scholarly journals Expansion of Tussilago farfara L. in disturbed environments. II. Population reaction to simulated cultivation

2014 ◽  
Vol 62 (1-2) ◽  
pp. 83-89
Author(s):  
Anna Namura-Ochalska
Keyword(s):  
Population Density ◽  
Morphological Properties ◽  
Favourable Effect ◽  
Mean Values ◽  
Tussilago Farfara

The effects of systematic cutting, fragmentation and burying on weeded and renewing fallow plots on the density and morphological properties of vegetative and generative <i>Tussilago farfara</i> shoots were studied. As the presence of other species increased on fallow plots, the <i>T. farfara</i> population regressed. Under such conditions, fragmentation and burying ensured the renewal and expansion of individuals and persistence of the population. On weeded plots, however, additional cultivation reduced the population density and mean values of the analyzed shoot parameters. These results show that systematic cultivation is a prerequisite for persistence of <i>T. farfara</i> populations. Its favourable effect is exerted through eliminating potential competitors.

scholarly journals Recession of Tussilago farfara (L.) population from the agrocoenose as a result of cultivation abandonment. II. The effect of fallowing on shoot morphological properties and their biomass

2014 ◽  
Vol 58 (2) ◽  
pp. 285-299 ◽  
Author(s):  
Anna Namura-Ochalska
Keyword(s):  
Leaf Blade ◽  
Dactylis Glomerata ◽  
Belowground Biomass ◽  
Morphological Properties ◽  
Grass Species ◽  
Shoot Height ◽  
Mean Values ◽  
Tussilago Farfara ◽  
Strong Competition ◽  
Fallow Age

The paper is concerned with changes in morphological properties of <em>Tussilag farfara</em> (L.) shoots in the abandoned agrocoenose. An increase in the shading and a decrease in the available space, both caused by overgrowing of two grass species <em>Agropyron repens </em> (L.) PB. and <em>Dactylis glomerata</em> (L.), resulted in considerable changes of all analysed properties. In the first three years after cultivation had been abandoned both shoot height and leaf blade size increased, but later a decrease in both was found due to a growing intensity of interspecific competition. Mean values of other properties decreased with the fallow age. Under the conditions of strong competition the variation of <em>Tussilago </em>shoots increased while their above and belowground biomass diminished.

scholarly journals Limnology of wastewater treatment lagoons at Pagla, Narayanganj

1970 ◽  
Vol 40 (1) ◽  
pp. 35-40
Author(s):  
Md Ataul Gani ◽  
Md Almujaddade Alfasane ◽  
Moniruzzaman Khondker
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Population Density ◽  
Water Temperature ◽  
Significant Positive Correlation ◽  
Secchi Depth ◽  
Gradual Improvement ◽  
Mean Values ◽  
Chl A ◽  
Suspended Matters

Limnology of two wastewater treatment lagoons, (Lagoon numbers 1 and 10 are treated as L-1 and L-2, respectively) at Pagla, Narayanganj considering 15 water quality variables had been carried out for 10 months. Air and water temperature did not vary significantly. Secchi depth (Zs) showed gradual improvement from the lagoon 1 to lagoon 10 due to low loading of suspended matters. Improvement of water quality from L-1 to L-2 has also been observed in respect to alkalinity, conductivity and TDS. Similar trends were also seen for SRS and SRP. In L-1 anoxia occurred three times whereas it was absent in L-2. In the present study, improved DO prompted NO3-N and TDS concentration. However in L-2, mean values of SRP dropped by about 13% than L-1. A significant positive correlation between the density of phytoplankton and SRP in L-2 at 5% level was obtained. A total of 105 species of phytoplankton belonging to 6 different algal classes were recorded from the lagoons. Highest number of species was obtained from Chlorophyceae followed by Euglenophyceae, Bacillariophyceae, Cyanophyceae, Cryptophyceae and Dinophyceae. The population density of phytoplankton and that of zooplankton in L-1 was low compared to L-2. Higher number of genera and species occurred in L-2 than L-1. Chl a and pheopigment concentrations were also higher in L-2. Results indicated that water quality has increased in the treatment pond number 10. Key words: Limnology; Wastewater treatment lagoons; Pagla; Bangladesh DOI: http://dx.doi.org/10.3329/bjb.v40i1.7995 Bangladesh J. Bot. 40(1): 35-40, 2011 (June)

