Influence Of Ecological Factors Research Articles

The Influence of Ecological Factors on the Transmission and Stability of Avian Influenza Virus in the Environment

Ecology is a science studying the correlation among organisms and some environmental factors. Ecological factors play an important role to transmit Avian Influenza (AI) virus and influence its stability in the environment. Avian Influenza virus is classified as type A virus and belong to Orthomyxoviridae family. The virus can infect various vertebrates, mainly birds and mammals, including human. Avian Influenza virus transmission can occur through bird migration. The bird migration patterns usually occur in the large continent covers a long distance area within a certain periode hence transmit the virus from infected birds to other birds and spread to the environment. The biotic (normal flora microbes) and abiotic (physical and chemical) factors play important role in transmitting the virus to susceptible avian species and influence its stability in the environment. Disinfectant can inactivate the AI virus in the environment but its effectivity is influenced by the concentration, contact time, pH, temperature and organic matter. Key words: Avian Influenza, stability, transmission, ecological factors

Hantaviruses—Globally emerging pathogens

Hantaviruses are emerging zoonotic viruses which cause human disease in Africa, America, Asia, and Europe. This review summarizes the progress in hantavirus epidemiology and diagnostics during the previous decade. Moreover, we discuss the influence of ecological factors on the worldwide virus distribution and give an outlook on research perspectives for the next years.

Ecosystem stability in space: α, β and γ variability.

The past two decades have seen great progress in understanding the mechanisms of ecosystem stability in local ecological systems. There is, however, an urgent need to extend existing knowledge to larger spatial scales to match the scale of management and conservation. Here, we develop a general theoretical framework to study the stability and variability of ecosystems at multiple scales. Analogously to the partitioning of biodiversity, we propose the concepts of alpha, beta and gamma variability. Gamma variability at regional (metacommunity) scale can be partitioned into local alpha variability and spatial beta variability, either multiplicatively or additively. On average, variability decreases from local to regional scales, which creates a negative variability-area relationship. Our partitioning framework suggests that mechanisms of regional ecosystem stability can be understood by investigating the influence of ecological factors on alpha and beta variability. Diversity can provide insurance effects at the various levels of variability, thus generating alpha, beta and gamma diversity-stability relationships. As a consequence, the loss of biodiversity and habitat impairs ecosystem stability at the regional scale. Overall, our framework enables a synthetic understanding of ecosystem stability at multiple scales and has practical implications for landscape management.

Hypothèses historiques à propos du comportement d’utilisation d’outils par les chimpanzés en relation avec les changements naturels et anthropiques d’une forêt tropicale d’Afrique de l'Est

Chimpanzees and humans have co-existed in Africa for millennia. The forests inhabited by chimpanzees have experienced numerous changes in recent time, most notably during the last 12,000 years, as the current interglacial age started. In this article, I will study the case of Western Ugandan forests to describe the different factors, natural and human-induced, which affect a tropical forest, and draw hypotheses on the influence of these changes on chimpanzee cultural behaviour. Before colonial times, the Budongo Forest was shaped by elephant migrations and fires lit by the pastoralists who settled in the area. Later on, the British colonial power organized the exploitation of the forest through work plans aimed at insuring sustainable extraction of valuable timber. The human activity resulted in unexpected consequences in the forest. Interestingly, the resident chimpanzees are nowadays remarkable in the small size of their tool use repertoire. Ecological analysis and tool use observations in Uganda only support partly the opportunity and necessity hypotheses that are currently proposed to explain the influence of ecological factors on tool-using behaviour. Rather, the data I present here suggest that the temporal dimension of ecological changes in the forest must be taken into account to explain tool use behaviour variation in Ugandan forests. I propose a dynamic model connecting the necessity and opportunity factors influenced by ecological changes over time, most salient in Ugandan forests through the variability in food diversity. Finally, I conclude on the ever-changing ecological situation in Budongo Forest.

