Deciphering the signatures of weathering and erosion processes and the effects of river management on Li isotopes in the subtropical Pearl River basin

•The riverine dissolved Li budget is mainly controlled by silicate weathering.•The variations of dissolved δ7Li values reflect the change of weathering intensity.•River management by damming insert a control on the river sediment geochemistry.•The Li isotopic fingerprint of weathering is preserved in river sediments.