scholarly journals Low interannual precipitation has a greater negative effect than seedling herbivory on the population dynamics of a short‐lived shrub, Schiedea obovata

2017 ◽  
Vol 8 (1) ◽  
pp. 176-184 ◽  
Author(s):  
Lalasia Bialic‐Murphy ◽  
Orou G. Gaoue
Keyword(s):  
Population Dynamics ◽  
Seedling Herbivory ◽  
Negative Effect

scholarly journals The consequences of polyandry for population viability, extinction risk and conservation

2013 ◽  
Vol 368 (1613) ◽  
pp. 20120053 ◽  
Author(s):  
Luke Holman ◽  
Hanna Kokko
Keyword(s):  
Population Dynamics ◽  
Extinction Risk ◽  
Population Level ◽  
Female Fitness ◽  
Male Care ◽  
Negative Effect ◽  
Adverse Environmental Conditions ◽  
The Cost ◽  
Cost Of Sex ◽  
Population Fitness

Polyandry, by elevating sexual conflict and selecting for reduced male care relative to monandry, may exacerbate the cost of sex and thereby seriously impact population fitness. On the other hand, polyandry has a number of possible population-level benefits over monandry, such as increased sexual selection leading to faster adaptation and a reduced mutation load. Here, we review existing information on how female fitness evolves under polyandry and how this influences population dynamics. In balance, it is far from clear whether polyandry has a net positive or negative effect on female fitness, but we also stress that its effects on individuals may not have visible demographic consequences. In populations that produce many more offspring than can possibly survive and breed, offspring gained or lost as a result of polyandry may not affect population size. Such ecological ‘masking’ of changes in population fitness could hide a response that only manifests under adverse environmental conditions (e.g. anthropogenic change). Surprisingly few studies have attempted to link mating system variation to population dynamics, and in general we urge researchers to consider the ecological consequences of evolutionary processes.

scholarly journals Population dynamics and biting rhythm of the anthropophilic sandfly Lutzomyia cruciata (Diptera: Psychdidae) in Southeast, Mexico

1996 ◽  
Vol 38 (1) ◽  
pp. 29-33 ◽  
Author(s):  
Eduardo A. Rebollar-Tellez ◽  
Filiberto Reyes-Villanueva ◽  
Ildefonso Fernandez-Salas ◽  
Fernando J. Andrade-Narvaez
Keyword(s):  
Population Dynamics ◽  
High Temperature ◽  
The State ◽  
Endemic Focus ◽  
Host Seeking ◽  
Biting Rate ◽  
Population Peak ◽  
Negative Effect ◽  
Southeast Mexico

Sandflies attracted by human bait were caught in an endemic focus of localized cutaneous leishmaniasis in the state of Campeche, Mexico. Catches were carried out monthly from February 1994 to January 1995 between 18:00 and 22:00 h. Lutzomyia cruciata was the only species caught. The highest population peak of Lu. cruciata was found in March with lesser peaks in February, December 1994, and January 1995. Maximum biting rate of Lu. cruciata was found between 18:00 and 19:00 h. The host-seeking females of Lu. cruciata were directly related to levels of humidity between 88 and 100%. Low and high temperature had a negative effect upon Lu. cruciata activity. The possible role of Lu. cruciata as vector of leishmaniasis in the state of Campeche, Mexico is discussed.

scholarly journals DINAMIKA PENDUDUK DAN PERTUMBUHAN EKONOMI DI INDONESIA

2020 ◽  
pp. 22
Author(s):  
Adhitya Wardhana ◽  
Bayu Kharisma ◽  
Sarah Annisa Noven
Keyword(s):  
Economic Growth ◽  
Population Dynamics ◽  
Infant Mortality ◽  
Time Series Data ◽  
Government Expenditure ◽  
Negative Influence ◽  
Least Square ◽  
Series Data ◽  
Negative Effect ◽  
Positive Effect

This study aims to see the effect of population dynamics variables on economic growth in Indonesia. This study uses the Ordinary Least Square model with time series data from 1986 to 2016. The data used are population dynamics variables, such as number of fertilities, infant mortality, with the variable control are the amount of labor, savings and government expenditure on economic growth measured through Gross Domestic Product. The results os the study showed that the fertility amount in Indonesia has a negative effect on the amount of economic growth in Indonesia, which means that increasing population will reduce economic growth in Indonesia. then, variable infant mortality has a negative influence on economic growth in Indonesia. Fertility variables and the population of productive age have a positive effect on labor force participation rates. Control variables, like savings and government expenditure, also have a positive effect on economic growth in Indonesia.

scholarly journals Population dynamics of Chaetocnema tibialis Illiger and Phyllotreta vittula (Redtenbacher) on the weed Amaranthus retroflexus L. and cultivated Amaranthus caudatus L.

