Item – Thèses Canada

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Numéro d'OCLC
979422711
Lien(s) vers le texte intégral
Exemplaire de BAC
Auteur
Grégoire-Taillefer, Amélie,
Titre
Phylogenetic, taxonomic, and functional diversity of wetland diptera communities
Diplôme
Ph. D. -- McGill University, 2017
Éditeur
[Montreal] : McGill University Libraries, [2017]
Description
1 online resource
Notes
Thesis supervisor: Terry A Wheeler (Supervisor).
Includes bibliographical references.
Résumé
"The goal of this thesis was to describe biodiversity and community composition of Diptera in wetlands across Quebec. Three approaches to community analysis were used to describe patterns: taxonomic identity, functional traits, and phylogenetic relationships. Diptera were sampled using standardized methods (pan traps, sweeping) across three types of wetlands (marsh, swamp, bog) in the Montreal region, and in 15 bogs distributed in three Quebec ecoregions. When comparing three types of wetlands, abundance and species richness did not differ even with wetland areas ranging from 6 to 161 ha. Bogs supported phylogenetically closely related Diptera species filtered by harsher environmental conditions compared to the other two wetland types. Clustering of closely related species was found in bogs, which is probably due to environmental filtering at the initial stage of community assembly postglacially. The slow peat accumulation process and characteristic plant composition adapted to acidic and low nutrient conditions potentially play a role in the structure of the Diptera community. Neutral processes were more important in marshes and swamps, as dispersal limitation explained species abundance dynamics of small and common Diptera species within each wetland type. The assembly of marsh communities is a balance between neutral processes and environmental filtering, while the assembly of swamp habitats is neutral. Clustering, thus environmental filtering, increased with environmental extremes. Rare species tended to be distantly related to common species, based on phylogenetic signal. They have unique habitat requirements and their diversity is maintained by temporal turnover during the active season of species with similar traits filtered by the environment. When the spatial extent of the research was expanded to bogs in three Quebec ecoregions, a selective filtering role of anthropogenic disturbance was found. Recent drastic human modification of the landscape in Eastern Great Lakes Lowland Forest ecoregion, less suitable peatland patches and more barriers to dispersal are adjacent to those bogs, so agriculture and urban development act as filters for the small proportion of species in the regional pool that can disperse in these conditions. In Eastern Canadian Forest and Central Canadian Shield ecoregions, stochastic processes such as dispersal limitation of abundant, small, multivoltine species seem to be the dominant influence. High diversity of Diptera species and different historical disturbances are at the origin of the functional and phylogenetic structure observed for peatland Diptera. Phylogenetic community structure and functional analyses revealed high value and complementarity to standard biodiversity measures. Using only traditional metrics, it would not have been apparent that bog communities are impacted by land-use changes and that these impacts change the species pool capable of inhabiting these isolated habitats. This suggests that the three levels of diversity studied should be used in environmental assessments to have a complete picture of macroecological patterns in wetlands. Conservation of mobile organisms in wetlands will depend on conservation plans focusing on both patch quality and surrounding landscape. Different conservation strategies need to be applied in the different ecoregions."--
Autre lien(s)
digitool.Library.McGill.CA
escholarship.mcgill.ca
escholarship.mcgill.ca
Sujet
Natural Resource Sciences