicate that, due to mass acquired from avalanches, these VSGs are maintained by acquiring a winter balance that is more than double that from the snowfall amount, thereby exceeding the summer balance. Therefore, we classify them as topographically controlled VSGs. We find almost no annual fluctuation in their summer balance; however, their winter balance, and annual balance, have large annual fluctuations. The annual balance, which mainly depends on the winter balance, showed accumulation throughout each glacier during heavy snow years and ablation throughout each glacier during light snow years. This characteristic differs from the upper accumulation area and lower ablation area that exists on most glaciers. These VSGs had negative annual balance gradients, which suggests that they did not have an equilibrium line during the observation period. Moreover, comparing to other glaciers worldwide, we find the mass balance amplitude of glaciers in the northern Japanese Alps to be the highest measured to date.


2021 ◽  
Vol 218 ◽  
pp. 103526
Author(s):  
Andrés J. Jaureguizar ◽  
Agustín M. De Wysiecki ◽  
Martina D. Camiolo ◽  
Moira Luz Clara

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 778
Author(s):  
Anna-Thalassini Valli ◽  
Christos Chondrogiannis ◽  
George Grammatikopoulos ◽  
Gregoris Iatrou ◽  
Panayiotis Trigas

The massive decline in biodiversity due to anthropogenic threats has led to the emergence of conservation as one of the central goals in modern biology. Conservation strategies are urgently needed for addressing the ongoing loss of plant diversity. The Mediterranean basin, and especially the Mediterranean islands, host numerous rare and threatened plants in need of urgent conservation actions. In this study, we assess the current conservation status of Micromeria browiczii, a local endemic to Zakynthos Island (Ionian Islands, Greece), and estimate its future risk of extinction by compiling and assessing scientific information on geographical distribution, population dynamics and reproductive biology. The population size and the geographical distribution of the species were monitored for five years. The current population of the species consists of 15 subpopulations. Considerable annual fluctuation of population size was detected. The species is assessed as Endangered according to the International Union for Conservation of Nature threat categories. According to population viability analysis results, its extinction risk was estimated to be 5.6% over the next 50 years, when six of the fifteen subpopulations (40%) might become extinct. The investigation of certain aspects of the species’ biology yielded important data necessary to identify critical aspects for its survival and to propose conservation measures.


2021 ◽  
Vol 41 (I) ◽  
pp. 46-54
Author(s):  
B. KLADOCHNYI ◽  
◽  
B. PALIANYTSIA ◽  

The aim of this work is to study the zenith tropospheric delay components fluctuations according to the atmospheric sounding data and analytical model in selected period and accuracy assessment of Saastamoinen model. Methodology. The main methods for calculation ZTD are atmospheric sounding and using analytical models. To study ZTD components we use atmospheric sounding data conducted at 4 Ukrainian upper air stations (Kyiv, Kharkiv, Lviv, Odesa) with 24 hours frequency, as well as near-surface atmospheric variables provided by weather stations with 3 hours frequency in the period from January 1 to December 31, 2019. ZTD components were calculated by integration using sounding data, and using Saastamoinen’s formulas. Based on the calculated data, created graphs comparing the values of sounding and model. Calculated the standard error of Saastamoinen model. Results. Compared ZTD components at points, located in different climatic zones, using the atmospheric pressure reduced to sea level. Both ZDD and ZWD are the largest at Odesa station. Annual fluctuation of ZDD are 8–20 mm and ZWD fluctuations are 75–95 mm. The daily amplitudes of ZDD are 5–6 mm in summer and 12–13 mm in winter. The daily amplitudes of ZWD are 20–30 mm in summer and 6–8 mm in winter. The standard error of Saastamoinen’s model is 7 mm for ZDD and 22 mm for ZWD. Scientific novelty and practical significance in that the study can improve accuracy and evaluate the feasibility of using different methods for calculating ZTD, see the dynamic of change ZDD and ZWD and their behavior over a long period. The results can be used for further studies of ZTD and improving the accuracy of satellite observations.


