Évaluation de la reproduction des oiseaux en forêt boréale aménagée
|Authors:||Corbani, Aude Catherine|
|Abstract:||The aim of this PhD is to assess the reproductive success of a managed boreal forest songbird community, and to explore its causality. The traditional method to achieve this objective is nest monitoring, but it is laborious in boreal forest where nests are often on the ground or hidden at the top of trees. Alternative methods have already been used in boreal forest to document songbird reproduction without finding nests. They are based on observations of parental behavior (such as food provisioning) or fledglings accompanying their parents. However, these observations suffer from significant detection bias, parents not displaying success indicators all the time. In the three chapters of this thesis, I am interested in two stages of bird reproductive cycle: nesting success (i.e. the presence of young at the nest) and fledging success. The first chapter presents an innovative method to measure nesting success from food provisioning observations taking into account of parental status detection bias. I show that this bias may be significant (detection does not exceed 38%), and that the application of two-state occupancy models (presence/absence) to nesting success (young/no young at nest) is possible and effective. In a second chapter, I apply my analytic method to food provisioning observations collected since 1995 in the study area (Forêt Montmorency, Québec, Canada). I show that nesting decreases during the 17 studied years, in correlation with habitat modifications and meteorological changes over time. Additionally, nesting success is greater in older and more even-aged forests, as well as far from forestry roads and trails. In the third chapter, I show that, in half of the cases where adults are found without fledglings at the end of the reproductive season, they do in fact have fledglings. After accounting for this imperfect detection, I estimate fledging success as 59%, uncorrelated to landscape attributes (stand age and homogeneity). All results in this thesis support the claim that boreal forest represents an important breeding ground for birds in North America. I highlight the importance of detection bias when using alternative methods to nest monitoring in order to measure reproductive success and propose applications of these new tools for atlassing and similar large-scale ornithology initiatives.|
|Document Type:||Thèse de doctorat|
|Open Access Date:||19 April 2018|
|Collection:||Thèses et mémoires|
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