Grass pollen and phytoliths of the Falkland Islands

Abstract

In the Falkland Islands, Poa flabellata (tussac grass) is regarded as a keystone species forming coastal breeding habitat for seabirds and pinnipeds. Tussac also produces high-resolution peat deposits that are useful paleoecological archives, but reconstructing its long-term dynamics in the pollen record requires species-level identifications. Grass pollen is notoriously difficult to differentiate to species, and is often identified to family or subfamily. Where pollen is unable to provide species-level taxonomic resolution, phytoliths can provide complementary information. We investigated morphological variations of pollen and siliceous phytoliths of native grasses to determine whether P. flabellata was distinctive at the species level. We found that while P. flabellata pollen cannot be distinguished from other native grasses, its phytoliths are distinctive. These findings reveal the potential for phytoliths to shed light on questions about the response of South Atlantic grasslands to environmental change using multi-proxy analyses.