Plant waxes of co-dominant cushion plant species in a bofedal peatland on the Andean Altiplano

Plant waxes, widely used as biomarkers for paleoenvironmental reconstructions in boreal peatlands, remain relatively understudied in Andean “bofedales” peat meaning that their application in these ecosystems requires a better understanding of local vegetation. This study therefore compares four plant wax classes – n -alkanoic acids, n -alkanes, n -alkanols, and sterols – in leaves and sheaths of Distichia muscoides and Oxychloe andina , that form cushions (or mounds), in a bofedal in northern Chile. Analyses indicate that wax concentrations were higher in D. muscoides and n -alkanoic acids were dominant in both species and showed significant differences in the average chain length (ACL; O. andina = 27.3, σ = 0.78; D. muscoides = 26.8, σ = 0.18; p < 0.05), while those for the n -alkanes were similar. Mean n -alkanol abundances were significantly higher in D. muscoides (171.5; σ = 76.7 μg/g) than in O. andina (32.1; σ = 53.5 μg/g, p < 0.05) and among sterols, β -sitosterol was the most abundant in both species. Plant wax distributions were similar between organs, except for the ACL of the n -alkanoic acids in D. muscoides (leaves = 26.8, σ = 0.2; sheaths = 25.9, σ = 0.1; p < 0.001). For both species, leaf–sheath differences in plant wax abundance and size suggest that leaves contribute most to peat (∼4× n -alkanoic acids, ∼2× n -alkanes). The study reports four compound classes detected in “cushion” plants towards their application in the bofedales peat of the Andean Altiplano. In particular we find that n -alkanes show minimal differences between species, suggesting suitability for testing for compound-specific isotopic analysis-based paleoclimate proxies in bofedales. β -Sitosterol is highly abundant and may serve as a biomarker for the presence of the studied species. Overall, the bofedales have potential as archives of plant wax from these cushion plants towards paleoenvironmental reconstructions.