2021 ◽  
Vol 13 (4) ◽  
pp. 1862
Author(s):  
Liang Zhang ◽  
Xubing Zhang ◽  
Shenggu Yuan ◽  
Kai Wang

In recent years, with the rapid development of urban transportation network in China, many problems have been exposed, especially in the Beijing–Tianjin–Hebei (BTH) region. Under the call of sustainable development, it is of great significance to evaluate the economic, social, and ecological (ESE) impact of transportation network in BTH urban agglomeration for promoting the sustainable development of transportation ESE in BTH urban agglomeration. In this paper, 12 indicators in the field of transportation are selected to build the evaluation index system of ESE effects of transportation network in BTH urban agglomeration. By using entropy weight TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) model and the Jenks natural breaks classification method, the ESE impacts of transportation network in 13 cities of BTH from 2013 to 2017 are analyzed from the temporal and spatial dimensions. The research shows that: (1) From 2013 to 2017, the economic impact degree of traffic network shows an annual fluctuation trend, the social impact degree increases year by year, and the ecological impact degree decreases year by year; (2) For the cities of BTH, the ESE impact assessment results of transportation network from 2013 to 2017 can be divided into seven clusters. Except Handan City, the ESE impact assessment categories of other cities’ transportation network have been improved, but the proportion of cities in the transition period is still large, especially the “Low-Low-Low” cities. The types of cities in the transitional period need to be focused. It is still a heavy burden to realize the ESE coordination and sustainable development of BTH urban agglomeration transportation network.


2020 ◽  
Vol 7 ◽  
Author(s):  
Stephanie Plön ◽  
Christine Erbe ◽  
Sabine Wintner

Bather protection nets have been in place off the coast of KwaZulu-Natal (KZN), South Africa, since the 1950’s. Besides sharks, they also catch a number of other marine vertebrates, including dolphins, the majority of which are Indo-Pacific bottlenose dolphins Tursiops aduncus. Previous analyses of dolphin bycatch in the nets indicated the potential impacts on the local populations, but a lack of information on population structure has to-date hindered a more detailed assessment. A recent re-assessment of the status and population delineations of T. aduncus off South Africa prompted a re-examination of demographic, spatial, and temporal patterns of its catches in bather protection nets over a 36-year period (January 1980 to December 2015). In total, 1169 dolphins were caught, including a slightly greater number of females and juveniles than other sex-classes, raising concern about the potential long-term effects on population demographics. More dolphins were caught off the North than the South coast. Temporal trends indicate that the bycatch during June and July every year (peak Sardine Run period) as a percentage of overall dolphin bycatch has been steadily decreasing from 39.8% in 1980 to 13% in 2015. A large inter-annual fluctuation can be seen, probably as a result of the inter-annual intensity of the Sardine Run. Although our results do not indicate a long-term decline of the individual populations as previously predicted, revised abundance estimates and data on the demographics and movement patterns of the animals are urgently required to accurately assess the impact of bycatch on the Indo-Pacific bottlenose dolphin populations off KZN and to advise conservation and management decisions going forward.


2020 ◽  
Vol 66 (4) ◽  
pp. 40-49
Author(s):  
Petar Vušković

AbstractThe ISO 9001:2015 certificate of quality is nowadays the most renowned quality standard in the world. Standardised quality has become an imperative competitive advantage on the market for all serious business organisations. The fluctuation of the number of certificates of quality indicates to what extent companies are willing to ensure the quality of their products and services to customers and clients, and how fast the domestic market is standardised and integrated into the global economy. This paper presents the results of two empirical studies. The first one focused on the analysis of the fluctuation in the number of ISO 9001:2015 certificates in the period from 2008 to 2018, while the second aimed to determine the satisfaction of leadership with the certificate. The study has shown that, during the observed period, the number of certificates of quality in Croatia fluctuated between – 18% and +22% annually. At the annual level, a certain number of companies lose their certificates or opt for decertification. For that reason, a study of the leadership’s level of satisfaction with the ISO 9001:2015 certificate was conducted using a sample of 296 certified business organisations. The study has proven that the leadership showed a high level of satisfaction with the certificate of quality and that they appreciate business organisations with certificates of quality. It demonstrates that the quality management certification has a bright future regardless of the annual fluctuation of the number of certificates.


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