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Theses

Habitats urbanisés : des trappes écologiques potentielles pour les oiseaux sauvages ?

Abstract : Urbanization is an increasing phenomenon inducing dramatic modifications of natural habitats facing biodiversity. These rapid and drastic environmental changes create new conditions, potentially constraining individuals. Indeed, artificial parameters, such as light, noise and chemical pollution, coupled with human presence and food resources which are often modified and less available, should constrain survival and reproduction of urban species. Moreover, urban habitat changes could lead individuals to misinterpret natural environmental cues, inducing maladaptive responses and populations into an ecological trap. In this context, we developed this research project on great tits, Parus major to improve our understanding of avian adaptation in cities. We monitored great tit reproduction breeding in nest-boxes within an urbanization gradient, which has been quantified, in the city of Montpellier. We experimentally manipulated nesting-cavity size using different types of nest-boxes. We found that the birds preferred the largest artificial cavities for breeding when they could choose between small, medium-sized and large cavities. Individuals from the largest cavities also invested more in egg production, yet had a lower fledging success than those from medium-sized cavities. These results are an experimental demonstration of a trap mechanism in free-living animals. To test our hypothesis that food resources are an environmental key factor limiting reproductive performance in our urban great tit population, we conducted experiments modulating constraints on food resources. The conclusion of these experiments is that food is a limiting factor for reproduction. In addition, in a local adaptation framework, we examined if urban great tits possess particular phenotypic traits that differ from great tits that live in more natural conditions. We found that urban and rural great tits expressed differences in morphology and personality profiles both at the inter-habitat and intra-habitat level. Additional studies will be required to better understand the underlying mechanisms that link phenotypic and reproductive performance in individuals that face rapid environmental change and increased urbanization, also to improve biodiversity conservation programs in these environments.
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https://tel.archives-ouvertes.fr/tel-01589669
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Submitted on : Monday, September 18, 2017 - 7:02:08 PM
Last modification on : Monday, November 30, 2020 - 9:52:28 AM

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  • HAL Id : tel-01589669, version 1

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Virginie Demeyrier. Habitats urbanisés : des trappes écologiques potentielles pour les oiseaux sauvages ?. Ecologie, Environnement. Montpellier SupAgro, 2016. Français. ⟨NNT : 2016NSAM0028⟩. ⟨tel-01589669⟩

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