Projets 2014 |
MUltiproxy investigation of human-climate Disturbance interaction in a high altitude catchment using CoUPled bio-geological archives (MUDCUP) Porteurs du projet :
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Résumé du projet MUDCUP : The MUDCUP project proposes a multiproxy historical ecological investigation of human-climate-landscape interactions in a high altitude glacial basin (Lake Majeur, Haut-Vicdessos, Eastern Pyrenees) using disturbance proxies found in coupled bio-geological archives. Knowledge of historical disturbances that helped to shaped contemporary landscapes is paramount for designing adaptive conservation and management policy (Dearing et al. 2011). However, landscape trajectories in socio-ecological systems are ultimately determined by synergistic interactions between human land use, climate, and the biophysical template that are often not evident without long term perspectives. Thus, a principal question for sustainable management of socio-ecological systems concerns how human-driven (anthropogenic) disturbance such as landscape fire, interacts with climate and landscape over the long term. The key to answering this question will involve understanding the relationships between humans, climate, and landscape evolution. In 2010 and 2011, 40 subfossil pine trunks (Pinus spp.) and 4 lacustrine sediment cores were collected from Lake Majeur as part of two separate Haut-Vicdessos, OHM Pyrenees initiatives. Along with an additional sediment core extracted from Lake Sigriou directly above the southern shore of Lake Majeur, lacustrine sediment cores revealed a variable sediment rate, with increasing sedimentation during the last 2,000 years. Lacustrine sediments also revealed a chronological series of sandy layers associated with the mid-holocene reactivation of clastic canyons during extreme hydrological conditions or events (e.g. extreme storms or avalanches) (Simonneau et al. 2013). Based on dendrochronological measurements and radiocarbon dates of 9 trees, the sandy layers appear to coincide with the occurrence of subfossil pines (figure 1). This evidence suggests that these climate-driven hydrological disturbances have played a role in the death, transport, and deposition of the subfossil pines. Further, some of the subfossil pines are characterized by human modifications and tree-ring fire scars indicative of agro-sylvo-pastoral land use (e.g. resin tapping, timber extraction, and pastoral fire use). Thus far, radiocarbon dates of the subfossils suggest that these proxies of human-driven disturbance begin around 1800 cal. BP and increase in intensity between 1400 and 1100 cal BP (figure 1). This anthropogenic disturbance history is coincident with an increase in hydroclimate event frequency and a two fold increase in the sedimentation rate (Simonneau et al. 2013).
Objectifs The objectives of the proposed research are to develop a transdisciplinary approach, in order to :
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