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Reference : UMR7372-KARMON-002
Workplace : VILLIERS EN BOIS
Date of publication : Friday, April 30, 2021
Scientific Responsible name : Karine Monceau (MCf La Rochelle université, HDR prévue 2021) & Jérôme Moreau (MCf uB-FC, HDR)
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 October 2021
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
Investigating the effects of pesticides on the physiology and behavior of individuals is only rarely done using the monitoring of wild species. Yet, as highlighted by EFSA (2009), this type of monitoring provides substantial advantages over laboratory experiments, i.e., realistic exposure without extrapolation from a model species. The common harrier appears to be a particularly interesting species to be bioindicator of the impact of pesticides on avian fauna given its ecology. Harriers nest on the ground in cereal plots, exposing them directly to pesticide treatments or to the persistence of certain molecules in the soil. In addition, it is a superior predator of micromammals likely to be more impacted at large doses of toxic molecules by biomagnification (accumulation of toxins along the trophic chain). For example, common harrier chicks are likely to be particularly exposed to cocktails of toxic molecules during development, a critical stage in a bird's life. Within agrosystems, we assume that pesticide molecules applied by farmers can interfere with their physiology and metabolism and thus cause disorders at different levels, particularly to their immune system, their growth and their behavior. We therefore expect to observe physiological, behavioral and developmental differences (growth curves and body condition at fledging) between the broods examined on plots in organic farming (no phytosanitary treatment) compared to those on plots. in conventional agriculture. Moreover, depending on the year, this contrast could be more or less exacerbated. In fact, the preferred prey of harriers, the common vole, has a cyclical population dynamic. During years of low vole abundance, the survival conditions of the young become more drastic (reduction of broods and the number of fledged chicks) and the parents include more insects in their diet. As a result, there is not only a change in the availability of prey and their nutritional quality, but also in their level of exposure to plant protection products.
The distribution of common harrier nests on the ZAPVS (Zone Atelier Plaine et Val de Sèvres) allows us to work on a gradient of exposure to pesticides by considering nests in the middle of the plot in conventional agriculture to nests in the heart. from organic farming. Depending on the year and the abundance of voles, the number of harrier nests varies between 30 and 60. Thus, each year, we expect to have 50 to 100 chicks available for our analyzes. The nests are visited four times during the rearing of the young, which allows us to carry out longitudinal monitoring of their growth and ontogeny. We will focus more particularly on the development of chicks, their physiology (immune, endocrine and nervous system) and their behavior up to fledgling. These parameters will be compared with the spatial location of the nests in the gradient of intensification of pesticide use, but also with more precise data on toxicity dosages in chicks and ingested prey. This will also be put in parallel with the quantity of resources available in the area both in micromammals (vole, preferred prey of harriers) but also insects.
The PhD student will join the Agripop team and will work within Zona Atelier Plaine et Val de Sèvre
Constraints and risks
No associated risk
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