scholarly journals Long-term vegetation change in species-rich Nardus grasslands of central Germany caused by eutrophication, recovery from acidification and management change

2019 ◽  
Author(s):  
Cord Peppler-Lisbach ◽  
Nils Stanik ◽  
Natali Könitz ◽  
Gert Rosenthal
Keyword(s):  
Species Composition ◽  
Nitrogen Deposition ◽  
Central Europe ◽  
Community Change ◽  
Soil Parameters ◽  
Moderate Increase ◽  
Sulphur Deposition ◽  
Biogeographic Region ◽  
Recovery From Acidification ◽  
The Impact

AbstractQuestionsThe impact of environmental changes on species-rich Nardus grasslands has been documented from the Atlantic biogeographic region but not from Central Europe. Which patterns and trends of community change in species-rich Nardus grassland of the Continental biogeographic region occurred in past decades? Are patterns and trends similar across areas within the Continental biographic region of Germany? Do they correspond to identified changes in the Atlantic biogeographic region of Europe?LocationEast Hesse Highlands, GermanyMethodsIn 2012/15, we re-surveyed vegetation relevés on quasi-permanent plots originally surveyed between 1971 and 1986/87 and re-measured soil parameters. We tested for differences in species frequency and abundance, mean Ellenberg indicator values, diversity measures and soil variables. Nitrogen and sulphur deposition data were analysed to evaluate effects of atmospheric pollutants. We used regression analyses to identify the contribution of environmental drivers to changes in species composition.ResultsWe found significant increases in soil pH, Ellenberg R and N values, species of agricultural grasslands and grassland fallows. C:N ratio, Nardus grassland specialists and low-nutrient indicators declined, while changes in species composition relate to changes in pH and management. There was a strong decrease in sulphur and a moderate increase in nitrogen deposition. Local patterns in atmospheric depositions did not correlate with local changes in species composition and soil parameters.ConclusionThe findings indicate significant overall eutrophication, a trend towards less acidic conditions, and insufficient management and abandonment. This is widely consistent across study areas and correspond to recent reports on vegetation changes and recovery from acidification in the Atlantic biogeographic region. We strongly assume reduction in sulphur deposition during recent decades to be a major driver of these changes combined with increased nitrogen deposition and reduced management intensity. This suggests a large-scale validity of processes triggering changes in Nardus grasslands across Western and Central Europe.NomenclatureThe nomenclature follows the German taxonomic reference list (GermanSL version 1.3) of Jansen & Dengler (2008).

Lichen community change over a 15-year time period: effects of climate and pollution

2013 ◽  
Vol 45 (1) ◽  
pp. 35-50 ◽  
Author(s):  
Marianne EVJU ◽  
Inga E. BRUTEIG
Keyword(s):  
Species Composition ◽  
Nitrogen Deposition ◽  
Community Change ◽  
Repeated Measurements ◽  
Natural Ecosystems ◽  
Humid Climate ◽  
Sulphur Compounds ◽  
Clear Trend ◽  
Sulphur Deposition ◽  
Generalist Species

AbstractOver the last decades, levels of sulphur deposition from air pollution have been substantially reduced in Norway, whereas levels of nitrogen deposition have been stable or somewhat increased. In parallel, a clear trend of increasing annual temperatures, as well as precipitation, is evident. Human impact on natural ecosystems is predicted to reduce biodiversity at regional scales through facilitating a few generalist species at the expense of species with narrow habitat requirements. In this study, we investigate changes in community composition and the abundance of dominant lichen species on birch in subalpine forests over a 15-year period. The study is based on repeated measurements in five monitoring sites in Norway, representing regional gradients in temperature and precipitation as well as in deposition of nitrogen and sulphur compounds. Two dominant species are studied in particular; the generalist Hypogymnia physodes and the subalpine birch specialist Melanelia olivacea. The largest change in species composition was found in the site with the biggest reduction in sulphur deposition during the 15-year period, whereas the site with low precipitation and low pollution loads had small changes in species composition. The abundance of the generalist H. physodes increased in all sites and the specialist M. olivacea decreased in abundance, especially in sites with both high precipitation and heavy nitrogen deposition. Our study thus suggests that a warmer, humid climate is beneficial for the generalist H. physodes.