Neophytes in Pannonian hardwood floodplain forests – History, present situation and trends

Invasions of neophyte plant species are considered as one of the major threats to the diversity of natural ecosystems including floodplain forests. Pressure from human activities has increased rapidly during last few decades, therefore we suppose that the penetration of neophytes into forest habitats is greater nowadays than it was in the past. The aims of our study were: to find out if there is a significant increase in the number of neophyte species and their cover in the hardwood floodplain forests in the Pannonian region over time; to compare the occurrence of neophytes in Slovak and Hungarian datasets in different periods; and to explain the relationship between ecological factors and species richness of native vegetation, and the level of invasion of hardwood floodplain forests.The study is based on the dataset of 365 relevés ordered within the suballiance Ulmenion (riparian mixed oak–elm–ash forests along great rivers) in the Slovak national database of phytocoenological relevés and 216 relevés ordered within the Ulmenion in the Hungarian national database. The dataset was divided into decades, and the number and cover of neophytes in each period was compared by Kruskal–Wallis nonparametric ANOVA, with multiple comparison of mean ranks for all groups. To analyze the influence of ecological factors we used the number of native species in the plot, Shannon–Wiener diversity index and information about vegetation structure – cover of tree, shrub and herb layers, together with Ellenberg’s indicator values for ecological factors, namely light, temperature, moisture, soil reaction and nutrients. The influence of time and other factors on the number of neophyte species was tested using generalised linear models (GLM).Along the time gradient, there is a significant increase in the number and cover of neophytes between analyzed periods in the Pannonia. Plots from Slovakia had higher number and cover of neophytes in comparison with plots from Hungary from the same periods. Eight ecological factors were involved in the minimal adequate GLM – with six of them being significant and two being close to the significant level. In a broader analysis, where more ecological factors were included, time emerged as one of the most significant factors positively affecting the number of neophytes. The most important ecological factor is the amount of nutrients. Other significant factors are light, soil reaction, cover of herb layer and moisture.

An ontogenetic perspective on the study of sexual dimorphism, phylogenetic variability, and allometry of the skull of European ground squirrel, Spermophilus citellus (Linnaeus, 1766)

Most studies of morphological variability in or among species are performed on adult specimens. However, it has been proven that knowledge of the patterns of size and shape changes and their covariation during ontogeny is of great value for the understanding of the processes that produce morphological variation. In this study, we investigated the patterns of sexual dimorphism, phylogenetic variability, and ontogenetic allometry in the Spermophilus citellus with geometric morphometrics applied to cross-sectional ontogenetic data of 189 skulls from three populations (originating from Burgenland, Banat, and Dojran) belonging to two phylogenetic lineages (the Northern and Southern). Our results indicate that sexual dimorphism in the ventral cranium of S. citellus is expressed only in skull size and becomes apparent just before or after the first hibernation because of accelerated growth in juvenile males. Sexes had the same pattern of ontogenetic allometry. Populations from Banat and Dojran, belonging to different phylogroups, were the most different in size but had the most similar adult skull shape. Phylogenetic relations among populations, therefore, did not reflect skull morphology, which is probably under a significant influence of ecological factors. Populations had parallel allometric trajectories, indicating that alterations in development probably occur prenatally. The species’ allometric relations during cranial growth showed characteristic nonlinear trajectories in the two northern populations, with accelerated shape changes in juveniles and continued but almost isometric growth in adults. The adult cranial shape was reached before sexual maturity of both sexes and adult size after sexual maturity. The majority of shape changes during growth are probably correlated with the shift from a liquid to a solid diet and to a lesser degree due to allometric scaling, which explained only 20 % of total shape variation. As expected, viscerocranial components grew with positive and neurocranial with negative allometry.

Influence of ecological factors on the growth of crustaceans from the genus Artemia in Ural and Siberian populations

A morphometric analysis of crustaceans from the genus Artemia inhabiting nine Ural and Siberian populations has been carried out. An effect of the total mineralization of water reservoirs and some ions on the characteristics of Artemia growth has been discovered. The number of setae on furca and its length are most affected by the factors under consideration. A trend toward a decrease in the manifestation of fluctuating asymmetry alongside an increase in the total mineralization of water reservoirs has been found.

