Kerguelen sedaDNA
While the Antarctic region has experienced significant climatic changes over the Holocene, few high-resolution records have examined their effects on the local biota. The windy Kerguelen Archipelago in the subantarctic Indian Ocean is covered by relatively sparse vegetation which grows close to the ground. We use sedimentary ancient DNA (sedaDNA) metabarcoding to characterise the local flora on the island of Grande Terre over the past 11,080 years. We identify a shift in vegetation composition at approximately 8,700 cal years BP, similar to the northward shift of the Southern Hemisphere Westerlies (SHW) inferred from a previous pollen record, when a dynamic Azorella- and other forb-dominated Early Holocene flora shifted toward one dominated by Azorella and bryophytes. This suggests a shift from a warmer Early Holocene to a colder Mid- to Late-Holocene. The high representation of bryophytes in the flora was revealed by the local record provided by sedaDNA, which are difficult to detect using traditional proxies. We discuss potential climate drivers based on vegetation changes throughout the core, including the effects that changes in the SHW and glacial dynamics may have had. Overall, our sedaDNA record provides an example of a dynamic Early Holocene followed by a relatively stable flora on a subantarctic island prior to human impact, enriches our knowledge of this unique and isolated archipelago over time, and showcases the potential of using sedaDNA to reveal past bryophyte communities.