{"id":21462,"date":"2023-10-31T11:29:57","date_gmt":"2023-10-31T10:29:57","guid":{"rendered":"https:\/\/www.cerege.fr\/?page_id=21462"},"modified":"2023-11-02T16:11:00","modified_gmt":"2023-11-02T15:11:00","slug":"msca-thresholds","status":"publish","type":"page","link":"https:\/\/www.cerege.fr\/en\/sciences\/climat\/projets-climat\/msca-thresholds\/","title":{"rendered":"MSCA THrESholds"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-page\" data-elementor-id=\"21462\" class=\"elementor elementor-21462\" data-elementor-post-type=\"page\">\n\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-748bad5 elementor-section-full_width elementor-section-height-min-height elementor-section-height-default elementor-section-items-middle\" data-id=\"748bad5\" data-element_type=\"section\" data-e-type=\"section\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-3541241a\" data-id=\"3541241a\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap\">\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-27ba7016 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"27ba7016\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-40f79235\" data-id=\"40f79235\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-41cc1ed8 elementor-widget elementor-widget-shortcode\" data-id=\"41cc1ed8\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"shortcode.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-shortcode\"><nav aria-label=\"breadcrumbs\">\n            <div class=\"breadcrumb-container theme1\">\n                <ol>\n                                    <\/ol>\n            <\/div>\n        <\/nav>    <script type=\"application\/ld+json\">\n        {\n            \"@context\": \"http:\/\/schema.org\",\n            \"@type\": \"BreadcrumbList\",\n            \"itemListElement\": [\n                            ]\n        }\n    <\/script>\n   \n    <script>\n            <\/script>\n<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<section class=\"elementor-section elementor-inner-section elementor-element elementor-element-227e0211 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"227e0211\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-wide\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-inner-column elementor-element elementor-element-313d8e8\" data-id=\"313d8e8\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-71c90c32 elementor-widget elementor-widget-text-editor\" data-id=\"71c90c32\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>Les for\u00eats et savanes tropicales abritent un cinqui\u00e8me de la population mondiale qui d\u00e9pend \u00e9troitement de ces \u00e9cosyst\u00e8mes pour leur subsistance. Avec le changement global en cours, pr\u00e9dire comment ces \u00e9cosyst\u00e8mes r\u00e9agiront aux changements de pr\u00e9cipitations et d&#8217;humidit\u00e9 relative est une priorit\u00e9.<\/p><p>Leur fonctionnement \u00e9cologique en tant qu&#8217;\u00e9tats stables alternatifs fait que leur r\u00e9ponse \u00e0 des changements environnementaux est non-lin\u00e9aire et particuli\u00e8rement difficile \u00e0 pr\u00e9voir. Cela est d\u00fb \u00e0 des r\u00e9troactions entre structure de la v\u00e9g\u00e9tation et feux qui stabilisent chaque \u00e9tat, et ce m\u00eame si les conditions environnementales changent, jusqu&#8217;\u00e0 un certain seuil. Une fois ce seuil franchi, il y a transition d&#8217;un \u00e9tat \u00e0 un autre et le retour \u00e0 l&#8217;\u00e9tat initial est quasiment impossible.\u2028L&#8217;une des principales limitations \u00e0 l&#8217;identification de ces seuils est que les processus \u00e9cologiques impliqu\u00e9s se produisent sur des \u00e9chelles de temps longues (&gt;100 ans), qui d\u00e9passent la profondeur temporelle des donn\u00e9es empiriques disponibles, souvent limit\u00e9e \u00e0 quelques d\u00e9cennies.<\/p><p>Les archives fossiles contenues dans les s\u00e9diments lacustres, dont les permettent de pallier \u00e0 cette limitation. Les reconstructions pal\u00e9o\u00e9cologiques repr\u00e9sentent toutefois un v\u00e9ritable d\u00e9fi m\u00e9thodologique, car les bio-indicateurs permettent d\u2019estimer les variables d\u2019int\u00e9r\u00eat dans le pass\u00e9 de fa\u00e7on plut\u00f4t qualitative (plus\/moins), mais l&#8217;identification des seuils dans les conditions environnementales \u00e0 l\u2019origine des transitions de v\u00e9g\u00e9tation n\u00e9cessite des reconstitutions quantitatives de la v\u00e9g\u00e9tation pass\u00e9e et des variables climatiques.