Modern pollen- and phytolith-vegetation relationships at a wetland in northeastern South Africa

Abstract

In palaeoenvironmental reconstructions, few studies have focused on comparing the presence of pollen and phytoliths in surface sediments to the local vegetation. Notwithstanding inherent differential pollen and phytolith preservation, production, and dispersal, which affect their recovery and interpretation in sediment archives, there remains a need to explore modern pollen-vegetation, phytolith-vegetation and pollen-phytolith relationships to improve palaeoenvironmental reconstructions. We carried out palynological and phytolith analysis on six surface sediment samples linked to the botanical survey of five vegetation survey plots at Gustav Klingbiel Nature Reserve, Mpumalanga province in northeastern South Africa, to understand the relationships between the modern pollen and phytolith assemblages in the surface sediments and the contemporary vegetation of the study area. Correspondence Analysis (CA) was undertaken to examine the fingerprint of the local vegetation in the modern pollen-phytolith assemblage and evaluate whether the phytolith and pollen assemblages were tracking each other. CA illustrated that pollen and phytolith proxies are not tracking the same primary vegetation signals; modern pollen assemblages best represent the components of forest and wetland vegetation. In contrast, modern phytolith assemblages best represent grassland vegetation. Our study shows that differential pollen and phytolith preservation, production and dispersal significantly affect sediment records more than anticipated, thus combining multi-proxies (e.g., phytoliths, pollen) provides a more accurate basis for the interpretation of fossil spectra in palaeoenvironmental reconstructions.