scholarly journals Effects of Disturbance on Understory Vegetation across Slovenian Forest Ecosystems

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 1048 ◽  
Author(s):  
Kutnar ◽  
Nagel ◽  
Kermavnar
Keyword(s):  
Species Richness ◽  
Forest Ecosystems ◽  
Ground Surface ◽  
Diversity Indices ◽  
Common Species ◽  
Mean Value ◽  
Forest Understory ◽  
Species Number ◽  
Ground Vegetation ◽  
The Mean

The herbaceous understory represents a key component of forest biodiversity across temperate forests of Europe. Here, we quantified changes in the diversity and composition of the forest understory layer in representative Slovenian forest ecosystems between 2004/05 and 2014/15. In total, 60 plots were placed across 10 different managed forest types, ranging from lowland deciduous and mid-altitude mesic mixed forests to mountain conifer forests. This network is part of an international network of sites launched within the ICP Forests Programme aimed to assess the condition of forests in Europe. To examine how disturbance influenced understory dynamics, we estimated the disturbance impacts considering both natural and/or anthropogenic disturbances that cause significant damage to trees and to ground-surface layers, including ground-vegetation layers and upper-soil layers. Species richness across 10 sites (gamma diversity) significantly decreased from 272 to 243 species during the study period, while mean species richness per site did not significantly change. The mean value of site level Shannon diversity indices and evenness significantly increased. The cover of most common plant species increased during the monitoring period. The mean value of disturbance estimates per site increased from 0.8% in 2004/05 (ranging from 0% to 2.5%) to 16.3% in 2014/15 (ranging from 5.0% to 38.8%), which corresponded to a reduction in total vegetation cover, including tree-layer cover. More disturbed sites showed larger temporal changes in species composition compared to less disturbed sites, suggesting that forest disturbances caused understory compositional shifts during the study period. Rather than observing an increase in plant diversity due to disturbance, our results suggest a short-term decrease in species number, likely driven by replacement of more specialized species with common species.

scholarly journals Effects of reindeer grazing and recovery after cessation of grazing on the ground-dwelling spider assemblage in Finnish Lapland

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7330
Author(s):  
Teemu Saikkonen ◽  
Varpu Vahtera ◽  
Seppo Koponen ◽  
Otso Suominen
Keyword(s):  
Species Richness ◽  
Rangifer Tarandus ◽  
Forest Ecosystems ◽  
Grazing Pressure ◽  
Ground Vegetation ◽  
Total Abundance ◽  
Finnish Lapland ◽  
Species Specific ◽  
The Impact

The effect of reindeer Rangifer tarandus L. grazing on the ground-dwelling spider assemblage in Northern Finland was studied. Changes in species richness, abundance and evenness of spider assemblages were analyzed in relation to changes in vegetation and environmental factors in long term grazed and ungrazed sites as well as sites that had recently switched from grazed to ungrazed and vice versa. Grazing was found to have a significant impact on height and biomass of lichens and other ground vegetation. However, it seemed not to have an impact on the total abundance of spiders. This is likely caused by opposing family and species level responses of spiders to the grazing regime. Lycosid numbers were highest in grazed and linyphiid numbers in ungrazed areas. Lycosidae species richness was highest in ungrazed areas whereas Linyphiidae richness showed no response to grazing. Four Linyphiidae, one Thomisidae and one Lycosidae species showed strong preference for specific treatments. Sites that had recovered from grazing for nine years and the sites that were grazed for the last nine years but were previously ungrazed resembled the long term grazed sites. The results emphasize the importance of reindeer as a modifier of boreal forest ecosystems but the impact of reindeer grazing on spiders seems to be family and species specific. The sites with reversed grazing treatment demonstrate that recovery from strong grazing pressure at these high latitudes is a slow process whereas reindeer can rapidly change the conditions in previously ungrazed sites similar to long term heavily grazed conditions.

Moon and tide effects on fish capture in a tropical tidal flat

2010 ◽  
Vol 91 (3) ◽  
pp. 735-743 ◽  
Author(s):  
José Amorim Reis-Filho ◽  
Francisco Barros ◽  
José De Anchieta Cintra Da Costa Nunes ◽  
Cláudio Luis Santos Sampaio ◽  
Gabriel Barros Gonçalves De Souza
Keyword(s):  
Tidal Flat ◽  
Dominant Species ◽  
Full Moon ◽  
Diversity Indices ◽  
Tidal Range ◽  
Species Number ◽  
Trophic Groups ◽  
Significant Difference ◽  
The Mean ◽  
Tropical Tidal Flat