scholarly journals The influence of invasive Fallopia taxa on resident plant species in two river valleys (southern Poland)

2015 ◽  
Vol 84 (1) ◽  
pp. 23-33 ◽  
Author(s):  
Damian Chmura ◽  
Barbara Tokarska-Guzik ◽  
Teresa Nowak ◽  
Gabriela Woźniak ◽  
Katarzyna Bzdęga ◽  
...  
Keyword(s):  
Species Diversity ◽  
Species Composition ◽  
Negative Impact ◽  
Magnesium Content ◽  
Soil Parameters ◽  
Resident Species ◽  
Fallopia Japonica ◽  
Southern Poland ◽  
River Valleys ◽  
The Impact

Riparian zones in two rivers in southern Poland were studied in terms of species composition and soil parameters in patches dominated by three knotweed taxa (<em>Fallopia japonica</em>, <em>F. sachalinensis</em> and the hybrid <em>F.</em> ×<em>bohemica</em>). The main purpose was to detect any differences in species diversity, environmental conditions and in the impact of the three <em>Fallopia</em> spp. on resident species. Fieldwork was conducted in spring and summer in 30 invaded plots (in total 90 subplots). It was demonstrated that vegetation dominated by particular knotweed taxa differed in response to soil pH and ammonium, nitrate, and magnesium content. <em>Fallopia</em> spp. (living plants and necromass) had a stronger negative impact on the cover and species diversity of the resident species in summer in comparison with spring. Vegetation patches differed significantly in species composition in relation to the knotweed taxa present. These differences may be the consequence of the differentiated biotopic requirements of <em>Fallopia</em> taxa and the coexisting plants, or to the different impact of the knotweed taxa on the resident species.

scholarly journals Relationship between parameters of public parks and their surroundings and the richness, diversity and species composition of vascular herbaceous plants on the example of Krakow in Central Europe

2021 ◽  
Vol 94 ◽  
pp. 1-16
Author(s):  
Łukasz Moszkowicz ◽  
Izabela Krzeptowska-Moszkowicz ◽  
Karolina Porada
Keyword(s):  
Species Composition ◽  
Central Europe ◽  
Plant Species ◽  
Urban Space ◽  
Habitat Heterogeneity ◽  
Herbaceous Plants ◽  
Public Parks ◽  
Migration Corridors ◽  
Synanthropic Species ◽  
The Impact

Greenery is a natural value in urban space. To maintain the richness and diversity of greenery, it is necessary to understand the factors and mechanisms that influence vegetation. The purpose of this paper was to determine the impact of selected features of public parks and factors on the richness and diversity of herbaceous plants. In Krakow public parks, this richness and diversity is greater in parks with a larger area and habitat heterogeneity, the presence of migration corridors, and natural elements. Full stand coverage negatively affects diversity. Biologically inactive surface affects richness and diversity as well as a number of different groups of plant species. The presence of rare and non-synanthropic species is related to the park’s surface, natural elements, and its heterogeneity.

scholarly journals The relative importance of stochastic and deterministic processes on bryophyte community assembly changes with scale

2021 ◽  
Author(s):  
Nagore Medina ◽  
Joaquin Calatayud ◽  
Richard Ladle ◽  
Francisco Lara ◽  
Isabel Draper ◽  
...  
Keyword(s):  
Species Composition ◽  
Beta Diversity ◽  
Environmental Gradients ◽  
Geographic Distance ◽  
Small Scale ◽  
Stochastic Effects ◽  
Network Analyses ◽  
Biogeographic Region ◽  
Deterministic Processes ◽  
The Impact

Studies focused on the drivers of change in species composition often fail to integrate several aspects of beta diversity and scale. Here, we assess the impact of species pool, environmental gradients, geographic distance, and spatial scale on the diversity of epiphytic bryophytes. We identify biogeographic modules of co-occurring species using network analyses. For each biogeographic unit we study the effects of environment, abundance structure of the community and geographic distance on beta diversity. We analyse two aspects of beta diversity related to different scales of analysis: between-forests dissimilarity in species composition and within-forests heterogeneity in species composition. We show that the structuring of the communities is a by-product of niche-related and stochastic processes. The balance of these processes changes with biogeographic region and scale, neutral stochastic effects are more significant in the most favourable regions and for small-scale within-forest heterogeneity

scholarly journals Deep Neural Network and Polynomial Chaos Expansion-Based Surrogate Models for Sensitivity and Uncertainty Propagation: An Application to a Rockfill Dam