Efficacy of the predatory mite Cydnoseius negevi (Swirskii & Amitai) (Acari: phytoseiidae) as a shared predator for sucking pests on sweet pepper in a net house in Egypt

2021 ◽  
Author(s):  
El-laithy A.y. M., E, M.elseedy ◽  
Hoda E. Hussein
Keyword(s):  
Population Density ◽  
Biological Control Agent ◽  
Phytoseiulus Persimilis ◽  
Sweet Pepper ◽  
Predatory Mite ◽  
Control Agent ◽  
Mean Values ◽  
Negative Effect ◽  
Tetranychus Urticae Koch

A field experiment was carried out to evaluate the efficacy of the native predatory mite Cydnoseius negevi (Swirski and Amitai) (=Typlodromus negevi) as a biological control agent for Bemisia tabaci (Gennadius) complex, Onion thrips Thrips tapaci (Lindeman) and Tetranychus urticae (Koch). The efficacy of Phytoseiulus persimilis (Athias-Henriot) against these pests was also evaluated. The data obtained revealed reduction in population density of the above-mentioned pests in the experimental plots for P. persimilis and C. negivi compared to the control plot. Mean population density of each of the pests ranging from 32.2–0.5, 284.4–2.0 and 441.8–2.0 individuals / leaf for T. urticae, in the three plots respectively. The mean values of B. tabaci fluctuated between 41.1–2.1, 16.2–1.0 and 57.3–3.6. individuals / leaf and T. tabaci between 20.1–2.6, 13.7–1.4 and 24.9–1.9 individuals / leaf respectively. A slight non-consumptive negative effect is shown by P. persimilis against the pests B. tabaci and T. tabaci. This preliminary experiment hopefully will enhance the role of the native predator C. negevi to play a role in bio-control and its mass augmentation.

Home ranges, time budgets and food-tree use in a high-density tropical population of greater gliders, Petauroides volans minor (Pseudocheiridae : Marsupialia)

1996 ◽  
Vol 23 (4) ◽  
pp. 401 ◽  
Author(s):  
SS Comport ◽  
SJ Ward ◽  
WJ Foley
Keyword(s):  
Population Density ◽  
Home Range ◽  
Kernel Method ◽  
Radio Telemetry ◽  
High Population ◽  
Home Ranges ◽  
Time Budgets ◽  
High Population Density ◽  
Mean Values ◽  
Males And Females

The socio-ecology of Petauroides volans has been studied for subtropical and temperate populations, but not for the northern tropical subspecies, Petauroides volans minor. Data on the effects of a high population density on home ranges, time budgets and food-tree use were obtained by means of radio-telemetry. Three techniques were used to estimate home-range area (kernel, MCP and harmonic mean) and the kernel method was preferred. Estimates of home-range area (defined by the 95% kernel) gave mean values of 2.5 and 1.3 ha for males and females, respectively. Broad overlap of home ranges of males was observed, which has not been reported previously for populations of P. volans. Behaviour patterns for males and females were similar to those in previous studies, although the mating system may differ, possibly because of the high population density. Dietary patterns were similar to those previously reported for this species, the most important food items being young leaves and flower buds of particular eucalypt species, notably Eucalyptus acmenoides.

Temporal variation of a syllid (Syllidae: Polychaeta) taxocoenosis associated with Stypocaulon scoparium (Stypocaulaceae: Phaeophyceae) in the western Mediterranean

2006 ◽  
Vol 86 (1) ◽  
pp. 51-59 ◽  
Author(s):  
Eduardo López ◽  
Ramón Gallego
Keyword(s):  
Population Density ◽  
Relative Abundance ◽  
Total Population ◽  
Local Population ◽  
Western Mediterranean ◽  
Present Species ◽  
Strong Variation ◽  
Dominance Index ◽  
Mean Values ◽  
Representative Species