Biophysical Methods of Ecological Monitoring. Photosynthetic characteristics of tree plants growing in Moscow city

In this work, we studied an influence of ecological factors (a distance from the highway) on photosynthetic characteristics of leaves of four species of tree plants growing in Moscow city. Photosynthetic activity of leaves was assayed by instrumental methods of probing the functional state of photosynthetic apparatus, using electron paramagnetic resonance method for measuring the kinetics of photooxidation of P700 centers, thermoluminescence, and slow induction of chlorophyll fluorescence. It has been shown that kinetic parameters of the induction curves, as measured from the kinetics of photooxidation of P700 and slow induction of chlorophyll fluorescence in dark-adapted leaves, are sensible to variations of plant growing conditions. These parameters can be used as informative characteristics for ecological monitoring of the environment.

Концепция здоровья: Космос–Земля

In article the new approach to an estimation of a health state of cosmonauts, sportsmen, pilots, drivers, operators, persons of dangerous trades is considered. It has been created and developed in Institute of biomedical problems of the Russian Academy of Sciences under the direction of academician A.I. Grigoriev. Results of works of last decade, by the Program of Presidium of the Russian Academy of Sciences carried out at support of "Fundamental sciences--are submited to medicine". The new system for an estimation of a functional states of an organism at stressful influences in submitted. The methodology of remote studying of influence of ecological factors on health which has begun a new scientific--practical direction--to telemedical ecology is created. In conclusion of the article it is discussed questions of the further introduction of new concept of health and technologies prenosological diagnostics in practice of public health services.

Sources of variability of yarrow (AchilleaSPP.) essential oil

Achillea species have been traditionally utilized as raw material for tea mixtures and pharmaceutical preparations. The most important active agent of the drug is the essential oil which influences both the aroma and the effect of the tea. Most frequent monoterpene components of the oil are 1,8-cineole, camphor, borneol and α- and β-pinenes. Among sesquiterpene compounds, chamazulene, caryophyllene and oxides, as well as germacrene are to mention. Intrageneric and intraspecific chemical variability is a characteristic feature. Composition of the oil is highly variable, data on heritability are scarce. Differences in the oil composition have been detected in consequence of ontogenesis and organic differentiation. The influence of ecological factors (altitude, association, nutrients, etc.) seems to be an indirect one. Oils produced by different extraction methods, may show diverse composition.In the practice, variability of essential oil content and composition often degrades the quality of the raw materials for herbal teas. Solution may be development of agrotechnology and utilisation of standard cultivars.

A Comparison of Invasive Acer platanoides and Native A. saccharum First-Year Seedlings: Growth, Biomass Distribution and the Influence of Ecological Factors in a Forest Understory

Invasive shade tolerant species can have profound and long-lasting detrimental effects even on previously undisturbed forests. In North American forests, the invasive Acer platanoides is capable of dominating the understory where it could displace the native Acer saccharum. To understand the relative importance of various ecological factors in a forest understory on their establishment, we transplanted A. platanoides and A. saccharum seedlings in an urban sugar maple forest understory and their growth and survival were compared over a growing season. Seedlings did not differ in height, but biomass growth and assimilation rates were twice as high for the invasive species. Ecological variables accounted for only 23–24% of variation in growth. Seedlings of A. platanoides appeared to capture light more efficiently, with over 150% greater foliage biomass and surface area. A. saccharum seedlings were more negatively affected by herbivory. The more robust A. platanoides seedlings presented characteristics that could allow them to better grow and survive in shaded understories than their native congeners.

Influence of Ecological Factors on the Patterns of Fish Species Richness in Tropical Indian Rivers

Background. Rivers in India harbouring a rich diversity of fish are at present subjected to intense anthropogenic stress leading to degradation of the habitat. An understanding of the complex ecological variables determining species richness in these rivers is lacking. The relation between the ecological parameters (climate, hydrology, and morphometry) and the fish species richness were assessed in fourteen major rivers of India. Materials and methods. The data of seven ecological variables of fourteen major rivers of India for the years 1994–2009 were quantitatively analysed for determining their influence on fish species richness. Principal factor analysis (PFA) was carried out for dimension reduction and eliminating collinearity. Subsequently, fish richness was regressed on the retained factors under generalised linear model (GLM) for determining contribution of factors towards species richness in rivers. Results. The most influential determinants of species richness were the factors such as: surface area of the river basin (0.439) followed by fish habitat availability potential (0.326) a synthesis of the variables rainfall, discharge and sediment load. The predicted loss of fish species is evident at a 10% alteration in the ecological variables of the rivers. Conclusion. The predicted loss of fish species richness is indicated at a10% alteration of the habitat factors in most of the rivers and can be useful for river planners and conservationists.

