par- 3 mai 2016 ( dernière mise à jour : 25 janvier 2017 )
Paleo-environnements : trajectoires à long terme des écosystèmes de montagne
How environmental systems change, which factors determine their modifications, and which are the consequences for ecosystemic properties and services remain central themes of ecology. Many factors such as climate, disturbance, isolation, environmental heterogeneity and biotic interactions influence the composition of communities, and human-related factors certainly play a prominent role. However, the relative importance of human and natural factors on environmental changes remains poorly understood and controversial. Ecological history based on retro-observatory approaches allows understanding the long-term dynamics of ecosystems, to identify determining factors and to anticipate how near future local and global changes might affect the response of systems.
The study of past environments requires multidisciplinary approaches, and the integration of competences from researchers with background in both life and earth sciences. PaleoEnv is a concerted research theme involving four laboratories (LECA, EDYTEM, CARRTEL & LCME) with the aim of developing an integrated research on the reconstruction of ecosystem dynamics and on the drivers of environmental changes in mountain and non-mountain areas over decadal to millennial time scales. This theme will also be one of the major research topic of the Fédération pour la Recherche en Ecologie et Environnement - Alpes (FREE).
Our three main objectives and associated methods are :
1) to reconstruct the trajectories of human-nature interacting systems at different temporal scales and to identify the drivers of the observed changes.
Lake sediment cores are ideal sources of information on the past environments and allow to reconstruct the links between ecosystem and geological dynamics at the landscape scale. Additional archives may also be targeted and provide information on different systems, such as permafrost, archaeological remains, soils, stalagmites. To analyse lake sediments, we combine environmental DNA (eDNA) metabarcoding, isotope geochemistry, ancient DNA (aDNA) extracted from archaeological remains and human artefacts.
2) to understand the impact of human activities (e.g. domestication, pollution, soil erosion, management of pastoral environments and agro-forestry, urban growth and waste water effluents) on the dynamics and functioning of mountain, lacustrine and other environments.
3) to understand and model how these dynamics impact the distribution of biodiversity. A major topic will be analysing the development of communities after the glacial retreat, through the study of environmental DNA from soil samples and ancient DNA from paleontological remains. Important information will be provided by the analysis of chronosequences such as glacial forefronts representing space-for-time substitution and allowing to study the kinetics of ecological processes such as soil development, biological communities’ assembly, biogeochemical fluxes etc.
Philippe Choler — philippe.cholerat]univ-grenoble-alpes.fr
Francesco Ficetola — ficetola.francescoat]univ-grenoble-alpes.fr
Pierre Taberlet —pierre.taberletat]univ-grenoble-alpes.fr