Communication Dans Un Congrès Année : 2025

Strengthening CLAMP: New calibration sites to improve paleoclimate reconstructions.

Résumé

Reconstructing continental paleoclimates is a major scientific challenge. Among available archives, fossil paleoflora provide a powerful proxy to infer the environmental conditions under which ancient plants developed. The CLAMP method (Climate Leaf Analysis Multivariate Program), based on fossil leaf morphology, has been used for over thirty years for this purpose. It relies on modern calibration sites where both leaf trait variability and detailed climate data are available. Currently, 379 calibration sites exist, but their geographical distribution is uneven: Europe and the Mediterranean region are represented by only six sites (four in the UK, one in Ukraine, one in Crimea). As a result, extant analogues are underrepresented, potentially leading to inaccurate reconstructions for paleoflora from these regions. To address this gap, eleven presumed equilibrium forests were recently surveyed, and about 600 herbarium specimens collected to expand CLAMP’s reference dataset. Here, we present results from five sites representing Mediterranean (four) and oceanic (one) climates. Using the existing Physg3ar calibration (Northern Hemisphere including Alpine Nest), we applied CLAMP to estimate climate parameters. Temperatures were underestimated at all stations, particularly in Mediterranean ones. Significant differences were also found between CLAMP-predicted and Météo France-measured precipitation parameters. Next, we assessed the similarity between new and existing calibration sites using a permutation test based on leaf physiognomy. Mediterranean sites clustered together and showed affinities with Japanese sites characterized by humid subtropical climates. These new stations were then incorporated into the CLAMP calibration, and this updated version was used to reinterpret Oligocene paleofloras from Cervera (Catalonia, Spain) and Bois d’Asson (Luberon, France). Results are promising and open new avenues for refining paleoclimate reconstructions of Paleocene–Eocene floras in southwestern Europe.

Mots clés

Fichier non déposé

Dates et versions

hal-05161115 , version 1 (14-07-2025)

Identifiants

  • HAL Id : hal-05161115 , version 1

Citer

Flora Depaix-Piettre, Aixa Tosal, Jérémie Bardin, Dario De Franceschi, Cédric Del Rio, et al.. Strengthening CLAMP: New calibration sites to improve paleoclimate reconstructions.. 9th meeting of Agora Paleobotanica, Jul 2025, Paris, France. ⟨hal-05161115⟩
157 Consultations
0 Téléchargements

Partager

  • More