Search results for "field experiment"
showing 10 items of 65 documents
COST OF REPRODUCTION IN THE WILD: MANIPULATION OF REPRODUCTIVE EFFORT IN THE BANK VOLE
2003
For three years, we manipulated litter size by adding or subtracting pups in eight wild populations of the bank vole, Clethrionomys glareolus, to examine reproductive costs and allocation of reproductive effort between offspring number and size. In general, litter enlargements did not increase the number of weanlings per mother and significantly decreased the size of weanlings. Reproductive effort and the breeding success of individuals varied within breeding seasons, but time of breeding and litter manipulation did not interact to affect reproductive trade-offs. Our 3-yr field experiment revealed that litter enlargements also reduced survival and fecundity of mothers. Small mammals have be…
Consumers' willingness to pay for natural food: Evidence from an artefactual field experiment
2018
Abstract Among foods with credence attributes, food with “natural” components have received in the last years particular attention by consumers. This study applies the BDM incentive compatible mechanism to explore young (18–35 years old) consumers’ interest and willingness to pay for chewing gums having the natural attribute. Our analysis shows that over 68% of consumers are interested in the natural attribute and are willing to pay a price premium. We also find that consumers’ higher age and interest in the environment have significant impacts on consumers’ preferences for the natural attribute.
Examining the side effects of organizational Internet monitoring on employees
2020
PurposeInternet monitoring in organizations can be used to monitor risks associated with Internet usage and information systems in organizations, such as employees' cyberloafing behavior and information security incidents. Extant research has mainly discussed the effect of Internet monitoring in achieving the targeted goals (e.g. mitigating cyberloafing behavior and information security incidents), but little attention has been paid to the possible side effects of Internet monitoring. Drawing on affective events theory, the authors attempt to reveal that Internet monitoring may cause side effects on employees' Internet usage policy satisfaction, intrinsic work motivation and affective organ…
Impact of tillage system on arbuscular mycorrhiza fungal communities in the soil under Mediterranean conditions.
2012
A more diverse arbuscular mycorrhiza (AM) fungal community should be more versatile and resilient to variation in environmental conditions over space and time. To evaluate the effect of no-till and conventional tillage systems, AM fungal diversity was assessed as part of a long term field experiment by sequencing of DNA, extracted from soil, that encoded the large ribosomal sub-unit and was obtained by nested-PCR. In comparison with no-till, conventional tillage decreased AM fungal diversity by 40%. Differences between treatments in the frequency of the operational taxonomic units (OTUs) present in soil, confirm that AM fungi are differently vulnerable to soil disturbance.
Changes of Photosynthesis-Related Parameters and Productivity of Spring Oilseed Rape under Different Nitrogen and Sulphur Fertilizers Supply
2015
Fertilization with essential mineral elements is important to get high quality yield results. The lack of necessary mineral elements in soil can affect oilseed rape plant physiological functions, photosynthesis and plant productivity. Oilseed rape plants have high requirements for nitrogen and as oil crop – for sulphur. The aim of the investigation was to explain changes of chlorophyll a fluorescence parameters in spring oilseed rape leaves and yield changes under nitrogen and sulphur supply. During laboratory experiments changes of chlorophyll a fluorescence parameters and during field experiments changes of yield parameters under different nitrogen and sulphur supply were observed. Labora…
Effects of hard frost and freeze-thaw cycles on decomposer communities and N mineralisation in boreal forest soil
2003
Abstract Decomposition and mineralisation rates generally increase with increasing moisture and temperature. The expected global climate change may enhance precipitation and raise the temperatures at boreal latitudes, but absence of snow together with occasional low temperatures may cause disturbances in soil processes and faunal communities. To test the effects of disturbances such as hard frosts and freeze-thaw cycles on decomposer populations and N mineralisation, we performed two experiments. In the field experiment, carried out in a pine forest, we induced low soil temperatures by preventing snow covering the ground. In the laboratory test we established three “winter” temperature regi…
Measuring rill erosion using structure from motion: A plot experiment
2017
Abstract In this paper the results of a plot experiment on rill erosion are reported. The rill network, manually incised on the soil and further shaped by a clear inflow discharge, was surveyed using the three-dimensional photo-reconstruction (3D-PR) technique which allows to obtain a digital terrain model (DTM) by a large series of oblique images of the channel from consumer un-calibrated and non-metric cameras. The three-dimensional (3D) DTM and the quasi-tridimensional (2.5D) model were generated by Agisoft Photoscan software. For a single rill channel, the reliability of the 3D image-based ground measurements of morphological and hydraulic variables was positively tested by the correspo…
Eradicating Mosquitoes using Translocations: a First Field Experiment
1972
THEORETICAL considerations have led to the assumption that chromosomal translocations with ensuing semisterility could be used to control pests1–3. Inversions could have the same effect in animals and plants in which crossing over occurs in both sexes4. Many translocations of different type and with various degrees of sterility have been produced in the mosquito Culex pipiens5–8. Preliminary laboratory experiments with these translocations have shown that a cage population can be diminished and finally exterminated after a few generations by the release of translocation heterozygotes into the population9.
Effects of isolation, area and predators on invasion: A field experiment with artificial islands
2007
Abstract The three most important ecological factors affecting the success of island invasions are the area of the island, isolation of the island and occurrence of predators on the island. Traditionally, invasion success has been studied on natural islands, which partly explains the rarity of controlled and replicated experiments. Here we report results from a field experiment investigating the influence of the above three factors in artificial islands. As an experimental system, we used predatory mites and a nematode community occurring naturally in boreal coniferous forests. We found that all three factors had an effect on invasion success, but surprisingly, that there were no interactio…
The responses of shoot-root-rhizosphere continuum to simultaneous fertilizer addition, warming, ozone and herbivory in young Scots pine seedlings in …
2017
Abstract It is not clear how climate change in combination with increasing soil nitrogen availability and herbivory affects boreal forests, the largest terrestrial biome in the world. In this study, Scots pine ( Pinus sylvestris ) seedlings were exposed to moderate warming (ca. 1 °C), 1.5 × ambient ozone (O 3 ) concentration, fertilizer addition (120 kg N ha −1 yr −1 ) and shoot herbivory by pine sawfly ( Acantholyda posticalis ) alone and in combination. We measured fine root morphology, mycorrhizal colonization level, root fungal biomass (ergosterol), rhizosphere emission of biogenic volatile organic compounds (BVOCs), and microbial biomass (PLFAs) in the rhizosphere soil as well as seedl…