第七届青年地学论坛

Understanding the complex, human-dominated Earth surface processes has long been a major research priority for sustainable management of ecosystems and landscapes, however, hindered by the lack of integrative approach and multi-decadal records. Extracellular DNA in lake sediments has recently emerged as a promising proxy, allowing exceptional reconstructions of community changes through time. This study evaluated the high-resolution application of DNA metabarcoding and geochemical approaches to subtropical lake sediments, for the first time, to reconstruct one-century dynamics of vegetation communities and landscapes. We found that plant communities shifted from quasi-natural state to crop related species and greening vegetation dominated state, due to agricultural intensification and urbanization in the 1980s. This process accompanied with severe ecological degradation, such as soil erosion and deterioration of water quality. Then we developed an integrated framework integrating multi-decadal social and biophysical records at regional scale, and revealed recent critical social-ecological transitions in the lake-watershed system. Our findings highlight the complex linkages between agricultural land-use, urbanization, and accompanying ecological processes in human-dominated landscapes, which have great implications for sustainable land management from a long-term perspective.

沉积物DNA,土地利用变化,古湖沼与古生态,社会-生态耦合,人类世