Skip to Main content Skip to Navigation
Theses

15 000 ans d'évolution des écosystèmes sous contrôle climatique et anthropique entre Jura et Bas Dauphiné : végétation, feu et erosion des sols

Abstract : This thesis aims to reconstruct vegetation and soil dynamics, as well as ire activity variabilityin the East-central part of France since the Last-glacial period (ca. 15000 yr). The objective is mostparticularly to disentangle the role of climate and anthropogenic forcing factors in ecosystems dynamics.Actually, the problematic concerns the switch from a climatic- to anthropogenic-driven ecosystemsand the study of agro-pastoral practices impact which leads to an ecological trajectory change. Thus,palaeoecological analysis (pollen, geochemical and micro-anthracological) were performed from threelake sediment records of Southern Jura Mountains and Bas Dauphiné areas.During the Late-glacial and the early Holocene period (14700 to 9000 cal. BP), palaeoecologicalchanges appear strongly correlated to regional and global climate oscillations. Until the mid-Holocene(9000 to 5000 cal BP), pollen analysis record a small-scale human impact on forest cover and nosigniicant changes in ire activity and soil erosion. Moreover, none climate change has been suficientlyintense or sustainable to generate remarkable modiications of the ecosystem. From 5000-4500 cal. BP,the sedimentary deposits recorded an increase in ire activity related to its use as a clearing tool. Thisperiod corresponds to the switch from a natural to an anthropogenic control on ires activity.It was only from ca. 2300 cal BP (Late Iron Age) that agro-pastoral activities become enoughintense to induce sustainable change in the vegetation cover and generate unprecedented erosion of soils.In parallel, the ire use changed and it became a tool for the management of agro-pastoral areas. Therefore,the human impact can be considered as permanent and a tipping point has been reached in the history oflandscape shaping. However, three main periods: Iron Age to roman period, medieval and modern timescan be distinguished through the development of agro-pastoral practices and their impact on ecosystems,most particularly on soil erosion.
Document type :
Theses
Complete list of metadatas

Cited literature [158 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-01723175
Contributor : Abes Star :  Contact
Submitted on : Monday, March 5, 2018 - 1:26:08 PM
Last modification on : Tuesday, October 27, 2020 - 2:34:36 PM
Long-term archiving on: : Wednesday, June 6, 2018 - 3:11:12 PM

File

these_A_DOYEN_Elise_2012.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01723175, version 1

Citation

Elise Doyen. 15 000 ans d'évolution des écosystèmes sous contrôle climatique et anthropique entre Jura et Bas Dauphiné : végétation, feu et erosion des sols. Sciences de la Terre. Université de Franche-Comté, 2012. Français. ⟨NNT : 2012BESA2039⟩. ⟨tel-01723175⟩

Share

Metrics

Record views

140

Files downloads

213