The influence of the lunar phases and tidal range on the fish capture was analysed in a tidal flat in Barra do Paraguaçu (Baía de Todos os Santos). The sampling was realized in the flood tide and ebb tide of the spring (full moon) and neap (waning moon) tides, between June 2007 and May 2008. At all sampling occasions, two parallel drags were accomplished to the tidal flat, in the same direction of the current, in a 100 m long area marked on the beach beforehand, using a seine net of 15 m × 2.0 m with a mesh of 12 mm between adjacent knots. A total of 2312 fish specimens were captured (26.5 kg), belonging to 75 species from 45 families. The mean number of captured fish was significantly larger in full moon at ebb tides, while the mean weight in the captures was larger in ebb tides. There was significant difference in number of species, number of fish, richness and diversity between full and waning moons. The number of fish and biomass were significantly different between tides. Significant differences were found in community structure regarding trophic groups in relation to tide and moon, although the classic diversity indices did not capture this effect between tides. Furthermore, it was possible to identify preferences of occurrence related to the change of tide in dominant species.

scholarly journals Surface Radio Refractivity of Akure and Ondo town, Southwest Nigeria

2021 ◽  
Vol 4 (1) ◽  
pp. 212-219
Author(s):  
IP Onujagbe ◽  
F Ahmed-Ade ◽  
M Mopah ◽  
AJ David
Keyword(s):  
Meteorological Parameters ◽  
Ground Surface ◽  
Mean Value ◽  
Strongly Correlated ◽  
K Value ◽  
Earth Radius ◽  
A Value ◽  
Daily Data ◽  
Southwest Nigeria ◽  
The Mean

The surface radio refractivity, refractivity gradient at 1km above ground surface and the effective earth radius factor, K over Akure and Ondo town of South west Nigeria has been investigated using Ten (10) years daily data of the meteorological parameters of Pressure, air temperature and humidity. The result showed that the mean monthly value of the surface refractivity at the Ondo station is generally slightly higher than that of Akure. The monthly mean value of refractivity at the two stations was found to be strongly correlated with a value of 0.915. The most negative refractive gradient value observed at Ondo and Akure are of -46.48N-units/km and -45.64N-units/km respectively and the least effective earth radius factor, k value of 1.421 and 1.410 were observed at the station respectively. These results showed that the Ondo and Akure station were generally super-refractive. The Ondo station was however found to be slightly more super-refractive than the Akure station.

scholarly journals KOMPOSISI JENIS DAN STRUKTUR VEGETASI HUTAN DI KAWASAN SUAKA MARGASATWA CIKEPUH, SUKABUMI – JAWA BARAT

2016 ◽  
Vol 11 (2) ◽  
pp. 147
Author(s):  
Ruddy Polosakan
Keyword(s):  
Key Words ◽  
Forest Ecosystems ◽  
Common Species ◽  
Species Number ◽  
Phyllanthus Emblica ◽  
Game Reserve ◽  
Total Species

A study on the structure and composition of trees species was carried out in Cikepuh Game Reserve. The informations and data on forest ecosystems of Cikepuh Game Reserve was still very limited. Method of study used point centered quarter. The results of study recorded total species number was 55 species of trees consisted of 35 genera and 26 families, while saplings (Belta) recorded was 51 species consisted of 34 genera and 23 families.The common species of trees in the area were Vitex pinnata (Important Value = 53.37%), Alseodaphne cunneata (IV = 44.12%), Aporosa microcalyx (IV =25.88%) and Helicia robusta (IV = 24.38% ), while saplings were Vitex pinnata (IV =27.82%), Dillenia aurea (IV = 27.11%), Microcos tomentosa (IV = 25.72%), Aporosa microcalyx (IV = 23.10%) and Phyllanthus emblica (IV = 21.62%).Key words : structure, composition, trees species, Cikepuh Game Reserve

Study on Ground Surface Roughness of Engineering Ceramics Based on Grayscale Information

2012 ◽  
Vol 429 ◽  
pp. 9-13
Author(s):  
Xin Li Tian ◽  
Jian Quan Wang ◽  
Fang Guo ◽  
Ke Ling Lin
Keyword(s):  
Surface Roughness ◽  
Ground Surface ◽  
Mean Value ◽  
Direct Proportion ◽  
Key Factors ◽  
Engineering Ceramics ◽  
Acquisition Device ◽  
The Mean ◽  
Processing Techniques ◽  
Ground Surface Roughness

Surface roughness is one of the key factors to evaluate the grinding quality for engineering ceramics. This study introduces a new method based on grayscale information of surface images, to assess and predict the roughness of ground ceramics rapidly and effectively. The investigation sets the functional parameters of digital acquisition device as Brightness 140, Contrast 42, Saturation 24 and Acutance 9. Afterwards, it selects the mean value and the mean square deviation to describe surface roughness, and some image processing techniques are adopted to reduce noises and enhance the images. Lastly, it gives the relation curves on Ra，Rz，Ry versus grayscale information, and concludes a direct proportion law between the grayscale information and ground surface roughness.

