Detecting Rates Of Vegetation Change In Africa From The Last Glacial Maximum To The Present
Open Access
- Author:
- Early, David
- Graduate Program:
- Geosciences
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- May 21, 2024
- Committee Members:
- Sarah J Ivory, Thesis Advisor/Co-Advisor
Peter Daniel Wilf, Committee Member
Donald Fisher, Program Head/Chair
Mark E Patzkowsky, Committee Member - Keywords:
- Pollen
Rate-of-Change
Database
Paleoecology
Palynology
R
Holocene
Pleistocene
Land Use
Africa - Abstract:
- Detecting the timing and rate of past vegetation changes and linking these to climate and anthropogenic change is essential to understanding the turnover observed in modern ecosystems. Recent studies assessing global Rates-of-Change in Holocene plant assemblages suggest that rapid ecosystem turnover can occur on human timescales, but it is unclear if this is the case in underrepresented regions with insufficient spatial coverage. Africa’s ecosystems, ranging from the Guineo-Congolian tropics to the Fynbos bushland, are an example of underrepresented regions where many highly endemic, charismatic, and culturally important taxa are at risk today. 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. Datasets were standardized, processed, and assembled using the newly released R-package RFossilpol which allows users to filter and select data, construct age models, and harmonize taxa within a reproducible workflow. Continental and regional Rate-of-Change calculations, along with their peak points, were calculated from paleoecological data. Results indicate an elevated rate of turnover between 20 and 12 ka, corresponding with abrupt climate change facilitated by northern hemisphere deglaciation at the end of the Pleistocene. The rate of turnover remains consistent in the Holocene until 3 ka to the present. Based on a synthesis of archaeological records and reconstructions of fire, we suggest human land use changes as the primary driver of ecosystem turnover in Africa over the last 3 kyr.