2010 ◽  
Vol 42 (No. 2) ◽  
pp. 72-80
Author(s):  
Ľ. Cagáň ◽  
P. Tóth ◽  
M. Tóthová
Keyword(s):  
Population Dynamics ◽  
Wild Species ◽  
Low Temperatures ◽  
Flea Beetle ◽  
Amaranthus Retroflexus ◽  
Amaranthus Caudatus ◽  
Flea Beetles ◽  
Amaranth Species ◽  
Negative Effect ◽  
Cultivated Species

In 1995–1997, the population dynamics of the flea beetles <i>Chaetocnema tibialis and <i>Phyllotreta vittula</i>, associated with <i>Amaranthus retroflexus</i> (wild species) and <i>Amaranthus caudatus</i> (cultivated species), were studied at the locality Nitra-Malanta (48°19'N, 18°09'E) in south-western Slovakia. On both plant species, the number of <i>C. tibialis</i> adults was usually very low until the beginning of July. During July the number of <i>C. tibialis</i> increased, but sooner on cultivated amaranth. An increased number of <i>C. tibialis</i> adults was observed on both amaranth species until the middle of September. The results showed that amaranth plants are a very important reservoir of <i>C. tibialis</i> during summer. <i>P. vittula</i> was a common flea beetle on amaranth during the whole summer, but its numbers never exceeded more than 10 adults per 25 plants. Low temperatures in winter had a negative effect on populations of <i>C. tibialis</i> on both amaranth species and also on populations of <i>P. vittula</i> on <i>A. retroflexus</i>. The lower the precipitation was in July, the higher were the populations of <i>C. tibialis</i> on both amaranth species and the populations of <i>P. vittula</i> on <i>A. retroflexus</i>.

scholarly journals Study of population dynamics of the olive fruit fly Bactrocera oleae (Diptera, Tephritidae); (Rossi, 1790) in the Mezghenna area

2019 ◽  
Vol 9 (3) ◽  
pp. 309-314
Author(s):  
A. Achouche ◽  
F. Abbasi ◽  
A. Benzahra ◽  
Z. Djazouli
Keyword(s):  
Population Dynamics ◽  
Olive Tree ◽  
Fruit Fly ◽  
Early Spring ◽  
Bactrocera Oleae ◽  
Olive Fruit Fly ◽  
Olive Fruit ◽  
Ongoing Work ◽  
Negative Effect ◽  
Individual Farm

The population dynamics of the Olive Fruit Fly in the Tell Atlas has been studied for two years (May 2017-April 2019) on all phases of olive tree growth. The test was installed on an individual farm in the Mezghenna region. It is part of the ongoing work to assess the damage caused by the diptera Bactrocera oleae. The objective of this study is to collect information on adult flight and to calculate the population index (FTD) . On the other hand, we studied the annual variation of this last. The results of this study show that the olive fruit fly population fluctuates over time and from one period to another in the study area; Overall, we recorded a low density of Bactrocera oleae during the first year of study (less than 0.08 flies / trap / day). In addition, in the second year, we observed 3 population peaks concentrated in autumn and early spring; the high temperatures of summer have a negative effect on the density of the Diptere.

scholarly journals Population dynamics of Cacopsylla sp. (Hemiptera: Psylloidea: Psyllidae), pest insect of Prunus africana (Rosaceae), medicinal plant species in Cameroon

2020 ◽  
Vol 12 (2) ◽  
pp. 221-228
Author(s):  
Dzokou Victor Joly ◽  
Yana Wenceslas ◽  
Soufo Laurentine ◽  
Tamesse Joseph Lebel
Keyword(s):  
Population Dynamics ◽  
Climatic Factors ◽  
Effective Control ◽  
Prunus Africana ◽  
Young Leaves ◽  
Negative Effect ◽  
Numerical Variation ◽  
Two Peaks ◽  
The Impact ◽  
Positive Effect

