Major changes in the global environmental conditions on Earth are expected to cause ecological disruption of the ecosystems. Deciphering the processes that affected past floras and faunas during periods of extreme environmental change may be a clue to understand the dynamics of the current change. The period at the Devonian-Carboniferous boundary (ca 359 Ma) is a candidate for such approach as it covers one of the six major crises (Hangenberg Event), documented for terrestrial floras and aquatic faunas. The project aims at better constraining the abiotic changes occurring during this period, and at understanding the timing and the processes of the biotic responses. This will be done at several scales: (1) at the community level, by assessing diversity and disparity patterns through the perturbed period; (2) at the species level, by attempting to develop tracers of demographic selection regimes (investment in reproduction or survival) based on phenotypic traits. A further originality of the project will be to target an integrative approach of the marine and terrestrial ecosystems, in order to assess the synchronicity or diachrony of their response.