Between May of 2000 and July of 2001 a study aiming to determine the seasonal variation of syllid local population abundances was carried out. Samples were taken every second month and consisted of two replicates, each one being a quadrat 20 cm wide. After fixing, the samples were washed and the draining water was passed through a 1 mm sieve; then the syllids were identified and counted. For each replicate a number of ecological indexes were calculated, namely population density, number of species and Shannon's and Simpson's diversity indexes, computing mean values for each sample. In order to identify the most representative species of the taxocoenosis the Ci (constancy index, frequency of the species ranging from 0 to 1) and Di (dominance index, relative abundance ranging from 0 to 100 considering all the collected individuals) were computed for each one.Analysis of the eight samples yielded 6548 individuals and 48 species belonging to the four subfamilies of Syllidae, of which Exogoninae and Syllinae were the most abundant and diverse. During the study period, the syllid taxocoenosis suffered dramatic changes. The abundance, that in May of 2000 was 33,375±775 individuals/m2, diminished to 2162.5±37.5 in September. After this date, the population density slowly increased. The number of present species evolved in a very similar way. Twelve species occurred in all the samples, although just six were abundant enough to yield Ci×Di products exceeding 5, thus being considered as good descriptors of the taxocoenosis. The variation of population density for most of these species more or less paralleled that of the total population of syllids. With regards to relative abundance, the taxocoenosis was always clearly dominated by Exogoninae species, especially by Salvatoria vieitezi, whose dominance scores always fluctuated around 45%. Syllis prolifera was the only important non-Exogoninae species in terms of dominance, although this parameter showed strong variation in this species.

Influence of Monsoon on Macrobenthic Assemblage in Outer Channel Area of Chilika Lagoon, East Coast of India

2010 ◽  
Vol 3 ◽  
pp. 57-68 ◽  
Author(s):  
Debasish Mahapatro ◽  
R.C. Panigrahy ◽  
Sudarsan Panda ◽  
Rajani K. Mishra
Keyword(s):  
Population Density ◽  
East Coast ◽  
Monsoon Season ◽  
Diversity Indices ◽  
Chilika Lagoon ◽  
East Coast Of India ◽  
Mean Values ◽  
Outer Channel ◽  
Density And Biomass ◽  
Richness Index

Abundance of macrobenthos in the outer channel area of Chilika lagoon in the east coast of India was studied during Monsoon season of 2007 & 2008. In total 27 species of macrobenthic organisms were collected during the study period season. Crustacea was emerged as the most dominate group representing 9 species followed by polychaetes with 8 species while 5 species belonged to bivalvia and 3 species to gastropoda. The others group in the study area included nematodes and echiurids. The mean density of macrobenthos was 378 organism m-2 and 392 organism m-2 in 2007 & 2008.The biomass was measured as and biomass 0.525 g m-2 and 0.575 g m-2 during 2008 &2007. Mean values of diversity indices like Margalef's richness index was 2.7 in 2007 and 3.0 in 2008. While Shannon's H' was 1.7 of 2008 and 1.8 in 2007. The Evenness J was calculated as 0.76 in 2008 and 0.94 in 2007. The result of the study shows that hydrographical parameters like Temperature (°C), pH and Salinity (psu) parameters had modest relationship with population density and biomass. The preference of macrobenthic organism to any specific parameter couldn't be established clearly and this would be due to the presence of more opportunistic filters feeders than the deposit feeders. The opening of a new outlet connecting with the sea had good influence on species richness and population density. Key words: Chilika lagoon; Macrobenthos; Population density; biomass; diversity indices DOI: 10.3126/jowe.v3i0.2223 Journal of Wetlands Ecology, (2009) Vol. 3, pp 56-67

scholarly journals Common opossum population density in an agroforestry system in Bolivia

2020 ◽  
Vol 50 (3) ◽  
pp. 246-251
Author(s):  
Camila BENAVIDES ◽  
Alejandro ARCE ◽  
Luis F. PACHECO
Keyword(s):  
Population Density ◽  
Agroforestry System ◽  
Encounter Rate ◽  
Secondary Forests ◽  
Lower Range ◽  
Anthropogenic Landscapes ◽  
Mean Values ◽  
Agricultural Community ◽  
Line Transects ◽  
The Common

ABSTRACT The common opossum, Didelphis marsupialis thrives near human settlements. Understanding its ecology could help planning management decisions about this species, especially in anthropogenic landscapes. Yet, there are no density estimations for this species throughout its distribution range in Bolivia. We estimated the density of D. marsupialis in a rural agricultural community, where agroforestry plantations and fallows cover most of the land. We counted individuals in line transects and used DISTANCE software to calculate density. We covered a total of 70.21 km in 143 night counts, obtaining 38 records of D. marsupialis. We estimated a density of 0.30 individuals ha-1 (SE = 0.062; range: 0.20 - 0.45 individuals ha-1), with a mean encounter rate of 0.54 individuals km-1. Encounter rate varied between habitats, with mean values of 0.20 in secondary forests and 0.64 in agroforestry plantations. Our density estimate is near the lower range of previously reported values for the common opossum in other countries. We argue that our results may reflect the response to the availability of food resources and predation pressure in agroforestry plantations.