scholarly journals Radiological risk assessment of fuel fabrication facility at Al- Tuwaitha nuclear site

2019 ◽  
Vol 14 (31) ◽  
pp. 99-107
Author(s):  
Yousif M. Zayir Al-Bakhat
Keyword(s):  
Gamma Ray ◽  
Specific Activity ◽  
Ground Surface ◽  
Mean Value ◽  
Radiological Hazard ◽  
Radiological Risk ◽  
Limit Value ◽  
Fuel Fabrication ◽  
Nuclear Site ◽  
The Mean

The specific activity of 29 soil samples collected from FuelFabrication Facility FFF at AL-Tuwaitha site, 20 km south ofBaghdad were determined using HPGe detector in a low backgroundconfiguration, it's relative efficiency of 40%, and resolution of 2keVfor the 1332 keV gamma ray emission of 60Co. The range of activityconcentrations of 226Ra, 232Th and 40K were between (12.56-31.96),(10.2-18.4) and (47.47-402.1) Bq/kg respectively. In order to assessany radiological hazard to human health, the absorbed gamma doserate D in air at 1m above the ground surface was calculated in therange (18.87 to 36.46) nGy/h; the outdoor annual effective doseequivalent AEDE was evaluated to vary from 0.0039 to 0.0076mSv/y with the mean value 0.0059 mSv/y, this value comparable tothe worldwide effective dose 0.48mSv/y. The Radium EquivalentRaeq for all samples were evaluated and were lower than the acceptedsafety limit value of 370 Bq/kg. The results indicated that theradiation of hazards from primordial radionudlides in all samples inthis study is not significant.

scholarly journals Analyses of floristic composition of the abandoned Cu-dump field Piesky (Staré Hory Mountains, Slovakia)

Web Ecology ◽  
2016 ◽  
Vol 16 (1) ◽  
pp. 97-111 ◽  
Author(s):  
Ingrid Turisová ◽  
Peter Sabo ◽  
Tomáš Štrba ◽  
Samuel Koróny ◽  
Peter Andráš ◽  
...  
Keyword(s):  
Species Richness ◽  
Extreme Environments ◽  
Floristic Composition ◽  
Common Species ◽  
Metal Mobility ◽  
Alien Invasive Species ◽  
Species Number ◽  
Forest Stands ◽  
Successional Stages ◽  
Edaphic Variables

Abstract. The Cu-dump field Piesky is an important historical abandoned mining area in the region of central Europe, well known for the high content of heavy metals in its soil, especially copper, the content of which varies from 933.40 to 1485.40 mg kg−1. Floristic and phytosociological research was carried out here during the vegetation seasons in 2011–2014. Altogether a total of 156 taxa of vascular plants were found. The most common species were Acetosella vulgaris, Agrostis capillaris, A. stolonifera, Arabidopsis arenosa and Festuca rubra, which were important constituents of all mine heaps in central Slovakia. We examined a total of 11 phytosociological relevés at various sites, which were selected to capture the variability of plant communities throughout topographical and ecological variability, various successional stages and impacts from humans. They were classified into five habitats: initial successional stages, grasslands, forest stands, wetland and feeding grounds for wild animals. Each site was evaluated in terms of its species richness, index of diversity and the representation of metallophytic, alien invasive species, synanthrophytes and native non-apophytes. This representation is based on species number and abundance, and their ratios to all taxa abundance and species richness are reflected by several indicators, which we have called indexes of metallophytization, synanthropization and naturalness of the vegetation (community) composition. In addition, indexes of invasive alien taxa and native non-apophytes proportion were used. Furthermore, each of the 11 sites was characterized by its basic topographic properties and climatic and edaphic variables, using the phytoindication approach based on the Ellenberg indicator values. The correlation analysis has uncovered several important and significant associations between some of these indicators and the climatic and edaphic variables. The negative correlations between the number of native non-apophytes and temperature (and between their relative abundances in the individual habitats and light) partially confirm that on mine heaps the numbers of synanthrophytes retreat into climax forest stands. Other correlations confirm that synanthropisation of the vegetation at a site is also higher in more eutrophic and less acidic soils for mine heaps. The species richness was highest in the grasslands and wetland and lowest in the initial succession stages, while beta diversity decreased in an opposite direction. Most synanthrophytes were found on grasslands, attracted by higher amount of nutrients in the soil, brought by sewage sludge from water treatment plants during partial recultivation of this mine heap in the years 2000 and 2010. The idea behind it was to support and accelerate the succession, however the use of the sludge may not have been the best option. Despite strict control of its chemical content, a high input of nutrients inevitably increases numbers of synanthrophytes in the vegetation cover. Finally, planting deciduous trees on young mine heaps as a method of directed succession is a better option than planting coniferous ones. The latter trees create acidic litter, increasing heavy metal mobility in the soil. We have found the dump heap Piesky to be a very suitable locality for studying processes of primary and directed succession in extreme environments and their impacts on the floristic composition of vegetation.

