Dynamique d'une population faunique en expansion sous différents scénarios climatiques : le dindon sauvage (Meleagris gallopavo)
|Advisor:||Tremblay, Jean-Pierre; Blanchette, Pierre|
|Abstract:||Recent global climate changes have resulted in range expansion for many temperate species but have also led to local extinctions for species living at the fringe of their environmental tolerance. These expanding populations may prioritize different life history strategies by responding differently to limiting factors. In this thesis, we aim to assess and quantify the effect of climate and extreme events on the whole life cycle of an expanding wildlife species (wild turkey) to understand population change and range expansion. I defined an extreme climate event for rain, snow depth and temperature, as events rarer than the 10th and 90th percentile. Using a Measure-Understand-Predict (MUP) approach, I first followed three populations along a latitudinal gradient in winter harshness to measure the effect of weather variables on population dynamics. Winter survival of wild turkeys decreased dramatically when snow depth was over a 30 cm threshold and also decreased with temperature. Snow persistence and precipitation in spring negatively impacted initiation nesting rate and nest survival, respectively. In a second step, I examined the impact of extreme climate events and the demographic mechanisms driving their expansion in the context of life history theory to understand the relationship with climate. I showed that the frequency of extreme winter events and to a lesser extent extreme summer events limited the northern expansion of wild turkeys. I supported the hypotheses of the classical biological invasion theory, with empirical data and modelling, as establishing populations prioritized reproductive parameters while adult survival was the key demographic parameter driving the dynamics of well established populations. Furthermore, more northern populations were composed of younger individuals with a lower life expectancy but had a higher potential growth rate than populations located more southerly as predicted by this theory. Finally, I predicted the impact of the harvest on population dynamics as well as the population growth rate of this species using future climate conditions projected by IPCC-class models. Establishing populations had a higher harvest rate potential but the proportion of adult males, possessing enhanced characteristics sought by hunter, decreased faster than in established populations. In the future, frequency of rain extreme events is predicted to increase while frequency of winter temperature and snow cover extreme events should decrease after 2060, potentially restraining wild turkey northern expansion until at least 2100. This thesis increases our understanding of the effect of weather and climate on range expansion and their underlying demographic mechanisms, and allows us to predict the likelihood of the northern expansion range of wild turkey in response to climate changes.|
|Document Type:||Thèse de doctorat|
|Open Access Date:||24 April 2018|
|Collection:||Thèses et mémoires|
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