scholarly journals Evaluation of Morphological Properties of Avenue Tree Species and Concentrations of Pollutants Under and Outside Their Canopies in Port Harcourt, Nigeria

2019 ◽  
Vol 10 (2) ◽  
pp. 1
Author(s):  
Uzoma Darlington Chima ◽  
Miriam Ugochi Opara
Keyword(s):  
Tree Species ◽  
Anthropogenic Activities ◽  
Morphological Properties ◽  
Exposure Limits ◽  
Morphological Attributes ◽  
Mean Values ◽  
Port Harcourt ◽  
Significant Difference ◽  
Tree Canopies ◽  
Rivers State

We evaluated the morphological attributes of three major avenue tree species (Delonix regia, Gmelina arborea and Terminalia mantaly) and the concentrations of pollutants under and outside their canopies at four locations reflecting different levels of anthropogenic activities that contribute to pollution, in Port Harcourt, Rivers State, Nigeria. The sites are: Shell Petroleum Development Company (SPDC) Agbada (II) Flow Station, Aluu; LNG Seaport (LNG), Trans-Amadi; Isaac Boro Park (IBP), Mile 1; and Rivers State University (RSU), Nkporlu. Three trees belonging to each of the three species were randomly selected at each site and measurements of their total height (THT), diameter at breast height (DBH), crown diameter (CD), and basal area (BA), were taken. Concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), ammonia (NH3), methane (CH4), sulphur dioxide (SO2), and particulate matter (PM) under and 50 m outside their canopies, were also measured. One-way Analysis of Variance (ANOVA) was used to test for significant difference (p ≤ 0.05) in tree attributes and the concentrations of pollutants under canopies of each tree species among sites, while t-test was used to test for significant difference (p ≤ 0.05) in the concentrations of the pollutants under and 50 m outside tree canopies at each site. THT, DBH, CD and BA of the three tree species varied significantly at the four sites with highest and lowest mean values recorded for RSU and LNG, respectively, except for D. regia where DBH and BA were highest and lowest at IBP and LNG, respectively. The concentration of pollutants under tree canopies at different sites did not vary significantly (p > 0.05) in most cases (except PM) despite the significant differences in tree growth/morphological attributes. There was no significant difference between the concentrations of pollutants under and 50 m outside tree canopies in all the sites. Higher concentrations of CO and PM were recorded under trees at LNG Seaport while NO2, SO2 and CH4 were higher under trees at SPDC, indicating that the level of pollutants at each site reflected the nature of the activities associated with the sites and not differences in tree morphological attributes. However, concentrations of the pollutants, except CH4, were below recommended exposure limits under and outside tree canopies, at all the locations.

Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

2000 ◽  
Vol 179 ◽  
pp. 263-264
Author(s):  
K. Sundara Raman ◽  
K. B. Ramesh ◽  
R. Selvendran ◽  
P. S. M. Aleem ◽  
K. M. Hiremath
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Ultra Violet ◽  
Active Regions ◽  
Morphological Properties ◽  
Energy Storage And Conversion ◽  
The Sun ◽  
X Rays ◽  
The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust &amp; Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust &amp; Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

Characterization of Tamm-Horsfall Urinary Glycoprotein

1973 ◽  
Vol 31 ◽  
pp. 420-421
Author(s):  
John P. Robinson ◽  
J. David Puett
Keyword(s):  
Electron Microscopy ◽  
Circular Dichroism ◽  
Secondary Structure ◽  
Quaternary Structure ◽  
Normal Adult ◽  
Morphological Properties ◽  
Adult Males ◽  
Circular Dichroïsm ◽  
Urinary Glycoprotein

Much work has been reported on the chemical, physical and morphological properties of urinary Tamm-Horsfall glycoprotein (THG). Although it was once reported that cystic fibrotic (CF) individuals had a defective THG, more recent data indicate that THG and CF-THG are similar if not identical.No studies on the conformational aspects have been reported on this glycoprotein using circular dichroism (CD). We examined the secondary structure of THG and derivatives under various conditions and have correlated these results with quaternary structure using electron microscopy.THG was prepared from normal adult males and CF-THG from a 16-year old CF female by the method of Tamm and Horsfall. CF female by the method of Tamm and Horsfall.

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