{"id":12898,"date":"2026-09-30T12:05:09","date_gmt":"2026-09-30T10:05:09","guid":{"rendered":"https:\/\/www.imbe.fr\/?post_type=tribe_events&#038;p=12898"},"modified":"2026-09-30T12:15:37","modified_gmt":"2026-09-30T10:15:37","slug":"these-de-charlotte-rault-avian-community-assembly-across-environmental-gradients-insights-from-migratory-and-sedentary-bird-guilds","status":"publish","type":"tribe_events","link":"https:\/\/www.imbe.fr\/en\/evenement\/these-de-charlotte-rault-avian-community-assembly-across-environmental-gradients-insights-from-migratory-and-sedentary-bird-guilds\/","title":{"rendered":"Charlotte Rault\u2019s PhD thesis: \u00abAvian community assembly across environmental gradients: insights from migratory and sedentary bird guilds\u00bb"},"content":{"rendered":"<p><strong>Ms Charlotte Rault <\/strong>PhD student at the IMBE<a href=\"https:\/\/www.imbe.fr\/en\/ecologie-ecotoxicologie-chimie-appliquees-a-lagroecologie-et-a-la-restauration\/\">,<\/a>\u00a0<strong>will defend his PhD thesis in public on Monday 12 October 2026, at 2.00 pm in the CEREGE conference room at ARBOIS.<\/strong><\/p>\n<p><strong>In front of a jury made up of :<\/strong><\/p>\n<ul>\n<li>Ana RODRIGUES, Rapporteur, CNRS Montpellier<\/li>\n<li>Jean-Baptiste MIHOUB, Rapporteur, Sorbonne University<\/li>\n<li>Caterina PENONE, Examiner, CNRS, Universit\u00e9 Grenoble Alpes<\/li>\n<li>Rapha\u00ebl GROS, Examiner, Aix-Marseille University<\/li>\n<li>Fr\u00e9d\u00e9ric M\u00c9DAIL, Chair of the Jury, Aix-Marseille University<\/li>\n<li>Yoann PINGUET, PhD supervisor, Aix-Marseille University<\/li>\n<\/ul>\n<p><strong>Summary of work:<\/strong><\/p>\n<p>Migration enables many animal species to make use of seasonal resources and cope with environmental fluctuations. Among birds, it is particularly common and leads to the coexistence of migratory and sedentary species within communities. However, the mechanisms that determine the balance between these two guilds remain poorly understood.<\/p>\n<p>This thesis examines the composition of these guilds within breeding bird communities in the Provence-Alpes-C\u00f4te d\u2019Azur region. It draws on citizen science data from the LPO PACA and covers 224 species, including 75 long-distance migrants and 149 sedentary or short-distance migrants. The analyses were carried out on 5 \u00d7 5 km grids, suited to mobile species and to the joint study of the landscape and biotic interactions.<\/p>\n<p>The first article shows that the composition of migratory and sedentary species results from interactions between altitude, species richness and landscape structure. The most species-rich communities have a higher proportion of migratory species, particularly at low altitudes. This finding suggests a mechanism of heterospecific attraction, whereby migratory species preferentially settle in habitats rich in sedentary species, which serve as indicators of habitat quality. With increasing altitude, this relationship weakens and migratory species become under-represented, reflecting a growing effect of environmental filtering, which limits the establishment of species. The effects of landscape structure also vary with altitude, indicating that the mechanisms governing the balance between the two guilds evolve along the altitudinal gradient.<\/p>\n<p>The second article tests the hypothesis that functional traits can be used to distinguish the roles of biotic interactions and environmental filtering in community assembly. The results reveal distinct functional profiles between guilds, linked to their mobility and resource utilisation. At low altitudes, a higher proportion of migratory birds is associated with high functional redundancy within this guild, supporting the hypothesis of heterospecific attraction. In the montane zone, migratory species are more prevalent when the two guilds occupy more distinct functional positions, suggesting that niche differentiation favours their co-occurrence. Overall, the findings indicate a gradual decrease in biotic interactions in favour of environmental constraints with increasing altitude.<\/p>\n<p>The third article examines the representation of the taxonomic, migratory and functional dimensions of avian biodiversity within the regional network of protected areas. The analyses reveal low spatial congruence between these dimensions, as only 7.5 % of the grid cells exhibit high values for all of them simultaneously. Despite better representation of migratory dimensions within Special Protection Areas, nearly half of the grid cells with high multidimensional biodiversity remain inadequately protected. These results highlight the value of a multidimensional approach to identifying conservation priorities that complement those based solely on species richness.<\/p>\n<p>&nbsp;<\/p>\n<p>Overall, this thesis demonstrates that the balance between migratory and sedentary species results from deterministic processes involving environmental gradients, biotic interactions and the functional structure of communities. The results reveal a gradual shift from heterospecific attraction mechanisms towards environmental filtering mechanisms as altitude increases. The multidimensional approach links an understanding of community assembly mechanisms to conservation issues.<\/p>\n<p>&nbsp;<\/p>","protected":false},"excerpt":{"rendered":"<p>Madame Charlotte Rault doctorante \u00e0 l\u2019IMBE,\u00a0soutiendra publiquement ses travaux de th\u00e8se le lundi 12 octobre 2026, \u00e0 14h dans la salle de conf\u00e9rence du CEREGE \u00e0 l&#8217;ARBOIS. Devant le jury [&hellip;]<\/p>\n","protected":false},"author":300,"featured_media":0,"template":"","meta":{"_acf_changed":false,"_tribe_events_status":"","_tribe_events_status_reason":"","footnotes":""},"tags":[],"tribe_events_cat":[30],"class_list":["post-12898","tribe_events","type-tribe_events","status-publish","hentry","tribe_events_cat-soutenance","cat_soutenance"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.imbe.fr\/en\/wp-json\/wp\/v2\/tribe_events\/12898","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.imbe.fr\/en\/wp-json\/wp\/v2\/tribe_events"}],"about":[{"href":"https:\/\/www.imbe.fr\/en\/wp-json\/wp\/v2\/types\/tribe_events"}],"author":[{"embeddable":true,"href":"https:\/\/www.imbe.fr\/en\/wp-json\/wp\/v2\/users\/300"}],"version-history":[{"count":5,"href":"https:\/\/www.imbe.fr\/en\/wp-json\/wp\/v2\/tribe_events\/12898\/revisions"}],"predecessor-version":[{"id":12904,"href":"https:\/\/www.imbe.fr\/en\/wp-json\/wp\/v2\/tribe_events\/12898\/revisions\/12904"}],"wp:attachment":[{"href":"https:\/\/www.imbe.fr\/en\/wp-json\/wp\/v2\/media?parent=12898"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.imbe.fr\/en\/wp-json\/wp\/v2\/tags?post=12898"},{"taxonomy":"tribe_events_cat","embeddable":true,"href":"https:\/\/www.imbe.fr\/en\/wp-json\/wp\/v2\/tribe_events_cat?post=12898"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}