New Models and Insights into Primate Evolutionary Morphology

New Models and Insights into Primate Evolutionary Morphology

Effect of biotic and abiotic factors on composition and foraging intensity of subterranean termites

Elucidating the influence of ecological factors on composition and foraging intensity of subterranean termites is critical in development of sustainable termite management strategies. Our aim was therefore to analyze the effect of selected biotic and abiotic factors on composition and foraging intensity of termites. We used principal component and canonical correspondence analysis to select appropriate factors and to model relationships respectively. Macrotermes species occurred in sites where the quantity of litter was generally above the mean. However, Macrotermes herus (Rambur) and Macrotermes spp.4 occurred in sites where the litter quantity was below the mean. Trinervitermes oeconomous (Tragardh) and Odontoremes spp.1 were noted to occur in the direction of increasing quantity of biomass. Generally, most species occurred in sites where soil pH was above or slightly below the mean (4.8). Majority of the species were also noted to occur in sites where bulk density was below or slightly above the mean (1.55 g/cm 3 ). Highest bait consumption (95%) occurred within a range of 55 to 60% basal cover beyond which the amount of bait consumed reduced. Litter and biomass quantity, pH and bulk density were noted as the most influential environmental variables determining composition of termites while basal cover was the major determinant of foraging intensity. Key words: Rangelands, Macrotermes, rangelands, vegetation, litter, biomass, basal-cover.

Parsing the roles of abiotic and biotic factors in Douglas-fir seedling growth

Summary Many studies have confirmed the potential importance of mycorrhizas to plant growth and community structure. Needed now are studies that focus on the relative ecological importance of mycorrhizas, specifically how the effect of mycorrhizas compares with other environmental factors present in soil that may affect plant growth. In a greenhouse, we grew Douglas-fir seedlings in soil collected from 6 sites in a dry region in British Columbia, Canada, predicting that these soils would vary in the ectomycorrhizal fungi present, and in several physical characteristics. In addition, we imposed a gradient of soil moisture. Using model selection based on information theory and multimodel inference, we ranked the relative importance of several abiotic (watering level, pH, C:N) and biotic (ectomycorrhizal richness and % colonization by ectomycorrhizal fungi) variables in models predicting seedling biomass. Variation in abiotic factors, namely watering level and pH, tempered by the effects of ectomycorrhizal richness, contributed most to variation in seedling growth. For young Douglas-fir seedlings growing in disturbed environments, small shifts in the species richness of ectomycorrhizal fungi bear importance, yet overall remain subordinate to abiotic gradients. By utilizing natural variability in soil abiotic properties and mycorrhizal community composition along with experimental manipulations of additional factors, the experimental approach utilized here helps to move us beyond simply testing for the significance of mycorrhizas for plants to understanding the relative importance of mycorrhizas in comparison with other influential ecological factors.

Bentgrass Distribution Surveys and Habitat Suitability Maps Support Ecological Risk Assessment in Cultural Landscapes

The bentgrasses comprise an adaptable group of grasses that include introduced species, cultivated turfgrasses, and native plants in North America. Their distribution in cultural landscapes has not been documented, and this gap in knowledge has limited the development of predictive ecological risk assessments for creeping bentgrass engineered for herbicide resistance. In this study, bentgrass distribution and abundance were surveyed in 289 plots in an 8.5 km2 site surrounding a golf course in the northeastern United States. Four introduced species and two native bentgrasses were identified in seminatural and managed plant communities. Across the study site, 77% of the plots containing creeping bentgrass also had invasive plants. Bentgrasses co-occurred with critical habitat for threatened or endangered animals. Multivariate logistic regression analysis showed that bentgrasses were positively correlated with herbaceous plant cover and mowing, but negatively correlated with tree canopy cover, shrub cover, poorly drained soils, and leaf litter. The most influential ecological factors were tree canopy cover and soil moisture. Geospatial information about these two ecological factors was combined with mathematical models to generate two habitat suitability maps. The favorable environments map (FEM) showed that highly suitable bentgrass habitat covered 36% of the study site and included common features such as home lawns and railroad right-of-ways. Our results suggest that release of herbicide-resistant creeping bentgrass in this cultural landscape could potentially result in pollen-mediated gene flow, interspecific hybridization, environmental hazards, and herbicide selection pressure in some areas. Habitat suitability maps could be critical tools for predictive ecological risk assessments, monitoring projects, and management of herbicide-resistant bentgrasses.

