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Guillaume Rheault

 

Ph.D. student

Department of Environmental Sciences, UQTR

Léon-Provancher Building
3351, boul. des Forges
UQTR
Quebec, Canada
G9A 5H7

819.376.5011 extension 3373
Guillaume.Rheault@uqtr.ca

 

 


 

Direction

 
 

Research project

Influence of biotic and abiotic factors on wetland plant communities' phenology

Plant phenology (e.g. Growth and flowering) is now recognized as one of the best indicators of climate change observed across the globe. Through studies conducted in recent years, climatic factors involved in the regulation of plant phenology are now better understood. Thus, many of these studies suggested that the temperature is one of the most important factors in the regulation of plant phenology of temperate and boreal ecosystems. Studies at the species scale also suggested the existence of significant interspecific differences in terms of responses to temperature changes suggesting that some biotic factors such as species composition and species richness may also influence the phenology at the community scale. However, few studies have focused on the phenological variability that these interspecific differences were generating at the level of plant communities and ecosystems. A great part of the actual knowledge of plant phenology comes from the observation of deciduous forests and meadows and very few studies have focused on the plant phenology of wetlands. Knowledge surrounding the biotic and abiotic factors involved in the phenology of wetland plant communities are even more limited. The functioning of wetlands is highly dependent on the phenology of plants inhabiting these ecosystems. Therefore, a better understanding of biotic and abiotic factors involved in the regulation of the phenology of plant communities of wetlands would help better anticipate the effects of climate change on the functioning of wetlands.
The objectives of my PhD are to 1) quantify the phenological variability within plant communities and within wetland ecosystems of Quebec, 2) quantify the interannual phenological variability of plant communities in these ecosystems and 3) determine the relative contribution of biotic factors such as species composition of vascular plants and species richness and abiotic factors such as climate and soil conditions on the phenological variability of plant communities inhabiting the wetlands present in the Province of Quebec.
As part of my PhD, I use the facilities of the réseau de suivi automatisé de la végétation et des écosystèmes riverains (SAuVER, Canada Research Chair in Ecological Integrity) established since 2012, which includes the monitoring of 108 plant communities in five wetlands ecosystems type. These ecosystems are spread across a latitudinal gradient extending from marshes and shorelines located along Lake St-Pierre to the Arctic wet meadows located in the Nunavik region near the Umiujaq community through the bogs present in the ecological reserves of Lac-à-la-Tortue (Shawinigan) and Bog-à-lanières (Lac Édouard). The monitoring of plant communities' phenology is done using Timelapse cameras which are taking pictures 3 times daily from April to November in the southern part of Quebec and from June to October in the north. These photos are used initially to determine the species composition in plant communities in an area of eight meters square. Subsequently, the information related to the color contained in these photos is used to track the phenology of plant communities so the beginning, the end and the extent of the growth and flowering periods of each community. Edaphic characteristics (soil and water pH, water redox potential, soil texture, soil moisture, soil conductivity and soil temperature) of all monitored plant communities are also measured.

 
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