Long-period modulated superstructures in Pd-12.5 at.%Ce and Pd-15 at.%Ce alloys

1990 ◽  
Vol 48 (4) ◽  
pp. 164-165
Author(s):  
Noriyuki Kuwano ◽  
Masaru Itakura ◽  
Kensuke Oki
Keyword(s):  
Electron Microscopy ◽  
Mean Value ◽  
Heavy Elements ◽  
Arc Furnace ◽  
X Ray ◽  
Long Period ◽  
Ultra High Purity ◽  
Heat Treated ◽  
Atomic Scattering ◽  
The Mean

Pd-Ce alloys exhibit various anomalies in physical properties due to mixed valences of Ce, and the anomalies are thought to be strongly related with the crystal structures. Since Pd and Ce are both heavy elements, relative magnitudes of (fcc-fpd) are so small compared with <f> that superlattice reflections, even if any, sometimes cannot be detected in conventional x-ray powder patterns, where fee and fpd are atomic scattering factors of Ce and Pd, and <f> the mean value in the crystal. However, superlattices in Pd-Ce alloys can be analyzed by electron microscopy, thanks to the high detectability of electron diffraction. In this work, we investigated modulated superstructures in alloys with 12.5 and 15.0 at.%Ce.Ingots of Pd-Ce alloys were prepared in an arc furnace under atmosphere of ultra high purity argon. The disc specimens cut out from the ingots were heat-treated in vacuum and electrothinned to electron transparency by a jet method.

Partition Coefficient Ratios and Tumour Perfusion Studied with 85mKr and 133Xe

1987 ◽  
Vol 26 (06) ◽  
pp. 253-257
Author(s):  
M. Mäntylä ◽  
J. Perkkiö ◽  
J. Heikkonen
Keyword(s):  
Partition Coefficient ◽  
Partition Coefficients ◽  
Regional Blood Flow ◽  
Blood Perfusion ◽  
Compartmental Analysis ◽  
Malignant Tumour ◽  
Mean Value ◽  
Perfusion Rate ◽  
Biological Variables ◽  
The Mean

The relative partition coefficients of krypton and xenon, and the regional blood flow in 27 superficial malignant tumour nodules in 22 patients with diagnosed tumours were measured using the 85mKr- and 133Xe-clearance method. In order to minimize the effect of biological variables on the measurements the radionuclides were injected simultaneously into the tumour. The distribution of the radiotracers was assumed to be in equilibrium at the beginning of the experiment. The blood perfusion was calculated by fitting a two-exponential function to the measuring points. The mean value of the perfusion rate calculated from the xenon results was 13 ± 10 ml/(100 g-min) [range 3 to 38 ml/(100 g-min)] and from the krypton results 19 ± 11 ml/(100 g-min) [range 5 to 45 ml/(100 g-min)]. These values were obtained, if the partition coefficients are equal to one. The equations obtained by using compartmental analysis were used for the calculation of the relative partition coefficient of krypton and xenon. The partition coefficient of krypton was found to be slightly smaller than that of xenon, which may be due to its smaller molecular weight.

Detection of Soluble Fibrin Monomer Complexes in Blood by Means of Protamine Sulphate Test

1968 ◽  
Vol 20 (01/02) ◽  
pp. 044-049 ◽  
Author(s):  
B Lipiński ◽  
K Worowski
Keyword(s):  
Human Subjects ◽  
Coronary Thrombosis ◽  
Mean Value ◽  
Healthy Human ◽  
Protamine Sulphate ◽  
Soluble Fibrin ◽  
Fibrin Monomer ◽  
Dog Plasma ◽  
The Mean ◽  
Precipitable Protein

SummaryIn the present paper described is a simple test for detecting soluble fibrin monomer complexes (SFMC) in blood. The test consists in mixing 1% protamine sulphate with diluted oxalated plasma or serum and reading the optical density at 6190 Å. In experiments with dog plasma, enriched with soluble fibrin complexes, it was shown that OD read in PS test is proportional to the amount of fibrin recovered from the precipitate. It was found that SFMC level in plasma increases in rabbits infused intravenously with thrombin and decreases after injection of plasmin with streptokinase. In both cases PS precipitable protein in serum is elevated indicating enhanced fibrinolysis. In healthy human subjects the mean value of OD readings in plasma and sera were found to be 0.30 and 0.11, while in patients with coronary thrombosis they are 0.64 and 0.05 respectively. The origin of SFMC in circulation under physiological and pathological conditions is discussed.

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