One of the key challenges in biology today is to understand the origin of biodiversity, its evolution and dynamics, and the underlying mechanisms. The fossil record provides a unique perspective to study these processes. It also reveals patterns that cannot be predicted using living taxa alone and provides information on how organisms and ecosystems have responded to major environmental changes in the past. In this context, my research focusses on fossil plants from the Paleozoic and early Mesozoic (400-200 million year old) in order to:
(1) document past plant diversity and understand the origin and evolution of key groups of plants,
(2) reconstruct the biology of fossil plants and the evolution of selected functionnal traits,
(3) propose hypotheses about how plant systematic and functionnal diversity was impacted by major environmental changes in the past

frise
Plant systematic diversity 

One main objective of my work is to provide a better understanding of the composition of Devonian- Jurassic floras, including (a) the time of apparition and diversification of some key groups and (b) how/if plant diversity was impacted by major environmental changes.

I focus particularly on the Devonian to early Carboniferous period (420-340 millions years ago). This corresponds to a key time in plant evolution, with the gradual colonization of continental surface, the apparition of numerous biological novelties, and diversification of all major groups of vascular plants. My work includes the description of new specimens from localities in Europe, North Africa and Australia, including some that represent new species and genera. We also investigate how plant diversity changed around the Devonian-Carboniferous boundary, a period marked by an important extinction event.

Fossil plants from the Carboniferous of France

I also study plants from the Permian and Triassic, a period characterized by a very strong warming with a change from an icehouse to a greenhouse climate. Understanding the plants that grew in these conditions can provide keys to predict the evolution of our current vegetation in the context of climate change. I have contributed to describe some of the plants that grew in high- to very high latitude (>70°S) forests in Antarctica during the Permian and Triassic. I am also interested by the plants that grew in Europe during the Permian and by the information they can provide on the impact of global warming on tropical floras.

Fossil woods from the Jurassic, Permian & Triassic of Antarctica
Functionnal diversity: structure-function and paleobiology

Exceptionally well-preserved specimens can give us access to fine anatomical details that provide insights into the biology of fossil plants and the evolution of functionnal traits at different scales. Our research focusses on several aspects of the evolution of plants vegetative body including  (1) the evolution of the tree habit in the Devonian, (2) the evolution of secondary phloem and bark anatomy, (3) the evolution of roots, (4) the potential for vegetative regeneration  in fossil trees [root suckers, epicormic shoots], and (5) the evolution of wood in the Paleozoic from both an anatomical and a functional point of view. We also contribute regularly to projects investigating plant interactions with micro-organisms in the fossil record. All of this information allow us to understand fossil plants as organisms that have lived and interacted with their environment and to study past plant diversity from a functional angle.

Growth, secondary tissues, water transport modelling, root mechanics

Recent participation in externally funded projects
  • 2021-(2023): DECA– Quelles modalités de récupération post crise Dévonien-Carbonifère? Interrvie-INSU, coord. Anne-Laure Decombeix.
  • 2018-2019: MARCON – Biotic responses of faunas and floras to abiotic changes in deep time. Labex Cemeb, coord. Catherine Girard (ISEM).
  • 2016-2020: NSF1443546Collaborative Research: Permian and Triassic Icehouse to Greenhouse Paleoenvironments and Paleobotany in the Shackleton Glacier Area, Antarctica. NSF, PIs Edith L. Taylor (University of Kansas) & Patricia E. Ryberg (Park University).
Main fieldwork areas
  • Antarctica: Beardmore Glacier region, 2010; South Victoria Land, 2012, 2014; Shackleton Glacier region, 2016. Permian, Triassic & Jurassic floras
  • Australia: Queensland, 2005, 2008. New South Wales, 2013, 2018. Devonian & Early Carboniferous floras.
  • France: Montagne Noire, Lodeve Basin. Early Carboniferous, Permian floras.
  • Ireland: County Clare & County Kerry, 2018, 2019. Devonian & Early Carboniferous floras.
  • Morocco: Anti-Atlas, 2013. Devonian floras