Comparative palynomorph signals of vegetation change preserved in an adjacent peat swamp and estuary in North-West Nelson, New Zealand

A history of vegetation for the mid-late Holocene was extracted from the southern margins of Whanganui Inlet and Mangarakau Swamp. These two sites represent very different pollen sinks with the estuary being dominated by fluvially transported material and the swamp by in situ pollen rain. They are, however, located very close to each other and therefore provide a unique study area to investigate how differing source environments affect pollen signals. A vegetation change from podocarps to beech forest is recorded in both settings at around 4000 years CalBP which is similar to that recorded at higher altitudes in the region. Robust palynomorphs were found in greater abundance in the inlet while the swamp contained a higher proportion of wetland species. Despite these differences both environments appeared to record a similar regional vegetation Signal. This shows that estuarine environments, often characterised by material that has been transported, can provide accurate reconstructions of vegetation change.