Search results for "Temporal variation"
showing 6 items of 16 documents
Temporal dynamics of arable weeds communities assembly : interactions between farming practices and ecological processes across crop sequences
2018
Understanding how farming practices affect weed community assembly in arable fields is a core challenge of agro-ecology. Weeds are supposed to share particular ecological characteristics that allow them to colonize arable fields despite environmental constrains exert by farming practices. In addition, interactions between ecological processes operating during a cropping season (eg: abiotic filtering) and at the scale of crop succession (eg: temporal dispersal) are supposed to drive weed community assembly in arable fields. These two hypotheses have been tested in my phD work.First, we compared a pool of weed species to a pool of non-weed herbaceous plants based on several functional traits …
Limited effects of size-selective harvesting and harvesting-induced life-history changes on the temporal variability of biomass dynamics in complex f…
2023
Harvesting has been implicated in destabilizing the abundances of exploited populations. Because selective harvesting often targets large individuals, some studies have proposed that exploited populations often experience demographic shifts toward younger, smaller individuals and become more sensitive to environmental fluctuations. The theory of consumer–resource dynamics has been applied to address the impacts of harvesting in simple modular food webs, but harvested populations are embedded in a complex food web in nature. In addition, exploited populations have been shown to undergo trait evolution or phenotypic changes toward early maturation at smaller sizes. Using an empirically derive…
Variability of the human gut microbiota in space, time, and associated with the irritable bowel syndrome
2013
Esta tesis doctoral se centra en el estudio de una de las comunidades microbianas más complejas y de mayor interés biomédico: la microbiota asociada al intestino distal de humanos. El objetivo principal ha sido estudiar las alteraciones potenciales de la microbiota intestinal en relación con el síndrome del intestino irritable (SII), el desorden funcional del tracto gastrointestinal más común en sociedades occidentales. Nuestra aproximación forma parte de una visión actual sobre las relaciones entre microorganismos y hospedadores que trasciende la clásica y estrecha mirada sobre patógenos concretos y enfermedades infecciosas y la desplaza hacia una concepción más de conjunto, que valora los…
Sequential infection can decrease virulence in a fish-bacterium-fluke interaction: Implications for aquaculture disease management.
2018
Abstract Hosts are typically infected with multiple strains or genotypes of one or several parasite species. These infections can take place simultaneously, but also at different times, i.e. sequentially, when one of the parasites establishes first. Sequential parasite dynamics are common in nature, but also in intensive farming units such as aquaculture. However, knowledge of effects of previous exposures on virulence of current infections in intensive farming is very limited. This is critical as consecutive epidemics and infection history of a host could underlie failures in management practices and medical intervention of diseases. Here, we explored effects of timing of multiple infectio…
Sequential infection can decrease virulence in a fish–bacterium–fluke interaction: Implications for aquaculture disease management
2019
Hosts are typically infected with multiple strains or genotypes of one or several parasite species. These infections can take place simultaneously, but also at different times, i.e. sequentially, when one of the parasites establishes first. Sequential parasite dynamics are common in nature, but also in intensive farming units such as aquaculture. However, knowledge of effects of previous exposures on virulence of current infections in intensive farming is very limited. This is critical as consecutive epidemics and infection history of a host could underlie failures in management practises and medical intervention of diseases. Here, we explored effects of timing of multiple infection on viru…
Variazioni temporali della struttura di taglia in popolazioni sfruttate di Haliotis tuberculata (Mollusca Gastropoda) nel Golfo di Sferracavallo (PA)
2007
This study aims at evaluating the differences in size structure of population of H. tuberculata in the Gulf of Sferracavallo (northern Sicily) which experienced the co-occurrence of high exploitation and decrease of eutrophic conditions during the eighties and early nineties. Comparison of size structure showed significant differences between length frequency distributions of 1970-75s and 2002-2005, being the latter formed by smaller size green ormer.