\u2028<\/p><p>Le projet Thresholds a deux principaux objectifs :<\/p><ul><li>participer au d\u00e9veloppement m\u00e9thodologique d&#8217;un nouvel indicateur quantitatif d\u2019humidit\u00e9 relative pass\u00e9e bas\u00e9e sur l&#8217;analyse de la triple composition isotopique de l&#8217;oxyg\u00e8ne (17O-excess) des phytolithes, indicateur r\u00e9cemment d\u00e9velopp\u00e9 au CEREGE<br \/><br \/><\/li><li>identifier les seuils d\u2019humidit\u00e9 relative \u00e0 l\u2019origine de transitions for\u00eat-savane, et les plages de valeurs ayant permis une certaine r\u00e9silience de la for\u00eat, au cours des 5 000 derni\u00e8res ann\u00e9es en Afrique, et cela en utilisant des reconstitutions quantitatives de l\u2019humidit\u00e9 relative, et des comparaisons avec reconstitutions de la v\u00e9g\u00e9tation et des feux.<\/li><\/ul><p>Les r\u00e9sultats de ce projet aideront \u00e0 mieux identifier et quantifier les seuils d&#8217;humidit\u00e9 relative qui \u00e9taient associ\u00e9s aux transitions de la v\u00e9g\u00e9tation. In fine, les r\u00e9sultats de ce projet permettront de mieux connaitre le fonctionnement \u00e9cologique des for\u00eats et savanes tropicales, et notamment leur r\u00e9ponse aux changements environnementaux pass\u00e9s, afin de mieux l\u2019int\u00e9grer dans les mod\u00e8les de v\u00e9g\u00e9tation et de fournir des projections plus pr\u00e9cises de leurs r\u00e9ponses au changement climatique en cours.<\/p><p>Ce projet a \u00e9t\u00e9 r\u00e9alis\u00e9 dans le cadre et avec le soutien technique, mat\u00e9riel et les collaborations des ANR HUMI-17 et PAST-17<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-inner-column elementor-element elementor-element-317685f8\" data-id=\"317685f8\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-55cc86e3 elementor-widget elementor-widget-text-editor\" data-id=\"55cc86e3\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<h2><span style=\"font-weight: normal;\">2021-2023 : MSCA THrESholds (<\/span><span style=\"font-weight: normal;\">bourse europ\u00e9enne Marie-Curie)<br \/><\/span><\/h2><p>Responsable CEREGE : <br \/><strong><a href=\"https:\/\/www.cerege.fr\/fr\/cerege\/julie-aleman\/\">Julie Aleman<\/a><br \/><a href=\"https:\/\/www.cerege.fr\/fr\/cerege\/anne-alexandre\/\">Anne Alexandre<\/a><br \/><\/strong><\/p><p style=\"font-weight: 400;\"><em>Thresholds in past relative Humidity and Ecosystem Structure in Africa<\/em><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<div class=\"elementor-element elementor-element-39e00bf3 elementor-widget elementor-widget-spacer\" data-id=\"39e00bf3\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-21ce73f elementor-widget elementor-widget-spacer\" data-id=\"21ce73f\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Les for\u00eats et savanes tropicales abritent un cinqui\u00e8me de la population mondiale qui d\u00e9pend \u00e9troitement de ces \u00e9cosyst\u00e8mes pour leur subsistance. Avec le changement global en cours, pr\u00e9dire comment ces [&hellip;]<\/p>\n","protected":false},"author":749,"featured_media":16058,"parent":4955,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-21462","page","type-page","status-publish","has-post-thumbnail","hentry"],"acf":[],"publishpress_future_action":{"enabled":false,"date":"2026-04-24 04:12:55","action":"change-status","newStatus":"draft","terms":[],"taxonomy":"","extraData":[]},"publishpress_future_workflow_manual_trigger":{"enabledWorkflows":[]},"_links":{"self":[{"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/pages\/21462","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/users\/749"}],"replies":[{"embeddable":true,"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/comments?post=21462"}],"version-history":[{"count":5,"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/pages\/21462\/revisions"}],"predecessor-version":[{"id":21503,"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/pages\/21462\/revisions\/21503"}],"up":[{"embeddable":true,"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/pages\/4955"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/media\/16058"}],"wp:attachment":[{"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/media?parent=21462"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}