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1830
Author(s):  
Gullnaz Shahzadi ◽  
Azzeddine Soulaïmani
Keyword(s):  
Polynomial Chaos ◽  
Complex Structure ◽  
Uncertainty Propagation ◽  
Surrogate Models ◽  
Polynomial Chaos Expansion ◽  
Soil Parameters ◽  
Chaos Expansion ◽  
Rockfill Dam ◽  
Parametric Studies ◽  
The Impact

Computational modeling plays a significant role in the design of rockfill dams. Various constitutive soil parameters are used to design such models, which often involve high uncertainties due to the complex structure of rockfill dams comprising various zones of different soil parameters. This study performs an uncertainty analysis and a global sensitivity analysis to assess the effect of constitutive soil parameters on the behavior of a rockfill dam. A Finite Element code (Plaxis) is utilized for the structure analysis. A database of the computed displacements at inclinometers installed in the dam is generated and compared to in situ measurements. Surrogate models are significant tools for approximating the relationship between input soil parameters and displacements and thereby reducing the computational costs of parametric studies. Polynomial chaos expansion and deep neural networks are used to build surrogate models to compute the Sobol indices required to identify the impact of soil parameters on dam behavior.

scholarly journals Effects of COVID-19 Pandemic on the Treatment of Pancreatic Cancer: A Perspective from Central Europe

2021 ◽  
Vol 38 (2) ◽  
pp. 158-165
Author(s):  
Ilaria Pergolini ◽  
I. Ekin Demir ◽  
Christian Stöss ◽  
Klaus Emmanuel ◽  
Robert Rosenberg ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Cancer Patients ◽  
Central Europe ◽  
Pancreatic Surgery ◽  
Online Survey ◽  
Viral Infections ◽  
High Volume ◽  
Tumor Board ◽  
Standards Of Care ◽  
The Impact

Background: This survey aimed to register changes determined by the COVID-19 pandemic on pancreatic surgery in a specific geographic area (Germany, Austria, and Switzerland) to evaluate the impact of the pandemic and obtain interesting cues for the future. Methods: An online survey was designed using Google Forms focusing on the local impact of the pandemic on pancreatic surgery. The survey was conducted at 2 different time points, during and after the lockdown. Results: Twenty-five respondents (25/56) completed the survey. Many aspects of oncological care have been affected with restrictions and delays: staging, tumor board, treatment selection, postoperative course, adjuvant treatments, outpatient care, and follow-up. Overall, 60% of respondents have prioritized pancreatic cancer patients according to stage, age, and comorbidities, and 40% opted not to operate high-risk patients. However, for 96% of participants, the standards of care were guaranteed. Discussion/Conclusions: The first wave of the COVID-19 pandemic had an important impact on pancreatic cancer surgery in central Europe. Guidelines for prompt interventions and prevention of the spread of viral infections in the surgical environment are needed to avoid a deterioration of care in cancer patients in the event of a second wave or a new pandemic. High-volume centers for pancreatic surgery should be preferred and their activity maintained. Virtual conferences have proven to be efficient during this pandemic and should be implemented in the near future.

The impact of nitrogen deposition on upland surface waters in Great Britain: A regional assessment of nitrate leaching

1995 ◽  
Vol 85 (2) ◽  
pp. 297-302 ◽  
Author(s):  
T. E. H. Allott ◽  
C. J. Curtis ◽  
J. Hall ◽  
R. Harriman ◽  
R. W. Battarbee
Keyword(s):  
Great Britain ◽  
Nitrogen Deposition ◽  
Surface Waters ◽  
Nitrate Leaching ◽  
Regional Assessment ◽  
The Impact

Concrete and Fiber Reinforced Concrete Subjected to Impact Loading

1985 ◽  
Vol 64 ◽  
Author(s):  
Surendra P. Shah
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Basic Material ◽  
Strain History ◽  
Moderate Increase ◽  
Fiber Reinforced ◽  
The Impact

