DETECTING RATES AND PATTERNS OF VEGETATION CHANGE IN AFRICA FROM THE PLEISTOCENE-HOLOCENE TRANSITION TO THE PRESENT

Detecting the timing and pace of past vegetation changes and linking these to climate change and/or human impacts is essential to understand the degree of turnover observed in modern ecosystems. Recent studies assessing global rate-of-change in Holocene plant assemblages suggest that rapid ecosystem turnover can occur on human timescales and are particularly evident in data-dense regions across the Americas and Europe. However, regions within the tropics were underrepresented in these analyses due to insufficient spatial coverage of paleoecological records, despite being biodiversity hotspots. Here, we target that gap and present an unprecedented continental and sub-regional rate-of-change analysis for Africa during the last 18 kyr. We use a new compilation of pollen datasets as a part of the recent relaunch of the African Pollen Database (constituent database of the Neotoma Paleoecology Database). Datasets were standardized and processed using the new FOSSILPOL R-package that allows users to filter and critically select data, construct age models, and harmonize taxon names within a single, reproducible workflow. Rate-of-change calculations and their peak points were calculated from multivariate paleoecological data using the newly released R-Ratepol R-package.

We expect high turnover rates in African ecosystems between 18 and 16 ka during the Pleistocene-Holocene transition, and between 4 ka and the present. Furthermore, elevated rates are expected from 8 and 6 ka to coincide with the African Humid Period. Our analysis will establish the timing and extent of synchronous ecosystem turnover across sub-Saharan Africa, Arabia, and Madagascar during the Holocene, while setting a baseline understanding of past natural variability against modern anthropogenic change in ecosystems. Our study will provide foundational knowledge to enable future attribution studies (i.e. detecting of significant relationships between environmental change and human impact with vegetation/assemblage turnover) in the region.