Prunus africana is threatened in Cameroon by xylophagous and sap-sucking pest as Cacopsylla sp. This last causes deformations of the young leaves and buds and the plant end up losing all its leaves. Effective control of phytophagous pests requires a thorough understanding of their seasonal population dynamics. The objective of this work carried out on 150 young plants of P. africana in the nursery in Dschang, was to study the population dynamics of Cacopsylla sp. and the impact of climatic factors on the population. From January 2006 to December 2007, monthly collections of larvae, males and females of Cacopsylla sp. were carried out. The results showed, in 2006, three peaks (March, August and December) and two peaks in 2007 (March and August) with larvae. The fluctuation of males' population showed five peaks with two peaks in 2006 (March and December) and three peaks in 2007 (March, June and December) while in females' population, four peaks with two peaks in 2006 (March and December) and two peaks in 2007 (March and November). The annual numerical variation of Cacopsylla sp. individual is statistically correlated with variation of precipitations and the insolation. The precipitations have a negative effect on the numerical variation of males (r=-0.430, p<0.0360) and females (r=-0,434, p<0.0336) of Cacopsylla sp. The insolation has a positive effect on the numerical variation of males (r=0.732, p<0.0000002), females (r=0.653, p<0.000523) and the total individuals (r=0.601, p<0.00197) of Cacopsylla sp. With the larvae, the correlation was negative and non-significant. This work showed that March and December were better indicated to engage the fight against Cacopsylla sp. in Dschang.

scholarly journals Timing outweighs magnitude of rainfall in shaping population dynamics of a small mammal species in steppe grassland

2021 ◽  
Vol 118 (42) ◽  
pp. e2023691118
Author(s):  
Guoliang Li ◽  
Xinrong Wan ◽  
Baofa Yin ◽  
Wanhong Wei ◽  
Xianglei Hou ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Population Size ◽  
Population Level ◽  
Trophic Levels ◽  
Food Sources ◽  
Vole Population ◽  
Mammal Species ◽  
Generalist Herbivore ◽  
Negative Effect ◽  
Steppe Grassland

Climate change–induced shifts in species phenology differ widely across trophic levels, which may lead to consumer–resource mismatches with cascading population and ecosystem consequences. Here, we examined the effects of different rainfall patterns (i.e., timing and amount) on the phenological asynchrony of population of a generalist herbivore and their food sources in semiarid steppe grassland in Inner Mongolia. We conducted a 10-y (2010 to 2019) rainfall manipulation experiment in 12 0.48-ha field enclosures and found that moderate rainfall increases during the early rather than late growing season advanced the timing of peak reproduction and drove marked increases in population size through increasing the biomass of preferred plant species. By contrast, greatly increased rainfall produced no further increases in vole population growth due to the potential negative effect of the flooding of burrows. The increases in vole population size were more coupled with increased reproduction of overwintered voles and increased body mass of young-of-year than with better survival. Our results provide experimental evidence for the fitness consequences of phenological mismatches at the population level and highlight the importance of rainfall timing on the population dynamics of small herbivores in the steppe grassland environment.

scholarly journals The effect of lead and copper heavy metal salts on soil microorganisms under laboratory circumstances

2013 ◽  
pp. 55-59
Author(s):  
Zsuzsa Kovács ◽  
Anita Jakab ◽  
Magdolna Tállai ◽  
János Kátai
Keyword(s):  
Heavy Metal ◽  
Population Dynamics ◽  
Chernozem Soils ◽  
Significant Difference ◽  
Negative Effect ◽  
Heavy Metal Salts ◽  
Effect Of Copper ◽  
Stock Solutions ◽  
Saline Solutions

he population dynamics of calcareous chernozem soils polluted with different concentrations of lead and copper heavy metal saline solutions was examined. The experiment was carried out in the soil biological laboratory of the Institute of Agricultiral Chemistry and Soil Science at DE AGTC MÉK in 2012. For the determination of the concentration of the undiluted stock solutions we multiplied the smallest toxic concentration values of the MSZ 08-1721/1-86 Hungarian standard by forty. The intermediary concentrations of the treatments were produced with adequate dilution of the stock solutions until a dilution level equal to the values of the standard. The statistical evaluation of the data was performed with ANOVA (Analysis of Variance) including the determination of the standard deviation and significant difference. Investigating the effects of the different treatments on the soil microbes we established that both heavy metal saline solutions had a negative effect on the population dynamics of bacteria and microscopic fungi living in the soils. The negative effect of copper – as a potential toxic micro nutrient – turned out to be less strong than the negative effect of the toxic lead. According to our results the correction of the treatment levels is recommended in order to further tolerance examinations and the determination of the tolerance levels.

