Comparison of n-alkane molecular, carbon and hydrogen isotope compositions of different types of plants in the Dajiuhu peatland, central China

•n-Alkane molecular distribution and δ13C and δD values are investigated in peatland plants.•Forb and graminoid growing in peatland have relatively higher ACL and CPI values.•δDalk values exhibit large differences among plant life forms.•Sphagnum have more negative δ13Calk and δDalk values in medium chain lengths.•Importance of plant community shifts when interpreting the δDalk records in peat sequences.