Growth and aflatoxin production of an Italian strain of Aspergillus flavus: influence of ecological factors and nutritional substrates

The aim of this study was to define quantitative relationships between temperature and water activity (aw), fungal growth and aflatoxin B1 (AFB1) production. A strain of Aspergillus flavus isolated from maize in north Italy, and previously tested and found positive for AFB1 production, was used for these experiments. The optimum temperature for AFB1 production was at 25 °C, slightly lower with respect to results obtained in other countries. 0.83 aw was the limit for growth of this strain of A. flavus after 60 days incubation at the optimum temperature. The solutes used to modify aw, glycerol and NaCl, influenced both growth and secondary metabolite production. Media modified with glycerol resulted in more AFB1 production when compared to the non-ionic solute NaCl added media. Maize based media, prepared with flour obtained from kernels at different ripening stages, only slightly influenced growth rates of A. flavus. The quantitative relationship obtained between fungal growth and AFB1 production in diverse temperature and aw levels were used to develop a valid predictive model for A. flavus presence and AFB1 production in the field.

Influence of Ecological Factors on Carvacrol Content of Satureja khuzestanica Jamzad

The genus Satureja constitutes about 200 species of herbs and shrubs, widely distributed in Mediterranean area, Asia and boreal America. Fourteen species of Satureja are growing wild in western and northern parts of Iran. Satureja khuzestanica Jamzad is an endemic plant that is widely distributed in the southern and western parts of Iran. It is famous for its medical uses as analgesic and antiseptic in folk medicine. This work was conducted to study ecological factors that could affect carvacrol content and plant height of ten populations of Satureja khuzestanica from Iran (Khuzestan and Lurestan Provinces). The essential oils were obtained by hydro-distillation and analyzed by high performance liquid chromatography (HPLC). Results showed that plant height varied significantly between populations of Satureja khuzestanica. Also, our investigation showed that there is a positive and linear relationship between content of carvacrol as major component with latitude.

Antropogenically Created Forest Edge in the Starohorské Vrchy Mts. on the Example of Donovaly Village

Forest edges represent specific elements forming the character of landscape. They are very important factors in ecological stability. To know and to understand them as a part of dynamic and hierarchic structure in vertical and horizontal shaping of the landscape contributes to understanding of the processes between forest and non-forested landscape in connection to influence of ecological factors towards broad knowledge of the country in the shape of its utilization and monitoring of its dynamic changes. The aim of the paper is to analyze in a geographic sense the types of anthropic forest edges in the area of Starohorské vrchy Mts. (on the example of Donovaly village) and their partial geographic synthesis in the frame of chosen attributes and forest edge functions. Basic question is whether human activity influences the dynamics of environmental variables, its structure, taxonomic diversity and other attributes of forest edges.

Temporal dynamics of genetic diversity of Japanese scallop Mizuhopecten yessoensis (Jay, 1856)

The season and age-related dependence of the distribution of the frequency of alleles and of five polymorphous loci have been studied for eight cultivated samples of the Japanese scallop M. yessoensis (Jay) from Alexeev Bay (Popov Island, Sea of Japan) using polyacrylamide gel electrophoresis. The consistency of the frequency of alleles and of heterozygotes was revealed for samples with an age greater than one year independently of the season and age. Samples of the younger (11 months) mollusks can have reliable deviations of the frequency of allele and of heterozygotes. However, as the sample reaches a certain age, these genetic parameters correspond to values general to the whole population. The episodic influence of ecological factors on the younger age groups of mollusks is discussed.