scholarly journals Spatial heterogeneity and its influence on Copaifera langsdorffii Desf. (Caesalpiniaceae)

2003 ◽  
Vol 46 (3) ◽  
pp. 405-414 ◽  
Author(s):  
Júlio Carlos França Resende ◽  
Carlos Augusto Klink ◽  
Ivan Schiavini
Keyword(s):  
Population Dynamics ◽  
Population Structure ◽  
Spatial Heterogeneity ◽  
Plant Height ◽  
Mortality Rates ◽  
Gallery Forest ◽  
Edge Zone ◽  
Negative Effect ◽  
Copaifera Langsdorffii ◽  
Population Mortality

Population dynamics and structure of young individuals of the tree Copaifera langsdorffii Desf. (Caesalpiniaceae) were studied in the gallery forest of the Panga Ecological Station, Uberlândia, MG, Brazil. Three distinct habitats were recognized in this forest, Dike, Middle and Edge zone. Four annual surveys of plant height, diameter at plant base and density were made between 1993 and 1996. The species showed an aggregated distribution in all three habitats. Population structure in all four surveys presented the typical reversed "J" form, characteristic of populations in local regeneration. For the whole population, mortality rates during the four years were constant and low (average of 4.8 % per year), while recruitment declined during the same period (average of 2.9 % per year). The C. langsdorffii seedling and sapling intraspecific density had a negative effect on growth, possibly due to the action of herbivores and pathogens.

Continuous Bioleaching of a Cobaltiferous Pyrite in Stirred Reactors: Population Dynamics and EPS Production vs. Bioleaching Performances

2007 ◽  
Vol 20-21 ◽  
pp. 62-65 ◽  
Author(s):  
P. D'Hugues ◽  
Catherine Joulian ◽  
P. Spolaore ◽  
C. Michel ◽  
F. Garrido ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Molecular Ecology ◽  
Negative Influence ◽  
Bacterial Attachment ◽  
Major Influence ◽  
Operating Parameters ◽  
Bacterial Strains ◽  
Bacterial Productivity ◽  
Negative Effect ◽  
Stirred Bioreactors

In the frame of a European project (BioMinE - FP6), a continuous bioleaching operation was carried out in a laboratory-scale unit using a cobaltiferous pyrite. The objective of the work was to use this system to investigate mechanisms of microbial activity and mineral oxidation in continuous stirred bioreactors (1x50L - 3x20L). A combination of scientific and technical approaches (molecular ecology, biochemistry and microscopy) was used and various key operating parameters were tested (temperature, nitrogen source, CO2 availability, designed consortia). An increase of temperature of 10°C (35°C to 45°C) had no major influence on the bioleaching efficiency. When the ammonium source was limiting, there was a negative influence on both bacterial growth and bioleaching efficiency. This result was related to a combination of factors such as less bacterial attachment to the pyrite surface and less precipitate formation. CO2 limitation had a very significant negative effect on the bacterial productivity and consequently on the bioleaching efficiency. Nevertheless, the population composition remained unchanged. An important decrease of EPS (sugar) production was also observed. The bacterial strains, that dominate the culture, originated from the deposit in Uganda. It seems that their bioleaching ability was improved over the time when cultured in continuous mode. The culture composition was very stable. The iron-oxidizer L. ferriphilum was the dominant organism in standard (not limiting) conditions, and was always very well represented during the first 3-4 days of residence time. Sulfobacillus sp. BRGM2 also played an important role in the process. This study gives new insights for the application of this technology, and more specifically on the influence of key operating parameters on bioleaching performances, population dynamics and attachment of bacteria to the solid surfaces.

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