ABSTRACTDespite its extensive use, low tensile strength has been recognized as one of the major drawbacks of concrete. Although one has learned to avoid exposing concrete structures to adverse static tensile load, these cannot be shielded from short duration dynamic tensile stresses. Such loads originate from sources such as impact from missiles and projectiles, wind gusts, earthquakes and machine vibrations. The need to accurately predict the structural response and reserve capacity under such loading has led to an interest in the mechanical properties of the component materials at high rates of straining.One method to improve the resistance of concrete when subjected to impact and/or impulsive loading is by the incorporation of randomly distributed short fibers. Concrete (or Mortar) so reinforced is termed fiber reinforced concrete (FRC). Moderate increase in tensile strength and significant increases in energy absorption (toughness or impact-resistance) have been reported by several investigators in static tests on concrete reinforced with randomly distributed short steel fibers. A theoretical model to predict fracture toughness of FRC is proposed. This model is based on the concept of nonlinear elastic fracture mechanics.As yet no standard test methods are available to quantify the impact resistance of such composites, although several investigators have employed a variety of tests including drop weight, swinging pendulums and the detonation of explosives. These tests though useful in ascertaining the relative merits of different composites do not yield basic material characteristics which can be used for design.The author has recently developed an instrumented Charpy type of impact test to obtain basic information such as load-deflection relationship, fracture toughness, crack velocity and load-strain history during an impact event. From this information, a damage based constitutive model was proposed. Relative improvements in performance due to the addition of fibers as observed in the instrumented tests are also compared with other conventional methods.

scholarly journals Biofeedback Intervention for Stress and Anxiety among Nursing Students: A Randomized Controlled Trial

ISRN Nursing ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Paul Ratanasiripong ◽  
Nop Ratanasiripong ◽  
Duangrat Kathalae
Keyword(s):  
Nursing Students ◽  
Stress Level ◽  
Clinical Training ◽  
Intervention Program ◽  
Controlled Trial ◽  
Controlled Study ◽  
Control Group ◽  
Moderate Increase ◽  
Randomized Controlled ◽  
The Impact

Purpose. It has been well documented that nursing students across the world experience stress and anxiety throughout their education and training. The purpose of this randomized controlled study is to investigate the impact of biofeedback intervention program on nursing students' levels of stress and anxiety during their first clinical training. Methods. Participants consisted of 60 second-year baccalaureate nursing students. The 30 participants in the biofeedback group received training on how to use the biofeedback device to assist in stress and anxiety management for 5 weeks while the 30 in the control group did not receive any training. Findings. Results indicated that the biofeedback group was able to maintain the stress level while the control group had a significant increase in the stress level over the 5-week period of clinical training. Additionally, the biofeedback group had a significant reduction in anxiety, while the control group had a moderate increase in anxiety. Conclusions. The better the nursing students can manage their stress and anxiety, the more successful they can be in their clinical training. Ultimately, the more psychologically healthy the nursing students are, the more likely they will flourish and graduate to become productive and contributing members of the nursing profession.

Impact of random soil properties on stress–strain response

2004 ◽  
Vol 41 (2) ◽  
pp. 351-355 ◽  
Author(s):  
Dieter Stolle ◽  
Peijun Guo ◽  
Gabriel Sedran
Keyword(s):  
Soil Properties ◽  
Constitutive Modelling ◽  
Soil Parameters ◽  
Strain Response ◽  
Constitutive Behaviour ◽  
Stress Strain ◽  
Deterministic Analysis ◽  
Model Predictions ◽  
Random Variability ◽  
The Impact

This paper analyzes the impact of natural random variation of soil properties on the constitutive modelling of geomaterial behaviour. A theoretical framework for accommodating variation in soil properties is presented. The framework is then used to examine the consequence of parameter variability on stress–strain relations. An important observation is that average soil parameters from a series of tests on small specimens, in which density of the specimens varies randomly, do not necessarily reflect the average constitutive behaviour of soil. Model predictions are shown to be consistent with the experimental data.Key words: random variability, deterministic analysis, soil parameters, constitutive model.

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