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

Detecting the timing and rate 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 evident in data-dense regions, however insufficient spatial coverage led to underrepresented regions. Among these underrepresented regions are tropical ecosystems, especially the African tropics which contain many highly endemic, charismatic, and endangered organisms. Understanding how these ecosystems have changed in the past is imperative for preserving their future. Here, we present an unprecedented continental and regional rate-of-change analysis for Africa during the last 20 kyr using 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, processed, and assembled using the newly released R-Fossilpol package, which allows users to filter and select data, construct age models, and harmonize taxon names within a reproducible workflow. Continental and regional rate-of-change calculations, along with their peak points, were calculated from multivariate paleoecological data using the R-Ratepol package. Results indicate elevated rate of turnover between 20 and 12 ka, potentially corresponding with the abrupt climate change facilitated by Northern Hemisphere deglaciation at the end of the Pleistocene. The rate of turnover remains consistent until elevating again around 4 ka to the present. Future studies may use these results to help attribute a causal relationship between elevated rates of turnover and changes in climate or human land use.